To: BroJoeK
What's the difference between a breed and sub-species? It's simply a matter of scientific definition.
And that is where you try to slide int he falsehood, or the "difference" between micro-evolution and macro-evolution.
There is a defining point which can be used to show difference in species or type or genus or whatever word you try to use to confuse.
Can the species breed and is there a change in the blood chromosome count or makeup. Once you have a change in the chromosome count, you have a new type. And there has never been an offspring with a different chromosome count. There are no "hopeful" monsters.
Without that change in the blood, there is no real evolution, the change of one species into another.
134 posted on
11/13/2015 10:47:40 AM PST by
wbarmy
(I chose to be a sheepdog once I saw what happens to the sheep.)
To: wbarmy
wbarmy:
"Can the species breed and is there a change in the blood chromosome count or makeup." Interbreeding is not a matter of "yes" or "no", there are varying degrees of "interbreed-ability" and they are a large part of what makes different "breeds", versus "sub-species", "species", "genera" or "families".
- Breeds of, for examples, humans (races) or dogs all interbreed easily, even eagerly.
Their offspring are sometimes the best of both and normally fertile.
- At the level of sub-species interbreeding still happens in the wild, but perhaps with less frequency.
Here we might think of dogs & wolves or humans & Neanderthals.
- At the level of separate species within the same genus, differences have now grown to the point where interbreeding in the wild is quite rare.
Here the example of Polar Bears & Brown Bears illustrates the point: classified in different genera previously, they were reclassified in the same genus (Ursus) as different species once it was confirmed they do occasionally interbreed in the wild.
- At the level of different genera in the same family, the differences are so great that interbreeding approaches physically impossible.
Many examples can be cited: horses & donkeys, Asian & African elephants, lions & tigers, humans & chimps.
Yes, in some cases offspring can be produced by artificial insemination, but these are nearly always bizarre, infertile or otherwise unsustainable.
- At the level of different families in the same order, there are no examples of interbreeding among more advanced creatures, that I know of.
But we should mention that amongst lower, simpler biological orders interbreeding may be less difficult than, for example, among primates.
You mentioned human/chimp chromosome count -- humans have 23, chimps 24 -- as a major factor.
Physically what happened was two smaller chromosomes fused in pre-humans, making a larger combined chromosome #2, restricting interbreeding -- even though overall human & chimp DNA is about 97% the same -- and making human linage separate from that point forward.
For more on the human-chimp genome project, see here.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Humanchimpchromosomes.png/800px-Humanchimpchromosomes.png)
136 posted on
11/13/2015 11:33:44 AM PST by
BroJoeK
(a little historical perspective...)
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