So Simon, how do you explain the cheetah's relative low genetic variability? Shouldn't the cheetah be thriving now as populations are smaller? After all, you claimed smaller populations increase genetic variability.
Because the Cheetah's population as a whole are much smaller as quixotecoyote mentioned.
It's not isolation the problem, it's the basic reducing in numbers...
Some of your comments:
Ok, so can you explain to your fellow evos that isolation is indeed part of the process of orginating new species, then new species after that and so on. They don't seem to get that basic point that evo theory advocated sequential speciation in origin of the higher taxa.
It's the main process at least in terrestrial environment. Isolation and, in particular, geographic isolation.
Oceanic populations might be
a different story although, my personal guess, who be a variant of geographic isolation where the many miles of empty ocean act as the barrier...
Things are a bit different if, like paleo, you are looking at evolution over significant periods of time. There speciation can occur over time, one population can progressively give birth to another species that paleontologists will agree is a different one...
Here, time itself can be considered as a dimension and populations separated through vast lapses of time can be considered like geographic barriers...
I tried to tell them that, and they said I was lying. Note: I was just saying what evos believe, not that I agree with them.
Considering how this post you are so approving of was pointing out the mistakes, three very serious ones in a one sentence post, I can understand a certain level of incomprehension about what you actually think or believe...
Finally someone that has at least a very basic idea of what evolutionist theory is today.
I sincerely think that quite a few people here have such a basic idea. Some people, not me, even seem to have quite a good understanding of the state of modern evolutionary science.
As I said before, you repeating of deep misunderstandings and creationist lies about the theories lead to believe that you belong to neither of these categories...
Case in point:
Yes in part and no, in another. If there is mutation, that is said to increase genetic variability, but only if the mutation is not a decrease in genetic sequences.
Nope.
Let's take one random sequence: CGTA ATCG AACC CGCT TTAG CCGG GGTC
Let's imagine all the individuals have this one sequence.
Then, suddenly, deletion mutation and little Henry only have: CGTA ATCG AACC CCGG GGTC.
There is now
TWO sequences present in the population. The number of alleles at this locus, a good measure of genetic diversity has
doubled!
BUT the process of subgrouping involves a decrease in genetic variation to begin the process. That's a major reason we consider smaller isolated groups of animals, for example, are in danger of extinction of they cannot mate with other populations.
Nope.
Isolation, in itself, does not reduce diversity.
As explained to you, isolation can occur through a variety of reasons. Geographic isolation is a major one such variant. But isolation as been observed, for example, between two population of insect preferring different flowers or, on the other hand, flowers from the same species preferring different insects as polinizing insects...
In these case, we have reproductive isolation without loss of the numbers of individuals.
Once the two populations are isolated to a significant degree, their process of evolution become separated. They each go in different direction, the mutations will only occur in one population and spread through this population but not in the other. This means that the differences between them will start to accumulate, hence, an
increase in diversity.
Now, especially in a small populations, we have what we call genetic drift. Basically, the less prevalent alleles, will be squished away. That's a reduction in diversity within the
smaller population. The "parent" population, of course, will remain mostly unaffected.
Of course, it does not mean that this reduction will overcome the other means of increase in diversity. Indeed, in the vast majority of cases, isolation leads to an
increase in diversity.
Let's say I sell something new for $5 that I paid $500 for. It doesn't take a genius to see I am losing money on the sale even though technically, that one small part, the $5, did add some money to me. The process as a whole though is a losing proposition.
Evos have never substantiated the claim that mutations can add genetic variability faster than are lost due to subgroup isolation.
If you disagree, show me one study comparing the 2.
Why one study? Why this obsession with the one study? Don't you think that there is enough variability out there so that one study taken out of its context means little?
You'd need to look at the effect over a variety of species in a variety of environments and see what the general rule is.
The consensus is: the effect of genetic drift is more important in smaller population: there is first the founder effect, and then, the number of individuals carrying the genes is smaller and so do not buffer as much for stochastic variations. On other hand, because there are less individuals reproducing, there is a lower number of mutations taking place.
So, below a certain number of individuals termed N
e, there is a point where, indeed, genetic drift will overwhelm the gain of diversity from random mutations and natural selection. That is what is called a "population bottleneck".
N
e, of course, varies between one population to another based on what level of genetic diversity it had to begin with, its mutation rate and reproductive mechanism...
Anyway,
here, is the one article for you to ignore and wave away... But it's hardly new science.
And, anyway, it has little to do with microevolution as mentioned in your initial point: "The mechanism of microevolution itself. It's a process of subgroup isolation, which is a process of decreasing genetic variability.
Link."
Don't think that because you shifted the goalposts and did some wikying in the meantime to make it sound less imbecilic we forgot that initial point that betrayed a sharp lack of understanding of evolution...
