KMart has brought up alot of points I will put each major point in a separate thread which I am hoping will maintain its narrow focus so that the reader does not have to become overloaded.AttentionKMartShoppers wrote: There are no other times that mass speciation occurred. It is you, young grasshopper, who is wrong.
The theory goes that when a new innovation takes place that all the existing organisms must contend with the new advantage or die out.
Innitially there was no large hard bodied multicellular organisms.
Pre Cambrian soft bodied medusae sponges and primative Arthropods
Hard Bodies
Then the Cambrian Explosion
Then Mobility Increased
The rapid speciation of Fish in the Devonian
Reptile and Amphibian development.
Mammal explosion after massive dinosaur extinction.
If you examine the fossils, the various representives of the different Phyla are not very morphologically different from one another. It was not until millions of years of evolution that the different morphologies have differentiated to the point it can be seen today. So to intrepret the many phyla originating in the cambrian and precambrian and later in the mesazoic as meaning that many distinct forms appeared all at once is misleading. Take a look at the forms they are all similar and are primative representations of existing phyla. It is true however than many forms did come into existance suddenly.
An arthopod, mullusk, annelied and chordate today is as diverse as a crab, an octopus, an earthworm, and an ostrich, but if you examine the fossil record the primative forms are not as morphologically distinct. After millions of years of genetic issolation they have become.
Why do new forms not appear in the fossil record? All subsequent "explosions" are charachterized by a specific body type which suddenly fill many ecological niches. This is perhaps explained by the knowledge that any beneficial mutation is isolated to one population. In other word the benefit does not spread to the entire spectrum of organisms, only the ones it originated it.
So in the Precambrian imagine an organism, in this case it appears to be a primitive pre-arthropod now has a body type which allows it to become predatory or grow to a large size. All of a sudden every other organism is under pressure to adapt. The pre-arthropod body plan now radiates to annelids, chordates, arthropods, and extinct forms. Annelids, Jellyfish and Sponges which dominated the seas earlier are now pushed to the edges as the new forms take over. Innitially with little competition and vast open niches there is little pressure so many forms can coexist. But as the competition builds up many forms are now put to the test and go extinct. Every time a new advantage arises it elevates this specific organism and all descendants.
Now all this is theory, but as you can see in the fossil record new forms are always appearing. How would you explain the occurance of these new forms? Were there multiple creation events? If it were creation than why not new Phyla? Why do the new forms follow the body types of previous periods? In evolutionary theory it would predict diversification of existing forms. Because life begets life.
