AP BIOLOGY

Detailed explanation-1: -Scientists think that species with a shorter evolution evolved mostly by punctuated equilibrium, and those with a longer evolution evolved mostly by gradualism. Gradualism is selection and variation that happens more gradually. Over a short period of time it is hard to notice.

Detailed explanation-2: -Phyletic gradualism is a model of evolution which theorizes that most speciation is slow, uniform and gradual. When evolution occurs in this mode, it is usually by the steady transformation of a whole species into a new one (through a process called anagenesis).

Detailed explanation-3: -Evolution over a short period of time at the level of the population is called microevolution. Evolution over a long period of time above the level of the species is called macroevolution. Microevolution occurs in a population when its allele frequencies change over time.

Detailed explanation-4: -In modern biology, gradualism, or “phyletic gradualism, ” refers primarily to a pattern of sustained, directional, and incremental evolutionary change over a long period during the history of a species.

Detailed explanation-5: -Evolution is a gradual process in which something changes into a different and usually more complex or better form. The mechanisms of evolution include natural selection acting on the genetic variation among individuals, mutation, migration and genetic drift.