Differences between human and ape

[Glee]

Hey all. So what exactly are the differences between a human and an ape? By reducing each difference down to their component level, why is it considered by some that it is just not possible for humans to have evolved from them? What individual change cannot be the product of 'microevolution', and when does it change to 'macroevolution'?


I shall use the dog as an example for microevolution in some cases, as they all developed from the same 'kind' via 'micro'...

For example:

Skeletal structure? - The number of bones is almost identical at certain stages of development. The lengthening of certain bones and fusing of others really isn't that much of a jump to make in terms of microevolution. If a jack russel and a great dane evolved from the same animal via microevolution, how is this change any different? Same goes for size.

Skull shape? (tied in with skeletal structures)- The difference between a greyhound and a bulldog?

Hair? Really, there are a lot of really hairy people out there, and some that have no hair at all. Is it that far a strectch to image a minor genetic change that reduced the amount, or that once some ansector was that hairy?

Intelligence? See http://www.medicalnewstoday.com/medical ... wsid=31235 - most of the difference in intellignece are because of different levels of hormones in the body. The hormones are all there, just different quanitites regulate the size of growth and brain development. We have many genetic conditions today which create different levels of hormones which influence intelligence, growth and development within humans already today. Is there really that much of a difference?


Is there any single change which is not possible between the two? Where is the line drawn for microevolution?

[McCulloch]

Time
According to creationist population growth mathematics, 4000 years is enough time for a population of humans to grow from 8 to 6 billion. (8 - 6,000,000,000 - just to see it expanded) Exponential growth of apelike species, with faster brithrates, earlier sexual maturity but lower expected life expectency would probably result in a similar growth pattern...

Umm, yeah, except that Creationist "population growth mathematics" (is that different from regular mathematics?) would have there being about 1,000 people to populate the entire Earth and maybe a few dozen of them to build the Pyramids, and only several hundred thousand humans in existance when we know Rome alone had a population of 1,000,000. Exponential extrapoloations work great in theory, but tend to fail in real life.

Using constant exponential growth from 8 people 4000 years ago to 6 billion now, we would have a world population of about 220,000 at the time of the Roman empire; and about 450 million at the time of the Spanish discovery of America and 1.9 billion at the time of the signing of the American Declaration of Independence. I think that we can safely rule out a constant exponential growth of human population using the YEC model.

[Glee]

Wow. That reply came off as especially bitter... so in reply let me first say:

Carnac holds the envelope to his turban - "What is pi** and vinegar?"

Well, your whole premise is faulty since we know that all dogs are the same species effected by human selection, but we don't find some dogs with curved spines and others with straight ones. We don't find some dogs with splayed knees, but linear shoulders but others not, as we do with chimps and humans. And don't find virtually identical carpal structure, but different tarsal structure in dogs like we do with humans and chimps. Oh, and there's a very important skeletal structure, but since you're trying to get to much mileage out of this issue....

The premise is not faulty because the example of dog evolution shows an example of the flexibility of 'microevolution', whether it be by human selection or natural selection. It shows a great amount of change within a very limited time span (4000y by creationist reconing) and thusly a great amount of potential change over longer periods of time. Of course since these animals are of the same species and very time limited the amount of variation between them will be less than that of between species, but it does show how selective breeding within the same gene pool can lead to great changes in size and shape of an animals skeleton.

Curved spines should be a natural result of using constant bipedal locomotion. It is possible to inflict a curved spine on an animal purely by keeping them in a curved position for a long time, here, for reference. Surely a creature that spends more and more time in a standing position (which would naturally put pressure on the spine), and a selection process that favors creatures with curved spines, would result in a speices that may have a curved spine?

Skull shape? (tied in with skeletal structures)- The difference between a greyhound and a bulldog?

Oooo! It was almost painful to read this. Do you know what the Foramen Magnum is? I'm assuming you don't since it eviscerates your argument. It's the hole at the base of the skull that allows the brain stem to connect with the spinal collumn. In quadrapeds, it's always posterior, but in bipeds, it's ventral. (Keep in mind a biped ventral is it's feet, not it's frontside) In Chimpanzees the Foramen Magnum is mostly posterior, but in each of the skulls we find of Australipiticus and Homo species we find, it moves progressively to the ventral.

Such a progression is exactly what we'd expect from evolution and common ancestry.

Wow. Just wow. No, i wasn't aware of the Foramen Magnum, so i went and googled it. Amazing stuff. Found a nice little picture of it here: http://www.amonline.net.au/human_evolut ... e_info.htm . Moved a whole lot towards the base of the skull. Note the sarcasm. Man, totally eviscerated. Guts out everywhere.

Actually, i think we are on the same side.

Go check those bulldog/greyhound skull pic links, shouldn't be too hard on your 56k, not much else on the pages. The amount change that is recognised by creationists to be possible within 4000 years is much greater than the expected change that a ape to human skull, Foramen Magnum included. It is interesting to note the movement, but the mere growth of crainal capacity would also help push the FM towards the centre as well.

This is rediculous. By this logic, since whales, manatees and rhinos are as comparatively hairless as humans, they were either specially created or are not mammals since one of the phylogenetic parts of being mammal is being covered with hair. And humans are covered with hair despite what Playboy would have us believe. Well, except for around our eyes (excluding eyebrows) on our palms and feet... just like chimpanzees.

All creatures were specially created, didn't you get the memo?

Sorry if it wasn't made clear, but this debate is trying to restrict itself to the creationist limitations of microevolution but maintaining evolutionist time periods, to see what about the evolution from ape to human is so impossible. The 'loss' of hair (sorry, i should have said reduction in hair thickness and length) would be easily explainable by microevolution, so I see no problem at this point. No special creation required to create the species because of hair quality difference.

Your intelligence objection isn't worth consideration because giving a Stanford-Binet to a Frenchman, New Guinea highlander or Honduran Mayan is about as worthless as applying human intelligence standards to a Chimp, Gorilla, Orang, Gibbon, Dolphin, Bandicoot or Rat. There are definate analogies to be drawn, but unless we can really communicate with these species in their language, we really have no idea about their level of intelligence.

You raise an interesting point in that human intelligence standards would be a worthless comparison, but looking at the change in brain size from chimp to human, what evolutionary process could explain the change in brain size? The link I posted gave the difference as merely a change in the
thyroid and sex steriods in the body at certain periods of time were the only changes necessary to increase the size of the brain - possible with microevolution, therefore, not a point of conflict with the evolution of ape to man.

The question put is: Is there a single change in the evolution of Ape to Man that cannot be explained by microevolution? So far most of the changes seem possible. Do you have any that aren't?

[Glee]

Time
According to creationist population growth mathematics, 4000 years is enough time for a population of humans to grow from 8 to 6 billion. (8 - 6,000,000,000 - just to see it expanded) Exponential growth of apelike species, with faster brithrates, earlier sexual maturity but lower expected life expectency would probably result in a similar growth pattern...

Umm, yeah, except that Creationist "population growth mathematics" (is that different from regular mathematics?) would have there being about 1,000 people to populate the entire Earth and maybe a few dozen of them to build the Pyramids, and only several hundred thousand humans in existance when we know Rome alone had a population of 1,000,000. Exponential extrapoloations work great in theory, but tend to fail in real life.

Using constant exponential growth from 8 people 4000 years ago to 6 billion now, we would have a world population of about 220,000 at the time of the Roman empire; and about 450 million at the time of the Spanish discovery of America and 1.9 billion at the time of the signing of the American Declaration of Independence. I think that we can safely rule out a constant exponential growth of human population using the YEC model.

The whole point of bringing creationist population growth models to the table is to use an accepted piece of creationist mathematics as a basis for building an arguement that is irrefutable by the people that use those numbers themselves. You have to go and spoil it all.

[jcrawford]

Glee, now that we've got our chimps standing upright with shorter arms, searching for prey amidst African grasslands, how do we get rid of their facial hair, funny noses, enlarged ears, and enlarge their brains in order to make them a little more presentable as primitive ancestors of African people on the Hominidae family tree in Africa?

I trust that you take neo-Darwinist beliefs in human evolution out of chimp-like critters in Africa seriously and can show us how African people were 'naturally selected' by neo-Darwinists to evolve from non-human species in Africa. After all, I just showed how their legs got longer and stronger while their arms got naturally shorter.

[QED]

Glee, now that we've got our chimps standing upright with shorter arms, searching for prey amidst African grasslands, how do we get rid of their facial hair, funny noses, enlarged ears, and enlarge their brains in order to make them a little more presentable as primitive ancestors of African people on the Hominidae family tree in Africa?

I think you'll find the answer lies in sex appeal. If you need any reminding of how this works please ask and I'll elaborate for you.

[jcrawford]

Glee, now that we've got our chimps standing upright with shorter arms, searching for prey amidst African grasslands, how do we get rid of their facial hair, funny noses, enlarged ears, and enlarge their brains in order to make them a little more presentable as primitive ancestors of African people on the Hominidae family tree in Africa?

I think you'll find the answer lies in sex appeal. If you need any reminding of how this works please ask and I'll elaborate for you.

Are you suggesting that the chimps with the longer and stronger legs which enabled them to stand up longer in the tall grass found each other more attractive than shorter chimps and naturally selected those whose more developed legs resembled their own to mate with? It seems to me that the male chimps with longer stonger legs would go after the female chimps with shorter, weaker legs because they could catch them easier.

How would sex appeal alter the facial physiognomy of chimps to look more human though? And why would chimps with less facial hair, smaller and lower ears, smaller jaws and teeth, protruding noses and bigger brained skulls necessarily have more sex appeal than less evolved chimps? Why wouldn't they be regarded as mutants to the lesser evolved chimp community and be shunned or cast out of the main group?

Would all chimp facial features gradually evolve into more human ones all together equally at the same time or would some chance genetic mutation first cause the nose to become more prominent in the first generations to be followed by smaller and lowered ear adjustments in subsequent generations? After all, a chimp with a human nose might look like a freak to the rest of the chimp family especially if it spent more time standing up on it's hind legs than ambling around on all fours.

[QED]

Selection of sexual partner is just one of many selection pressures but I think it's pretty obvious how it accounts for a large degree of the aesthetic. There are plenty of conclusive studies that show how choice of mate drives the appearance of animals into weird and wonderful places. But I think we all know this for ourselves anyway. Fads and fancies are the stuff of history -- and of culture. I'm sure we've all wonder at what some considered to be attractive in the past and in different societies. It's also clear that tastes in such matters are inherited. Add a little random variation and plenty of time... you know how it goes.

Quite often the pressures to be practical while maintaining a breeding partners interest come into conflict. Peacocks would be a good example of this. That sexual selection based on arbitrary aesthetic criteria plays a big role in shaping the individuals of a species is also supported by the dramatic differences seen between male and female birds. In this case the female's the one dong all the choosing so what they look like is of lesser consequence. The males are the ones who's appearance is driven the most.

[Glee]

There is also the possibility of a female dominated society where, obviously, the female gets to chose the mate, see bonobos for this example. Therefore the selection of partners would not be the rape/chase the female with the shorter legs scenario that you put forth, rather that of slightly more mature partner selection. Such as, the dominant female choosing the healthiest male, etc.

As far as i know monkeys have reservations about the whole rape thing to an extent, as they would prefer to trade food or the like for sex... Then again, mutants can potentially rape too to pass on their genes.

If the mutation is so severe that they are shunned and cast out of the main group, then this can lead to evolution as well. Isolation is another accepted factor that can drive evolution, and as long as this 'mutant' has male/female company and survives to have children, all decendants will have those genes.

[Jose]

Are you suggesting that the chimps with the longer and stronger legs which enabled them to stand up longer in the tall grass found each other more attractive than shorter chimps and naturally selected those whose more developed legs resembled their own to mate with? It seems to me that the male chimps with longer stonger legs would go after the female chimps with shorter, weaker legs because they could catch them easier.

How would sex appeal alter the facial physiognomy of chimps to look more human though? And why would chimps with less facial hair, smaller and lower ears, smaller jaws and teeth, protruding noses and bigger brained skulls necessarily have more sex appeal than less evolved chimps? Why wouldn't they be regarded as mutants to the lesser evolved chimp community and be shunned or cast out of the main group?

Would all chimp facial features gradually evolve into more human ones all together equally at the same time or would some chance genetic mutation first cause the nose to become more prominent in the first generations to be followed by smaller and lowered ear adjustments in subsequent generations? After all, a chimp with a human nose might look like a freak to the rest of the chimp family especially if it spent more time standing up on it's hind legs than ambling around on all fours.

Why do you speak of chimps turning into humans? Even evolutionists recognize that this isn't what evolutionary theory indicates.

It might be better to think of various features, and then compare the ancient pre-chimps' environment and the ancient pre-humans' environment, to see why chimps went one way evolutionarily and humand went a different way. You speak of pre-humans (which you called chimps) on the grasslands. Pre-chimps were in the forests. The common ancestor of both was in the forests, so it seems that the pre-humans wandered out onto the grass.

Were there predators on the grasslands? Could it have been helpful to be able to run quickly back to the edge of the forest and get behind (or in) a tree? It's hard to run fast if your arms are long and your legs short, so running would have been a selective pressure that enabled those with longer legs and shorter arms to avoid being eaten. Running also selects for large butts, since butt muscles are important for running.

It would also be helpful to be able to walk (or run, as needed) long distances in search of food on the grasslands. In the forests, it's better to climb. There's selection for toes that can hold onto trees pretty well in the forests, but no such selection on the grasslands.

But there would be selection on the grasslands for losing excess heat. Sparse hair might be selected for. There would not be such selection in the forests.

Food in the grasslands is more likely to be meat than berries, so we'd take a tip from the archeology and say pre-humans became pretty good hunters. That fits with running a lot--and it also provides selection for being fairly thin. You can't run fast and far with a big gut full of herbivore-type intestines. But if you're a hunter, you can tolerate mutations that make your intestines shorter--and you can run better and hunt better with a shorter intestine.

If this results in having to obtain vitamin B12 from meat instead of directly absorbing it from your intestinal bacteria, that's OK--because you're a hunter. [I suppose we could have acquired the instinctive behavior that dogs have, and eat feces to give the intestinal bacteria a second chance at releasing B12, but there were probably selective pressures against this behavior, and they won.]

In the forests, where our siblings were eating leaves and fruits, and not running, a long intestine would be necessary. It just plain takes longer to extract nutrients from plant cells, because of that danged cell wall. Herbivores have longer intestines--and they can, therefore, absorb B12 in sufficient quantity. [That's why we can get B12 by eating herbivores.]

So, you don't need to look at sexual selection (or rather, selection by mate choice) for explanations of all of the things you've mentioned.

But what might be a result of selection via mate choice in humans? Well, think about the features of members of the opposite sex that you pay particular attention to when determining whether they are "attractive." Then, think about features of your own that you worry about inordinately when considering your "attractiveness" to others. What one thing pops out as particularly important?

Did everybody say "hair"?

We are just about the only mammal that has hair that grows continously. It's just on top of our heads. Elsewhere, our hair is well-behaved, like that of other mammals. But on our heads, it grows and grows and grows. We worry about it a lot. We look at others' hair a lot. We talk about "bad hair days." We never talk about "bad elbow days." It seems to me that hair appearance is a good candidate for selection by mate choice. We use hair as one of the measures of attractiveness. After all, "blondes have more fun" according to Clairol.

[Cathar1950]

I am not sure if we can say sexual selection is all of it. Just a big part...lol
I think the "out of water" theory is interesting and even makes some sense. The jury is still out. But it is interesting.
Did JW say women had shorter legs so we could catch them?