Why are the offsprings of some animals large but some small?

Discussion in 'Physiology and Biology' started by Jonybhai, Dec 15, 2009.

  1. Jonybhai

    Jonybhai Larval Mass Registered

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    A human has relatively large offspring compared to a panda, who usually have two very small offspring. Why is this? What are you thoughts?


    Thanks











    photographie culinaire - location camionnette
     
  2. ckeiser

    ckeiser GPO Supporter

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    There are numerous factors, but parental investment strategy is one of the most basic. In the animal kingdom, parents can go one of two ways (with countless intermediates, of course): 1) Have many, many offspring with no parental care, hoping that the dilution effect and pure chance will aid in their survival. 2) Have a small clutch of young, and invest time and energy into ensuring their survival.
    As for juvenile size, I would guess some traits of natural history would affect the size of young, not sure what in those cases though. Good inquiry!
    Cheers.
     
  3. Damien

    Damien O. vulgaris Registered

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    The example of panda is extreme in comparison of mankind, last research about Panda seem to suggest that this species is naturally in way to extinction ( The man had only accelerated it).

    His Digestive tract seems to be still made for carnivore food and not bamboo ...

    At first parental investment strategy is clearly a basic indeed.
    But growth speed and longevity are anothers.

    Some species ( insects) are using parthenogenesis to conquier quicly a territory ( and if there are no close Sexual partner ) and after then use sexual reproduction to provide genetical variations.


    If you want to have an idea of the speed of Population growth speed, you can find some information about humpack whales, who are growing since the moratorium. At the same time you can compare it to others species.

    big animals ( including mammals) on the top of trophic chain are growing slowly in comparison to others species.
     
  4. CrossFire86

    CrossFire86 Pygmy Octopus Registered

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    There are so many factors that can play into this. The human body generally only has one offspring at a time but can have many more such as Octomom, had to throw the ceph joke in there,... but this reduces the chance of survival for all the offspring as less nutrients will be received by each individual and it will not grow as much within the gestation period. Another thing to take into consideration is the gestation period. Generally the longer the gestation the more time for growth. The average Panda's gestation period is about 135 days as where the average human's is around 270 days. More time more growth. Then there is always evolution that plays into things. They are mammals as well as we are and generally in mammals we have fewer offspring and are live bearing and tend to care for young. Panda's have many predators in the wild as well as man hunting them for fur even on the edge of extinction. If they had many of them and they were larger perhaps they would be more vulnerable as where fewer and smaller they are easier to protect in the wild. Maybe they are smaller because their mother's diet consist of primarily bamboo and plant proteins alone are not enough for them to grow on, nutrition could play a roll in it. Countless other speculations could be made but it's always fun to wonder why...
     
  5. ckeiser

    ckeiser GPO Supporter

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    An eloquent (under?)statement. Beautiful in its ability to encompass all forms and functions of life in so few words; indeed I know exactly what you are talking about. Maybe it is the strong winter ales talking, but I much enjoyed reading it.

    Cheers.
     
  6. Teuthman

    Teuthman Pygmy Octopus Registered

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    I do not know if this answers your question exclusively but this sounds very similar to the r/K selection theory in ecology. This theory is based on different strategies that animals use to adapt to their environment and quality of offspring is one of the traits looked at.

    Here is the wikipedia article to give you a general idea: http://en.wikipedia.org/wiki/R-selection

    Hope this helps.
     

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