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Macroevolution-Do people come from apes?

Debate and discussion of any biological questions not pertaining to a particular topic.

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Macroevolution-Do people come from apes?

Postby Chris » Tue Nov 23, 2004 8:29 pm

I personally think this notion is absurd. But I am curious to see other people's opinions on this. What do you think?

(For those of you unaware of what macroevolution is...it is the notion that one species can evolve into a brand new species- I.E. monkeys to humans)
Chris
 

Postby Chris » Tue Nov 23, 2004 9:12 pm

Please understand that I never made any claim of idiocy toward anyone. Just the general idea that a monkey can turn into a person. I am sorry if I came off the wrong way but I certainly never meant to offend you or anyone for that matter with my statements. Now that I have said that, I would like to see if I understand what you are saying correctly. You believe that apes and humans have the same common ancestor. What would that be though? Are you saying that every species of hominid came from one original species? Also, you said that no scientist would ever make the claim that humans evolved from apes...however I recall old Darwin forming some kind of theory about it. So you can't say the claim has never been made because it is out there and many people believe it. What I am trying to understand is, simply, how would one species go about evolving into a new one. I mean, with your wolf example, both species are still wolves. I am talking about a complete change...like frog to bird (completely hypothetical example there). What do you think? Once again, please don't take anything I say as a direct threat to you as a person.
Chris
 

Postby biostudent84 » Tue Nov 23, 2004 9:38 pm

Sure, they are both wolves...but the wolf is an entire group of species that we give the same name. They are still different species. Where you said "Are you saying that every species of hominid came from one original species?" I did mean that...SOMEWHERE along the line, this happened. And that one species was grouped together coming from one other species and so on and so on.

When looking at macroevolution, you really do need to take a huge step back and understand the entire picture before even being able to address individual happenings such as humans.

Have you heard of the archaeopteryx? (forgive me, I know that's spelled wrong). It was a skeleton of a lizard/bird. What phylum do we put it in? We can't...because in biology, (evolution especially), EVERY rule has thousands of exceptions. Most believe this is a transitory species between two phylums. Similar to dinosaurs...lizard/birds. We always say that dinosaurs were more closely related to birds...but no one can refute that they were at least partially related to lizards =).
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Postby Chris » Tue Nov 23, 2004 9:47 pm

But how do you know that these aren't just similarities. It doesn't necessarily mean that they came from the same species. Maybe apes and humans are just similar. But you need to realize there are several differences as well. So maybe there is no relation. Maybe they never were related. It says in the Bible that lizards and birds were created seperately. So have you ever considered this?
Chris
 

Postby Chris » Tue Nov 23, 2004 9:49 pm

And yes, you are right. No one can refute that last statement of yours...but at the same time no one can prove they have any relation either...
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Postby Chris » Tue Nov 23, 2004 10:11 pm

I don't know if you know this or not, but evolution relies on the fact that mutations are selected for in every species. 99% of every genetic mutation is detrimental to the species. the odds of macroevolution taking place are astronomical even given billions and billions of years.
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Postby biostudent84 » Tue Nov 30, 2004 6:24 pm

Evolution is not only based on mutations. Mutation, however, are the only factor that brings new genes into the pool.

Look at Darwin's Finches. When he explored the Galapagos Archepelago, he found over ten different species of finch. However, only one species of finch actually came from mainland South America. What's going on? Mutations could not possibly work this fast!

They didn't. They separated mainly out of what they ate. The original finch could eat either nectar from flowers, or nuts from trees. Naturally, there is variation within this original species (this is called the Founder Species). Finches best adapted for eating nectar spent most of their time in the flowers, and finches best adapted for eating nuts spent most of their time in the trees.

Over time, these finches began to mate with those closest to them. Natural selection chose for the necter-drinkers to have increasingly longer and longer bills...better to get to the nectar! It also chose for the nut-eaters to have increasingly shorter and squatter bills...better to break open nuts.

Eventually, the gene frequencies in the nut-eaters and nectar-drinkers changed so much that the two groups of finches were genetically far apart enough so that they could no longer breed to produce fertile offspring.

There is a real-life example of evolution. It does not have to include mutations.

Here's an example of how gene frequencies can change this way:

Let's look at the nectar-eating finches. They know that long bills are needed to reach the nectar within flowers. The longer the bill, the greater chance of survival. Therefore, finches choose mates with long bills. Have you ever seen children taller than their parents? Same thing here. Often, finches bills will grow longer than their parents'. This happens over and over, making yet longer bills every generation.

This has acutally been studied in the Galapagos today. Ecologists have measured over a millimeter length increase in nectar-drinking finches over the last fifty years. A millimeter or two is not much, true...but apply this over a thousand years. Hey! We have a finch with a two centimeter longer bill! The Galapagos Archapelegao is only 5 million years old. The islands of Hawaii are over 75 million years old!!!!!

Look at the variation in the human race. Due to the lack of effective transportation, the human race was on its way to forming four different species of modern humans: Africans, Caucasians, Mongoloids, and Aboriginals (I will address it here that no good scientists would ever make conjecture as to which group is more advanced...each has traits to let each group best adapt to their area of origin...I will also say that historical data has led scientists to believe the first Homo sapiens originated in the Middle East/Northwest Africa region and spread out from there...Three Hundred Thousand years ago.)

Signed,
Someone VERY tired of defending the Principle of Evolution to fundamentalists...
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Postby Chris » Tue Nov 30, 2004 11:10 pm

dude, the topic is macroevolution. i know things evolve, it is proven. however the topic of this discussion is MACROEVOLUTION. it is simply impossible that we came from apes. period flat and final. look at the facts. that is all i am arguing. the finch example is an example of microevolution in which i completely agree.
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Postby biostudent84 » Wed Dec 01, 2004 6:23 am

Do you understand the idea of Wholistid science. It is the basis of any large-scale science out there. First you look at the little things, then you take a step back and look the the entire picture.

You might look closely at one or two drops of paint on a canvas, but when you look at the whole work, you look at the overall pattern...NOT the countless dots. Look at each individual dot and you would never even be able to comprehend the work.

I was refuting your statement that evolution is dependant completely on mutations.
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Postby pfudd » Mon Dec 13, 2004 7:03 am

There is no way you can take a monkey, go 'alakazaam', and *poof*, get a human.

However, take a pair of monkeys, let them give birth to baby monkeys, and if one of the babies has less hair than their parents, let that baby grow up and have babies of its own. If any of those babies have less hair than the parents, let those babies grow up and have babies of their own.

In a given generation, there may be no difference in hairiness between baby and parent. Be patient: eventually you'll find a baby that's different, in this generation or the next, or some later generation.

Eventually, you'll have hairless monkeys.

Now, I won't say that humans *are* hairless monkeys, but if you repeat the process outlined above with intelligence, posture, muscle development, and all the rest of the features that differ between monkeys and humans, you will end up with a critter that looks a lot like a human, and can probably behave like one too. If there are still some differences, by all means, work on breeding the differences out, and you will have done what evolution did.

Of course, if you're impatient, you can take shortcuts; start copying and pasting human DNA into the egg and sperm cells of monkeys, take out monkey DNA that doesn't exist in humans, and in no time flat, you'll have a monkey giving birth to a human baby. That's not how evolution works, that's just copy-and-paste cloning, but if you want human babies coming out of monkeys, that'll get you where you want to go.

I imagine that if you *really* wanted to have a monkey turn into a human (*alakazaam* style), you'd have to copy-and-paste human DNA into *every* cell of the monkey, delete the monkey-only DNA from *every* cell, and then perform a lot of surgery on that poor monkey. You'd have to change the length and shape of every bone in his body, and somehow force his brain to grow a little more. Fix the vocal cords and give him a whole-body shave, and *voila*, ersatz human. The monkey would be human, at least from a DNA point of view.

Ok, ok, there are more things to fix, and when all is said and done, it probably would be a *lot* easier to just tinker with the DNA in the sperm and eggs and wait for the baby to be born. It's like trying to convert a computer from windows to linux; sure, it's technically possible to do it while it's running (don't know of anyone who's done it), but it's much easier to reboot it (after putting linux on the hard drive).

Selecting for desirable properties is what evolution is all about. That's why there's a zillion breeds of dogs; they're still all the same species (can interbreed), but people have been selecting for "interesting" characteristics for thousands of years. Same for the finches of the Galopagos, nature has been selecting for ability to feed on different food sources for many thousands of years.

I hope this has been a clear explanation of macroevolution, as I'm studying for a biology class and macroevolution is on the final exam. If I wasn't clear, I need to work on my presentation! :-)
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Evolution and mutations.

Postby pfudd » Mon Dec 13, 2004 7:24 am

Already I'm seeing things I should have mentioned.

A species has of a fixed number of genes; each one is like a multiple-choice question, like "what color eyes does this organism have?"

An organism has an alelle in each gene; each one is like an answer to the mc question, like "blue", or "green".

The gene pool for a species is the set of all alelles that exist in living organisms of that species (colours of hair, eyes, skin; size of brain, hands, torso, etc; hairiness).

The only way to form new alelles is through mutation; each mutation adds one more alelle to the gene pool ("purple eyes", "green hair").

If there were no mutation, there would be no humans. No monkeys, for that matter. I don't know if the first cell counts as a mutation of some inorganic process, so I can't say whether the planet would be covered with verbatim copies of that first cell or not.

If mutation were to stop today, the gene pool would stop growing, and all you could do is shuffle the alelles that exist with sexual reproduction. If you could count the alleles in the gene pool, you could find out how many possible humans there will ever be before they start repeating. If there are people with rare alleles that don't have kids, then the gene pool would shrink.

So, is evolution dependent completely on mutations? Hmm. How about "evolution is completely dependent on mutations AND allele shuffling"? Well, in organisms that don't do sex and don't swap dna with any other organism, then mutations are the only way to change.
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Postby biostudent84 » Mon Dec 13, 2004 3:03 pm

Yes. The point I was making, however, is that evolution is not entirely dependant on mutations. I do agree, as will all scientists, that mutations are the only source of NEW genes in a species.
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