Evolution: The Scientific Evidence

[jinydu]

Well, according to a life sciences class I took, one definition of a species is a group of organisms that are capable of interbreeding. So all that is required is for the variation to become large enough so that the populations are unable to interbreed. This almost surely would have happened if they remained isolated for a few million years.

Besides, the definition of evolution I learned encompassed both small changes (such as from one generation to the next) and large changes (such as across thousands of generations). You have probably heard many times before that the latter is far more difficult to observe directly than the former because of the large time spans involved. Less direct methods, such as DNA analysis, must be used instead.

[ewmayer]

Originally Posted by Uncwilly

That is not 'Evolution'.

Huh? It sounds like selection for a genetic trait that increases fitness in the context of a population's current (or recent) environment. Hello - that's classical Darwinian evolution.

Your followup comment tells me that you also a confusing "evolution" with "speciation" - evolution by way of mutation and selection is in fact occurring all the time within individual species and their geographic/genetic subpopulations - it's only when two or more of those subpopulations became sufficiently genetically different that they can no longer interbreed and produce viable offspring that one can speak of a new species having arisen.

Thanks for the link, Mike.

[brunoparga]

Originally Posted by Uncwilly

Movement within the bounds of a species is normal and not the same as the branching out of a species into a different one.

I'd refer Uncwilly to this article.

Bruno

PS: I'd also like to hear his comments on it.

[Uncwilly]

Originally Posted by brunoparga

I'd refer Uncwilly to this article....
PS: I'd also like to hear his comments on it.

That is an interesting article.

Problem is that it lacks the detail need for a more robust commentary. What type of hybrids (qv) form? Are they fertile? Can the they breed with others like them? With either parent group? What about the hybrid one over?

Based upon the hybrid link above, and its off shoot to bovid hybrids, how would you classify the yaks, cattle, bison? Are they a ring species?

I have no problem with hybrids existing.

[brunoparga]

Originally Posted by Uncwilly

That is an interesting article.

Problem is that it lacks the detail need for a more robust commentary. What type of hybrids (qv) form? Are they fertile? Can the they breed with others like them? With either parent group? What about the hybrid one over?

Based upon the hybrid link above, and its off shoot to bovid hybrids, how would you classify the yaks, cattle, bison? Are they a ring species?

I have no problem with hybrids existing.

Let me try to understand your position. You don't see any problem with genetic variation inside one species; what you don't believe is that one species (e.g. us) might derive from another (e.g. our extinct ancestors). Is that it?

Bruno

[Jwb52z]

I wish I had a source to link to for you all about this, but it was just on the news probably a few weeks ago. Scientists have discovered that within the human species there can be as much as 12 percent difference between 2 people.

[retina]

Originally Posted by Jwb52z

I wish I had a source to link to for you all about this, but it was just on the news probably a few weeks ago. Scientists have discovered that within the human species there can be as much as 12 percent difference between 2 people.

That just shows how much junk DNA there is in things. So much stuff in there doing nothing at all.

[ewmayer]

Originally Posted by Jwb52z

I wish I had a source to link to for you all about this, but it was just on the news probably a few weeks ago. Scientists have discovered that within the human species there can be as much as 12 percent difference between 2 people.

Given that chimp and human DNA have been shown to differ by "only" around 3%, a 12% variation in DNA overall between any 2 humans is simply not plausible. Either the article was simply wrong, or perhaps it was discussing variation at one particular hotspot in humans, and you misread it.

See my post #53 earlier in this thread for more details about chimp v. human differences.

[Jwb52z]

Originally Posted by ewmayer

Given that chimp and human DNA have been shown to differ by "only" around 3%, a 12% variation in DNA overall between any 2 humans is simply not plausible. Either the article was simply wrong, or perhaps it was discussing variation at one particular hotspot in humans, and you misread it.

See my post #53 earlier in this thread for more details about chimp v. human differences.

It wasn't an article. It was on the news. It also said that "junk DNA" is not always junk because they were discovering some new purposes for certain things they had no idea about what they did before now.

[mfgoode]

Originally Posted by Jwb52z

It wasn't an article. It was on the news. It also said that "junk DNA" is not always junk because they were discovering some new purposes for certain things they had no idea about what they did before now.

You are quite right Jwb52z.

To give you a true to life example on more practical terms, when I got on the Boeing 707's in the mid sixties I used to be fascinated by the cockpit.

It had a variety of navigational aides to name just one aspect which were built in, for the future airports, which were lagging behind. So there were many gadgets which the pilots could not use at the time and therefore were not trained in the Art. One such device was the ILS (instrument landing system) installed in the planes which our international airports were not equipped with. But they were installed with forethought.

To the many pilots who flew those planes in those days these gadgets may as well have been called 'Junk DNA' as they could not use them.

Nature is never superfluous and has intelligence in design. Every thing it provides in an organism had been put there for a purpose. It has even taken into acccount the probability of one spermatozoa going up the vaginal canal to impregnate the ovum by giving an ample amount of it to make sure the human race is propagted despite the environmental odds!

There is no doubt about it!

Isaiah 40: 12,15, 22 (OT) 'Who hath measured the waters in the hollow of His Hand, and meted out the heaven with the span, and comprehended the dust of the earth in a measure and weghed the mountins in scales, and the hills in a balance?'

15:' Behold the nations as a drop of a small bucket, and are counted as small dust of the balance: behold he taketh up the isles as a very little thing'

22: 'It is He that sitteth upon the circle of the earth, and the inhabitants therof are as grasshoppers; that stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in :'

Mally

[cheesehead]

Originally Posted by mfgoode

Nature is never superfluous and has intelligence in design.

Mally, that's ridiulous.

Every thing it provides in an organism had been put there for a purpose.

Humans have tailbones because -- their evolutionary ancestors had tails. But humans don't have tails now (except that once in a while a human baby does have a tail), so why do the tailbones exist? Evolution can answer that.

Humans have appendixes because --- their ancestors had multiple stomachs for digesting their vegetarian diets. But we're now omniverous enough to no longer need the extra digestive chambers, so why have an appendix that once in a while kills people when infected? Evolution can answer this.

Oh ... and just what is the "purpose" of such "intelligently-designed" defects as spina bifida, microencephaloism (spelling?), myasthenia gravis, congenital blindness, multiple schlerosis, polio, malaria, smallpox, et cetera, et cetera? (No, it's not because Eve ate an apple.)

It has even taken into acccount the probability of one spermatozoa going up the vaginal canal to impregnate the ovum by giving an ample amount of it to make sure the human race is propagted despite the environmental odds!

... and just what is the intelligently-designed purpose of having a reproductive tract that allows fallopian pregnancies? Evolution can answer.

There is no doubt about it!

... until one actually notices all the flaws in the "intelligent design" argument and thinks about them in light of modern scientific knowledge.