evolution question....?

Question

some lineages branch out many times and are represented by many living species. What ecological coditions would result in rapid diversification of some lineages?

Answer 1

Many ecological conditions could diversify living species. But, key to what makes them actually diversify is the fact that conditions that ancestors might have lived in are different from the descendants' conditions. Thus, these changes in ecological conditions drive the descendants to diversify mainly to adapt to the changing the conditions. Hence, we cannot tell which ecological conditions particularly would drive the diversification.
Hope that helps!

Answer 2

Geographic isolation plays a big role. A subset of a population can be geographically isolated by a variety of mechanisms. Examples might be a river altering it's course, rifting (formation of the African Rift Valley resulted in rapid speciation/ diversification), or formation of new mountain ranges to name just a few.

Formation of new ecological niches also plays a big part. Extinction events that left many niches vacant have been major drivers for subsequent biodiversification and rapid speciation. The most famous event was the mass extinction event at the end of the Cretaceous period but there have been many such events. A much larger one, in fact, occured at the end of the Permian period. Rapid climate changes also create new and different ecological niches to be rapidly filled. Glaciation is an example.

Answer 3

Changes happen in genetic coding every so often. If this change survives, it gets passed along to off spring. The environment does not drive these changes in that is causes them. The environment selects changes that aid is survivability.

Most genetic changes are probably negative, and that trait dies out. Some are fairly neutral, and survive. Others give a survival edge, and this genetic change is then passed on to more off spring than the original.

Say, a genetic change causes longer fingers. Both genetic traits survive. You will find short and long fingers in the species. If another change like this happens, you could find all three traits existing.

However, if something happens in the environment that makes the individuals with the longer fingers survive better by being able to reach food that the others can't. Even one extra surviving baby per so many births will eventually give the edge to those with this trait and the shorter fingers will no longer occur.

Answer 4

A permissive ecology.

The situation that would allow the most rapid speciation from one ancestor, would be from a species that survived a mass extinction event.