[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: ... vs energy deficient gigantothermy (boo hiss)



Randy Irmis (rbi@dana.ucc.nau.edu) wrote:

<Ummmm....if you look at all extant mammals, they follow the
trend that as body size increases, litter size and frequency
decreases.>

  Not neccesarily. Yes in marine animals, but terrestrial
predators do not follow this pattern. The largest predatory
mammals have the same relative litter count as quarter-sized
mammals. A house cat and a lion, for instance. Large herbivores
have an effective need to either produce numerous young to
ensure that some succeed the generation, or one or two
heavily-invested young that are well-protected from predation so
that succession is virtually insured. This appears irreletive of
size.

<The real advantage that archosaurs have is when environmental
pressures on a population rear their head.>

  It is singularly advantageous when environment works to one's
advantage, wether one is archosaurian or mammalian. In optimal
conditions, all organisms prosper.

<Because of the large reproductive capacity of large archosaurs,
they can rebound much faster than a large mammal.>

  This is because, as Bakker puts it, a cold-blooded animal is
restricted environmentally and geographically where changes that
occur are minor. We find the most changes in heavily influenced
areas that are inhabited by reptiles (including archosaurs) that
are not corrolary to mammals due to environment-dependant
metabolism and thermobiology. Even mammals in extreme
environmental conditions (including man-influenced, but also
arctic, etc.) are prone to more changes influenced by their
environment than those in more temperate regions. Consider the
caribou relative to the wildebeest. While Wildebeest must deal
with more predators, environment does not affect as much as
arctic climes do, where the environment is claimant to caribou
in greater degrees than wildebeest are subject to. In optimal
conditions, an Australian freshie probably has it better than an
American 'gator.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - buy the things you want at great prices
http://auctions.yahoo.com/