MadSci Network: Evolution

Re: your opinion of evolutionary anomolies? (maybe Zoology)

Date: Tue Sep 27 22:19:55 2005
Posted By: dave armstrong, Faculty, Biology, Cricklade college
Area of science: Evolution
ID: 1121491220.Ev


Evolution, by its very nature, has thrown up many organisms which basically go against the flow. Your examples are just a few.

If we can add the green plants to your interests, just think about those that behave a little like predators by trapping extra "nitrogen" in their leaves. The American Venus' Fly Trap (Dionaea sp.) is most likely to be known to you. Dwarf trees, too, evolved not to please bonsai experts, but to form true species designed to live in places such as the top of mountains where it would be downright absurd to grow above a low level. Your example could be Dwarf Birch (Betula nana) which doesn't appeal to the bonsai faction because it spreads itself out for mutual protection.

The animals and other groups have evolved completely to rely on others for energy. How selfish! That means that any useful form of chemical energy can be exploited, which is probably why we are looking for life among the hydrocarbons of Titan. We know so little about fossil creatures and how they were specially adapted, it's best to stick to those we know a little more about.

For example, we have some simple knowledge of the power of one giant bird from old Maori accounts, and its bones and feathers from the most recent dead. Animals always seem so wonderful and almost mythical when they are just out of reach — they might well be absolutely boring when you have them for breakfast every day. Anyway, the Moa was killed off by the newly-landed Maori after it had had the islands of New Zealand to itself for millions of years. It was 3 metres high (twelve feet) and pretty wide too, with a beak that must have killed a lot of people. The most amazing fact that is almost mythical is that there was really only one predator that arrived by air before the Polynesian Maori. As we argue, if there is an energy source to be expolited, then organisms will adapt to predate upon it. The New Zealand eagle is the largest ever known but of course became extinct when its main food source was killed off. How big it was and how it dealt with the beak of the Moa is one of those stories that would have to come out of the Greek myths. We can, however, look at the many flightless birds of the unique protected New Zealand fauna and try and work out all of the feattures of their precious lost ecosystem before they are all threatened with extinction.

I'll try and get you some more information on these creatures if you are interested. Meanwhile, simply enjoy your Mammalian anomalies as you do. These last 65 million years have produced big changes in our nearest relatives, and the most familiar ones could even turn out to be the most fascinating. There have been adaptations that worked for a while and then became uncompetitive when the new model came out. For instance, study how present-day baleen whales evolved completely seperately from the toothed whales to present us with a double take on huge marine Mammals that is probably the most successful and therefore the most amazing evolutionary move among the animals. Consider too, how the land-living ancestor became more and more aquatic. It is more useful to study living animals because you can access all of the facts. Go to the Galapagos finches and see if they are really adapted like the vampire bat. Then you can decide for yourself whether they are a unique bird or just an experiment to take advantage of a vacant niche in the island ecosystem.

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