Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum Extinction of specific shapes like the raptor.

OK Here's the puzzle.
The great extinctions wiped out the dinosaurs. But a few of their shapes survived. Tricerotops came back as a rino although a modern rino is a closer genetic relative to a dog than a triceotops and a triceratops closest living relative is a bird. Ankylasourous made a come back when turtles evolved to tortises etc etc.

But the raptors. The top predators.

In the age of the dinosaurs ALL or the top predators but the crocs ran on two legs. Even in the first age after the cretaceous, (eocene I think) the top predators were flightless birds who hunted on two legs.
But, in the modern age ALL or the top predators hunt on four legs. Why? What long term environmental change occurred.??

The second question, on the same issue, concerns human evoloution. Neandertal man was an ice age hunter. When modern homo sapiens appeared the ice age was waning and man was starting the first farms.
BUT! Homo sapiens, with his longe r arms and legs and greater speed would have been a better hunter and the strong stocky neandertals would have been better farmers. Why did these humans, so much morre suited to farming, go extinct, right when the first farms were being established.

Wierd!!!

I disagree with both of your premises.

The dinosaurs were not wiped out in the great extinction and are doing quite well thank you.

Your assumptions with respect to Neandertal's vs modern homo sapiens are seemingly without foundation.

Truth is no one has a clue as to what aspects of human evolution contributed to the rise of farming from hunter-gatherers.

A few post extincition dinosaur like fossils have been found and he birds are all flying dinosaurs.
But thats not the mystery. The mystery is why almost all of the top predators stopped hunting on two legs and started hunting on four.

We havnt got any conclusions as to the rise of farming communities but we have plenty of clues.
One of the big ones is that the warmer world made more land suitable for cultivation.
Another one is that the mammoth, the giant sloth, and numerous other giant ice age mammals were unable to cope with the warmer climates and died out, leaving the nandartals wihtout a food source, so they had to take to farming.
But even then the question remains. Why did a species, apparently more suited to farming than hunting, die out, right when farming was getting started?

socrates states:
"The mystery is why almost all of the top predators stopped hunting on two legs and started hunting on four."

Why is that a mystery? The top predator on the planet has hunted on two legs for hundreds of thousands if not millions of years.

And would have killed any other predator that dared to challenge it position at the top of the food chain.

Don't believe me? Ask a Neandertal.

The question of a change from two legs to four is still interesting. Humans didn't always use two we suppose, and one exception doesn't change the puzzling question. Maybe if evolution starts with two, it stays at two unless everything is wiped clean, but if so, why.

PMSL
Yea I take your point about the top predator but although that predator hunts on two legs what he really hunts with is tools and a brain. So thats not really a part of the action.
Mammals, which all walked on four legs in the dinosaur age could have evolved two legged propulsion and one species, kangaroos did. But why only the roos and why none of the top predators. ???

Dogrock wrote:
"Humans didn't always use two we suppose...."

Far enough back for it not to matter we have.

socrates wrote:
"what he really hunts with is tools and a brain. So thats not really a part of the action."

Nonsense. All animals have a brain so throw that away immediately. The tools are nothing but an artificial replacement for the teeth and fangs we don't possess.

But if you want a long list of top predators that hunt on two legs you might add a large number of former dinosaurs ... we call them birds.

Right then. We have birds and???
and???
humans, although they have gone from predation to breeding and cultivation.
and???

The main predators are various species of dogs, cats, and bears although the bears eath almost anything. With a few oddities such as heyanas and tassie tigers (now extinct) thrown in. All four legged. A few croc and the occasional anaconda covers most of the big biters.
And no two legged top enders.
And I think you know what I mean by two legged. I mean the top, large, LAND predators. So strike out birds and sharks. At least strike out birds since the eocene or so . The hudge predatory terra birds were a two legged land predator but they are long gone.

What happened to the enviroment to cause such a sudden shift.

socrates wrote:
"Right then. We have birds and??? and??? humans ..."

Well that's one more than existed before isn't it.

Your "main predators" list is nonsense. The main predators are spiders and ants and zooplankton. We are insignificant. Have been and always will be.

You are beating a dead horse. Keep it up if you wish but your arguments are unsupported and unsupportable.

Neandertals where either chopped up or incoorperated into the homo sapien race. We don't know if the two were friendly or hostile towards eachother. Dinosaurs had quite a lot of time to evolvo, the tiger in India is still walking on 4 feet because it has existed for a very short period of time. And it will probably never stand on 2. On the other hand. Some apes eat meat. As do I.

Perhaps the hunter evolved because the hunted evolved.

Most four legged herbivores look as though they were slow, easier for the two legged carnivores to catch (which is why herbivores had to have defenses such as horns and "armor").

But now, most herbivores are four legged and fast. It seems now that most carnivores are four legged, simply because they evolved that way. It seems to me that when it comes to speed that having four legs is an advantage, after all, when was the last time you could out run a rabbit?

So the shape is simply making both the predator and prey faster. Plus if you ezamine carnivorous dinosaurs, they were hunched over, which is sort of the same shape as a four legged animal.

I think some of what I said last might of contridicted some of things i stated early in my post. If this is so then take it easy on my, it was late and this is my first post here. I have to say I feel a little intimidated by some of what you guys (and gals) are saying.

The theory that I was taught (read my signature) is that we evolved to walk on two legs when we moved from heavily forested areas to open plains. We are more suited to walking long distances and standing for long periods (check out your knees locking out when you stand up) this allowed us to see predators at a greater distance. If this is true then when the previous ice age began the forests would have receded meaning that there would have been fewer primary carnivores for the two legged secondary carnivores to consume, the numbers of their food source diminish so do they, and then die out. And up we pop. this may all be rubbish, it's not really my subject.

About the Neanderthals though, is there any evidence that they tried farming. I thought they were only hunter/gatherers until they died out (either though competition or incorporation with us).

www.google.com

search criterion: "Neandertal" and "farming"

You might want to start with the very first link:
www.nhm.ac.uk/education/activities/schoo...n_evolution.pdf