Human evolution from a scientific stantpoint - Scientific debate, not a religious one

Well nosoul closed the religion topic, but not before blanka was able to make a post concerning the topic of human evolution that I brought up. Thus, I'd like to talk a little more on the topic of human evolution.

This topic is from a SCIENTIFIC standpoint, not a religious one. So if anyone posts here saying something like "ur wrong tho cuz evolutin doesnt exist god made man," then that's gonna be considered spam. I've been in search of a clean, straightforward debate for quite some time now. My debates on BG have more or less run their course, so I figured I'd return to my roots here on this forum. Now, let the human evolution debate begin!

blanka09 said...

Ok.. Let me put it this way.. Humans didn't evolve from chimpazees.. cause if they did.. Why didn't the other chimpazees involve??

There was a special on the discovery channel a year or so ago that I really wished I had recorded. You might be able to find an article about the program on the Discovery Channel website, or possibly backorder a copy of the program.

Either way, that's a good question. If humans evolved from chimpanzees, then why didn't ALL chimpanzees evolve? First, you'd have to take a look at evolution at large.

What causes evolution? The biological definition of "evolution" is the "change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species." (source: http://dictionary.reference.com)

The result of natural selection. Look at wild animals, or more specifically, animals that hunt and live in packs or herds. More specifically, look at creatures such as the wolf, lion and monkey. All three of these creatures are family-type animals. The females protect the children, and the males protect both the females and the children. Now, the males in the pack do not always get along. When this happens, one or more males will challenge the leader of the pack. The loser is exiled from the social group. Sometimes, the loser will be followed by a share of females and children, and strike out on their own. Scientists believe that this is the spark that lit the fuse of the stick of dynamite called "human evolution."

Take a look at a human and a chimpanzee. If you look at a strand of chimpanzee DNA, you will find that it matches a strand of human DNA almost completely, making a match at 99.4% indenticality. Now take a look at the physical aspects. Both human and chimpanzee have two arms, two legs and a head. The head contains two eyes, two ears, a nose and a mouth, in almost exactly the same facial positions. Chimpanzees have tails, while humans do not. HOWEVER, we do have a tailbone, which provides evidence that human beings, lower on the evolutionary ladder, once had tails. But for some reason, we no longer needed them, and eventually evolved to the point where tails were no longer part of our anatomy. Humans and chimpanzees share the exact same internal organs and various systems--nervous, reproductive, digestive. All organs are located in the exact same areas of the body as in humans. Finally, take a look at their brains. Similar brain size and shape (proportionally). They have the ability to think...they can plan, they can solve puzzles, and they have the ability to use simple tools. Socially, they contain the same basic primal social, family and hierarchial traits as basic humans. Both are also very territorial, and will protect their territories and families with fierce savagery.

How can two creatures be so similar, both anatomically and mentally, and yet not be related? Now, for the theory of the human evolution.

Remember what I said above about natural selection? About how one group of creatures from a larger social family will be outcast? Well scientists have conjured up the following theory:

Around five million years ago, there was a schizm in the social structure of a large group of mammals....either a relative of the modern-day chimpanzee or ape or whatever. A large portion of this social structure was outcast, being cast out of the jungles and forests and into the grasslands and plains of africa (where most scientists believe human evolution first began). Over time, these monkeys became bipedal. They learned to balance, stand and walk on their hind legs. The reason for this was so they could peer over the tall grass in order to spot predators. Therefore, the first step of human evolution. Over the next 4.8 million years or so, this large group of human-like mammals continued to evolve, until finally forming homo sapiens around 200 thousand years ago. To be honest, I'm not too sure about the details surrounding the period of time after the outcasts were sent into the grasslands, which is why I didn't specify on anything. Once I find the program or article from the Discovery Channel, I'll elaborate a bit more. But that's what scientists believe. Human beings evolved from an outcast group of chimp-like mammals.

Now, why didn't the rest of the chimpanzees evolve into humans, you ask? Simple....they had already adapted to their jungle- and forest-type of environments. Therefore, no evolution was necessary. The outcast group, however, was suddenly thrust into an alien environment. They had no instincts of how to survive in such an environment, and therefore were forced to adapt and evolve. No evolution was necessary for the jungle chimps because they had already adapted to their environment.

Now an earlier species known as the Australopethicus Africanus or in the early man is where we evolved from. From that to the homo habilis (cause they could handle stuff).. to the homo erectus (cause they could walk straight) and to the present homo sapiens.. (cause they think.. which isn't sometimes good for them.) Now do I believe in what I've just wrote.. maybe.. maybe not. But that's just the origin of the present human beings according to science.

Actually, the origin of present-day humans goes back a little farther than the africanus, and you also skipped a few key stages in human evolution. The origin of present-day humans actually looks something like this:

(source: http://www.onelife.com/evolve/manev.html)


[quote]If infact the science was true and correct and accurate all along, then why haven't the homo sapiens evolved.. after living for such a long time?? These are just some of the questions.. that how should I say.. distorts my belief in science and evolution as the origin of man.

Take a look at the chart displaying the origins of human evolution. The first stage of human evolution lasted 1 million years. The second lasted 300 thousand. The third lasted 1.3 million. The fourth lasted 1 million. The fifth and sixth, which coexisted at the same time, lasted 800 thousand. The seventh lasted 1.6 million. The eighth lasted 200 thousand before we split off into neanderthals and humans, and the neanderthals died off after 170 thousand years. Now I know that adds up to more than 5 million years, but there was some overlapping of species here and there (anamensis to afarensis, afarensis to africanus, and homo erectus briefly overlapped with the existence of both Australopithecus robustus and Homo habilis, which coexisted with each other.

So in the past 5 million years, there have been 10 different species of human in the evolutionary ladder, including present-day humans. Now you say "why havn't homo sapiens evolved?" Well there are a number of answers to that question...

1. We have indeed stopped evolving, due to the fact that we no longer have to adapt to our environment. Due to our technology, we are no longer forced to adapt to our environment, because we now have the ability to make our environment change in order to accustom our needs and comforts. Therefore, evolution is not forced upon us.

2. Evolution is still occuring, but has slowed down (due to the same reason stated above). We no longer have the need to physically evolve, so our brains and mental capabilities will continue to evolve over the millenia. At this moment in time, we are only able to consciously access 10% of our brain. Over time, maybe we will evolve the ability to access even more.

3. Evolution is still continuing, but we just havn't seen any sudden changes yet. Remember, homo sapiens are still young. We have only been around for 200 thousand years. If you do the math, the average amount of time it takes for one specie in that chart to evolve to the next is an AVERAGE of 500 thousand years. We aren't even halfway through that. Therefore, we havn't seen as much change becuase we havn't been around long enough to require change, which gives rise to the BELIEF that we have stopped evolving, which is highly unlikely.



Okay, like I said above, I want a SCIENTIFIC, FACT-BASED discussion here. This topic is NOT about the existence of god, heaven & hell, the bible, the torah, the teachings of Siddharta Guatama, etc. This debate is about the idea of human evolution. If you can't provide facts and evidence to support your case, then don't post.

I'm *HOPING* for an actual debate here. Let's see if anyone can give that to me. I mean, if Hibiki could make a successful topic last year about the theory of relativity, I HOPE i can create a successful topic about human evolution.



Edited By Shauku on Mar. 22 2004 at 18:17