Define genetic drift and state two types of genetic dritt.
wo types of genetic drift. give an example of each type.

Change/error in the gene pool of a population is called genetic drift.

When a change or an error occurs in a said gene pool, it is called gene drift. It occurs due to an event strictly based on chance. A particular genetic trait is either lost or spreads in the said population.  "Population bottlenecks and the founder effect" are the two types of gene drifts.

Bottlenecks effect:  Drastic degradation in the size of a population due to a large-scale environmental hazard.

Example: Floods

Founder effect: Formation of separate colonies by a few individuals of the said population. It results in a decrease in population as well as genetic variation.

Example: Colonization of certain individuals carrying a contagious virus.

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.