Biology Chapter 16.2 Flashcards

Questions and Answers

What is immigration?

Movement of individuals OUT of a population

Process of a gene moving between populations

Movement of individuals INTO a population (correct)

Change in the allele frequency of a population

What is emigration?

Selection favoring individuals with average traits

Process of a gene moving between populations

Movement of individuals OUT of a population (correct)

Movement of individuals INTO a population

What is gene flow?

Process of a gene moving from one population to another.

What is genetic drift?

A change in the allele frequency of a population as a result of chance events rather than natural selection. Signup and view all the answers

What is sexual selection?

Males are chosen with certain traits. Signup and view all the answers

What is stabilizing selection?

Individuals with the average trait form of a trait have the highest fitness. Signup and view all the answers

What is disruptive selection?

A form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle. Signup and view all the answers

What is directional selection?

Natural selection in which individuals at one end of the phenotypic range survive and reproduce more successfully than do other individuals. Signup and view all the answers

List five conditions that can disrupt genetic equilibrium.

<ol> <li>Allele frequencies change due to mutations. 2. Population remains constant. 3. Presence of a large population. 4. Random matings. 5. Absence of natural selection.</li> </ol> Signup and view all the answers

Explain the role of mutations in evolution.

Mutations are the material upon which natural selection acts. Signup and view all the answers

Contrast gene flow with genetic drift.

Gene flow happens when organisms move into or out of a population, while genetic drift happens when a population gradually accumulates changes. Signup and view all the answers

Explain why genetic drift is more significant in smaller populations.

Less mating possibilities because of smaller population. Signup and view all the answers

Contrast stabilizing selection, disruptive selection, and directional selection.

Directional selection favors one extreme trait value, disruptive selection favors extreme trait values over intermediate ones, and stabilizing selection favors intermediate trait values. Signup and view all the answers

Study Notes

Population Dynamics

Immigration: Refers to individuals moving into a population, which can increase population size.
Emigration: Involves the movement of individuals out of a population, resulting in a decrease in population size.

Genetic Processes

Gene Flow: The transfer of genetic material between populations, which can introduce new genes or alleles to a gene pool.
Genetic Drift: A random change in allele frequencies within a population, particularly significant in small populations due to chance events.

Selection Types

Sexual Selection: A process where certain traits in males are favored for selection by females, influencing mating success.
Stabilizing Selection: Favors average traits in individuals, leading to higher fitness for those with traits near the mean.
Disruptive Selection: A form of natural selection that favors individuals at both extremes of a trait distribution, potentially leading to speciation.
Directional Selection: Occurs when one extreme of a trait is favored, shifting the population traits towards that extreme.

Evolutionary Mechanisms

Disruption of Genetic Equilibrium: Five conditions that can alter allele frequencies, promoting evolution:
- Changes in allele frequencies due to mutations.
- A constant population size.
- Presence of a large population minimizes fluctuations.
- Random mating conditions.
- Absence of natural selection.

Role of Mutations

Mutations generate genetic variation that serves as the substrate for natural selection, influencing evolutionary change.

Comparisons and Contrasts

Gene Flow vs. Genetic Drift:
- Gene flow introduces new genetic material, whereas genetic drift leads to accumulation of changes in a population over time.
Stabilizing vs. Disruptive vs. Directional Selection:
- Directional Selection favors one extreme trait, shifting the mean trait value.
- Disruptive Selection supports extreme traits over intermediates, increasing variance and facilitating speciation.
- Stabilizing Selection promotes intermediate traits, reducing variance and genetic diversity.

Description

Explore key concepts in Biology Chapter 16.2 with this set of flashcards. Each card presents a vital term and its definition, focusing on immigration, emigration, gene flow, and genetic drift. Perfect for students looking to deepen their understanding of population dynamics.