Lecture 15- Microevolution and Genetic Mechanisms

Practice flashcards covering the concepts, mechanisms, and examples of microevolution, including genetic drift, natural selection, and coevolution.

What is the difference between an organism's genotype and its phenotype?

An individual's genotype is their genetic blueprint, while their phenotype refers to their physical and physiological characteristics.

How is a 'gene pool' defined in the context of a population?

A gene pool consists of all the alleles that exist within a population.

What is the definition of microevolution?

Microevolution is evolutionary change resulting from a change of the allele frequencies of a population.

How does macroevolution differ from microevolution?

Macroevolution is large-scale change occurring over long periods of time that results in the formation of new species, known as speciation.

What are the four mechanisms of evolutionary change within a population?

1) Mutation, 2) Gene flow, 3) Genetic drift, and 4) Natural selection.

In terms of inheritance, which types of mutations can be passed on to offspring?

Only mutations that affect reproductive cells can be inherited.

What is 'gene flow' and how does it affect genetic differences between populations?

Gene flow is the movement of alleles from one population to another; it can reduce genetic differences between populations.

What occurs during the process of 'fixation' in genetic drift?

Fixation occurs when genetic drift leads to an allele’s frequency becoming $100\%$ in a population.

Under what population conditions is genetic drift most pronounced?

Genetic drift is most pronounced in small populations.

What is the 'founder effect'?

The founder effect is a change in allele frequencies that occurs when a new population is established by a small group of individuals.

What is a 'genetic bottleneck' and what are two species provided as examples?

A genetic bottleneck is a sudden reduction in the alleles of a population; examples include Elephant seals and Cheeta’s.

What is 'artificial selection' and what is one plant species used to demonstrate it?

Artificial selection is the selective breeding of plants or animals for a desired trait; an example is the Wild mustard plant ($Brassica\,oleracea$).

How is 'biological fitness' defined?

Biological fitness is the ability of an individual to produce offspring, relative to other individuals of the same species.

What is an 'adaptation' in evolutionary terms?

An adaptation is a heritable trait that increases the reproductive success of an individual relative to individuals lacking that trait in the same environment.

In the Peppered moth example, how did the population percentage of the black morph change between 1848 and 1900?

In 1848 the black morph was not dominant ($gray\,morph\,\approx\,98\%$), but by 1900 the black morph increased to $\approx\,95\%$ of the population due to soot from coal factories.

How did environmental conditions affect the beak size of Galapagos Finches?

During drought years, bigger beaks were selected for to eat large, hard seeds; in wet years, smaller beaks were selected for to eat small, soft seeds.

Why are carriers of the sickle cell trait abundant in malaria-stricken regions?

Sickle cell anemia is a recessive trait, and carriers of the trait have a strong resistance to malaria.

What is 'coevolution' and what are three examples of species interactions that drive it?

Coevolution is the process where two species interact and influence each other's evolution; examples include predator/prey interactions, competitive species, and mutualistic relationships like pollinators and plants.

What is an 'evolutionary arms race' and which specific pair of animals is cited as an example?

An evolutionary arms race is coevolution between predator and prey where adaptations in one drive counter-adaptations in the other; an example is the Garter snake and rough skinned newt.

What is 'sexual dimorphism'?

Sexual dimorphism refers to phenotypic differences in the males and females of the same species.