Animal species and Punctuated Equilibrium

[4gold]

I am just a beginner on this series of Evolution and Creationism, so please take it easy on me

As I read books on the origins of man, I have come up with a few questions that I have not been able to find an answer to in my readings. If you could, please let me know what the answer is and where I can read up on it.

Fossil records demonstrate a very vast array of plant and animal species discovered throughout millions of years of geological formations. Yet, no new animal species has been discovered or observed since the fossil records of man's first entrance onto this Earth.

I have read Stephen Jay Gould's book on punctuated equilibrium and understand that scientists explain this by saying we are in an era of relatively little to no macroevolutionary change. I do understand that we have massive documentation of microevolutionary change, such as the finches on the Galapagos Islands.

I understand punctuated equilibrium and it makes sense to me, since fossil records show periods of massive special change and minor special change -- it is rarely steady. But my question is: Why have there been NO new animal species observed, instead of relatively FEW new animal species?

[ST88]

One of the problems you have is that we've been around for an amazingly short period of time, you don't get new species in a short period of time.

Not only that, but we've only been studying these things for a small fraction of the time we've been here.

[ST88]

Putting aside island effects, the most rapid speciation is likely to be in the most rapidly reproducing organisms -- protozoa, bacteria, &c. Occasionally a species' novelty can be deduced historically -- antibiotic or nylon eating bacteria, for example. Most of the time it happens right under our noses and we just don't notice.

This is true but in populations that are vast, mutation that does not itself give huge advantage is quickly overwhelmed by dominant traits within the gene pool. As you rightly point out bacteria change quickly when treated with antibiotics, this is due to the resistant ones having huge advantage in terms of survival and reproduction. These same bacteria can also be shown to have been virtually unchanged in the preceding millions of years(or in the case of certain treponemes to have very little resistance to antibiotics but be very good at adapting to different environments).

I think has more to do with natural variation than mutation. The bacteria don't "mutate" in order to be resistant to the antibiotics, the resistant ones are those who had already had that resistance feature. As far as I can tell, it's up in the air as to whether or not toxin-eating bacteria actually mutate to gain the feature or are simply variants in a population. For example, in this article: Bacteria Turn Toxins Into Plastic it states that the bateria in question must be "isolated" in order to be useful.

[Curious]

I think has more to do with natural variation than mutation. The bacteria don't "mutate" in order to be resistant to the antibiotics, the resistant ones are those who had already had that resistance feature. As far as I can tell, it's up in the air as to whether or not toxin-eating bacteria actually mutate to gain the feature or are simply variants in a population. For example, in this article: Bacteria Turn Toxins Into Plastic it states that the bateria in question must be "isolated" in order to be useful.

But mutation is one cause of natural variation within a species. While some mutations are not compatible with heredity, others certainly are. The mutation need not arise at the same time as, or as a response to, changing environment but may have existed within the species for an indefinite time already. The fact that the environment occupied by some bacteria naturally contain penicillin would account for the survival of such a mutation and subsequent spread throughout the population, while treponemal organisms such as the ones that causes syphilis (treponema pallidum) inhabit an environment that does not naturally produce such a substance and therefore such a mutation would have little chance (unless linked to another beneficial side effect) in asserting dominance over none resistant traits.