Primate Origins

[CDarwin]

This forum seems to be atrophying somewhat, so let's talk about primate origins!

Does anyone have any personal favorite models?

 

I like Rasmussen's idea. He sees the urprimates as mounting to the trees in order to exploit the new resource of fruits on terminal branches, but then evolving other adaptations (such as stereoscopic vision) for exploiting the insect resources that would be disturbed in the course of fruit foraging. It's a sort of synthesis of Cartmill's Visual Predation Hypothesis and Sussman's Angiosperm Hypothesis.

[jackson33]

from what we see in primates today, its hard to imagine any problem in climbing or managing trees. remember this ability was and remains a means for safety against many predators as well. i would rather think the extension of the safety factor, as predators figured how to climb in some manner, the primates for speed, agility and movements between trees finally led to a separation of leg/arm movements.

[CDarwin]

You have to consider the fact that most arboreal mammals don't look like primates. Arboreality can't be the only prime mover in primate evolution. Any arboreal animal is going to have to escape from predators, why do most still have claws, eyes on either side of the head, no post-orbital bars, etc?

[jackson33]

You have to consider the fact that most arboreal mammals don't look like primates. Arboreality can't be the only prime mover in primate evolution. Any arboreal animal is going to have to escape from predators, why do most still have claws, eyes on either side of the head, no post-orbital bars, etc?

 

tree and primates don't take me to mammals in general. in the generic line or what lead to man or the ultimate upright, independent arm/leg my analogy would fit.

 

keep in mind many traits in animals, do change with time and generally for the reverse predator theory. domestic chickens or turkeys do not fly, yet both did at some point, to avoid natural predators, wild turkeys still having limited success.

 

the point of your question, as i understood was; that evolution was in part to food supply which i find faulty, only that the time required would not likely permit most, as supply should either be temporary or that the species would simply die off...99% of species have.

 

my personal interest in the subject are in human migrations and cause, not so much vertebrate evolution, but find the causes similar, in theory.

[CDarwin]

Uhm... what? I don't think we're understanding each other, or at least I'm not understanding you at all.

 

I grant that escaping predators is important, but all animals have to do it, and a lot of animals other than primates have to do it in trees. That doesn't explain why primates are different.

[jackson33]

to escape predators, as opposed cause to pick fruit at higher levels...

[bombus]

Uhm... what? I don't think we're understanding each other, or at least I'm not understanding you at all.

 

I grant that escaping predators is important, but all animals have to do it, and a lot of animals other than primates have to do it in trees. That doesn't explain why primates are different.

 

HANDS. That's the difference with primates. Primates started using hands to grab things. Every other animal uses its mouth, even squirrels which hold things in their paws when eating use their mouths first. I have no evidence for this, but I think it's correct.

 

I can't think of anything else other than primates that uses hands/paws like that. Can anyone think of any other animals that do?

[ecoli]

HANDS. That's the difference with primates. Primates started using hands to grab things. Every other animal uses its mouth, even squirrels which hold things in their paws when eating use their mouths first. I have no evidence for this, but I think it's correct.

 

I can't think of anything else other than primates that uses hands/paws like that. Can anyone think of any other animals that do?

 

Specifically, our opposable thumbs allow us to grab things easily. This is a common school of thought. Also, our brain chemistry allows us to work together and create tools to defeat natural enemies.

 

I think the current idea, is that opposable thumbs came first. Not entirely sure, though.

[CDarwin]

HANDS. That's the difference with primates. Primates started using hands to grab things. Every other animal uses its mouth, even squirrels which hold things in their paws when eating use their mouths first. I have no evidence for this, but I think it's correct.

 

I can't think of anything else other than primates that uses hands/paws like that. Can anyone think of any other animals that do?

 

That is a characteristic of primates. Primates are food to mouth feeders as opposed to mouth to food. We bring things into our mouths using our hands as opposed to sticking our heads down to what we're eating. This however, isn't a universal behavior among primates, nor is it unique to them. Squirrels also tend to feed food to mouth, as do other animals such as otters and many marsupials.

 

Greater use of the hands in feeding, especially in retrieving food, is something that might have served to select for greater dexterity in the hands of early primates, however. Good point.

 

Also, our brain chemistry allows us to work together and create tools to defeat natural enemies.

 

Only a small proportion of primates create tools.

 

I think the current idea, is that opposable thumbs came first. Not entirely sure, though.

 

Opposable thumbs are evident in the earliest adapiod and omomyiod primates from the early Eocence, about 50 million years ago. Tool manafacture is a little harder to pin down. After all, termite fishing sticks don't preserve very well in the fossil record, and if they did, who'd realize it? It could hardly have predated the mid Miocene, the period when you first start seeing really large-brained apes. Maybe 15 million years.

[bombus]

Strangely, the closest (genetically speaking) group to humans other than primates, is the cats. I have seen domestic cats use their paws to scoop food from a tin and bring it to their mouths. Maybe there's more going on there than people have realised!

[CDarwin]

Strangely, the closest (genetically speaking) group to humans other than primates, is the cats. I have seen domestic cats use their paws to scoop food from a tin and bring it to their mouths. Maybe there's more going on there than people have realised!

 

Uhm... no. The closest orders to Primates are those in the superorder Archonta, the treeshrews, bats, and flying lemurs. We're also possibly of some relation to the rodents and elephant shrews, the systematics are kind of fuzzy, but I've never heard that cats are very closely related to the primates, at least not more than any of the other Carnivora.

[bombus]

Uhm... no. The closest orders to Primates are those in the superorder Archonta, the treeshrews, bats, and flying lemurs. We're also possibly of some relation to the rodents and elephant shrews, the systematics are kind of fuzzy, but I've never heard that cats are very closely related to the primates, at least not more than any of the other Carnivora.

 

Alledgedly it's cats by some strange quirk of fate. They are not as close to us as some other animals (cladistically speaking) but for some reason have more of the same genes than anything else.

 

Can't remember how I know this - I heard it somewhere recently, BBC Radio 4 maybe??? It wasn't in a tabloid newspaper! 'Tis true I tell you!

[CDarwin]

I can't find anything about that on the internet... Are you sure?

[PhDP]

Cats ?

 

How ?

 

The order Carnivora is pretty far from Primates. If what you say is true, this is a serious problem for evolutionists.

[Sisyphus]

 

Can't remember how I know this

 

A dream you had, perhaps?

[CDarwin]

Here's an actual article on the subject:

 

Molecular divergence between Carnivores and Primates

[bombus]

I can't find anything about that on the internet... Are you sure?

 

I am sure I heard it recently, I am sure it was on one of the Radio 4 science programmes and it made me sit up. I think the gist was that we share more genes with cats than anything else (other than primates of course) but apparently this doesn't mean we are necessarily closer (evolutionarily speaking) to them. As I said, it's apparently a quirk of fate.

 

However, it may have been April 1st!

 

If there are no references to it anywhere, it's probably nonsense...

[bombus]

Found this...

 

http://www.genomenewsnetwork.org/articles/04_00/cat_humans.shtml

[CDarwin]

Bloody interesting. Excellent find.

 

Cats aren't similar to humans in the content of the actual code, but in the arrangement of the genes on the sex chromosomes. A remarkable convergency.

[D H]

Another article:

http://biology.plosjournals.org/archive/1545-7885/4/4/pdf/10.1371_journal.pbio.0040091-S.pdf

 

The predecessors of cats and humans split when dinosaurs still roamed the Earth.