The Evolutionary Hotseat

[HyToFry]

[Borodog]

Will: Why did this so called evoultion decide to make more reptles when they were weak and couldn't survive very well?

Go wrestle a crocodile, or an alligator, or a Kamodo dragon, or a black mamba, and then you can get back to me on how "weak" reptiles are, and how they can't "survive very well."

No really, go wrestle a crocodile.


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[pikachamp]

will, evolution doesn't decide anything, it's pretty much random. besides, it's not like it's the dinos' fault anyway, not only that but i think that the underwater creatures survived, mean ing thinks like crocs, so not all the dinos died

[Will]

Mother nature is part of evultion and we are hurting her by our pulltion. So why can't evultion do away with us to help mother nature?

[pikachamp]

do you think there were such things as birds that didn't have hollow bones? (they'd obviuosl die out soon due to the weakness of a bird out of flight)


if every species evolves from anopther, where did the first one celled thing come from?

[Borodog]

pikachamp: will, evolution doesn't decide anything, it's pretty much random. besides, it's not like it's the dinos' fault anyway, not only that but i think that the underwater creatures survived, mean ing thinks like crocs, so not all the dinos died

Not so nitty pick: Evolution is NOT random.

Also, the land extinction of the dinosaurs was matched by an equally massive extinction of ocean life. Theories differ, but personally I think that crocdiles and other true reptiles survived when the dinosaurs and their ocean-going counterparts did not is because the reptiles were cold-blooded, and could hibernate (many reptiles do this today) or otherwise survive in "low energy" states. Warm blooded dinosaurs could not. Still, you are partially correct; some small dinosaurs had developed thermal insulation (i.e. feathers) and had relatively modest food requirements, and survived, just like the small mammals, with their thermal insulation (i.e. fur) and small food requirements did. We call these dinosaurs birds.

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[Logain]

Would you consider selective breeding to be a form of forced evolution by humanity?

[pikachamp]

yeah, and what about those crossbred ligers?

[Borodog]

Will: Mother nature is part of evultion and we are hurting her by our pulltion. So why can't evultion do away with us to help mother nature?

I'm not quite sure what an "evultion" is. Is that like a "pulltion" ?

pikachamp: do you think there were such things as birds that didn't have hollow bones? (they'd obviuosl die out soon due to the weakness of a bird out of flight)

Yes, they were called "dinosaurs". Small therapod dinosaurs/birds evolved spongy, light-weight bones in order to be lighter on the wing. Even birds that have lost the ability to fly (emus, ostriches, for example) reatin this characteristic.

Also: if every species evolves from anopther, where did the first one celled thing come from?

Modern single celled organisms are, as are all of the cells that make up multicelled organisms, colonies of bacteria that have grown to depend on each other. The "original" single celled organism's orgins (i.e. abiogenesis) are a separate field from that of evolution. All that evolution requires is that differentially reproducing, heredity-based, imperfect replicators exist. That's it.

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[Borodog]

Logain: Would you consider selective breeding to be a form of forced evolution by humanity?

Yes. It's called artificial selection, as opposed to natural selection. Witness the Great Dane and the Chihuahua, both bred from wolves in of order 10,000 years.

pikachamp: yeah, and what about those crossbred ligers?

What about them? There are many crossbreeds of closely and marginally distantly related animales, horses and donkeys, horses and zebras, dolphins and whales, dogs and wolves, etc. Some are bred by people, some happen naturally (as in the wolphin). All are practically guaranteed to be sterile.

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[pikachamp]

so how would i fi8nd out about the creation of the first thingy?

[Borodog]

Do some research on "abiogenesis".

It's not that difficult to imagine. All you need is a lucky configuration of a few organic molecules that just happened to have the property that they catalyzed a reaction that produces more of the same. Only not perfectly. Evolution and natural selection take off from there.


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[Bicho the Inhaler]

Someone did an experiment (U. of Chicago? I forget where) where they gathered some simple compounds (to attempt to simulate very early pre-life Earth conditions) and shocked it with high-current electricity (to simulate lightning) and behold: amino acids could be detected. It's not really that far-fetched that very simple cells pop up by random chance, when you think about the sheer number of opportunities for chemical reactions to take place. Amino acids -> proteins; nucleotides -> DNA, RNA; get some lipids and some more stuff in there and presto.

[Hitchhiker]

Note about ligers and tigons: while all ligers to date have been sterile, there have been documented cases of fertile tigons -- their offspring are called ti-ti's. (Yes, really.)

[Borodog]

Cool. Thanks. You learn something new every day.



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[pikachamp]

what's the difference between a liger and a tigon?

[Bicho the Inhaler]

Which one was mommy, I believe.

[Fried Egg]

IF anyone's interested in how order can spontaneously emerge from chaos, check out these computer simulations that demonstrate this behaviour. They can be downloaded from this site.

[Borodog]

So we're all clear then? Good. I'm glad we got that all settled, and everyone now understands evolution. Well, everyone intelligent enough to spell it, at least.

But if there are any other little tidbits you've always wondered about, fire away!


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[Internet Stranger]

If humans finally decide to mine the asteroids and colonize in space, over time, how will evolution allow humans to adapt to their new environment?

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"I didn't know she was your sister I swear!"

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[Borodog]

It won't. As I mentioned before, humans have already evolved the perfect adaptation. We change the environment to suit ourselves. For evolution to work, natural selection has to work. The human race is very near (within 30 years I think) from effectively ending natural selection within its population. Remember what natural selection is: it's things dying. People are preventing themselves from dying at an ever increasing rate. Pretty soon, people won't die at all, and what happens to natural selection then? The human race will never stop evolving, since gene frequencies in the population will always change. But will human beings as they are now ever speciate again? I doubt it. Not unless something very, very drastic happens.

Although, the increasing ubiquity of caesarian sections is allowing average infant brain size to increase, so who knows?


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[mole]

Well, that answers my question as well, I guess: How have our medical advances affected our evolution?

[extropalopakettle]

If humans ever make it into space, permanently, and start travelling in different directions, they'll speciate, I think. Given geographic isolation, genetic drift alone should do it.

[Borodog]

Excellent point. Multiple reproductively isolated populations may become unable to interbreed due to genetic drift, but the populations themselves are likely to be large enough, and the aforemention propensity of mankind to remove it's selection pressures, that genetic inertia will keep them looking more or less familiar. I could be wrong - as I said, brain size may continue to grow, height may increase, they might fix male pattern baldness. Who knows?


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[Internet Stranger]

If we take every human, male and female 6'6" and taller and let them colonize mars; then we take every person 5'6" and smaller and have them colonize Venus.

In time, will the average martian end up being over 7' tall?

Will the Venutians end up being under 5' tall?

What would happen to the leftovers on earth?

Will the different gravitational levels have a factor in this?

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www.InternetStranger.com

[Buzzsaw]

Why have humans increased in size over the past centuries, esp this last one? Better food availability? To aid in battle? (Coyote could have made me become extinct)

Do you think we might be gradually evolving to eventually be lacking an appendix?

Do you think that the Coelecanth is a transitional animal - meaning one that was becoming a land animal? (that fish is fascinating to me, from what little I've read about it)

[Ameb]

What's the difference between genetic "drift" and "shift"?

[PuzzleProdigy]

How do they tell which fossils are 'transitional'? For example, suppose Species A branches off into two very similar Species B and C. B dies out, but C further evolves into Species D. How can they tell that it's C, rather than B, that is the transitional step between A and D?
Seemingly Logical Answer Even Though I'm Clueless:
Hmm... I would think that if B died out, then C must have had a characteristic that made it more apt to survive. Since that characteristic is more likely to make the species survive, unless there's some sort of environmental change that makes that characteristic more detrimental, then Species D s likely to have the characteristic C did and B didn't.

[pikachamp]

what's a Coelecanth?

[Coyote]

In reading through discussions/debates about evolution, I occasionally see the term 'allele frequencies' (sp?) pop up. What exactly are 'allele frequencies'? (In layman terms, if you please.) And what is their significance in regards to evolution? (You needn't answer this one if the answer to the first question makes it pretty clear already.)

I know I could probably find this out for myself with a search engine , but:

a. It might take some doing to find a place that addressed the questions in layman terms.
b. The answer might be of interest to others here.
c. You offered your services in answering any of our questions.
d. I'm lazy.

[edit] to correct a potentially confusing typo [/edit]

[This message has been edited by Coyote (edited 07-09-2002 08:01 PM).]

[Will]

Testing Testing

[HyToFry]

On the subject of Will... what was evolution thinking?

[extropalopakettle]

I can take a stab at the "allele frequencies" thing (from ancient memory).

Alleles are alternative forms of a particular gene. An example in humans is the alleles for blood types A, B and O. Alleles occur in pairs (because chromosomes occur in pairs). So a person can have AA, AB, AO, BB, BO or OO. The combinations AA and AO both produce type A blood. Similarly, BB and BO both produce type B blood. The AB combination produces AB blood type, and the OO combination produces O blood type.

The frequency of the different alleles, which combine into pairs randomly in a population (with rare exceptions, such as where some combination is fatal), determines the frequencies of the different combinations, and their associated "phenotypes" (the way genes are expressed - for instance, the AA and AO combinations ("genotypes") both produce the same phenotype - type A blood).

Furthermore, the relative fitness of the different phentypes, over time, determines, in a very predictable way, the frequency of the alleles. An example: The gene for sickle cell anemia. There are two alleles, sickle cell and normal. If an individual has two sickle cell alleles, the have sickle cell anemia, and are less fit - less likely to reproduce. If an individual has one sickle cell allele, and one normal allele, the do not have sickle cell anemia, but they do have a resistance to malaria, and, in regions where malaria is prevalent, these individuals are more fit - more likely to reproduce - than individuals with two normal alleles. If you know (or assume) the relative fitness values (expected number of offspring) for the three different phenotypes, no matter what the frequency of the alleles (as long as none are 0%), you can determine the frequency of the alleles that will eventually be reached in the population; the frequencies shift to a state of equilibrium.

Or something like that.

[BraveHat]

Is it possible for both God and evolution to exist?

[HyToFry]

i'll take that one.

Bible says God created man from the dust of the Earth.

Evolution says man was created from two amino acids forming together and then many years of evolution.

Pretty close wouldn't you say?

[Will]

How did Life on earth start this is how?

By Cathryn Conroy, CompuServe News Editor
Bacteria. From Mars. Transported on meteorites. Stop laughing. This is not a joke. Serious international scientists with academic degrees and lofty work experience and fully-funded laboratories are suggesting that life on Earth could have arrived in the form of bacteria carried from Mars on meteorites. First brought forth in 1903, the theory is called "panspermia" and holds that life started elsewhere and was then spread through space. Fast forward almost 100 years. Scientists now think there is some plausibility to the idea. Recent discoveries of Martian meteorites on Earth have raised the possibility that bacterial spores could have hitched a ride on these rocks.

To test their theories, Gerda Horneck of the German Aerospace Centre and her colleagues in Cologne purposely sent millions of bacterial spores into outer space on a Russian satellite. No, they weren't trying to infect the solar system. They wanted to find out how those spores were affected by solar radiation. The results could tell them if this panspermia theory was something to be taken seriously--or laughed at. According to New Scientist, they learned that a single bacteria will not survive long enough in space to travel from one planet to another; however, meteorites protect the bacteria as it travels through space. Meteorites as small as a centimeter in diameter could carry life from one planet to another provided the journey was completed within a few years. "Early in the history of Mars and Earth, there could have been an exchange of biological material between the two planets," Benton Clark, a Mars exploration specialist at Lockheed Martin in Colorado, told New Scientist.

Well Boro if this is the case How come. We can't find the Bacteria on Mars? Where did bacteria come from in the first place?
How come all of a sudden life can be here but you say God can't be here?

[Neo]

*hopes Boro doesn't mind*

[BraveHat]

quote:

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Bible says God created man from the dust of the Earth.

Evolution says man was created from two amino acids forming together and then many years of evolution.

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But then Jesus called man "the salt of the earth." It is reasonable to assume he was not saying man is made up of sodium chloride. In this, man is not being equated with salt, but compared to salt.
Is it then unreasonable to assume that God was also referring to a comparison? That amino acids could be compared to dust? Remember that in this case, we are no longer speaking of Man as the object of comparison, but That Thing Which Man is Made From. So the question is, according to evolution, are amino acids the only thing that man can be said to be made from? What are other things that have made man, of which man consists of, and how can they be compared to dust?

[Death Mage]

Why are humans content to wait for the next evolutionary step rathar than stepping foward and create it on their own via genetic manuplation etc.?



[This message has been edited by Death Mage (edited 07-10-2002 03:23 AM).]

[Internet Stranger]

Because of religion.