Evolution FAQ

Century Soldier Joined: 15 Feb 2008 Posts: 124

Guru Parasky wrote:

Humans generally have no real defenses against predators; no claws, fangs, sharp teeth, poisons, armored skin, quills, stingers, ect. To cope, our first ape ancestors developed hips that allowed them to walk on their hind legs. This allowed them to see predators at a greater distance, and subsequently, escape before they were killed.

Parasky, your description is of modern humans. The hominid ancestors that first evolved bipedal locomotion were quite different from us, and were more similar to chimpanzees. They had somewhat sharper incisors, and were probably stronger. Other than that, neither chimps nor most other primates have claws or poisons or armored skins or stingers, yet none of them evolved to walk upright either.

The hypothesis that is currently best supported for bipedalism has to do with a changing environment. Most of Africa was at one time dense forest, such as the native habitat of chimpanzees. But the climate began to change, and the forest became grasslands with small patches of trees separated by relatively large distances. In order to eat, our ancestors had to travel a lot farther than they did before. And bipedal walking is far more efficient for long distance travel than the quadrupedal walking of chimpanzees - as has been show with comparative metabolic analyses of humans and chimps walking on treadmills (apparently, juice boxes were key to getting the chimps to be cooperative with the treadmills. :p).

Quote:

They also began using "tools" to fight off predators; throwing rocks and sticks to make up for their lack of defensive body parts. Pretty soon we learned that we could use the same method to kill animals (before we were just scavangers). This lead to the development of a more complex brain (with the added protein) and soon we discovered stone tools.

There are several hypothesis about why humans became so intelligent, and it was likely a combination of things. A lot of studies on social animals suggests that increasing social complexity may have promoted the development of more complex brain functions; many of the most intelligent animals on the planet have quite complex social lives - humans, the great apes, dolphins, elephants, etc.

Hunting and technology probably interacted with social complexity to further our brain development. As I mentioned above, finding food become more difficult for our ancestors, so scavenging for meat as an additional food source was beneficial. A higher energy food source allows for greater brain development, and greater brain development combined with our hands now being free thanks to bipedalism allowed us to make better use of technology, and to begin more active, more effective hunting, bringing us even greater amounts of high energy food allowing for even further brain development. Hunting is aided by cooperation and social interactions, which may also have increased in complexity.

There is still debate on the specifics of this course of events, but it most likely involved a kind of interaction of many different factors as I described above.

Quote:

As the ice age began to end (over several generations, mind you) we lost our fur, we didn't need it anymore. At that time humanity still lived in Africa, but when we followed our animal herds (we followed them for food) over the mountains into Europe, we lost our skin pigments (over time). By the time they were in Europe, they still had slightly dark skin. This is why Europeans are white (some are a bit darker) and Asians are a slightly darker color.

I'm not 100% on this, but I'm quite sure that we had lost our fur long before the beginning of the most recent ice age. Not to mention the fact that for equatorial African regions, ice ages bring dryness, not cold. And it probably was an ice age that contributed to the drying up of our ancestors' dense forests. Additionally, most animals, including primates, have light skin under their fur. It is likely that we lost our fur while still in hot Africa, and had to evolve darker skin in order to protect ourselves from the sun.

It was after the migration to Europe when, as you said, skin again evolved to be lighter. Melanin production is costly and will not be maintained if it doesn't bring a reproductive advantage; indeed, in more northern regions, darker skin can actually cause harmfully low levels of vitamin D.

Posted: Fri Feb 15, 2008 11:54 pm

For once, I'm not angry I was just totally destroyed. I learned from it, most of the time people just call me stupid or ignorant and tell me I'm wrong. You actually explain it to me, I happen to like that.

I'm happy to share the same first four letters of an internet alias with you...I guess...

Besides, I don't know much about human biological history (I'm an Eosapien Tongue

).

Leper Messiah Joined: 21 Mar 2007 Posts: 4117

this is weird.. such a big post, such potential argument! yet i find no flaw in the logic. i want to debate.. but it's like i wrote it! doesn't make sense Sad

never thought i'd say this, but i wish there were more christians on this board

someone advertise us at some jesus site

Posted: Sat Feb 16, 2008 12:00 am

Sorath wrote:

this is weird.. such a big post, such potential argument! yet i find no flaw in the logic. i want to debate.. but it's like i wrote it! doesn't make sense Sad

never thought i'd say this, but i wish there were more christians on this board

someone advertise us at some jesus site

I could clone Extra, would that help?

Posted: Sat Feb 16, 2008 12:01 am

And Sorath, I live in Kansas; the beating fucking heart of the bible belt (I hate living here), and you want me to find Christians? In a place that is 99% Christian and boring as hell? Sure, let me just go put up posters.

Century Soldier Joined: 15 Feb 2008 Posts: 124

Sorath wrote:

this is weird.. such a big post, such potential argument! yet i find no flaw in the logic. i want to debate.. but it's like i wrote it! doesn't make sense Sad

never thought i'd say this, but i wish there were more christians on this board

someone advertise us at some jesus site

haha, if you want to debate me, do some research and check how accurate my claims are. I wrote that off the top of my head, so I could be incorrect on some issues. Besides, then you'll become that much more knowledgeable in the subject, and there's no downside to that!

You know, if you really want to argue, I really recommend you check out Science Forums. I'm flattered that you're all so impressed by me, but I'm really just one of many sharp, quality posters at that forum, and they have a lot more to offer than just little ole me. And just wander into the religion forum if you're really up for an all out brawl - er, debate.

Posted: Sat Feb 16, 2008 12:15 am

lol

Just go to the religion section here for a riot-er braw-er debate.

Century Soldier Joined: 15 Feb 2008 Posts: 124

Guru Parasky wrote:

lol

Just go to the religion section here for a riot-er braw-er debate.

ah - you guys have them too, eh? Well, I shouldn't be surprised. They do outnumber us, after all. I just don't like to dwell on the fact because it's so depressing.

Posted: Sat Feb 16, 2008 12:21 am

Yea, they get out of control quite often.

Leper Messiah Joined: 21 Mar 2007 Posts: 4117

depressing? naw! it's fun!

Posted: Sun Feb 17, 2008 6:43 pm

Sorath wrote:

this is weird.. such a big post, such potential argument! yet i find no flaw in the logic. i want to debate.. but it's like i wrote it! doesn't make sense Sad

never thought i'd say this, but i wish there were more christians on this board

someone advertise us at some jesus site

What does Christians have to do with what Paralith said?

Lazy-ass Joined: 18 Feb 2008 Posts: 17

Paralith wrote:

The hypothesis that is currently best supported for bipedalism has to do with a changing environment. Most of Africa was at one time dense forest, such as the native habitat of chimpanzees. But the climate began to change, and the forest became grasslands .

My understanding is that this hypothesis is being called into serious question. The timing of the emergence of bipedalism and the transition to savanna simply do not gel. Some other driving force for the origin of bipedalism must be sought.
The bipedalism of humans is different in character to that of the chimpanzees, which is why they waddle in a bowlegged fashion, whereas we walk rather gracefully. (Consider Elle McPherson on a catwalk.)
This can be explained by an adaptation of a climbing behaviour, rather than the brachiation favoured by chimps.
An alternative exlplanation, though one that raises the anachronistic hackles of antrhipologists, is the aquatic ape hypothesis. This considers such diverse issues as bipedalism, depletion of body hair, body hair patterns, breathing peculiarities, birthing habits, brain expansion and the like, and relates them to a semi-aquatic lifestyle.

Guru Parasky wrote:

There are several hypothesis about why humans became so intelligent,

And one of these is that the diet of fish favoured by the aquatic ape favoured the development of the brain.

Lazy-ass Joined: 18 Feb 2008 Posts: 17

Paralith wrote:

The hypothesis that is currently best supported for bipedalism has to do with a changing environment. Most of Africa was at one time dense forest, such as the native habitat of chimpanzees. But the climate began to change, and the forest became grasslands .

My understanding is that this hypothesis is being called into serious question. The timing of the emergence of bipedalism and the transition to savanna simply do not gel. Some other driving force for the origin of bipedalism must be sought.
The bipedalism of humans is different in character to that of the chimpanzees, which is why they waddle in a bowlegged fashion, whereas we walk rather gracefully. (Consider Elle McPherson on a catwalk.)
This can be explained by an adaptation of a climbing behaviour, rather than the brachiation favoured by chimps.
An alternative exlplanation, though one that raises the anachronistic hackles of antrhipologists, is the aquatic ape hypothesis. This considers such diverse issues as bipedalism, depletion of body hair, body hair patterns, breathing peculiarities, birthing habits, brain expansion and the like, and relates them to a semi-aquatic lifestyle.

Guru Parasky wrote:

There are several hypothesis about why humans became so intelligent,

And one of these is that the diet of fish favoured by the aquatic ape favoured the development of the brain.

Century Soldier Joined: 15 Feb 2008 Posts: 124

See, guys? A little research and boom! Something to argue with me about.

Right you are, Obducted. I looked up the timelines, and the first appearances of bipdalism are as old as 4 mya, whilst the drastic changes to Africa's environment occurred between 2 and 1.5 mya. I found This article, which is a review of studies on human locomation, and a lot of the physical evidence does seem to suggest that bipedalism evolved from an arboreal form of locomotion, and not from a quadrupedal stance.

I have to say, I have my doubts about the aquatic ape hypothesis. I don't doubt that needing to maneuver in water would explain a lot of our traits - I just doubt why maneuvering in water would be so advantageous in the first place. For it to shape so many of our physical traits, it would have to be significantly important to our ancestor's reproductive success, and I just don't see how that could be. Only because there's not enough evidence at this point, though. I'm definitely leaving it open to possibility. There's just very little way to support or refute it at this point.

Leper Messiah Joined: 21 Mar 2007 Posts: 4117

i remember reading a more recent approach to the question of bipedal evolution - interestingly, these people thought the ancestry took up walking to fix chronic back problems. this is one of those discovery-type events in evolution. where it's not so much foreseen, but just a little lull in the logic of evolution's linearity. kind of like that hammerhead theory; the first hammerhead shark was an odd mutation. luckily, although however unbelievably rare the chance, this new mutation was very suitably adapted to its given environment. i realize there are some flaws here, but its inspiring nonetheless. it's more or less the same concept with the humans-survive-more-comfortable walking upright.. except instead of an insane genetic mutation triggering the new quality, it was just a different approach to their lifestyle.

Lazy-ass Joined: 18 Feb 2008 Posts: 17

Paralith wrote:

I have to say, I have my doubts about the aquatic ape hypothesis.

I have doubts too, as befits any properly skeptical stance on any hypothesis. What I like about it is:
1) Novelty - I like new ideas. This is a purely subjective basis for favouring a hypothesis, obviously and has more incommon with religion than science.
2) Elegance - the elements of the hypothesis blend together in a pleasing fashion. Often good theories are beautiful theories.
3) Opposition - rejection of the theory by many anthropologists appears to be based more on the source of the hypothesis - someone outwith the profession - than upon solid science.
4) Attenborough - populariser of the biological wonders of the planet through many BBC television series is solidly intrigued by the concept. I like Attenborough. Smile

None of these is in anyway evidence for the hypothesis, they are merely explanations of why I choose to take an interest in it. (Thank you for confirming the bipedal - savanna timing mismatch. I was working on a vague recollection rather than a published source.)

Lazy-ass Joined: 18 Feb 2008 Posts: 17

Paralith wrote:

I have to say, I have my doubts about the aquatic ape hypothesis.

I have doubts too, as befits any properly skeptical stance on any hypothesis. What I like about it is:
1) Novelty - I like new ideas. This is a purely subjective basis for favouring a hypothesis, obviously and has more incommon with religion than science.
2) Elegance - the elements of the hypothesis blend together in a pleasing fashion. Often good theories are beautiful theories.
3) Opposition - rejection of the theory by many anthropologists appears to be based more on the source of the hypothesis - someone outwith the profession - than upon solid science.
4) Attenborough - populariser of the biological wonders of the planet through many BBC television series is solidly intrigued by the concept. I like Attenborough. Smile

None of these is in anyway evidence for the hypothesis, they are merely explanations of why I choose to take an interest in it. (Thank you for confirming the bipedal - savanna timing mismatch. I was working on a vague recollection rather than a published source.)

Posted: Tue Feb 19, 2008 7:06 pm

True, new ideas do us much good, much like mistakes and coincidences do.

For instance, back in WW2 the Germans developed a code based on different combinations of 1's and 0's (binary code) and mathematical algorithms. The Allies, unable to break this new code, ordered a bunch of mathematicians from various nations to get together in a bunker and crack the code. To help break this new code, the scientists and mathematicians invented a handy little machine that could have data inputed into it, and could quickly do math efficiently. They called this handy little (wasn't actually little, it was huge) device a computer. Today, we wouldn't even be having this conversation if WW2 never happened.

Posted: Wed Sep 23, 2009 12:33 am

I apologize already for what is going to be a rather simple question, but:

What is the difference between micro and macro evolution?

Posted: Sat Sep 26, 2009 12:35 pm

Micro evolution deals with changes in genetic frequency and macro evolution is like when an elephant fucks a giraffe and you get some freaky elephant-giraffe thing.