The Problem with Panda Evolution
by Laurence D Smart B.Sc.Agr., Dip.Ed., Grad.Dip.Ed
[Free to print and distribute. Copy must be in full.]
In populations of wild animals, evolution works on many characteristics/characters at the one time. In herds of domestic animals, which are claimed to reflect evolution in action, only a few characters are selected by the breeder.
Every successful animal breeder knows that it is a waste of time trying to select for many characters at the same time. Usually breeders only select for one or two characters. When these characters are 'set' in the herd, the breeders select for others. This is not the same way that evolution is claimed to work.
Animal husbandry textbooks teach that all characters that need changing must be ruthlessly selected. "To eliminate the unwanted ones rigorous selection is necessary" (J. Hammond, et al., "Hammond's Farm Animals" (4th ed.) Edward Arnold Publishers Ltd: London, 1971 p:246)
In wild populations, however, natural selection works by the death of animals under circumstances not determined by human interests. The greatest selection pressure is placed on those animals that are the weakest. These are the ones that are more easily captured and eaten by predators.
The results of computer simulations, have shown that in theory, evolution working through natural selection will also select animals on their reproductive capacity. As many individuals are killed by predators, evolution favours those with the ability to produce large numbers of offspring, as well as those with speed and stamina to evade capture.
Less important features such as the shape of the eye or the size of the ear virtually take no part in the selection process. All characters other than those affecting reproduction and evasion should therefore remain constant in the population.
For characters which is controlled by many genes (rather than just one gene), genetic studies show that the character's heritability is crucial. Low heritability means that a character makes virtually no progress in taking over a population. While characters with higher heritability have difficulty spreading in a population. Evolution under natural conditions should therefore only work on one or two characters at a time, and then only on those characters that are controlled by a single gene.
It is interesting to note that the Giant Panda does not fit this scenario - it appears to be an exception. If evolution is true, with our knowledge only an interpretation of the past events, then animals should fit the scientific model.
An article in the Science section of The Canberra Times (14/10/97 p:18) records the lament of Dr Li Shaochang, director of China's Chengdu Research Base of Giant Panda Breeding. The doctor believes that Giant Pandas will only exist for the next one or two decades. They are not becoming extinct because of human slaughter, but because they are not good breeders in the wild.
Despite Giant Pandas having 'evolved', Chen Yucun, Director of the Fuzhou Zoological Society, reported that the male and female pandas have reproductive incompatibilities. Even with an IVF (artificial breeding) program, scientists foresee problems even with breeding pandas in captivity.
The problems of the pandas are:-
(1) Their genitals do not match in size
(2) The males do not instinctively know how to mate
(3) Females seldom come on 'heat'
(4) Females show no signs for males to know they are on 'heat'
(5) The females are irritated by the advances of males
(6) The pair often end up fighting each other causing injury
Now if evolution produces life on earth, the theory and simulations show that strong breeding ability has to be selected for, otherwise a species will not produce a large enough population for evolution act on.
Some may say that pandas have lost their reproductive ability because evolution is not working on them at the moment. With no natural predators to keep their breeding fine-tuned, pandas are "devolving" in that area. For this to be true, however, there must be active, natural selection to cause such changes. Clearly this is not the case