Weird animal forms (Introduction)

by David Turell , Tuesday, May 17, 2016, 23:17 (3110 days ago)
edited by David Turell, Tuesday, May 17, 2016, 23:38

Since we are discussing how evolution develops lifestyles and oddball results of innovation I've brought up the 8-9 steps to whales, which makes no sense as evolutionary improvements, since in my view all it does is create complexities of how to solve the problems of mammals in water. This article, while looking at the genetics that might have created them, also discusses the many physical adaptations that come with the giraffe:- http://phys.org/news/2016-05-giraffe-neck-clues-revealed-genome.html- "The giraffe's stature, dominated by its long neck and legs and an overall height that can reach 19 feet (~ 6 m), is an extraordinary feat of evolution that has inspired awe and wonder for at least 8,000 years-***-"The evolutionary changes required to build the giraffe's imposing structure and to equip it with the necessary modifications for its high-speed sprinting and powerful cardiovascular functions have remained a source of scientific mystery since the 1800s, when Charles Darwin first puzzled over the giraffe's evolutionary origins," - The giraffe's heart, for example, must pump blood two meters straight up in order to provide an ample blood supply to its brain. This feat is possible because the giraffe's heart has evolved to have an unusually large left ventricle, and the species also has blood pressure that is twice as high as other mammals..... [one of the] giraffe's unique characteristics, including sprints that can reach 37 miles per hour (60 km/h).-***-"The giraffe has an unusual diet of acacia leaves and seedpods, which are highly nutritious but also are toxic to other animals. The scientists speculate that the genes responsible for metabolizing acacia leaves may have evolved in the giraffe in order to circumvent this toxicity."-***-More about the weirdness of giraffes:-https://www.newscientist.com/article/dn19135-zoologger-how-did-the-giraffe-get-its-long-neck/-"Around 15 million years ago, antelope-like animals were roaming the dry grasslands of Africa. There was nothing very special about them, but some of their necks were a bit long.-"Within a mere 6 million years, they had evolved into animals that looked like modern giraffes, though the modern species only turned up around 1 million years ago. The tallest living land animal, a giraffe stands between 4.5 and 5 metres tall - and almost half that height is neck. 
 
"Most people assume that giraffes' long necks evolved to help them feed. If you have a long neck, runs the argument, you can eat leaves on tall trees that your rivals can't reach. But there is another possibility. The prodigious necks may have little to do with food, and everything to do with sex.-"The evidence supporting the high-feeding theory is surprisingly weak. Giraffes in South Africa do spend a lot of time browsing for food high up in trees, but elsewhere in Africa they don't seem to bother, even when food is scarce.-"Male giraffes fight for females by “necking”. They stand side by side and swing the backs of their heads into each others' ribs and legs. To help with this, their skulls are unusually thick and they have horn-like growths called ossicones on the tops of their heads. Their heads, in short, are battering rams, and are quite capable of breaking their opponents' bones."-Comment: Tell me this developed as a drive for improvement. Rubbish. The physiology of mammals shows us that high blood pressure causes hardening of arteries, damages kidneys, results in stokes, in heart failure, etc. The giraffe has modifications so none of this happens. Also other modifications protect it from poisonous acacia leaves. Its tongue is thicker than shoe leather to protect it from acacia thorns. (I've actually felt a tongue while feeding one in Kenya). There is lots of nutritious vegetation in Africa. Why all this bother. And their thick skulls batter other males, I'm sure without concussions. Not all evolution is obvious improvement, but instead a built in structural inventiveness, which doesn't seem to account for the physical complications as deterrents.