That is a goo definition but sometime too much interbreeding can cause the same species not to be able to produce vialble offsprings.
If you don't like Mayr's definition, what definition do you propose?
One reason Mayr's definition has become popular is that it is not subject to the charge of being either subjective or arbitrary. Put two groups of animals or plants together and see if they mate randomly or pick mates primarily from their own kind.
If you don't like that way of deciding that they are one or two species, what do you propose as an alternative?
The artilce I read he did not mentin groups.
Then we don't have his opinion on groups do we?
You can't have it both ways. If it is separate and distinct it is not intermediate.
Now you are making up arbitrary rules. Having characteristics intermediate between (or a mix of) those of two other species is no reason the organisms with those characteristics can't also be a species of their own. Tiktaalik has some of the character traits of a fish and some of the character traits of an amphibian, but no one is suggesting that it ever mated with either fish or amphibians. Neither is anyone suggesting that its parents were fish nor its offspring amphibians. It is its own species, distinct from both fish and amphibians; and it is also intermediate between fish and amphibians.
One fossil can never be classified an intermediate, You must have a succession. That is what they did in whale evolution.
Obviously an intermediate has to be intermediate between two other species, so yes, you need a succession of at least three. With whales we have many more than three. More than three in the fish to amphibian transition as well.
If you want to play that game, you need a lot more Similar characteristic than you have from one species to a completely different one.
Anything more similar than one species to a sister species would be a variety within the same species, not a different species at all. The differences between closely related species are often very few and difficult for any but an expert to pick out. Unless you know clams very well, you might be hard put to tell a cockle from a mussel or a winkle from a whelk.
<<
So you are saying Indohyus jumped into pakicetus in one generation?
Good Lord, no!!!! What a ridiculous idea. That is the sort of drivel that usually comes from anti-evolutionary creationists.
There is no evolutin withing a species.
Sure there is. You must not understand the definition of evolution.
What do you think scientists are talking about when they refer to evolution?
Even if it kept it leg bones, it lost its mobility and would still end up as luch.
Another silly assumption. It was never without bones nor without the muscles and nerves to move them. So whatever shape the limb took, it possessed mobility. After all, you have mobility in water even without flippers. Why not the descendants of Pakicetus too? Consider Ambulocetus which shows adaptations for being a strong swimmer but also had legs to support terrestrial locomotion. Dual duty limbs!
(Similarly in the reptile-mammal transition, we find fossils with double-hinged jaws between those with reptilian jaw joints and those with mammalian jaw joints.--so no problem with eating as one type of jaw replaces the other.)
Not ony that pakietus's parents needed an gene for fins and a blowhole, or their kid would never have gotten those charactreristics.
Well they did, but in Pakicetus those genes were expressed in the form of legs and end-of-the-snout nostrils.
Just like we have the same genes as fish use to make gills, but in us they make ear and throat bones instead.
Genes are not single-functioned. They can be used like ingredients in a recipe for all sorts of things. It depends on what instructions they get from the gene-signalling regulatory network.
Furthermore, not only can those instructions change, the genes themselves can change as well. So we have many levels of molecular change that impact on the final form of any organism.
You simply cannot explain how that happened genetically. Not even with mutations.
Sure I can, but it is easier (and probably more reliable) to get it from a good textbook. Why should you take my word for anything? I have already pointed you to a good online series that explains the basics of evolution quite well. If you are serious at all about discussing the fine points of how evolution happens, I suggest you refer to specifics in that series. Then we can have a good discussion about them instead of these vague assertions.
At some point it losts it legs and that had to have happened before it got the fins.
Not before. At the same time as. The flippers (they are not fins and any close examination of them would show you) did not replace legs. They are reshaped legs. They have the same bones, muscles and nerves as legs.
The reshaping took time and that is why we see fossil whales at different stages of the transformation.
You do not seen any gradual changes from Indohyus to pakicetus.
No reason we should. As these phylogenies show, Indoyus is considered to be a sibling to Pakicetus, not an ancestor.
http://www.debate.org/photos/albums/1/2/1222/30689-1222-md4mx-a.jpg
http://25.media.tumblr.com/f5f05cef69212ed41aac230e86052792/tumblr_mhypsyLFqh1qaitt0o1_1280.jpg
http://whyevolutionistrue.files.wordpress.com/2012/12/whale-phylogeny.png
You are missing the point. There is no reason for a species doing well as it is to suddenly need to be in the water.
So? Evolution doesn't happen because a species needs it to happen. It happens because the opportunity is there and it works well. The Wikipedia article on Indohyus suggests an advantage of being able to get into the water was to avoid predators like hawks. The eye orbits of Pakicetus suggest it adopted a nearly-submerged position in the water to hide itself either as protection or to avoid warning prey (much as hippos and crocodiles do).
We don't have to suggest the ancestors of Pakicetus were not doing well without the opportunity to submerge themselves in water. We just need to see that it provided an additional advantage to Pakicetus.
Itr doe snot matter how many mutatins you want. They will not be the mechanism of revolution.
I agree. Evolution is not a matter of how many mutations occur. It is a matter of what happens to the mutations that occur. Different mutations have different fates, so there are different impacts.
So, you are correct here. Mutations are not THE mechanism of evolution. They are only one factor in a more complex process. Do you want to look at more of that process? Do you want to consider what happens to mutations, how and why they spread or fail to spread through a population?
Not ony that , very few mutation are beneficial.
True. The question is, what happens to those that are and how does it happen?
Yes he did or he would have remained pakicetus forever.
Again, I think you mean the descendants of Pakicetus were not Pakicetus, and you would be right.
Yes it is. The parents MUST have the gene for any characteristic their kids receive. Tha tis genetics 101.
True, but the gene can be changed from what it was in the parent to what it is in the child during the process of germ cell replication and gamete formation.
I am not sure it can be prove that the rabbits you mentioned adapted only on the basis of a mutation giveing them the ability to have more fur. That gene could have been recessive is some and dominate in others.
Now here you touch on something that many creationists fail to understand. And it is why scientists call mutations random.
You seem to be thinking (as many do) that in order for rabbits to adapt to a colder climate with longer winters, a mutation has to happen
at the time they are introduced to that climate. But that is not the case. The mutation may have occurred while their ancestors lived in sunny Florida or at a time when the climate was mild. But, it was only when they migrated to a colder climate (or an ice age brought a colder climate to them) that it became an advantage. So mutation can happen a long time before there is any need to use it for adaptive purposes.
As you say, it could be a recessive allele.
Mutations occur all the time whether they are needed or not. And as long as they do no harm, they remain as part of the stock of variation in the species. So there is always some standing variation available to help a species adapt to differing conditions. Sometimes it is not enough. Sometimes a species could really, really use a new mutation. But since mutations don't happen because they are needed, the species may not be able to adapt and it becomes extinct. But all species have a range of old mutations somewhere in the population which provide a supply of variations and in special circumstances some of these neutral mutations may come in handy.
Suely you aer not going to try and equate and adaptice process with one that is not necessary and completely in a different ballpark. The rabbits all had fur. What is generally in the line of whale evolution does not start out with a gene for fins an a blohole.
Flippers and blowholes are adaptations to marine life,no?
And those genes were always there. In Pakicetus and Ambulocetus and some others, they produced legs and nostrils. In modern whales they produce flippers and blowholes.
Evolution of character traits happens because the genes themselves evolve.
It is no one mechanism. It is a process involving the interaction of many mechanisms. Some mechanisms are molecular; some operate on whole organisms; some on populations. That is what makes evolution fascinating but difficult to grasp, as many people focus on only one level of change, but evolution integrates several levels of change and every level has complexities.
That is the general evo rhetoric I complain about. Dogmatic statement with no evidence.
Are you really interested in the evidence? I am just warning you that there is a lot of it, it is complicated, and it takes a long time to cover. My past experience leads me to believe that most people find it too boring and time-consuming to really make the effort to understand it.
And I am not willing to take the time unless you are.
The peppered moth is know to be a fraud. They even pasted some to the trees to make it look like they had adapted, and there were still moths.
I have seen no evidence of fraud. Were the moths they pasted to trees made of cardboard? Did the birds pick them off the trees randomly rather than by a criterion of visibility? And did the researchers lie about the figures?
Some of those fruit fly experiments began with a single pregnant female (definitely one common ancestor) and ended up with 2 to 8 different species (as defined earlier--do not mate with other populations even given the opportunity.) The only differentiating factor over the term of the experiment was to give them a different habitat with different food. <<
But they remainde frit flies.
Of course. But you do realize there different species of fruit flies. So here we have an example of several different species emerging from one common ancestor in a fairly short time in a laboratory. So what can we expect over millions of years in nature. How many hundreds of different species might we expect to come from one fruit fly species of say a hundred years ago?
You see, even if they are all fruit flies, they are not all the same species; the species have changed and new species have emerged.
[quoted]It is not. Even you rabbit example proves that. The rabbits adapted, but they remained rabbits.
The main product of evolution is adaptation. We don't necessarily expect adaptive evolution to produce a new species, not even a new species of rabbit. The rabbits adapted because they evolved. Evolution is the cause of the adaptation.
I don' think they do. That is why some become extinct. They might could migrate to a warmer climate , like geese and buterflied do, but that is not adation.
Oh, so now you are telling me you don't believe species adapt to their environment?
Yes, some do become extinct, especially when environments change too rapidly (that is why we are seeing a mass extinction now, as humans are destroying natural habitats more rapidly than species can adapt). But there are plenty of observations that species do adapt to new conditions. One recent one are the lizards of Pod Mrcaru.
Lizards Undergo Rapid Evolution After Introduction To A New Home
And we are all aware of how efficiently viruses, bacteria and insects adapt to our attempts to destroy them.
When you can show HOW it happens biologically, I will get on your bandwagon.
I will accept Mayr's definiion. Now show me how it is biologically possible.
They are not. The inability to reproduce can be caused by several factors and in the case of the salamaners a few could still breed and produce offsprings.
Not only that, it is impossible to know what every species in a rign species are doing, uness each one has a person following its every move.
Yes they can because they are still the same species but something has happened to some tha makes them infertile.
Well, now you are touching on some specifics we can begin to deal with.
The most important thing is this. Almost everything we see morphologically as an organism's physical characteristics is the fruit of molecular action at the genetic level. And it takes following those actions not only in one cell or one organism but through a population and over many generations to see what is happening and why.
But if you are prepared to stick the course through at least another 20 posts back and forth, I can discuss some of this in more detail.
Better though that you get a textbook or study some of the good online material like Evolution Basics or Understanding Evolution.
