Regarding evolution...?

Question

Evolution is the result of variation and natural selection. After a certain point, an offspring will have to have some pretty significant mutations (in addition to natural selection for certain already-present alleles) present in order to be of a different species than the population it was derived from, although this can take many (an understatement) generations. Supposing that an offspring was a different species than its parents, it would not be able to produce offspring that could produce offspring. Are there supposed to be two of these new species being born around the same time, or are mutations supposed to be gradual, with offspring continuously being compatible with the rest of the population (intermediary species)? Also, what are the chances that these mutations come out favorably (i.e., Down Syndrome), and does the amount of time given for evolution to occur take this into account? Again, just asking, not trying to disprove anything.

What I meant to say was, "Supposing that an offspring was a different species than its parents, it would not be able to produce offspring." Also, I did not forget about natural selection, it's presumably occuring alongside mutations; however, mutations create the most significant evolutionary change. From what I gather from what people are saying, there is no distinct time when a new species is created that is markedly different from the last species which wouldn't be able to have offspring.

Let me re-attempt to clear this up. My question was about mutations, which could obviously be selected for, coinciding with the selection for certain alleles. All of this was just kind of assumed in my question about mutation.

Sorry, Kit F, but what you said was basically covered by the ambiguous wording of my question. I guess people are just expecting me to be pushing some sort of rigid, set point of view in the religion forum, but I got more responses here than in the anthropology forum. Also, I consider my theological reasoning for why I believe in God to be completely separate from any scientific field...

Answer 1

Hmm, if a sexually-reproducing animal became a different species from the parent within a generation, I'd suspect chromosome incompatibility (as in there might have been a problem during meiosis that resulted in a failure in cell division) in which case, I doubt it'd be able to further develop into a new species unless if another animal of the same species were to be born with the same number of chromosome sets. In plants, this would be known as polyploidy. Autopolyploidy could generate a new species because plants can reproduce asexually. Eventually, it may form a fertile polyploid (called an allopolyploid) that can reproduce sexually with each other.

As for the other part of your question, species can form either sympatrically or allopatrically. Allopatric speciation results from a geographic division between two groups of the same species. In the two isolated groups, different mutations would arise, genetic drift would result in different allele frequencies, sexual selection might differ, etc. Thus, gradually, the two groups could diverge enough to constitute different species because they can't or won't reproduce with one another when they do encounter each other. For sympatric speciation in animals, genetic factors might open up new resources for some of the organisms. In polymorphic populations, sexual speciation could also result in speciation.

For your last question, I don't think I have enough info to answer that conclusively (as in giving you actual numbers) but I would assume that most mutations are neither favorable, nor detrimental. =/

(EDIT: Found something called the "neutral theory" which states that much evolutionary change has little effect on fitness, and thus is not heavily affected by selection. I guess what it means is that many changes, if neutral, would not hinder the organism. So it would continue on into the population, thus allowing a rather steady rate of change in some genes. However, if the gene is important survival, then changes would more likely be on the harmful side.)

EDIT
To the person asking about flight, my biology book discusses a theory that the earliest feathers may not have been adapted to flight. These would be known as exaptions, structures that evolve for one thing and eventually become co-opted for another. It may be that feathers (the first of which were merely downy feathers that served no purpose in flight) might have evolved for uses in courtship, camouflage, thermoregulation, etc. Also, they could've increased the surface area of forelimbs, which would've helped tree-climbing and perching animals. Eventually, the organisms would've started gliding and over time, flight. As they say, evolution and selection don't anticipate future uses; they merely improve the structure in its current usage.

Answer 2

Because you are thinking of it as changing from one species to another in an abrupt step. The fact is that maybe one generations "mutation" will only be that they'll have 20/20 vision while another generation from some other animal will have larger wings. Some maybe parent bird had longer wings to fly better and passed it to all their kids, and once their kids mated with others that didn't have the long wings, the children would have a bit longer wings. Eventually through natural selection the children with smaller wings that would not be able to fly as high would have lesser and lesser reproductive rate until they end up not existing. Take these small changes in a huge time scale and you'll find that they start becoming a "new species" although their "transitional species" was 99% like them, thus mating ability.

As for the person that asked for flying "just asking," the most possible scenario I see is some small animal that lived in trees and jumped from one to another. Eventually "wing-like" attributes to glide to the other tree or resist from gravity might develop. Give it enough time and you'll have flying species.

Lastly, most mutations are actually neutral. There are a lot of mutations that are harmful, but there are also mutations that are good . Natural selection will make sure the good mutations are those that go onto the next round.

Answer 3

Mutation causes most of the changes. Both parents don't have to have the mutation to pass it along. It because part of the gene pool of the one mutated. Most mutations cause sterility, so only a select few get through. And then there's Natural Selection, which means the coin toss of whether a mate will select that mutated individual. Of course I'm speaking of the animal kingdom, but the same process happened with humans. A whole new species doesn't occur at once. It's gradual with time and change. But things like coloration are more rapid through mutation.

Answer 4

About halfway down you forgot about selection.

You also have a very common misconception about "species". We sort beings into species, but they're not natural kinds, so there's no such thing as "suddenly two animals have an offspring that's another species".

Later: Okay, the second half of your "more information" is correct. I don't think that the statement that mutations are the more important part of variation is true, though, especially in species that reproduce sexually.

It does sound as though you're making an honest attempt to understand this, so my hat is off to you. Looks like you got some good answers, too.

Answer 5

The usual nonense rolled out by the bible-thumpers. Ignore anyone who explains anything at all as being a result of an action by an imaginary being.
We, as a part of the family of mammals, are continually evolving. Evolution does not happen instantly but over thousands if not millions of years. Gradual IS the key word.
Science has just about exlained everything that was originally explained as created by a god. It won't be THAT long before everything will be explained.
Those with strong religious beliefs just won't listen to anything that doesn't agree with what their bible tells them, making them simple-minded, backward and incredibly stupid.
Read more. Ask more pertinent questions. Be of a strength of character that allows you to express your views but to be able to take another's point of view, examine it, assess it and make an educated decision one way or the other.
The evidence to support natural selection is clear, the evidence to support there being an imaginary friend in the sky - or wherever the concept exists - does not exist AT ALL other than what you have all been indoctrinated with as children.
Be fair to YOUR children - offer them a choice about religious beliefs and not force it into them as if they were sheep.
Especially muslims - give your children the choice. Give them all the facts and not a bunch of lies and false promises, which, in turn, create so many of the problems that we have in the world today - especially from muslims.
Islamic suicide bombers believe, with no doubt at all, that if they kill innocent people in the name of the defense of their religion, that they will immediately go to paradise, where 72 virgins await them. Yeah, right!
So, research your evidence about natural selection, compare it with the trash bandied about by the fools who will not accept any other explanation but creationism. Make your own mind up. You have a lot of material at your disposal. The others only have blind faith and a book of lies.
Should be an easy decision.

Answer 6

Yes, the idea is that the offspring are the same species as their parents, with just slight changes. Each generation can interbreed with the generations before it. But after a thousand generations, the species is different. There is actually a salamander on the west cost, where the northern Washington one is slightly different then the southern Washington one, but can still interbreed. And the southern Washington one, is slightly different then the northern Oregon one, but can still interbreed, and so on. But the Northern Washington one can't interbreed with the southern California one.

Answer 7

chemical imbalances, solar radiation, temperature, humidity established bio-forms... there are alot of unknowns that would cause an organism to mutate...look at us humans do we all look the same? no because some where sometime there were changes that caused us to branch out as we were evolving there will be no absolute answer,,,,we have to do the best with what we have

Answer 8

Along the same lines, how does evolution explain flight as a natural selection process? As you say, just asking ....

Answer 9

You've got it. Most mutations are harmful. It would be easier for a species to die out through mutations than survive.

Answer 10

In order for a mutation to be successful, to continue, it must be done in stages. Example would be breeding a horse and an *** (a,s,s) . You get a mule which is, with extremely rare exception, incapable of reproduction.


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