question: why the four seasons have the effect they do on animals (such as breeding or hibernating season) and vegetation (such as sprouting, growing produce) but don't seem to have an effect on humans?
comment: Well first off, there are seasonal variations in births and the tendancy for physical activity in humans. [BIRTH RATES] ( URL_0 ) [PHYSICAL ACTIVITY] ( URL_1 ) The changes are not a visually obvious because humans have highly complex thought processes that significantly mask any behaviour variation with tons of exceptions. Like people who give birth in summer or winter, or those people who stay fit all year. Additionally, at least in developed nations, the added layers of shelter (insulated housing, thermal and air quality control, the increasing amount of time spent indoors) shields us from experiencing seasonal variation as much as we used to. Its kind of like growing a plant indoors under a lamp. You can control when the light is on, so you control when the plant thinks its daylight and what season it is (ratio of light to dark, room temp). If we were still exposed to the outdoor environment for most of our lives, then the seasonal variations would probably be more obvious.
passages: The season in which babies are born can have a dramatic effect on their future risk relating to the development of conditions such as neurological disorders, including seasonal affective disorder, bipolar depression, schizophrenia and type I diabetes. Research has shown that the season a baby is born in can have a major effect on whether or not you will become a heavy smoker. This even varies between men to women.
  
  Section::::The results of the scientific researches.:Large-scale population analytic studies.
   Section::::Non-calendar-based reckoning.:Indigenous ecological.
   The Noongar people of South-West Western Australia recognise maar-keyen bonar, or six seasons. Each season's arrival is heralded not by a calendar date, but by environmental factors such as changing winds, flowering plants, temperature and migration patterns and lasts approximately two standard calendar months. The seasons also correlate to aspects of the human condition, intrinsically linking the lives of the people to the world that surrounds them and also dictating their movements, as with each season, various parts of country would be visited which were particularly abundant or safe from the elements.
   The effect of axial tilt is observable as the change in day length and altitude of the Sun at solar noon (the Sun's culmination) during the year. The low angle of Sun during the winter months means that incoming rays of solar radiation are spread over a larger area of the Earth's surface, so the light received is more indirect and of lower intensity. Between this effect and the shorter daylight hours, the axial tilt of the Earth accounts for most of the seasonal variation in climate in both hemispheres.
  
  Section::::Causes and effects.:Elliptical Earth orbit.
   The timing and feel of the seasons has been noted as having changed due to the current trends in climate change.
  
  The North American Cree and possibly other Algonquian speaking peoples used or still use a 6-season system. The extra two seasons denoting the freezing and breaking up of the ice on rivers and lakes.
  
  Section::::Non-calendar-based reckoning.:Tropical.
   Section::::Four-season calendar reckoning.:Astronomical.
  
  Astronomical timing as the basis for designating the temperate seasons dates back at least to the Julian calendar used by the ancient Romans. It continues to be used on many modern Gregorian calendars worldwide, although some countries like Australia, New Zealand, Pakistan and Russia prefer to use meteorological reckoning. The precise timing of the seasons is determined by the exact times of transit of the sun over the tropics of Cancer and Capricorn for the solstices and the times of the sun's transit over the equator for the equinoxes, or a traditional date close to these times.
   Six ecological seasons can be distinguished which do not have fixed calendar-based dates like the meteorological and astronomical seasons. Oceanic regions tend to experience the beginning of the hibernal season up to a month later than . Conversely, prevernal and vernal seasons begin up to a month earlier near oceanic and coastal areas. For example, prevernal crocus blooms typically appear as early as February in coastal areas of British Columbia, the British Isles, but generally don't appear until March or April in locations like the Midwest USA or parts of eastern Europe. The actual dates for each season vary by climate region and can shift from one year to the next. Average dates listed here are for mild and cool temperate climate zones in the Northern Hemisphere:
   Ecological reckoning of winter differs from calendar-based by avoiding the use of fixed dates. It is one of six seasons recognized by most ecologists who customarily use the term "hibernal" for this period of the year (the other ecological seasons being prevernal, vernal, estival, serotinal, and autumnal). The hibernal season coincides with the main period of biological dormancy each year whose dates vary according to local and regional climates in temperate zones of the Earth. The appearance of flowering plants like the crocus can mark the change from ecological winter to the prevernal season as early as late January in mild temperate climates.
   The relationship between birth month/season and increased risk of cardiovascular disease was also confirmed in a study of close to 130,000 canines. The birth season association was found among dogs not genetically predisposed to cardiovascular disease.
  
  Section::::The results of the scientific researches.:As a factor in infant growth.
  
  The season during which a birth takes place has been linked to the weight development of the infant as well as initial weight.
  
  Section::::The results of the scientific researches.:As a factor in academic development.
   In temperate and subpolar regions, four seasons based on the Gregorian calendar are generally recognized: "spring", "summer", "autumn" or "fall", and "winter". The definition of seasons is also cultural. In India from the ancient times, six seasons or Ritu based on south Asian religious or cultural calendars are recognised and identified even today for the purposes such as agriculture and trade. Ecologists often use a six-season model for temperate climate regions which are not tied to any fixed calendar dates: "prevernal", "vernal", "estival", "serotinal", "autumnal", and "hibernal". Many tropical regions have two seasons: the "rainy", "wet", or "monsoon season" and the "dry season". Some have a third "cool", "mild", or "harmattan season". Seasons often held special significance for agrarian societies, whose lives revolved around planting and harvest times, and the change of seasons was often attended by ritual.
   While phenology fairly consistently points to an earlier spring across temperate regions of North America, a recent comprehensive study of the subarctic showed greater variability in the timing of green-up, with some areas advancing, and some having no discernible trend over a recent 44-year period.
  
  Another 40 year phenological study in China found greater warming over that period in the more northerly sites studied, with sites experiencing cooling mostly in the south, indicating that the temperature variation with latitude is decreasing there.
   “The winter months cause changes to our internal biological clocks – our circadian rhythms – which affects how we sleep and when we wake, our metabolism, our desire to be outdoors and even perhaps our desire for richer foods.” She points out, “In the US, studies indicate people commonly put on 2–3kgs in autumn and winter. We don’t have specific data on seasonal inactivity in Australia, but our experience is likely to be similar and for some people those small gains each year will accumulate.” 
   Calendar-based reckoning defines the seasons in absolute rather than relative terms. Accordingly, if floral activity is regularly observed during the coolest quarter of the year in a particular area, it is still considered winter despite the traditional association of flowers with spring and summer. Additionally, the seasons are considered to change on the same dates everywhere that uses a particular calendar method regardless of variations in climate from one area to another. Most calendar-based methods use a four-season model to identify the warmest and coldest seasons, which are separated by two intermediate seasons.
  
  Section::::Four-season calendar reckoning.:Meteorological.
   Section::::Six-season calendar reckoning.
  
  Some calendars in south Asia use a six-season method where the number of seasons between summer and winter can number from one to three. The dates are fixed at even intervals of months.
  
  In the Hindu calendar of tropical and subtropical India, there are six seasons or Ritu that are calendar-based in the sense of having fixed dates: Vasanta (spring), Greeshma (summer), Varsha (monsoon), Sharad (autumn), Hemanta (early winter), and Shishira (prevernal or late winter). The six seasons are ascribed to two months each of the twelve months in the Hindu calendar. The rough correspondences are:
   The Bengali Calendar is similar but differs in start and end times. It has the following seasons or ritu:
  
  The Tamil calendar follows a similar pattern of six seasons
  
  Section::::"Official" seasons.
   Indigenous people in polar, temperate and tropical climates of northern Eurasia, the Americas, Africa, Oceania, and Australia have traditionally defined the seasons ecologically by observing the activity of the plants, animals and weather around them. Each separate tribal group traditionally observes different seasons determined according to local criteria that can vary from the hibernation of polar bears on the arctic tundras to the growing seasons of plants in the tropical rainforests. In Australia, some tribes have up to eight seasons in a year, as do the Sami people in Scandinavia. Many indigenous people who no longer live directly off the land in traditional often nomadic styles, now observe modern methods of seasonal reckoning according to what is customary in their particular country or region.
   Compared to axial tilt, other factors contribute little to seasonal temperature changes. The seasons are not the result of the variation in Earth's distance to the Sun because of its elliptical orbit. In fact, Earth reaches perihelion (the point in its orbit closest to the Sun) in January, and it reaches aphelion (the point farthest from the Sun) in July, so the slight contribution of orbital eccentricity opposes the temperature trends of the seasons in the Northern Hemisphere. In general, the effect of orbital eccentricity on Earth's seasons is a 7% variation in sunlight received.
   Recently, large-scale population analytics have allowed for the exploration of birth month/season hypotheses among large cohorts of people. One study used 1.7 million patients from Columbia University in New York City (NYC) to confirm associations between neurological conditions, respiratory condition and reproductive conditions with birth month. In addition, they uncovered an association between cardiovascular diseases and birth month. This was subsequently confirmed in a separate study, also using data from NYC. Researchers also explored mechanisms correlated with birth season in a large population study including data from 10.5 million patients, from three countries (US, South Korea, and Taiwan) and six study sites. They found correlations between relative age and school cutoff periods. And that first trimester exposure to fine air particulates increased the risk of atrial fibrillation later in life.
   This view is presented in English poet John Keats' poem "To Autumn", where he describes the season as a time of bounteous fecundity, a time of 'mellow fruitfulness'.
  
  In North America, while most foods are harvested during the autumn, foods particularly associated with the season include pumpkins (which are integral parts of both Thanksgiving and Halloween) and apples, which are used to make the seasonal beverage apple cider.
  
  Section::::Associations.:Melancholia.
   In some parts of the world, some other "seasons" capture the timing of important ecological events such as "hurricane season", "tornado season", and "wildfire season". The most historically important of these are the three seasons—"flood", "growth", and "low water"—which were previously defined by the former annual flooding of the Nile in Egypt.
  
  Section::::Causes and effects.
  
  Section::::Causes and effects.:Axial tilt.
  
  The seasons result from the Earth's axis of rotation being tilted with respect to its orbital plane by an angle of approximately 23.4 degrees. (This tilt is also known as "obliquity of the ecliptic".)
   The agricultural growing season has also expanded by 10–20 days over the last few decades.
  
  The effects of season creep have been noted by non-scientists as well, including gardeners who have advanced their spring planting times,
  
  and experimented with plantings of less hardy warmer climate varieties of non-native plants. While summer growing seasons are expanding, winters are getting warmer and shorter, resulting in reduced winter ice cover on bodies of water,
  
  earlier ice-out,
  
  earlier melt water flows,
  
  and earlier spring lake level peaks.
   Beginning in the "spring" (the month of the "Abib", a critical stage of barley maturation), and continuing through the year, four seasons are required for keeping all of the ordinances of the Law of Moses (, , , ). Tropical Mesoamerica experiences a wet and a dry season year round. There is presently no evidence of pre-Columbian barley in Central America. Evidence of barley cultivation in ancient northern American has been found near the Great Lakes . When the Book of Mormon mentions "seasons", it is clear from the context that only part of the year is referred to (, ). It may be concluded that Book of Mormon lands were subject to more than two seasons with no impediment to keeping the ordinances of Israel (). Evidence indicates that winters were milder in western New York during Book of Mormon times. Even in modern times, humid, western New York occasionally experiences a heat index of 80 - in the spring and early summer (). 
   As the orientation of Earth's orbit changes, each season will gradually start earlier in the year. Precession means the Earth's nonuniform motion (see above) will affect different seasons. Winter, for instance, will be in a different section of the orbit. When the Earth's apsides are aligned with the equinoxes, the length of spring and summer combined will equal that of autumn and winter. When they are aligned with the solstices, the difference in the length of these seasons will be greatest.
  
  Section::::Earth's movements.:Orbital inclination.
   Orbital eccentricity can influence temperatures, but on Earth, this effect is small and is more than counteracted by other factors; research shows that the Earth as a whole is actually slightly warmer when "farther" from the sun. This is because the Northern Hemisphere has more land than the Southern, and land warms more readily than sea.
  
  Any noticeable intensification of southern winters and summers due to Earth's elliptical orbit is mitigated by the abundance of water in the Southern Hemisphere.
  
  Section::::Causes and effects.:Maritime and hemispheric.
   Section::::Reception.
  
presuppositions: The four seasons don't have an effect on humans. The seasons do not affect humans.
corrections: The four seasons have an effect on humans but the changes are not visually obvious due to highly complex human thought processes that significantly mask behaviour variation. There are seasonal variations in births and tendancy for physical activity in humans.
raw_presuppositions: The four seasons don't have an effect on humans. The seasons do not affect humans.
raw_corrections: The four seasons have an effect on humans but the changes are not visually obvious due to highly complex human thought processes that significantly mask behaviour variation. There are seasonal variations in births and tendancy for physical activity in humans.