text:
Function of testosterone in women and estrogen in men
I was recently surprised to find out that testosterone and estrogen are found in both men and women albeit in different amounts.
I know that testosterone is related to the development of facial, body and pubic hair, deepening of the voice, and muscle development in men.  And that estrogen helps in maintaining the condition of the vaginal lining and its elasticity, and in producing vaginal lubrication in women among other functions.
But what could be the function of testosterone in women or estrogen in men? A simple Google search could give me no good results except for here where it says:

In men, estrogens have no known function. An unusually high level, however, may reduce sexual appetite, cause erectile difficulties, produce some breast enlargement, and result in the loss of body hair in some men.

and that

Large deficiencies of testosterone may cause a drop in sexual desire, and excessive testosterone may heighten sexual interest in both sexes.

Does anyone have any further knowledge?

As you know by now, both males and females have testosterone and estradiol. Of course, their levels are different in each sex, but both hormones are important to males and females. A human male with zero blood concentration of estradiol or a human female with zero blood concentration of testosterone wouldn't be possible.
Here are some famous examples:
Role of testosterone in human females:

Increase libido1,2
Modulate physiology of vaginal tissue3

Role of estradiol in human males:

Help to regulate spermatogenesis4
Reduce bone loss5


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What is the thickness of endothelial lining in blood vessels?
In capillaries, endothelial lining is one cell thick. Is same the case with bigger blood vessels?

Related http://biology.stackexchange.com/q/54562/3340

I believe apart from natural fluctuations of cellular size, the size of squamous epithelial cells (the cells making up the endothelium of blood vessels) remains the same. Therefore, the thickness of the endothelium does not significantly change for any blood vessel.

This is correct. Just to add on, capillaries are walled by essentially only endothelium; larger vessels are thicker because they have other types of tissue: elastic laminae, media and adventitia that contain smooth muscle cells and connective tissue.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


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How can the number of genes increase through evolution?
I am aware of the basics of evolutionary theory, however I don't understand how mutations can add genes over time.
Am I correct in thinking that creatures within the same species who mutate to have an additional gene in their genome would normally be infertile?  Or am I misunderstanding that?
Can someone explain the process of the creation of genetic material through evolution?  Citation to a decent academic paper or book on the matter would be appreciated too.

Mutations can have all sorts of impacts on genetic architecture. A mutation can have a small impact on a genetic architecture such as

Substitution
Insertion
Deletion

or can have a much bigger impact on a genetic architecture such as

Amplification (incl. gene duplication)
Deletions
Chromosomal translocations
Interstitial deletions
Chromosomal inversions
Chromosome duplication
Change in ploidy number

Some of these mutations (gene duplication, Chromosome duplication, change in ploidy number) typically allows duplicating DNA segments. After duplication, the two copies of a gene can diverge through neofunctionalization or subfunctionalization. Have a look at wikipedia > gene duplication to understand what biochemical processes can cause such mutations (e.g. ectopic recombination, retrotransposition event, replication slippage).

Am I correct in thinking that creatures within the same species who mutate to have an additional gene in their genome would normally be infertile?

You are being mistaken. I understand the naive intuition that a change in copy number of a given gene would be extremely deleterious but in reality, living organisms seem much more resilient to such Copy-Number Variation (CNV) than you would think. Of course, some CNV are associated with diseases but it is not the case of all (McCarroll and Altshuler 2007).
Gene duplications are actually quite common whether in C. elegans (Lipinski et al. 2011) or in humans (Cotton and Page 2005). Chromosomal duplications are also common (Bowers et al. 2002). Even whole-genome duplications (see a classical example in Wolfe 2015) have played major roles in the evolution of many lineages (Whitton and Otto 2010) including vertebrates (Dehal and Boore 2005).
Below is a phylogenetic tree of sequenced green plant genomes highlighting some of the main events of whole-genome duplication.

For the record, some species of strawberries are decaploid (10 copies) (Hummer 2012). Then there are the extremes. In Entamoeba populations, there can be variation in ploidy level among individuals ranging from diploid (2 copies) to tetracontaploid (40 copies) (Mukherjee et al. 2008)!

In flower breeding (and perhaps elsewhere) it's quite common to use chemicals to cause chromosome doubling.  As far as I can see (but maybe I only see the successes :-)), the usual result is a stronger plant with larger flowers.

Thank you, this is a comprehensive answer!  Just will take a little while to process.  Any delusions I had of being an educated person are shattered upon getting ten words into a Wikipedia article and not knowing what's going on.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

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Why are there six reading frames if only one strand of DNA is referred to as the ‘coding strand’?
We need to consider six reading frames when considering the potential of DNA to encode protein (three frames for each strand). But only one strand is transcribed into RNA — the so-called coding strand. It would therefore seem to me that there are actually only three reading frames to consider. Why, then, do people refer to six?
Another point concerning reading frames is the definition of Open Reading Frame — ORF. One text defines ORF as:

“An ORF is a continuous stretch of codons beginning with a start codon
  (usually AUG) and ending with a stop codon”

whereas another text defines it as

“An ORF is a continuous stretch of codons that do not contain a stop
  codon (usually UAA, UAG or UGA)”

It seems to me that the first definition is correct. Which is the generally accepted definition for ORF?

I have edited your question, not only to correct the English, but to clarify it. In a way, I have set it up so I can provide an answer (when I have a moment) that points out the source of confusion (not only yours, but also others'). However I think this is fair. I have also improved the presentation of the two alternative definitions of open reading frame (you should have defined the abbreviation, ORF, the first time you used it.) I see why you did it, but in general you should not ask two questions in one, because it can lead to answer being accepted which doesn’t  answer both parts well.

In my opinion this question reflects two things:

The difficulty students have in appreciating the historical experimental concerns of research workers in an area that is now well understood, and, hence, how it influenced the coining of new technical terms.
The way that the use of terms has changed with time as old concerns disappear and new ones arise. Thus, a term originally used in one sense may have subsequently been adopted to mean something else, even if this does not appear strictly logical.

What is a coding strand?
This is the crux of the first question, and the answer is that the term ‘coding strand’ does not mean anything (or at least is ambiguous) without context. Thus, I think the poster is assuming a genome context, and this is the fallacy of her argument.
If one talks (or thinks) about the ‘coding strand’ of a DNA genome, one is assuming that because many DNA genomes are double-stranded, if you separated the two strands (e.g. of a small DNA virus) and performed a conceptual translation (decoded the DNA into amino acids using a genetic code with T rather than U) one strand would have all the information for the genes and the other strand would have none. Another way of saying this is that you are assuming that all the genes in the genome have the same directionality (arrow direction on a genome diagram, such as that from E. coli, below). This is hardly ever the case. (The only examples I can think of are the genomes of single-stranded RNA viruses.)

So if you use the term ‘coding strand’, you must state that this is in the context of a single gene. Each strand of DNA in a genome (e.g. E.coli) will contain sections of DNA that are coding and some that are non-coding in terms of conceptual translation. (If you look at papers describing early isolations of genes you will find the words “coding strand” generally qualified by  “of the gene”
But cDNA has just one coding strand…
Historically one of the concerns was to sequence eukaryotic cDNAs, DNA copies of mRNAs. These would be monocistronic, i.e. encode a single protein. So here one strand would be coding and the other non-coding. Was it possible to reduce to three the number of reading frames it was necessary to analyse in this case? No! The fact that only one strand is coding was no help at all as there was no way of knowing which this was in the cDNA being sequencing. Likewise for a the fragment of any gene. You had sequenced a piece of DNA, cloned into some plasmid vector and there was no way of telling which strand the sequence you read out originated from. Hence you need to translate it in all six reading frames to find potential amino acid sequences.
So what is an Open Reading Frame?
Open Reading Frame is a term that is often used today in a manner distinct from the way it was used when it was coined. At the time it was coined one would be sequencing short stretches of cDNAs or virus or bacterial genes and there was a low likelihood that one would be sequencing through the C-terminus, i.e. the stop codon of the gene. One’s concern was to concentrate on reading frames that were not interupted by stop codons. This original usage is reflected in the definition of Open Reading Frame in Wikipedia:

“An ORF is a continuous stretch of codons that do not contain a stop codon (usually UAA, UAG or UGA)”

However as knowledge increased and technology improved, the focus switched to discovering genes in the genomic or long partial genomic sequences of organisms. Now one was working with long DNA sequences containing many whole genes. The focus became finding potential genes based on start and stop codons (and a cut-off length). This is reflected in the documentation for the EMBOSS program, getorf:

“An ORF may be defined as a region of a specified minimum size between two STOP codons, or between a START and a STOP codon.”

Note that even this last definition is ambiguous.
Which is correct? That is a concern of students. In the real world one must recognize that the meaning of expressions can change. If there is any ambiguity — as here — one must define the way in which you are using the expression.

The coding strand refers to the DNA strand with the same base order as the RNA transcript for a particular gene. As one gene is always entirely present on a single DNA strand there are indeed 3 reading frames possible in this strand, with only 1 actually containing the correct codon sequence for this gene.
However when we view an entire genome it is entirely possible for one gene to be present on one strand with another gene present on the other,  meaning that the coding strand for one gene is the non-coding strand for the other. This is why there are 6 possible reading frames for the genome as a whole as both strands can (and do) contain genes.
As to the ORF, both definitions seem to be in use. In the context of trying to discover genes by looking for long ORFs the first definition is probably more helpful as following the second definition could lead to a lot of falsely predicted genes (for an extreme example a long stop codon free sequence that has no start codons either would be considered a possible gene even though that should be impossible).

Thank you Koen. Your mean about the first question is some genes (coding genes? I'm not sure") are located on the non-coding strand, yes?, could you please tell me some example gene?

@Mary It isn't that genes are on the "non-coding strand" its that either stand can be a coding strand. Imagine a book arranged like this: on all the right-hand pages, the text is printed as normal, but on the left hand pages, a different, unrelated text is printed upside down. You would consider that side to be the "non-reading side". But behold! rotate the book 180 degrees and now suddenly the "non-reading side" is the reading side and vice-versa. Both strands can be coding strands, but you have to read them in the opposite direction.

@KoenvdH — I think your answer is correct. The reason I posted one of my own was to focus on what I think are the causes of confusion. It's an attempt to give a historical context, which I am able to do because of my, er, history.

@David Hah I reckon your answer is far better for clearing up the terminology confusion.


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Why does spiral or annular thickening occur in water conducting plant vessels?
From what I behold, spiral and annular thickening of xylem and trachied cell walls leaves a lot of not thickened regions of cell wall. Lignin is the material which prevents water from escaping these water conduits. If lignin is absent from certain regions, does not that mean that water flows out of the xylem vessels and trachieds through their cell walls? If so, is not this disadvantageous to a plant? Why can't a plant simply thicken the cell walls with uniform lignin deposition, only sparing pits to allow lateral flow into the required tissue? I would appreciate your kind response.

Lignin adds mechanical strength. Leakage from one xylem lumen to another can be seen to be advantageous as it lets water tension to equalize radially - else a plant would tend toward one-leaf-to-one-root (I exaggerate since there are also pits to distribute water). Trachieds are dead cells. Additions to their walls come from nearby parenchyma. Wouldn't it instead be curiously remarkable if the lignin depostion was uniform?.

Exactly, if pits have the function of lateral flow then why is not lignin deposition uniform? That is what I am curious about.

I think pits tend to be located at the ends of the trachaeids. So lateral flow is minor compared to axially. Water can flow laterally thru the unlignified cellulose walls by osmosis. Anyway, you pose an interesting question I cannot answer, though is does boarder on asking why there is air, IMHO. :)

Non uniform lignification of xylem vessels is beneficial to a plant in that it enables growth. It is at the unlignified parts of plants that growth occurs since fully lignified tissues are dead and so can not grow. Spiral and annular thickening allows for vessels to elongate and thus allows tissues to expand without breaking the vessel walls.
Water cannot just go on flowing from plant cells because they are not lignified, plant cells have cellulose cell walls and cell membranes which prevent water loss. In addition, water in the xylem is not under pressure so I do not think water would be able to flow out of the xylem vessels except in cases where water is forced to move to adjacent phloem tissues by osmosis during phloem translocation.

Welcome to Biology.SE! Your answer sounds reasonable, however, it is likely to receive a more favorable response if you include supporting references (primary literature is best, but a textbook available online would seem sufficient for this question).  You also should be able to easily remove the pictures by editing your post ...——— Please take the [tour] and then consult the help pages for additional advice on [Answer] effectively on this site and then edit your answer accordingly. Thanks!


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Is there any way to cultivate viruses without cells?
I know what viruses are. They replicate only inside the living cells, and so on, and so on.
I just interesting maybe there is some progress in this field. I don't know exactly, but I suppose before invention of the nutrient agar microorganisms were cultivated on substrates like eggs, potatoes, meat etc. Perhaps there is the same story for viruses.

No. A virus is a small infectious agent that replicates only inside the living cells of other organisms. -Wikipedia

+1'd and it doesn't seem like a homework question. It seems the OP want to tell they knows virus doesn't grow if not in living cell- but if there is any latter-discovery of any virus-like particle growing outside living cell.

I agree with @AlwaysConfused - I see no reason to close or put this question on hold, it does not seem like a homework question, especially after the OP's recent edits I would suggest the hold be removed.

I don't have a lot of experience in this field to give a full answer, but just for the OP's information, a couple things. First, viruses depend on many key proteins from their hosts. To have any possibility of growing a virus outside a cell, you would have to provide all these proteins, plus the proteins that support/regulate those proteins, a source of ATP, etc. Soon the list of ingredients is essentially just a cell, and (many) cells are fairly easy to grow, so I don't think there is a lot of motivation to finding a way to cultivate a virus outside of a cell, and it would take a lot of work.

Voted to reopen. I was reading a paper from the 30's which claimed to cultivate Vaccinia in the absence of living cells. However a later paper admitted that they couldn't be sure there were no living cells in the media. Of course, given what we now know, contamination with life cells seems most likely.

It depends. Some viruses (like Vaccinia used above) are highly complex and would need a cell to be synthesized (with today's tech). If you take simple viruses, say Poliovirus, you could make the RNA and that alone could be infectious if placed in a cell. This isn't a true virus though, more of a viroid. That being said, take PCV, the single protein will self-assemble and incorporate vDNA, while it might not have been done, this could be theoretically be made in vitro.

PCR may be called as a quite similar situation where outside the cell a piece of nucleic acid replicated.

@Artem Very helpful information.


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Identification of a Kakadu bird
This species of bird was spotted in Kakadu National Park, NT, Australia. It looks a bit like a lemon-bellied fly catcher, but I think my bird here is a tad bigger than the fly catcher, but I am unsure.
I was hoping one of the more ecologically proficient people here could help me out.

Note: This is the 3rd related question on this topic, so feel free to close-vote-for-whatever-reason, but I am generating a photo album with all the birds I have spotted there (heaps!), and a few of them I can't identify with the limited resources I have.

It is great bowerbird (Chlamydera nuchalis). It is much bigger than the mentioned flycatcher. I have seen both species and there is no room for confusion. Most of the pictures online are birds perched on the ground next to their "buildings", but I found a picture that should convince you.

Notice:
-Stout bill
-Patterned wing coverts
-Marks on the undertail coverts

Thanks!! Lovely :-) Could you add the link of the picture if possible? In my sources the bower bird looks brownish, whilst in my photo and your image above it looks yellowish - or is that a male/female difference perhaps?

Here is my resource - page 3, left column middle image - it looks brownish, not yellowish

@AliceD It was edited out I do not know why. (The picture is in the second page).  http://www.hbw.com/ibc/species/great-bowerbird-chlamydera-nuchalis        I think that the yellow is a picture effect, look at the color of the branch...that also look yellow.


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How closely related will your descendants be to you?
I wonder how similar my DNA will be to that of my great-grand-children. If a new person enters my family tree every new generation, he/she will bring in half of his/her DNA, therefore decreasing the amount of DNA that each new generation shares with me. I assume, then, that after several generations, my descendants are going to be no more closely related (genetically) to me than to random people on the streets?
I also once heard that even though the share of my genes will be descreasing, the mutations unique to me will stay. Is that true, and, if so, how is that possible?
And what about all-males descendants? For example, if I have a son and he has XY, then if there always will be a son down the line then will the Y chromosome stay the same through each generation? More specifically, will it still be the Y chromosome from me?

This hasn't been researched or even thought about at all before posting. I'm voting to close for hwk reasons. Clue: Children have ~50% of either parent. Keep halving the amount every generation.

This depends on what you mean by genetic similarity. If you mean the fraction DNA that are still direct copies of your DNA in the n'th generation, then the answer is (1/2)^n.  But if you mean sequence similarity, then the answer is quite different, and depends on the structure of genetic variation in the population.  If some piece of your DNA gets swapped for another piece of DNA, but this DNA has the exact same sequence, do you consider your genetic material to be lost?  See https://en.wikipedia.org/wiki/Identity_by_descent

For how genetically related to you your  my grand-grand-children will be....
Well on the surface the answer is simple. Your grand grand children will 12.5% of your DNA.
Dig a little deeper... the question becomes a bit more difficult to answer.
(1) Humans do cheat a small but significantly amount of time. On average about 0.7-3% of all children are unknowingly raised by men who are not their biological father http://theconversation.com/what-are-the-chances-that-your-dad-isnt-your-father-24802. This is less than the 9-30% which has been reported. The reason appears to be that the data was derived from paternity clinics where  there was already suspicion on paternity of the child. Not the best data set to represent the population, even if the data set was large and mostly free to researchers.
So which that factored in... it depend on what gender you are, and how said grand grand child is related to you. Are you a woman? Is that grand grand child, the child of your daughter's daughter. A pure maternal descended would guarantee a 12.5% genetic relatedness.
But if you are a man, and the grand grand child, is the child of your son's, son... on average genetic relatedness falls to 11-12% (on average). But since a person is related to your or not, there is a 3%-10% that your grand grand child is not related to you if that child is your son's son's child.
(2)Rural (old world) populations tend to share more genetic material since they have had less outside influence into the genepool. This is a reflection of history, where mobility was limited and families tend to stay for generations. In these places, a random stranger isn't that random after all. In which case genetic relatedness calculations become more complicated. Terms to look up are founder effect, population structure. Large cities, with massive influx of people moving in and out tend to be more mixed. Also note isolation, can also because by social stratification. The nobility is a great example where two random nobles are not as random as you think.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1685612/pdf/ajhg00202-0030.pdf
http://link.springer.com/article/10.1007/BF02442864
http://www.nytimes.com/2004/07/31/us/by-accident-utah-is-proving-an-ideal-genetic-laboratory.html rare american example.
https://en.wikipedia.org/wiki/Stoccareddo
http://gizmodo.com/5882644/iceland-is-so-inbred-it-needs-a-website-to-avoid-incest

And I also once heard that even though the share of my genes will be
  descreasing, the mutations unique to me will stay. Is that so and how
  is that possible?

Not quite. A mutation unique to you has only 50% chance of passing on to a child. (Or a 50% chance of not passing to a child.) So if you have 2 children, that mutation will have a (0.5*0.5=0.25) 25% chance of failing to pass to the next generation. In fact unless that mutation has some sort of selective advantage (awesome X-men powers), or your family has really big families for several generation or you and your families becomes a founder of a new colony/town (founder effect), your unique mutation will likely fallout after a few generations.

And what about all-males descendants? Like, if I have a son and he has
  XY, then if there always will be a son down the line then Y chromosome
  is going to stay the same, being the one from me?

yeah they will inherit your Y chromosome.. which will change very little over the generations. It will accumulate a few mutations but that is over thousands of years.

I am sorry you find that offensive. Most old villagers and towns are inbred. (Some more so then others.) It is very useful for population genetics especially when paired up with the marriages information from the local parish. Also depending on how you look at a population, everyone is inbreed. Go back 1000 years ago, and all europeans are related to each other. This is why population genetics has been such a minefield to work with.  I guess I am also not looking at people... but how they are related to each other over centuries. The effective founder population size.The genetic variability

I think we are imagining different countries and rural communities. Stay specific when possible. Which rural study are you referring to?

Thank you for your answer. Yes, I heard about that - how populations in countries that are isolated - like, islands, or just small communities tend to be really related to each other. But why does relatedness for all-male descendants fall to 11-12%? If the same Y chromosomes gets passed on. And it looks like for women the relatedness should be smaller - X chromosome can be piged both from mother and father and therefore already grand-daughter of a woman may not have her X chromosome, only that of her grandfather and her father...

Since at least 99% of all DNA is identical between all humans, it's a little strange to say that only 12.5% will be shared.

@swbarnes2 You're mixing up inheritance and shared DNA. So whereas 99.9% of the DNA is identical to every other human, 12.5% of your genome is from each of your great-grandparents.


text:
Calcium carbonate minerals in marine organisms shells
Calcium carbonate minerals exist in seawater in two main phases: calcite and aragonite. While calcite is the most stable phase, it is aragonite that precipitates first in seawater because of the high magnesium content of the oceans today. But for a similar environment, e.g., tropical shallow water, some organisms have a calcitic shell while some other have an aragonitic one. How can organisms choose which phase composes their shell?

The two minerals differ only in crystal structure. changing the assembly proteins is enough. https://www.researchgate.net/publication/232236795_Aragonite-associated_biomineralization_proteins_are_disordered_and_contain_interactive_motifs


text:
Can anyone identify these bugs in the soil?
I was checking the soil around my pineapple pear tree and found this living down in the dirt. My goal is to identify the insect so I can properly treat the soil in an organic manner.

This what? W/o a pick it's hard to answer the question :-) also add your whereabouts and the habitat

Could you provide your location please

They look like termites.

It would be better if you posted a close-up.

Mention size in the description. At least approximate.

How do they behave ? How do they move ?


text:
Does the saliva of a person just recovered from an infectious disease help to cure another persons having the same disease?
I have always had this 'weird' thought (But could never quite test it...). Would the saliva of a just recovered person contains antibodies, or other immuno-boosting substances that can help fight off the same pathogen in another person? If yes, is the concentration (dose) of them in saliva enough to have any considerable effect directly (without any further artificial concentration or extraction done)?

Cross posting on Stack Exchange is discouraged.  I'm with you that knowledge is our real motivation here, and that sometimes this policy gets in the way... but there are many good reasons for this policy. Are you the same user as a25bedc5-3d09-41b8-82fb-ea6c353d75ae? I suggest you close one post and focus on the other.

It's unfortunate that Health SE is so quiet, I'd love to see it grow and encourage the Biology contributors to interact there as well.  Perhaps in that motivation, and given that your question is probably more on point there, you should close this question and try over there.  Then if your question receives poor response you can request to have it moved/reopened here?

@JeopardyTempest Yep, thats me in Health SE. I have no idea why my name is different on the two sites.. And yes, Health SE is too quiet.


text:
How is Cas9-gRNA-tracrRNA complex lysed in mammalian cells?
I am interested in degradation of Cas9-gRNA-tracrRNA complex. I would like to understand how do the cas9 enzyme, gRNA and tracrRNA degrade in mammalian cells (with references, if possible).

There has not been much research on this part of CRISPR-Cas system, as everybody is interested in geting gene editing done, but very few think about what actually happens to the things we leave inside. So, the mechanism of its degradation is not well understood. But there has been some research on this, which leads to the conclusion that the Cas9-gRNA, being a ribonucleoprotein (RNP), degrades by the normal protein degradation pathways, and is indeed very quick process. See this article:

By contrast, Cas9 RNPs are delivered as intact complexes, are detectable at high levels shortly after transfection, and are quickly cleared from the cell via protein degradation pathways...Second, rapid clearance of Cas9 RNPs from the cell may increase CRISPR specificity by reducing the amount of time that Cas9 is available for off-target cleavage...Cas9 RNPs are active immediately following transfection and are quickly degraded within the cell. These fast degradation kinetics enable Cas9 RNPs to modify target genes with reduced off-target effects.

For more information about RNP degradation, you can have a look at this article. An example of RNP degradation pathway is this too:


text:
What is the lifespan of a human skeletal muscle cell (such as in the biceps)?
I have read that most human skeletal muscles (such as those in the biceps) cannot multiply after development (except for exceptional situations of severe damage that involve satellite cells) and that human adults generally have the same number of muscle cells as they did in their childhood or teen years. However, I have also read that skeletal muscle cells have an average lifespan of 10-15 years. If both facts are true, wouldn't that suggest that humans would lose most of their muscle cells by 10-15 years of age? If only the first fact is true, it would seem that the lifespan of skeletal muscle cells is approximately the same as the lifespan of the individual owner.


text:
What are the biological processes of ingesting radioactive particles?
As someone who has basic understanding/education in physics and how radiation works, there is something that is confusing me and which I would like to shed some light on (I posted about this previously, but the discussion diverted to the risk of radiation in North America from the Fukushima incident, rather than the biological processes of ingesting radioactive particles).
With background radiation, and even relatively high levels of surrounding radiation, I understand that the risk is non-existant to very minimal. However, it seems that lately, people and officials are saying that food near and even in Fukushima is completely safe to eat.
In the case of surrounding radiation, sitting next to something that reads 3000 μSv/h is completely different to eating food that also emits 3000 μSv/h of radiation. In the former situation, once you walk off, the exposure stops. In the latter, radiation is constantly emitted inside your body.
Even more, the amount of radiation is not absorbed by the body equally, but it is usually very concentrated in a particular area of the body, as the particles lodge somewhere and sometimes bioaccumulate. From my understanding, the exposure to the surrounding cells is therefore more intense and prolonged.
To what degree is ingesting radioactive particles in food considered safe (or if at all), such as those in food near Fukushima, when taking into consideration that a concentrated and continuous source of radiation is different from an external one?

You are asking too many questions at once. Please narrow it down to, preferably, single question.

@another'Homosapien' Edited it into one question.

Your question has a rather glaring assumption which is that the amount of radiation emitted by food sources is equivalent to the amount of radiation received while sitting on top of the Fukushima plant. Even if a fish was as radioactive as an equal mass of concrete at the site, the dose you are getting at the site is because of all of the other things surrounding you.
The answer is simply that the food sources near the plant have been deemed (by the officials you mention) to emit a dose of radiation that is less than the level deemed harmful (again, by the officials you mention). It is of course possible that either the estimate of the radiation dose from the food is low, or the level deemed harmful is too high; that discussion is too broad for an answer here.

"The answer is simply that the food sources near the plant have been deemed to emit a dose of radiation that is less than the level deemed harmful." Any reference to back up that claim? I would strongly doubt that ... as far as I know, there are still places in Europe you shouldn't collect mushrooms because of radiation poisoning caused by Chernobyl.

@AlexDeLarge I carefully used the word "deemed" in my answer: I'm referring to the comments made by officials that say the food is safe. Personally, I'd avoid eating food from that area. I only meant to answer the OP's edited question about continuous internal vs external radiation. I edited my post to clarify this.

@BryanKrause That was an example (and yes, slightly exagerated to make a point) and a very small part of the post. 3000 μSv/h isn't the equivalent of "sitting on top of the Fukushima plant."  It's possibly more than 1000 times less than that.


text:
Does human skeletal muscle fascia grow new additional collagen in response to increases in skeletal muscle size?
For example, if a human skeletal muscle is growing repeatedly due to periodic weightlifting, does the fascia eventually respond to the increasing volume by growing more quantities of collagen or other components to accommodate the growth? Or rather, does it only expand by "stretching" the existing amount of collagen without the growth of new material to accommodate the changes in muscle size (except perhaps to repair possible wear/damage that might've occurred during exercise)?


text:
Why are so few foods blue?
Although blue foods exist, they're rare enough compared to other foods for food preparers to use blue plasters as a convention. The natural colour of a given food is due to pigments that have some biological origin. Is there any evolutionary reason why these are rarely blue?

Fasinating research suggesting that in some cultures, people literally do not perceive blue: http://www.sciencealert.com/humans-couldn-t-even-see-the-colour-blue-until-modern-times-research-suggests

This New York Times article discusses the difficulty of acquiring natural blue dyes for the food industry...So far their best results come from the pigment phycocyanin via "spirulina" made from  the cynobacteria Arthrospira

Obligatory George Carlin link https://m.youtube.com/watch?v=l04dn8Msm-Y

@Tenfour04 There are a lot of popular articles about people in some cultures not perceiving blue, but they grossly overstate the case usually by misstating the evidence. Some (unlike you, props for that BTW) even claim they cannot see blue at all.  People in all cultures can perceive blue, they differ in the speed it takes to differentiate between shades and how language divides the color space.  Matt Yglesias (who is interested in how the Sapir-Whorf Hypothesis is overstated re: political language) has a very well referenced post about this topic at https://www.slowboring.com/p/greeks-blue

Short answer
Blue color is not only rare in edible organisms - Blue color is rare in both the animal and plant Kingdoms in general. In animals, blue coloring is generated through structural optic light effects, and not through colored pigments. In the few blue-colored plants, the blue color is generated by blue pigment, namely anthocyanins. The reason for the scarcity of blue pigments remains unknown as far as I know.
Background
The vast majority of animals are incapable of making blue pigments, but the reason appears to be unknown, according to NPR. In fact, not one vertebrate is known to be able to. Even brilliantly blue peacock feathers or a blue eye, for example, don't contain blue pigment. Instead, they all rely on structural colors to appear blue. Structural colors are brought about by the physical properties of delicately arranged micro- and nanostructures.
Blue morpho butterflies are a great example of a brilliant blue color brought about by structural colors. Morphos have a 6-inch wingspan — one side a dull brown and the other a vibrant, reflective blue. The butterflies have tiny transparent structures on the surface of their wings that scatter light in just the right way to make them appear a vibrant blue. But if you grind up the wings, the dust — robbed of its reflective prism structures — would just look gray or brown.
Similarly, the poison dart frog is blue because of the iridiphores in its skin, which contain no pigment but instead feature mirror-like plates that scatter and reflect blue light (source: By Bio).

Morpho and poison dart frog. sources: Wikipedia & LJN Herpetology
Similarly, in the Kingdom of plants less than 10 percent of the 280,000 species of flowering plants produce blue flowers. In fact, there is no true blue pigment in plants and blue is even more rare in foliage than it is in flowers. Blue hues in plants are also generated by floral trickery with the common red anthocyanin pigments. Plants tweak, or modify, the red anthocyanin pigments to make blue flowers, including pH shifts and mixing of pigments, molecules and ions. These complicated alterations, combined with reflected light through the pigments, create the blue hue (source: Mother Nature Network).
But why the blue pigments are so scarce, seems to be unknown as far as I know (MNN, NPR, Science blogs)
Sources
- MNN
- NPR
- Photobiology

I love it when someone explains something so complex in such a graceful and easily understandable way. Thank you so much :)

so blue pigment is rare in nature, but blue light abounds (so much that we nicknamed our planet after it). in human technology it seems to be just the other way round: blue pigment from minerals has been known to ancient civilizations, while (cold) blue light was engineered only recently after we had red and green luminescence for decades.

Things are not blue because they absorb the blue end of the spectrum. Most plants and animals need ultra-violet light which is at the blue end to photosynthesize either food or vitamin D. Conversely, they try not to bake... so they tend to reflect the infra-red end.

Is Rayleigh scattering also why water looks blue from a distance, but, when up close or in smaller doses, is clear (or at least, not blue)?

This seems to be a good answer except for the references to Rayleigh scattering. Structural coloration seems to be the proper umbrella term for these phenomenon, but the specific physical explanations seem to be mostly thin-film interference or diffraction. None of the references in this answer seem to mention Rayleigh scattering and I would be quite surprised if there actually was an animal whose coloration could be explained by Rayleigh scattering.

@TylerH Rayleigh scattering is the reason that clear skies appear blue. If you are looking at a large body of water outdoors on a clear day, it will be blue partly because it is reflecting the blue light from sky, but also partly because water is intrinsically blue. The intrinsically blue color of water is, however, not caused by Rayleigh scattering, but rather by absorption of shorter wavelengths. This absorption is, however, quite weak, so light has to pass a long distance through the water for this to be noticeable. This is the reason why water in a glass will not appear blue.

I would question the statement about less than 10% of flowering plants having blue flowers, at least if we limit that to plants having conspicuous flowers.  In my garden, and in the mountains & desert hereabouts, blue seems as common as white or yellow, and much more common than red/orange.

I don't have a source nor the knowledge to back it up, but Italian wiki a without a source that the biosynthesis of anthocyanin requires materials that are produced through photosynthesis. Moreover, not even water plants seem to produce them since the required energies are pretty high.

RadioLab did a great story on the scarcity of blue in nature.
http://www.radiolab.org/story/211213-sky-isnt-blue/

If memory serves, the Wikipedia article on Iridescence (or if not, an article it links to directly) has a terrific diagram illustrating the mechanics of the blue light reflected from peacock feathers, butterflies, and blue eyes. I think such a diagram would be a good addition to this answer.

More from NPR on the colour blue.

All of which raises the obvious evolutionary question: Why is one of our eyes three different color cones tuned to see blue?  That is, why can we see blue independently, if nothing actually is independently blue? (Okay, not nothing, but nothing of seeming evolutionary advantage)

A similar question was asked by the YouTube channel It's Ok to Be Smart: Why Is Blue So Rare In Nature?. The video provides some good visuals about blue butterflies (including a rare instance of real blue pigment)!

@RBarryYoung if you look at the natural environment on earth it is composed mostly or browns, greens, and blues. the sky and water, two very important things in your visual field, tend towards blue. without a blue receptor green plants and animals and blue sky would look extremally similar which would be bad. its not really surprising even mammals which lost much of their color vision kept the ability to distinguish sky from everything else. Blue is not rare in nature it is just rare in living things.

The scarcity of blue pigments in living things generally is thought to be due to the difficulty of biosynthesizing organic compounds with the required electronic configurations necessary to appear blue: typically by selectively absorbing orange as well as near orange-reds and yellow light of about 580 to 620nm wavelength.  Reflecting only blue will also do it, but this mechanism requires aborbing even more wavelegths and so encompasses the other mechanism.  I apologize in advance but a description of why this is the case exceeds the allowed comment length so I have to break this in two.

For a molecule to appear a color, an electron in the highest occupied molecular orbital of must absorb the energy corresponding to a particular wavelength of light, promoting it to the lowest unoccupied molecular orbital.  To absorb wavelegths in the 580-620nm range requires that the orbital energy gap be quite small.  In organic molecules, such conditions are obtained with large, complicated networks of alternating pi bonding electrons (mostly C=C bonds).  Thus the necessary compounds are very large, often unstable and require complicated biosynthetic pathways with large energy requirements.

t@DrRadium - you might wish to consider writing an answer with this material, it sounds interesting! Make sure to add a few references/sources

Although @AliceD's answer is a great simple demonstration of the rarity of blue in our natural world, there's likely a more nuanced/technical reason.
Short answer
Blue light was the most available wavelength of light for early plants growing underwater, which likely led to the initial development/evolution of chlorophyll-mediated photosytems still seen in modern plants. Blue light is the most available, most high-energy light that continues to reach plants, and therefore plants have no reason not to continue taking advantage of this abundant high energy light for photosynthesis.
Different pigments absorb different wavelengths of light, so plants would ideally incorporate pigments that can absorb the most available light. This is the case as both chlorophyll a and b absorb primarily blue light. (Absorption of red light likely evolved once plants moved on land due to its higher efficiency).
Pigments appear as whatever color is not absorbed (i.e, they appear as whichever wavelength(s) of light they reflect). Because blue pigment would reflect the majority of light that modern plants rely on for their chlorophyll-mediated photosystems, blue pigments remain scarce in plants.

Photosynthetic organisms would not remain competitive if they failed to absorb the readily available, high-energy blue light, and so therefore evolution has likely very infrequently favored the generation (or propogaiton) of blue pigments.

Long Answer
Atmospheric Transmission
As this page from Humboldt State University demonstrates, blue and green
light pass through the atmosphere to the earth's surface better than almost all other wavelengths of light:

transmission is when electromagnetic energy is able to pass through the atmosphere and reach the surface. Visible light, largely passes (is transmitted)
  through the atmosphere.

This means that blue and green light are the most available wavelengths of light.

Note that blue/green are followed closely by the rest of the visible spectrum and NIR (near infrared).
Also note that a large portion of ultraviolet is largely absorbed by atmospheric gases (primarily ozone), and therefore poorly transmitted.

Wave Properties
It's important to understand that (from U. Wisconsin):

More energetic waves have shorter wavelengths while less energetic waves have longer wavelengths.

As a result, blue light (being the most available highest energy wavelength of light), seems to be the optimal wavelength of light for photosynthesis.

Note that although available UV light is more energetic and can power photosynthesis, it's often a tad too energetic and can cause damage to cells. So it's often best for organisms to reflect UV.
More info about the physics behind light energy can be found here.

Photosynthesis
Photosynthesizing organisms contain pigments (typically heme/porphyrin-based chlorophylls and various carotenoids) that absorb light energy. Basically, the energy from a photon of light raises an absorbant pigment to a higher energy state (called an excited state), and then the pigment releases that unstable energy to return to it's ground state -- this excess energy is what powers the biochemical reactions of photosynthesis. See here for more details.
Here's two example graphs (from here and here) showing the absorption spectrum of typical plant pigments:

As you can see, plants have evolved to have pigments that absorb primarily blue light (followed by red light). These pigments reflect green light and so therefore appear green.

Presence of blue pigments (i.e., those that reflect highly abundant blue light), on the other hand, would be in direct contrast to these photosynthetic efforts. As a result, blue pigments remain rare in photosynthetic organisms powered primarily by chlorophyll-driven photosystems.

However a number of sources (e.g., Mae et al. 2000, Brins et al. 2000, and here) suggest that although plants absorb more blue light than other wavelengths, the most efficient photosynthesis does not occur using blue light. Instead, red light results in the highest photosynthetic efficiency.

One of the reasons that they (in this case Brins et al) found was that xanthophylls were dissipating the excess energy associated with blue light causing a rate decrease in blue-light photosynthesis.
This NIH page suggests that high-energy light isn't even necessary for plants:

Chlorophyll a also absorbs light at discrete wavelengths shorter than 680 nm (see Figure 16-37b). Such absorption raises the molecule into one of several higher excited states, which decay within 10−12 seconds (1 picosecond, ps) to the first excited state P*, with loss of the extra energy as heat. Photochemical charge separation occurs only from the first excited state of the reaction-center chlorophyll a, P*. This means that the quantum yield — the amount of photosynthesis per absorbed photon — is the same for all wavelengths of visible light shorter than 680 nm.

However, all of this may be for nought, because there is ample sunlight available to plants. Again from the NIH page:

However, even at the maximum light intensity encountered by photosynthetic organisms (tropical noontime sun, ≈1.2 × 1020 photons/m2/s), each reaction-center chlorophyll a absorbs about one photon per second, which is not enough to support photosynthesis sufficient for the needs of the plant. To increase the efficiency of photosynthesis, especially at more typical light intensities, organisms utilize additional light-absorbing pigments.

In other words, plants are not entirely photosynthetically efficient and do not typically use all of the light available to them. From Wikipedia:

Photosynthesis increases linearly with light intensity at low intensity, but at higher intensity this is no longer the case (see Photosynthesis-irradiance curve). Above about 10,000 lux or ~100 watts/square meter the rate no longer increases. Thus, most plants can only utilize ~10% of full mid-day sunlight intensity.

So in summary:

Blue and green light are the most available wavelengths of light.
Blue light is the most energy-rich of the high-availability wavelengths of light
Plant pigments absorb mostly blue light
BUT plants don't necessarily need the high energy of blue light for efficient photosynthesis.

So what gives?...
Evolution
So given all of that, the question still remains: why absorb mostly blue light and not green light?
The answer, though still somewhat conjectural, is likely due to the light availability of early plants. Early plants evolved, like all life, under water.
It turns out, just like the variability in transmittance of different wavelengths of light through the atmosphere, certain wavelengths of light are more capable of penetrating deeper depths of water. Blue light typically travels to deeper depths than all other visible wavelengths of light. Therefore, the earliest plants would have evolved to concentrate on absorbing this part of the EM spectrum.

However, you'll notice that green light penetrates relatively deeply as well.  The current understanding is that the earliest photosynthetic organisms were aquatic archaea, and (based on modern examples of these ancient organisms) these archaea used bacteriorhopsin to absorb most of the green light.

Early plants grew below these purple bacteriorhopsin-producing prokaryotes and had to use whatever light they could get. As a result, the chlorophyll system developed in plants to use the light available to them. In other words, based on the deeper penetrative ability of blue/green light and the loss of the availability of green light to pelagic prokaryotes above, plants evolved a photosystem to absorb primarily in the blue spectrum because that was the light most available to them.
So why have plants not evolved to use green light after moving/evolving on land? As stated above, plants are terribly inefficient and can't use all of the light available to them. As a result, there is likely no competitive advantage to evolve a drastically different photosystem (i.e., involving green-absorbing pigments). So earth's plants continue to absorb blue light and reflect the green, and blue pigmentation remain uncommon in our world.

Plants likely evolved to produce anthocyanins (the pigments responsible for the reds/blues/purples attributed to blueberries and violets) for reasons other than photosynthesis -- e.g., attraction, UV protection, or even protection against herbivores. See here, here, and here for examples.

So what about non-plant organisms?
According to Wikipedia:

Carotenoids are the most common group of pigments found in nature, including in animals.
Carotenoproteins complexes are responsible for the various colors (red, purple, blue, green, etc.)
Animals are incapable of making their own carotenoids and thus rely on plants for these pigments.

In other words, most pigments in non-plant organisms originate either directly or biochemically from the organism's diet. Without direct ingestion of blue pigments, these chemicals are unavailable or biochemically expensive to produce (see Crustacyanin). As a result, blue pigments are also uncommon in animals.
Though, as AliceD's sources point out, we still don't fully understand why animals don't produce more blue pigments.

That's good as far as photosynthesis goes, but blue (and purple to ultraviolet) pigments are pretty common in fruits & flowers.  One might speculate that this is because flowers and (ripe) fruits have evolved to be conspicuous to their pollinators, or to animals that eat the fruit and so disperse the seeds.  Green flowers are rare, and while immature fruit is green, mature fruit seldom is.  So much so that 'green' has become a synonym for unripe :-)

@jamesqf Yup exactly. See my point (and associated links) about anthrocyanins. However, that's an explanation for why we have any blue foods :p. The rest of my answer is about why we likely don't have more blue pigments in organisms!

I didn't get where exactly do you say anything about Why are so few foods blue?

@J.Manuel: Our food consists of animals and plants. This answer is a huge explanation of why animals and plants aren't blue. What more do you want?

@LightnessRacesinOrbit Forget about the natural world. Blue foods are less common than most others. Even in processed foods. A blue juice will probably be confused with some sort of detergent rather than a juicy drink. The reason is that, people will avoid a blue meal until proven safe

@J.Manuel: And why do you think that is? That's right - because animals and plants don't tend to be blue! It all comes back to that in the end.

Can we have a shorter short answer pretty please ?

@Nikana Plants evolved under conditions of mostly blue light, which led them to develop photosystems that use a pigment that absorbs primarily blue light. Once they moved to land, there was ample (often too much) high energy blue light (and other wavelengths of light, too) to ever necessitate evolving new pigments to become more  competitive. Even if plants were to add new pigments, they would probably not evolve to add more blue pigment b/c that would decrease their ability to photosynthesize using their current chlorophyll-mediated photosystem.

So... "As blue is the most energetic wavelength available to them, plants evolved so as to absorb blue radiations the most, therefore reflecting as little blue as possible. You cannot see blue light coming from a plant because plants eat blue light." Is that roughly correct ?

@J. Manuel: On the contrary, lots of people drink (dark) blue grape & blueberry juices.

Great detailed discussion, but the conclusion...? It seems all this photosyntesis stuff would, if anything, favour plants that can still make some use of the greenish ambient light beneath a forest canopy. Especially since, as you say, plants that are exposed to direct sunlight are basically out of worries anyway, hence no real evolutionary penalty.

@NikanaReklawyks The shortest answer I can think of is "TL;DR: If you don't have the capacity to take 15 seconds to read about a quarter page of text, you don't get to know interesting stuff about things."

I joined just to vote this up.  Wonderfully accessible answer.

This answer makes me wonder, if humans discovered an edible plant on another planet which had evolved blue pigments, cultivated it on earth, and incorporated it into our diets, how our appearances might change!

I'm confused by @theforestecologist's claim that "Blue light was the most available wavelength of light for early plants growing underwater". I'm no expert, but I've heard several times (and read on Wikipedia's Color of Water) that water is blue because it absorbs the red, orange, yellow, and green wavelengths of light and reflects the blue and violet wavelengths. Which seems to imply that blue was the wavelength least available to plants growing underwater.

@Elise van Looij I think your confusion comes from thinking of water as a single mass (i.e. a giant mirror) instead of thinking about it as a bunch of molecules. Each molecule absorbs those colors you list, but they absorb blue light the least effectively and as a result reflect blue light among themselves. In other words, the water molecules act as a massive network of miniature mirrors that continuously pass the color around until enough molecules have slowly absorbed the light (this is the no-light depth). For an extended discussion, see here

If you encounter any further knowledge regarding "why animals don't produce more blue pigments" please update the answer, the depth and details of this answer is really great.

blue pigment in single-celled protist Stentor coeruleus called stentorin (https://www.osti.gov/biblio/7191680-characterization-function-stentorin-photoreceptor-protein-stentor-coeruleus)

We do understand why animals don't produce more blue pigments.  The structural requirements for an organic molecule to produce the selective absorption of light needed for a pigment to appear blue are quite narrow.   It requires very large molecues with extensive networks of alternating pi bonding electrons that are often unstable and biosynthetically taxing with high energy requirements to produce. If blue color  is evolutionarily advantageous, structural color is far less costly to produce. Thus only one animal produces a blue pigment. See my comments to AliceD's answer for more details.

It is not that there are no blue foods, it is that the English language does not like calling foods "blue".
There are no natural borders between "colors" in a colorspace, all colors we name (and learn to distinguish) are culturally defined. So, an important thing to recognize is that, a color somebody calls "blue" can be called "purple", "red" or "maroon" or "green" or something else.
With that in mind, we can take a look at foods. Animal foods on the inside are protein, and cooked protein is usually a pale greyish goo (although muscle cooked medium still has reddish coloring). One of the rare examples would be some eggs with blue shells. In plants, basically all leaves we eat are colored by chlorophyl. So they are out of the equation.
Other plant parts, especially fruits, tend to be colored by one of a few other groups of pigments. And a major group of those pigments, the anthocyanins, ranges from blue to purple to red (they also change with pH). So a ton of foods have a somewhat purplish blue color, and are also named "blue" in other languages. Plums, aubergines, red grapes, red cabbage, and many berries are good examples for that. Then you have some plants which come in many colors, but the major cultivars happen to not be blue - potatoes and maize are the first to come to mind.
Other shades of blue are less common just because they don't happen to be covered by the major pigment groups, but if you go down into shade level, then "royal blue" is just one of many on the spectrum which is missing. Also note that there are still plants which have other shades of blue and are consumed, they are just not commonly thought of as "food". Lavender, chicoree, gentian and pansies all have blue flowers of various shades and are traditionally used in recipes.
So there is no special evolutionary reason why plants or animals should not be blue - many of them are blue, and we eat some of the blue ones. It is simply a cultural or linguistic trend for English speaking people to not see their food as blue.

I knew someone would answer or comment with some smug claim that colours are all completely subjective labels. The reality is that it doesn't matter.

@MilesRout I don't understand your comment - what doesn't matter?

What we call 'blue' in English. You thinking (rightly or wrongly) that we don't apply blue to some things that you think are actually blue isn't relevant to the question.

@MilesRout The question asks "why are there so few foods which are blue". If there are many foods which are blue, it makes no sense to search for reasons. And my answer says that this is the case - there is no lack of blue foods.

@rumtscho But there aren't many foods which are blue.

@MilesRout there are - the answer lists them. They are just not salient when people try to think of them. If you will, I answer the question "why does it seem that there are so few blue foods", which is better applicable to the OP's situation than the literal wording of their question.

@rumtscho No it doesn't. It lists foods that are colours like purple and pink and claims that they're really blue. But they aren't.

@MilesRout Look for example at this: https://commons.wikimedia.org/wiki/File:Close_up_grapes.jpg. I cut out a grape from this picture, went to a color palette creation tool, and picked out colors from it. All of them were blue-based (hue component in the HSV model was between 216 and 220), I would call them blue-greys when seen as colors only. This is why I claim that these foods are blue - because when you photograph or paint them, the color which represents them is blue. The language may call them "red grapes" but this does not make them red any more than a green monkey is green.

@rumtscho they're clearly purple.

Why are there relatively few foods that reflect light in the 450–495 nm wavelength range?

I agree with the critics: this has nothing to do with language. Food isn't called blue in English because it is not really blue. Grapes (like blueberries) look blue from the outside but this is just the “dusty” surface; what you actually eat/drink after washing/processing is not blue. Calling the foods you listed blue (as well as some which are called blue, in particular blue cheese, which is not really blue) would be as inaccurate as calling carrots yellow. Physically speaking, the hue difference between yellow and orange is way smaller than the difference between purple and blue.

@rumtscho: Grapes do come in many colors: purple/blue, red, green, yellow, and perhaps others.  Likewise a number of other fruits - plums, elderberries, & mulberries come to mind - of which at least some varieties are blue.  And for those that are blue when growing, the 'dusty surface' is no more important than the fact that some blue animals produce their color by structural manipulation rather than pigment. They still look blue when I pick them :-)

Debating the semantics of the word "blue" is something I would have expected from my fellow pedantic SO users, but @rumtscho, you surprise me.

This is quite possibly the wrong way around, in that it is plausible that one of the influences on languages that had a word what in English is "blue" through the spectrum to what in English is "green" sometimes changed to differentiate them is because green is so common in nature, including food, and blue so rare.

What we call it in the English language is irrelevant. There are only a handful of naturally-occurring, edible things in this world that the majority of people would consider the color English-speakers call "blue".

@rumtscho Even if we accept your position on the semantics of the word 'blue', it's not really an answer to the question, which in this new framing would be asked as "Why are there so few foods with colors that fall in that part of the VL spectrum that the OP so casually used the word 'blue' to refer to?"

@DanHenderson and others - I find that the foods which fall in that part of the spectrum are not at all "few".

What I meant is that when OP said "blue", they were actually referring to a specific subset of the colors that can be called "blue", and that this subset excludes most of your examples. Your answer is not incorrect, but it is framed around your broad application of the word "blue", which, as I'm sure you can recognize, is not the same as what OP is actually asking about.

@Jon Hanna I don't know that there are not numerous foods that refect in the 450–495nm range. To be true blue, you need to not only reflect in this range, but either absorb in the 580-620mn range or absorb everywhere in the visible spectrum except 450-495nm. As I note elsewhere, it is the conditions needed for an organic molecule to absorb at all in the 580-620nm range that are difficult to produce.  Which I suspect strengthens the overall case you seem to be making, there are very few foods that have a color that closely matches the colorspace of 450–495nm light.

@rumtscho why are there so few foods at the center of blue color space?  Is this true of any other color except varieties of blue like cyan?  I also know no other color (except maybe pure indigos and violets but not purples) where pigments of that color require such challenging and energetically disfavored biosynthesis to produce compared to blues.  If it is all just a matter of people's choice of langauge why is the chemistry of blue pigments so much more difficult to achieve?  And since it is, how can the question be approached without addressing this fact?

Summary
I would argue that the more appropriate question to ask is:
Why can we easily identify blue plasters, even though so few foods are blue?
(And the main part of this answer is why this even is a reasonable question.)
And the main answer to that is probably that a sufficiently large food-sparse region in colour space eventually got its own colour term, namely blue.
Terminology
A colour is a region in colour space that speakers of the respective language agree to assign the same name.
Basic colours are colours that you already know in kindergarten and wouldn’t consider a special case of another colour (like aquamarine being a special case of blue).
The evolution of colours
In their evolution, languages refine their segmentation of colour space step by step, usually starting with light-warm vs. dark-cool, then separating red, yellow, and green (further reading).
The fifth segmentation usually splits blue and green – or more precisely: something similar.
After this, English has white, black, red, yellow, green, and blue.
Now, languages split an existing colour when there is a relevant distinction to make within it.
And potential food was the predominant thing for humans to distinguish for most of their history.
If some fruit changing its colour from green to blue indicates that it has become edible, this is not only something relevant to communicate, but having a word for it makes it easier to remember this.
By contrast, humans looked at the sky on a daily basis but whether it was green or blue was nothing they ever needed to communicate.
Consequentially, the colours of foods were a driving factor for how we segment our colour space to begin with.
And here, the distinction between blue/green and purple/red seems to be dominated by exactly this:
Most food that leans on blue just remains within what we call purple (e.g., plums and aubergines) and often, turning from green to purple indicates ripeness.
(And in the case of blueberries, going from purple to blue indicates ripeness.)
However, I am not aware of any food that turns from green directly to blue.
So, there is some reason to assume that our colour space is segmented such that there is little food on the blue side of the blue–purple divide.
Feedback from language to perception
Another weird aspect of this is that language influences our perception:
If we learn a word for a colour from young age, we also become better at distinguishing that colour.
A striking example of this are the Himba people, whose language segments the colour space differently than English (and many other languages).
They find it much more difficult to distinguish certain a certain pair of shades of blue and green (because their language doesn’t) but find it easier to distinguish certain shades of green (because they are different basic colours in their language)¹²³.
So, if the English language didn’t make the blue–green distinction, you likely wouldn’t have asked this question – not only because you would lack the words, but also because you wouldn’t even notice³ that there is a family of shades of green that you find in all sorts of technological products (and the sky), but not in food.
Now, what’s so special about blue?
There are several other colours you will rarely find in food, e.g., fuchsia/magenta, neon green, and brick red.
Why did you not ask the question about them, and why don’t we use these colours for plasters for food preparers?
The answer is probably that blue is a basic colour term but that is only half the truth:
Because blue is a basic colour term, we are better at distinguishing it than e. g. neon green and thus it is more effective as a plaster colour.
This leaves the question:
Why did blue become a basic colour term and continued to exclude food?
The answer to this is naturally hidden within the mists of history.
However, the appearance of some sort of blue–green distinction is a common trait of languages, suggesting that it is more than just chance.
My educated guess it that what we call blue is simply the largest region of colour space that is sparse with food, for the reasons addressed in the answers by AliceD and Theforestecologist.
Mind that a difficulty with this explanation is that it is somewhat subjective how we even measure colour-space volume (and thus define largest) in a way that reflects human perception.
In contrast to other basic colour terms, blue (or more precisely: the blue–green distinction) seems to be caused by the introduction of a respective dye³ and not food.
This suggests in turn that the new colour term started off as an identifier for that particular dye (which is in fact common, see indigo, Prussian blue, etc.).
As such it doesn’t make sense that it covers the colour of something well known including food.
For example, if the new colour term had covered the colour of plums, people would rather call the new dye plum dye and forget about the new term (and the dye) quickly.
As a result, it is not surprising that the emerging colour term would start with a territory that excludes food.
Of course this might change later in a language’s development, but if a colour starts off as a non-food colour, there is some psychological momentum to keep it that way:
You are not used to eating blue stuff, hence you wouldn’t start calling food blue (see also Rumtscho’s answer).
This is paralleled in grey, the other basic colour term that we do not like to use to describe food, even though it is arguably the most fitting colour for meat in some conditions, certain fish, the inside of eggplants, etc.
Rather we tend to describe these by whatever remnant hue the food has or as white or black.
Some reading material

Language Log: It’s not easy seeing green
Gondwana Collection: How do Namibian Himbas see colour?
Business Insider: No one could see the colour blue until modern times

Your analysis fails to address the question, why are there so few foods which have colors in the blue color space regardless of where the margins of that space are placed by a culture.  I also have to note that the some additional reading material regardling blue perception is seriously flawed.  Your reference re: Namibian Himbas is based on a misleading dramatization of the research not the actual research.  See https://languagelog.ldc.upenn.edu/nll/?p=18237 which is an update to the "Not easy seeing green' reference.

The business insider reference also relies upon the inaccurate dramatization of the Himba research as well as claims about ancient Greek perception of blue that are challenged as simplistic assumptions by some scholors of the ancient Greek language, see http://kiwihellenist.blogspot.com/2020/05/ancient-greek-colours.html


text:
Can someone help me with this Pedigree Analysis?
$\text{So... here is the given pedigree chart:}$

My question is ... whether this is an autosomal or a X-linked recessive trait.

The book I was following gave me this info:

My Attempt:
Looking at the chart ... it all comes down to either X-linked recessive or Autosomal recessive.
According to Rule 1. under these conditions:

If it appears with equal frequency in both Males and Females -- Autosomal
Otherwise , if more male than female -- X-linked

But my teacher said ... "its not always so"

So.... I tried with both once (brute force method ... going through all possibilities) and I could not understand which one...
It seems both are correct (which obviously is not possible)
So can anyone please help me with this problem!?
Thanks!

Are squares males and circle females?

It is both possible that the trait is x-linked recessive and autosomal recessive. If autosomal recessive, that would require individual 12 to be heterozygous though.

@Remi.b Yes ... and the darkened ones are the affected ones

The rule is you have to see 1st if the pedigree obeys Y-liked inheritance, if not then whether dominant/recessive. Once you figure out that (say it turned out to be recessive) see if it obeys X-linked or not. If it does the pedigree shows X-lined(recessive) trait. If it doesn't then it is autosomal and applying the genotypes you'll see there's no conflict and it obeys Autosomal inheritance for sure. The list of characters they are not always true for all pedigree charts, you'll find some matching while others may not.

I would suggest you to consult your teacher because it is next to impossible to explain in a written Q&A format. Besides there are a number of ways this is taught, learning from more than one source will actually confuse you.

Looking through the table you provided, X-linked recessive trait seems the most plausible, since almost all of the conditions are precisely fulfilled. The only one that seems to challenge this conclusion is number 4: "is never passed from father to son". This is tricky because of the relationship between no. 4 and no. 7. However, this doesn't necessarily rules out X-linked recessive, since it is possible that no. 7's mother (no. 3) is a carrier and no. 7 got a defective X chromosome from her. We don't have her history, but this is possible and makes X-linked recessive a plausible option.

With the currently given information both autosomal and X-linked recessive is possible:
(WARNING extremely sloppy Paint editing ahead)
This is a possible scenario for an autosomal recessive trait:

And this is one for a X-linked trait:

Ideally you would extend the chart until you encounter a scenario where an affected female has healthy male offspring (which indicates an autosomal trait).

For both autosomal and X-linked recessive, we must make the assumption that 3 is heterozygous. The genotype of 1 shouldn't matter in either case, and is most likely homozygous.

Oops you are absolutely right

Thanks for your comment on my answer. You're absolutely right and, actually, the entire answer is now wrong.

@canadianer I suppose X-linked might still be slightly more likely as autosomal assumes subject 12 to be a heterozygous outsider.


text:
Alan Turing was treated with estrogen-analog, though he was gay. Shouldn't it actually increase his female-like desires?
Alan Turing was a great mathematical genius of all the time, as well was a homosexual-male. However, the biography of Alan Turing on Wikipedia ( Permalink ) tells that :

Turing was convicted and given a choice between imprisonment and probation, which would be conditional on his agreement to undergo hormonal treatment designed to reduce libido. He accepted the option of treatment via injections of what was then called stilboestrol (now known as diethylstilbestrol or DES), a synthetic oestrogen; this treatment was continued for the course of one year. The treatment rendered Turing impotent and caused gynaecomastia,fulfilling in the literal sense Turing's prediction that "no doubt I shall emerge from it all a different man, but quite who I've not found out".

Though upon modern medicine, probably Turing needed no medication; but medicine (and politics) of that time; needed to prescribe some medication for Turing.
Well. But why they've chosen an Estrogen analog? Shouldn't that actually increase Turing's female-like needs and behaviors? Or maybe it indeed increased the homosexuality in Alan Turing unintentionally or intentionally?

I wouldn't suggest looking for medical logic in this sort of forced treatment, but hormonal control of behavior certainly is not as simple as "more testosterone = seeks women" and "more estrogen = seeks men." The "treatment" was given to suppress sexuality viewed as inappropriate.


text:
Are there animals which produce their own colour pigments`?
After discovering flamingos natural colour isn't red, pinkish as one naively may have assumed though, I looked into the matter more deeply. I also found out that many other animals do not produce the respective colour pigments matching then their outer appearance.
Some seem to use certain optical effects like Rayleigh Scattering or applying several different layers of filters to absorb wave lengths of light from the spectrum just emitting the intended colour.
After browsing through some more cases several questions arose, which of course cannot be answer all in detail here. However most interesting to me were:

Why does it seem so difficult for animals in contrast to plants to produce their own colour pigments?
Some colours seem to be more difficult to achieve than others. For example I found that melanin and several variation of it as colour pigments are produced quite commonly by animals, however blue rather difficult. As the following post indicates, blue colour pigments seem to be in general difficult to produce: Why are so few foods blue?

As my previous comment on the question suggesting improvements has been read I have removed it. I'd suggest you clear your own when you have made modifications. That way just the science will be left, and, as I have said, I think it is worth discussing. If you don‘t get round to editing it yourself, I‘ll do it. Editing of questions and answers is encouraged where it will improve them.

@David, I edited parts but you are always welcome to edit / expand the question further. I consider myself not very well versed, maybe naive in the topic and thus miss certain opportunities. Better there are more questions / thoughts put together encouraging thinking and constructive discussions than ideas missed and lost.

Fine. If I ever get time I'll look in more detail into the metabolic pathways involved (although I'm not sure that this is your field.) As far as the patch of blue is concerned, I imagine that we are getting into colour chemistry as well as metabolism. The story of indigo comes to mind. However the title of the other post puts me off. Is it concerned with edibility or abundance? But I have given that question a wide berth.

Although no expert in this field, I think this question is interesting and I would like to put forward some tentative answers.
In a general evolutionary sense one might regard coloration as a secondary feature of living things — especially animals. Their primary concern is to obtain energy, synthesize structural components, reproduce etc. So the metabolism that evolves under this pressure is such as to allow them to do these things. Colour is not a primary concern. Pigments are complex molecules, and enzymes are only likely to evolve to produce them if there are already reasonably complex precursors available. I know little about plant biochemistry, and would welcome improvement of this answer, but it would seem to me that (1) plants have more complex or different metabolic pathways than animals, such as those for synthesizing chlorophyl, and (2) the pathways for producing pigment precursors are more widespread, perhaps because coloration affords a greater advantage to plants — for pollination etc.
There does appear to be pigment synthesis in animals — an article on pigmentation in bird feathers can be found on the website of The Cornell Lab, for example. That states that the pigments in bird feathers are based on three types of compounds: carotenoids (red or yellow), melanins (black to reddish brown and pale yellow) and porphyrins (pinks, browns, reds and greens).
Two of these are related to compounds the birds synthesize themselves from amino acids — melanins for skin pigmentation, and porphyrins for haem. However, it appears that carotenoids are not synthesized by the birds that employ them for coloured feathers, but are acquired from plants in their diet.
Finally, one might argue that producing colours by optical effects has certain advantages over the use of pigments, namely that they are ‘tunable’ — can be modulated or turned on and off.

I like this answer, but it seems to me that colouration need not always be a secondary concern. Colouration has evolved, for example, as camouflage or for mimicry.

I agree that it is important for those animals that use it. And of course they don't care how they achieve it — pigmentation or optics. My thought was just that central metabolism came first — indeed the terminology "secondary metabolism" reflects this. The pathways leading to anthrocyanin production seem to be widespread in plants, and quick googling indicates that anthrocyanins are made via the phenylpropanoid pathway, which apparently is used for other important non-pigment plant functions. Hence it would seem a more general plant feature. (Where are the plant biochemists when you…?)

Ah, you're thought is well taken.


text:
Modifications of free nucleotides
We know that RNA can get modified post transcriptionally (RNA modification). So when the RNA is degraded, is it possible for such modifications to still be present on the individual nucleotides -- such that when the nucleotides are recycled for constructing another RNA, those modifications persist?

It's unlikely that a chemically modified nucleotide would be recycled into a new RNA.

Why is that? As in which chemical reactions during the course of degradation -> recycling are likely to remove the modification(s)?


text:
Why is it good to use Glycerol as carbon source to produce intermediates in pharmaceuticals?
Why is it good to use Glycerol as carbon source to produce intermediates in pharmaceuticals?
My best guess would be because it produces a lot of ATP per carbon. But I haven't found anything to verify my hunch.

You might get better answers on Chemistry.SE if you are asking about the process of chemically synthesizing pharmaceuticals. However, I'm confused, why are you referring to ATP?

@BryanKrause okay thank you I will. Well okay maybe I'm thinking about this all wrong I just thought about how when using Glycerol as a carbon source for E.coli it produces more ATP/fuels more growth per carbon than for example Glucose.

Are you thinking about pharmaceutical production by E.coli? That's getting a lot more specific than your question suggested originally. If you have a citation to a particular protocol or something that might also help you get better quality answers.

Do you have a reference for the fact that more ATP per carbon is produced from glycerol than from glucose?

First, glycerol is economically and environmentally interesting as a substrate. It is a side product of first generation biodiesel production, which has been increasing in the past years. So large amounts of glycerol are being accumulated, while we make little use of it. Therefore it has become a necessity to develop glycerol utilizing industries. Another consequence is that glycerol is now a cheap and abundant substrate.
The metabolism of glycerol is quite complex and has many end products that are of industrial relevance. For example, 1,3-propanediol and succinic acid have commercial applications and can be produced directly from glycerol by some microorganisms. So depending on the strain you use, you may not need heavy metabolic engineering.
Here is an article that might help you.


text:
Making Cupriavidus metallidurans in laboratory?
This is probably a stupid question but would it be possible to 'make' Cupriavidus metallidurans? And if so how? I'am guessing it wouldn't be possible without the use of expensive equipment for genome sequencing.

What do you mean by "make"? It is not possible to synthesize living organisms de novo. Also, according to Wikipedia, the genome has already been sequenced.

ok thank you my question then is where can I 'find' them?

I would expect places with high heavy metal concentration. Don't expect to go swabbing some tailings pond and get a viable, pure culture.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2168447/ They found a strain in "the sludge of a zinc decantation tank in Belgium that was contaminated with high concentrations of several heavy metals."

Wouldn't I be able to just buy a sample and then create more from those?

Potentially. This species may be hard to find and I don't expect many distributors would sell to private individuals.

You can buy Cupriavidus metallidurans from various culture collections.
See these links below:

Cupriavidus metallidurans (Goris et al. 2001) Vandamme and Coenye 2004 - DSMZ
Cupriavidus metallidurans (Goris et al.) Vandamme and Coenye (ATCC® 43123™) - ATCC

As canadianer has already explained, it will be next to impossible to "find" a pure, viable culture out there in the environment.


text:
Australian Tree Identification Help
I am looking at identifying a tree for a friend who lives outside of Melbourne.  Being from Tennessee in the US, we don't have anything very similar to this at all and it doesn't look like any of the US tropical trees that I know of either.  Can anyone help?
This is the far away view of the tree
Specific location: It was taken in the laneway behind a property in Glen Iris, Victoria just outside of Melbourne (Australia).

Also ask for how it smells.

The first 2 photos posted by Whitney show Syzygium paniculatum, or perhaps S.smithii. Magenta Cherry or Lilliplly.

Cat Mackenzie is right.
The leaves are darker, thinner, and more shiny than eucalyptus. The leaves also have two different sides, unlike eucalyptus.
Syzygium paniculatum, or S.smithii. I suspect S. smithii.

Ok, this is more complicated than I first thought. I am pretty sure that we have an eukalyptus tree here. The species is more complicated, but I think it is likely Eucalyptus baueriana or one of its subspecies. To check this further, more detailed images of leaves, blossoms are needed. Check this image (from here):

It isn't the right species, the leaves in OP's picture are ovate but that of E. viminalis are lanceolate.

@SanjuktaGhosh You agree now?

I too think it is of that Genus, it is not my subject though. But looking at the leaves of E. baueriana, they are a little too ovate for OP's plant.

I think it is species E.ficifolia.

From the leaves, this could fit, but E. ficifolia has red blossoms, which the tree in the question has not.

Some variant of it has white flowers too.

Hey @Chris, your answer would be improved by providing further reasoning and support for why you think this is the correct species. You include a similar-looking image, but you don't really back up with any explicit characteristics or discussion for why your answer is correct. Please consider updating. Thanks!

I presume it is Corymbia ficifolia previously called Eucalyptus ficifolia, a white variant of this species which usually bears red flowers.
Image links:
Source

Another picture (with a better view of the leaves)

Hey @TytoAlba, your answer would be improved by providing further reasoning and support for why you think this is the correct species. You include a similar-looking image, but you don't really back up with any explicit characteristics or discussion for why your answer is correct. Please consider updating. Thanks!

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Is there a difference between an organizer and inducer substance?
There is a question in my Embryology textbook's exercise that asks about an organizer and inducer substance. I found their definitions and now I am wondering if they are the same things?

According to Merriam-Webster they are synonyms:

[An organizer is]  a region of a developing embryo or a substance produced by such a region that is capable of inducing a specific type of development in undifferentiated tissue —called also inductor

Lifemap and Biology Today support the terms being synonymous as well.
However, I think the most commonly used terminology here is that the organizer [used as a noun] induces [used as a verb] the differentiation of embryonic tissue. For example, consider the following quote (Arizona State University):

The Spemann-Mangold organizer, also known as the Spemann organizer, is
  a cluster of cells in the developing embryo of an amphibian that
  induces development of the central nervous system


text:
Lactobacillus casei and paracasei
I am carrying out a study of lactobacilli isolated from different samples.
Genus and species are identified using a sequenced 1000pb long 16S fragment in BLASTn.  I cannot distinguish between L. casei and L. paracasei because they have same score and query coverage when they appear as a hit for a sequence.
I read somewhere (cannot remember where) that L. casei and L. paracasei both should be itnegrated in a single L. casei species and their differences should be considered at strain level.
Should I focus my discussion on this fact? Or are they really different species?

My recommendation is to find that source you mention that you forget,  check to see if it's a reputable source, and (if it is)  use it to substantiate your discussion. Check to see if  anyone else has ever cited  the work,  and if so, make sure  the newer work doesnt contradict your first source.

The definition of a bacterial species and (even worse) strain are somewhat debatable unfortunately. As far as I know there is no real single authority with a standardised decision process on what is a separate species or not. At least none that everybody agrees on.

To me it seems like the OP asking whether the 2 "groups"  (whatever the rank is species/ strain/ etc) of former-sense are same or not.

As far as I am concerned L. casei and L. paracasei can be differentiated by the amplification of the 16S rRNA gene of the aforementioned species using PCR - please see the work done by Ward and Timmins (1999). An alignment of the V1 region of the 16S rRNA genes of Lactobacillus casei and Lactobacillus paracasei shows the bases comprising the species-specific PCR primers - screenshot taken from Ward and Timmins (1999):

So, perhaps in your study you have not amplified the correct region of the 16S rRNA gene of L. casei and L. paracasei?
With regards to the classification of these organisms. Just as @skymningen has already mentioned in the comment section, the definition of a bacterial species (not even to mention strains) is somewhat debatable and tricky.
However, here is what Mori et al (1997) suggest:

The primary structures of the 16S rRNA genes of the type strains of Lactobacillus casei and related taxa were determined by PCR DNA-sequencing methods. The sequences of Lactobacillus casei, Lactobacillus zeae, Lactobacillus paracasei, and Lactobacillus rhamnosus were different. The K nuc values ranged from 0.0040 to 0.0126. On the basis of the K nuc values and the levels of DNA-DNA relatedness among the strains of these species, the L. casei-related taxa should be classified in the following three species: L. zeae, which includes the type strains of L. zeae and L. casei; a species that includes the strains of L. paracasei and L. casei ATCC 334; and L. rhamnosus.


text:
Are there seeds intended to feed eaters?
Seeds are meant to survive digestive systems of the animals that disperse them. Are there seeds meant for a creature, who will digest most of the seeds for nutrition and disperse only a minority of intact seeds?

Doubtful because it would decrease the probability of that species remaining extant. Typically traits that would drive a species to be less competitive or less demographically fecund are traits that are heavily selected against in a population/community due to competitive pressures. Still, I think it's an interesting question, and anything is possible! It's fun to think about instances in which this could possibly happen and why...

@theforestecologist Not much of a botanist here, but...isn't that essentially what a fruit is (or a nut?)? I mean, I guess the OP is maybe asking for something more specific than that, but it seems like a fruit is essentially taking the role of the digestible part of the seed, and nuts are fruits that some animals bury and disperse and then only eat some of them - of course with the distinction that those dispersed, uneaten nuts never pass a digestive system.

"Meant" is the wrong word to use here.  (IMHO, anyway.)  But consider that almost all plants produce far more seeds - perhaps hundreds, thousands, or more - than they need to perpetuate themselves.  So if some animal is enticed into eating the seeds, digesting most, and dispersing a few (perhaps enclosed in a handy packet of fertilizer), then evolution has created an effective dispersal method.

There's a very interesting case of mutualism between the species Homo sapiens and Oryza Sativa (also Triticum aestivum...). The humans have bred the plants to produce highly nutritious seeds, much greater then non-adapted species, and in return the humans save a small fraction of the seeds and will cultivate the plant for many generations.
It goes further then that in that humans also will protect their mutualistic plant partners from other invasive species and cultivate them, ensuring their mutual survival.


text:
What kind of flower is this?
I was in my garden a few days ago and found the flower shown in the pictures.
Can anybody tell me what this flower is?
Location: Germany / northrhine westfalia
Date: February 2017
Season: Winter

[Edit]:
My neighbour thinks it is a Anemone hupehensis (en.wikipedia.org/wiki/Anemone_hupehensis), could be right.

Probably Gossipum sp.

You mean a cotton plant? This was the first thing I thought about, but I haven;t planted it. Maybe I have to look nearby my garden if there are more them. Thank you.

@SanjuktaGhosh Did you mean Gossypium sp? however I didn't knew it could grow at cold places as Germany.

I'm not sure. It just looked like one.

@LStrike Seemingly the white things are not flowers but fruits having wind-dispersed seeds. Do you have some more close-ups; especially the calyx-like thing at base of fruit (picture), close-up of seed-like things in the cottony zone, and the stem nodes and internodes, branching, stem-tip, it would greatly help.  And if you could collect the leaf (seemingly all are hardly dried) and soak it in water and expand it to reveal the leaf shape, it would help.

My neighbour thinks it is a Anemone hupehensis (https://en.wikipedia.org/wiki/Anemone_hupehensis), could be right.

I think it is Anemone hupehensis. We have this species in our garden, and the seeds and dead leaves look very similar to the ones in your picture. The leaves are large,jagged and palmate and they have beautiful flowers in the summer/autumn (I've seen red, pink and white). The fruits/seeds also look very distinctive and cotton-like. The species is originally from Asia/China.
Here is a picture of the fruits/seeds:

(Hard to find good ones, this from Instagram page http://www.ipopam.com/tag/höstanemoner)

Looks very similar to the one I have in my garden.