The other day I was looking at a Childrens' Zoology Encyclopedia and I had a random thought:
All the marsupials that live in Australia are more closely related to each other than they are to other mammals. Yet in terms of gross anatomy, each one resembles another common mammal. Koala 'bears", Tasmanian "wolves" (Thylacines), kangaroos, which look like the consequences of a Romeo & Juliet situation between a deer and a rabbit, echidnas which look a lot like hedge-hogs, platypi which are essentially beavers going as ducks for Halloween, etc.
What I am wondering is whether this is evidence of the limitations imposed on evolution either by environmental conditions or fundamental aspects of organic chemistry. Like there are only so many kinds of things that could thrive on planet Earth as it is, or even only a limited number of shapes that you can make with amino acids. Is there a well of untapped creativity in natural forms, or are the things that we see around us the extent of what could be?
4 comments:
Very interesting observation. If all the animals in Australia evolved after they were isolated there, that sounds really interesting. We sometimes think things are limitless, but maybe that's because we don't understand the rules.
his is called convergent evolution by us biologists. It is not a matter of physical limitations placed on the shaping of proteins, as similar ecological niches. There is a top predator, or was, the Thylacines. A top predator is fast and sleek with powerful jaws. You have something that moves into the trees, like a Koala. Something that burrows, like the wombat. If there is an unfilled niche something will evolve to take that place. The kangaroo is different for anything else though.
I see what you're saying, but I wonder if it wouldn't be possible to be successful in a given niche in a variety of ways? Like why are there no animals with wheels? They are way more mechanically efficient. And why is the kangaroo different? Does it hop for a reason related to the landscape, or is it just chance that most animals run, but some hop?
Also, while I respect your and Jeff's engagement of my ideas, I would prefer if you had just noted how funny my cartoon is and moved on.
Post a Comment