False and refuted by observation of new specie shown in photo below:
True dogs give birth to dogs, but not always with exactly the same DNA (I.e. microevolution is real). Each generation’s minor DNA difference can slowly accumulate in many thousands of generations to make a new species if the environment favors a new life form more than the old. (Macroevolution, the accumulation of microevolution changes, is real.)
Here is an example of guinea pigs becoming the quite different species, the Preá, shown in photograph, via thousands of generations of microevolution:
A case of microevolution producing new species (macroevolution via accumulated microevolution)
This happened very rapidly (in only 8000 years) for seven factors / reasons listed* at end of this post and discussed here:
http://www.sciforums.com/showpost.php?p=2687668&postcount=1016
Look carefully at photo: There was little evolutionary pressure to change the hair growth pattern, so you can still see the two locations on the sides of the head where guinea pig eyes are located. This new species evolved on tiny island with no predators so eyes slowly moved together every generation for better depth perception. - No need for 360 vision to watch out for non-existent predators, but good depth perception greatly aided survival . I.e. not being one of the many in each generation that starved to death in the dry season (as did more rabbit like hind legs for hopping over rocks). More discussion of this at end of this post.
“… There are approximately 40 of these little animals, called Preá in Portuguese, living on tiny island called Moleques do Sul, which is about 8 km separated for a much larger Island called Florianopolis that have been studied by Pontifica Universidade Católic under leadership of Sandro Bonatto. About 8000 years ago, these two islands were one as the sea level was much lower. The tiny island is about the size of a football field and mainly rocks. But has some grass on ~10% of it between the rocks.
These Preá are so inbreed that DNA tests (type used in Brazil to determine disputed paternity, at least) cannot determine any differences. They are about half the size of the main island animals they evolved from during 8000 years of separation. Smaller size was favored by selection because of the very limited food supply. They are the only mammals on the tiny island and have no predators. - I.e. population is limited only by the lack of food for more than 40 but probably has been slightly increasing as they evolved to be ever smaller each 1000 years. (Probably no more than 20 of them lived after the connection to the main island was cut off 8000 years ago by the melting ice.)
Their tiny island is part of a state park, now with special protection - only qualified researchers can legally visit, but some fishing boats do at times. The great fear is that one will leave a cat on the island. - Then this recently evolved new species will go extinct. ..." {It is new species by standard definition: They cannot breed with guinea pigs even by artificial insemination. – Researchers tried to help insure their unique DNA would not be lost. As the Preá lack genetic diversity they could all be wiped out by a disease as well as a fisherman's cat left on the island.}
Text quoted above is from:
http://www.sciforums.com/showpost.php?p=2205207&postcount=83
A final comment {from the next post, 84} on the evolution of the preá:
"... A tiny population (40 or perhaps only 20, initially) living on the edge of extinction for 8000 years (due to limited food, and no predators) have very rapid evolution compared to a large population living in relative ease with abundant grass, seeds etc., except for being caught and eaten. (The predators eat the beneficial genetic innovations often before they can become a dominate part of the large gene pool) Thus the preá did in 8000 years what normally might have taken 8 million years. - Became a new species. The "easy-living" main island guinea pigs did not evolve - they are still guinea pigs.
Also interesting to note that once genetic identity has been achieved and ill effects of incest eliminated, then when a hail storm or hurricane killed most of the preá, they could quickly rebuild the population back up to the food limit so long as one male and a few females made it thru the storm. In this sense, what is normally a problem (lack of genetic diversity) is actually a survival aid! ..."
Text below is from more recent post discussing eye locations at:
http://www.sciforums.com/showpost.php?p=2688946&postcount=1053
“… {Forward looking eyes} is normally the case for animals that prey on others, like eagles, hawks, lions, snakes, wolves, polar bears, man, etc. as that makes the field of vision of the two eyes overlap and thus give good depth perception (provides stereoscopic effects); however if the animal is the prey and eats grass etc then the eyes look out to both sides as nearly a 360 field of vision is more an aid to survival than good depth perception. Thus cows, zebras ,
guinea pigs, wildebeest, etc. (all the grass eaters), pigeons and other seed or fruit eating birds, and bottom of the food chain fish, have eyes on the side of the head for near 360 field of vision. (No need for depth perception as the grass, seeds or fruit doesn't try to escape. They don't need depth perception, to chase their food, but 360 vision helps them not be eaten.)
In the case of preá, their guinea pig ancestors 8000 years ago were no exception - they had eyes looking out to both sides. However as the ice melted and raised the sea level and separated about 20 of these guinea pigs (all there was food for on the tiny new island, 8km by boat from the main island), they were the only mammals on the football field sized rocky island (only 10% with grass between the rocks) - they had no other animals that would prey on them. So those in the next generation with slightly more forward looking eyes and slightly better depth perception were better able to jump over the rocks safely to find some grass to eat. (They also got more rabbit like hind legs to aid that jumping over rocks.)
As in-breeding made more individuals in each generation than could survive those with the slightly more forward looking eyes tended not to be among those that starved to death. Likewise the smaller ones tended to be among those that survived as they needed less food to do so. Now, 8000 years later, the preá have eyes very close to each other, which are only forward looking with excellent depth perception and are slightly less than half the size of guinea pigs so there is food (grass between the rocks) for 42 of them (or only 40 in dry years). …”
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* Enviromental theory does also predict what factors will speed the development of a new species. The major ones are:
(1) Isolated gene pool, so new beneficial gene for that environment will not be too quickly lost among a wider population
(2) Very small gene pool so new beneficial gene can quickly spread throughout the small gene pool.
(3) No Predators to eat the bearer of the new beneficial gene before it can be spread into later generations.
(4) Stable conditions may make a potentially beneficial gene have little difference in survival. For example, a creature that only can digest bananas might have a genetic change that allowed it to digest grass, but if there are lots of bananas available and bananas are what the bearer of the grass digestion gene had learned to eat from its mother, that gene, although potentially beneficial will not offer much survival advantage, but, when the massive banana blight hits and 90% of the gene pool starves to death it will be quite beneficial. Thus, guinea pigs living in a large gene pool with easy conditions (on the nearby large island) did not change.
(5)Very harsh environment conditions make even small genetic advantage (say eyes with only one degree more visual over lap than "normal") make a very big survival advantage. - Get that new gene quickly selected for in a small population. Minute shifts in eye location accumulated over thousands of generation converted the guinea pig's side looking eyes into forward looking eyes of the Preá .
(6) The same harsh condition lasting for long periods, not just a passing drought or fire etc. but same harsh conditions for tens of thousands of generation (such as a significant fraction of the gene pool starving to death each year due to over breeding) rapidly select for even tiny genetic advantages.
(7) Being trapped in a tiny areas with no means of moving to where conditions are less harsh.
PS. This post is for others.- I am under no illusion that facts will change your false, unfounded, beliefs.
