question: It seems like in the animal world, males compete for females so that the strongest genes are passed on, but if 50% of genes come from the mother, what ensures that the strongest male doesn't end up mating with a weak female?
comment: The "strength" of females in an evolutionary sense is how well they do at rearing children. If they're bad at that, the genes may be passed on, but won't spread because the children will die.
passages: Males, in contrast, can mate at a very low energetic cost once they have found a partner, but are only able to attract a female if they have physical or social characteristics that can be converted into resources—e.g., territory, food resources, status, power, or influence—or the strength and alliances to coerce females to mate. As a result, there is typically much greater variability in the reproductive success of males within a species and higher competition among males for mates. The strongest, best adapted, and most powerful males may have a harem, while less fit males never reproduce.
   Organisms with polygynous mating systems are controlled by one dominant male. In this type of mating system, the male is able to mate with more than one female in a community. The dominant males will reign over the community until another suitor steps up and overthrows him. The current dominant male will defend his title as the dominant male and he will also be defending the females he mates with and the offspring he sires. The elephant seal falls into this category since he can participate in bloody violent matches in order to protect his community and defend his title as the alpha male. If the alpha male is somehow overthrown by the newcomer, his children will most likely be killed and the new alpha male will start over with the females in the group so that his lineage can be passed on.
   Section::::Evolutionary theories.:Female's resistance.
  
  Female resistance is an evolutionary concept where females develop traits to counter the males' influence. This concept can be supported by the examples of sexual conflict in the water strider and pygmy fish.
  
  Male water striders exhibit forced copulation on the female. As a result, the female will struggle with the male to reduce the detrimental effects. Female struggle is a by-product of female resistance.
   Scramble competition can also be seen with the example of red spotted newts. Charles Darwin (1871) first explored the concept of "sexual dimorphism" which states that, "most sexually dimorphic species are also the most polygynous" which would enable males to "outcompete other males through female choice, combat, or scrambles to encounter females would be favored by selection, and sexual dimorphism would result". The key to red-spotted newts increased success in scramble competition is the newts enhanced or strengthened tailfins. 
   Female fecundity: Males benefit from a high female fecundity as it means that females can produce more offspring and have a higher potential for reproduction. It is important to note that females also benefit from high fecundity, and thus this trait is probably more affected by classical natural selection.
   The MWH argues that the sex differences in attitudes towards outgroup members may be a result of the different reproductive strategies used by males and females—specifically, the greater competition among males for mates. In mammals, males and females have distinct reproductive strategies based on the physiology of reproduction. Because females gestate, birth, feed, and invest more overall resources in each of their offspring, they are more selective with their mates but have greater certainty of being able to reproduce.
   These traits could be ones that allow him to fight off other males for control of territory or a harem, such as large size or weapons; or they could be traits that females, for whatever reason, prefer in mates. Male-male competition poses no deep theoretical questions but mate choice does.
   Maternal investment: In many species, males benefit from high maternal investment as it allows them to preserve more energy and time for additional matings rather than investing their resources on one offspring. Females are expected to invest a certain amount of time and resources, but it can also be detrimental to the female if too much maternal investment is expected.
  
  Section::::Sexual conflict/antagonism and sex biased gene expression.
   Some researchers have noted that in certain species, such as the horseshoe crab, males are most successful at mating when they are able to practice scramble competition polygyny where they do not defend their territory but rather mate and move on, thus providing the highest likelihood of species survival and reproductive prowess.
  
  Section::::Examples.
   "Condition" can be assessed in multiple ways, including body size, parasite loads, or dominance, which has also been shown in macaques ("Macaca sylvanus") to affect the sex of offspring, with dominant females giving birth to more sons and non-dominant females giving birth to more daughters. Consequently, high-ranking females give birth to a higher proportion of males than those who are low-ranking.
  
  Section::::Assumptions.
  
  The Trivers–Willard hypothesis rests on certain assumptions:
  
  BULLET::::1. Parental condition is associated with offspring condition;
  
  BULLET::::2. Differences in offspring condition will persist into adulthood;
   Just as a given amount of land can only produce a finite amount of grazing, and a limited amount of grazing can only support a limited number of grazing animals, so a given number of grazing animals can only sustain a limited number of predators. Similar limitations apply to all living things, and are known as the carrying capacity of a physical area. If males' burdens are more likely to draw the interest of local predators, then such males effectively shift predation away from females and their young. In this case, the females and young will gain an added benefit from decreased predation, and enjoy even higher rates of survivability.
   The nonequivalent ratio of men with "good genes" to a large number of accessible females also leads to female intrasexual competition. Biosocial status hypothesis indicated that to win in the female competition, it is thought to enhance in testosterone production thus facilitating violent, prevailing behaviours and exhibition of high status. Whereas, losing in female competition lowers testosterone levels which weaken the tendency of competing. Testosterone levels correspond to various factors such as form of competition, characteristics of opponent, psychological state and baseline hormone levels of the person competing.
  
  Section::::References.
   Local resource competition (LRC) was first hypothesized by Anne Clark. She argued that the African bushbaby ("Otolemur crassicaudatus") demonstrated a male-biased sex ratio because daughters associated with mothers for longer periods of time than did sons. Since sons disperse further from the maternal territory than do daughters, they do not remain on the territories and do not act as competitors with mothers for resources. Clark predicted that the effect of the LRC on sex allocation resulted in a mother investing preferentially in male offspring to reduce competition between daughters and herself. By producing more male offspring that disperse and do not compete with her, the mother will have a greater fitness than she would if she had produced the ratio predicted by the equal investment theory.
   Section::::Interference competition.
  
  ICE can also explain the theory of interference competition, which is most likely to be associated with opposing sets of genes that determine the outcome of competition between individuals. Different sets of genes may code for signal or receiver phenotypes, such as in the context of threat displays: when a competing male can win more contests by intimidation, rather than by fighting, selection will favor the accumulation of deceitful genes that may not be honest indicators of the male’s fighting capability.
   Female resistance has rarely been found to be effective. Male mammals and birds are usually larger than females, and the sheer size and strength difference makes this very difficult. However, it has been observed in some species, such as squirrel monkeys, patas monkeys, vervets, and captive chimpanzees, that females can “gang up” on males when they are being aggressive. They will even try to protect a female in distress. Females have even been observed to kill immigrant males in wild red colobus monkeys.
  
  Section::::Female counter-adaptations.:Acceptance/submission.
   Female-female competition is a common abnormality within animals with accepted sex roles. Females invest into choosing the best possible mate because they have more of a part in bringing up their offspring than males (gestation and lactation). Gestation and lactation are energy-consuming, which means their competition for resources is high. Female-female competitions are observed to gain access for better mates. Meerkat females acquire dominant status because resources for female reproduction are scarce. Dominant females in this species are heavier and win in competitions over other females.
  
  Section::::Postcopulatory mechanisms.
   In many sexually reproducing species, such as mammals, birds, and amphibians, females are able to bear offspring for a certain time period, during which the males are free to mate with other available females, and therefore can father many more offspring to pass on their genes. The fundamental difference between male and female reproduction mechanisms determines the different strategies each sex employs to maximize their reproductive success. For males, their reproductive success is limited by access to females, while females are limited by their access to resources. In this sense, females can be much choosier than males because they have to bet on the resources provided by the males to ensure reproductive success.
   A possible proximate benefit for females is that sometimes after a male mates with a female, he becomes her mate. Then, he would defend and protect her. This is seen in many primate species.
  
  Section::::Female benefits.:Ultimate.
  
  A possible benefit of sexual coercion that would come out in the long run is the “good genes” hypothesis. If males can overcome a female’s resistance, then they must possess good genes that would increase the survival, mating success, and ultimately the fitness of her offspring. The hypothesis is that females can use the sexual coercion process to assess the quality of a male.
   Sexual coercion has been observed in many species, including mammals, birds, insects, and fish. While sexual coercion does help increase male fitness, it is very often costly to females. However, in spite of these costs, a possible benefit to the females is a chance to test the stamina of the males, so that only those with "good genes" will father their offspring. Sexual coercion has been observed to have consequences, such as intersexual coevolution, speciation, and sexual dimorphism.
  
  Section::::Male adaptations.
  
  Section::::Male adaptations.:Harassment/aggression.
   A good example of intrasexual selection, in which males fight for dominance over a harem of females, is the elephant seal – large, oceangoing mammals of the genus "Mirounga". There are two species: the northern ("M. angustirostris") and southern elephant seal ("M. leonina") – the largest carnivore living today. Both species show extreme sexual dimorphism, possibly the largest of any mammal, with southern males typically five to six times heavier than the females. While the females average and long, the bulls average and long.
   An effective female strategy is the employment of protection and alliances. Some females, such as wild Trinidadian guppies (Poecilia reticulate) associate themselves with protective males who come to their rescue. This also occurs in hamadryas, savanna, and olive baboons, where males and females form friendships where the female gets male protection. In northern elephant seals, the females give loud cries when mounted by undesirable or subordinate males, which attract dominant males to help. A similar phenomenon occurs in elephants, bighorn sheep, and fallow deer, where the females stay close to dominant males for protection.
   Sexual conflict may lead to antagonistic co-evolution, in which one sex (usually male) evolves a favorable trait that is offset by a countering trait in the other sex. Similarly, interlocus sexual conflict can be the result of what is called a perpetual cycle. The perpetual cycle begins with the traits that favor male reproductive competition, which eventually manifests into male persistence. These favorable traits will cause a reduction in the fitness of females due to their persistence. Following this event, females may develop a counter-adaptation, that is, a favorable trait that reduces the direct costs implemented by males. This is known as female resistance. After this event, females' fitness depression decreases, and the cycle starts again. Interlocus sexual conflict reflects interactions among mates to achieve their optimal fitness strategies and can be explained through evolutionary concepts.
   As with many other insects, both intraspecies and interspecies competition occurs in "M. scutellatus" over resources. Hughes and Hughes performed experiments to test the results of asymmetric contests of "M. scutellatus" and "M. notatus", the eastern pine sawyer. They found that in "M. scutellatus", females laid eggs that were fertilized by the male with whom they were currently sharing a pair-bond with, and the certainty of paternity decreases once the pair-bond is over. Consequently, females are the most valuable resource that males compete over. 
   Section::::Male adaptations.:Intimidation.
   Support for the challenge hypothesis has been found in continuous breeders. For example, research on chimpanzees demonstrated that males became more aggressive during periods when females displayed signs of ovulation. Moreover, male chimpanzees engaged in chases and attacks almost 2.5 times more frequently when in groups containing sexually receptive females.
  
  Section::::Continuous breeders.:Implications for humans.
  
presuppositions: There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently.
corrections: The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat.
raw_presuppositions: There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently. There is nothing to prevent strong male animals from mating with weak female animals frequently.
raw_corrections: The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat. The children of weak female animals usually do not survive, which would prevent the genes from spreading across the habitat.