Chapter 24 and 25: FRQ Hints

Explain how speciation can occur spontaneously.

Adaptive divergence leading to speciation. Adaptive divergence is the evolution of new forms from a common ancestral form due to adaptation to different environmental conditions.

Explain what conditions are necessary for a fossil to form from the original organism.

Fossils of hard mineral parts (like bones and teeth) were formed as animals were quickly buried after their death (ex: by sinking in mud). Over time, more and more sediment covered the remains.

Describe relative fitness of an organism and how it can affect populations in the competition.

If the genotypes best suited for survival do not reproduce quickly enough, the species will become endangered or extinct.

Explain how fossils of the same organism can be found on multiple continents millions of years later and how this can cause an organism to go extinct.

Land masses drift apart, carrying species to different areas. This causes extinction because organisms need to adapt quickly to their new environment.

Describe relative fitness of an organism and how it can affect populations in the competition.

Relative fitness is the survival and/or reproductive rate of a genotype (or phenotype) relative to the maximum survival and/or reproductive rate of other genotypes in the population.

Know how the mechanisms of speciation occur and how it can lead to new species from a common ancestor.

Reproductive isolating mechanisms are either prezygotic or postzygotic. These mechanisms ensure that species remain distinct in nature. Prezygotic isolating mechanisms occur prior to the formation of the zygote. Postzygotic isolating mechanisms are when two different species can mate, but their offspring are infertile.

Know how the mechanisms of speciation occur and how it can lead to new species from a common ancestor.

Species formation can occur either through allopatric (geographic) speciation or through sympatric (new species evolve from a single ancestor) speciation.

Explain how fossils of the same organism can be found on multiple continents millions of years later and how this can cause an organism to go extinct.

The species is distributed through different land masses. Speciation is occurring or has occurred.