The gradualist population theory states that genetic change in a population occurs extremely slowly, over a long period of time. however, the catastrophist theory claims that populations may change drastically over a short period of time, due to catastrophic events like large-scale natural disasters. the theory is a sort of hybrid of the two above, and it contends that long stretches of incremental evolution are interspersed with short periods wherein drastic evolutionary changes occur. a) uniformist b) intermittent burst c) catastrophe-bottleneck d) punctuated equilibrium

The answer is D. Punctuated equilibrium theory stipulates that species remain unchanged (or change minimally) over long period of time until a short period of rapid changes probably due to sudden changes in the environment or adverse events. It is the main principle behind cladogenesis

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

c. heat from the poles back down towards the equator.