MICRO EVOLUTION

MICROEVOLUTION

It is the evolutionary change within populations. Five main forces cause microevolution. These forces include gene flow, natural selection, mutation,genetic drift, and non-random mating.

Natural Selection

A cause of microevolution. It is when variants of species are able to adapt and thrive better because of their genes. They are the variations that survive and pass down their genes to their offspring.

Directional Selection

A type of natural selection that favors an extreme phenotype. It is when nature pushes a trait in one direction over time. Like when favorable that allow an animal to adapt better, leading in a shift towards that trait for the population over time.

Disruptive Selection

A type of natural selection that favors extreme phenotypes. Meaning that phenotypes that are average, or in the middle are unable to thrive as much because of how average they are.

For example, birds with large beaks can break large seeds, small beaks with small seeds, but medium beaks cant break anything.

Stabilizing Selection

A type of natural selection that favors medium or intermediate phenotypes.

Sexual Selection

A type of natural selection where males and females adapt and change to find a mate.

Intrasexual Selection

A type of sexual selection wherein members of one sex fight one another to gain the attention and mate the opposite sex. This usually leads to the strongest male passing on their genes to the offspring.

Intersexual Selection

When the members of one sex choose their mates from multiple individuals of the opposite sex. This selection chooses the most attractive, intelligent mate that passes those genes down to the offpsring.

Mutation

A cause of microevolution which comes from a random change in the DNA sequence that results in a new variation of species. Not all mutations affect the genetic equilibrium of the population.

Gene Flow

A cause of microevolution wherein a new type of allele is migrated into a population of the same species. This disturbs the genetic equilibrium, as allele frequency is changed in the next generations.

Genetic Drift

A type of microevolution caused by a random or chance event.

Bottleneck Effect

A type of genetic drift that is the loss of genetic variation and diversity from natural disasters or events.

Founder Effect

A type of genetic drift that occurs when a small group of individuals from a large population break away to form a new population. Genetic variation is lost due to them not representing the original genes of the larger population.

Non-Random Mating

A cause of microevolution that occurs when organisms mate based on the specific trait they want, which leads to changes in gene frequency.

Assortive Mating

A type of non-random mating when individuals mate with those similar to themselves.

Disassortive Mating

A type of non-random mating when individuals mate with individuals dissimilar to them.