MODULE-7-PATTERNS-OF-DESCENT-WITH-MODIFICATION
Key Terms to Remember in Biology 2
Gene Pool
Definition: The gene pool is the sum of all alleles in a population.
Key Concept: It is essentially a collection of different genes within a population.
Important Terms Related to Gene Pool:
Allele: A variant form of a gene.
Sum of all alleles: The total collection of genetic variations present in a population.
Genetic Drift
Definition: Changes in the gene pool of a population due to chance events.
Two Major Types:
1. Bottleneck Effect
Occurs when a population decreases significantly due to environmental factors (e.g., natural disasters).
Result: Reduced genetic diversity as only a few individuals survive.
Example: Northern elephant seals faced a severe population bottleneck, resulting in reduced genetic variation due to hunting.
2. Founder Effect
Happens when a small group of individuals separates from a larger population to establish a new colony.
Result: Limited genetic diversity when the new population grows from a few founders.
Example: The Afrikaner population in South Africa has a high frequency of Huntington's disease due to genetic drift originating from a small founding population.
Genetic Flow
Definition: The movement of alleles between populations through migration.
Key Terms:
Immigration: Incoming individuals from other populations.
Emigration: Outgoing individuals leaving a population.
Mutations
Definition: Changes in the DNA sequence of an organism's genome.
Importance: Serve as a source of genetic variation, which is essential for evolution.
Types of Changes: Can involve alterations in physical appearance or result in genetic diseases.
Nonrandom Mating
Definition: Mating based on specific traits or preferences.
Implications: May lead to certain genotypes becoming more prevalent in the population due to mating preferences.
Mechanisms of Evolution
Key Mechanisms:
Mutation
Gene Flow
Nonrandom Mating
Genetic Drift
Natural Selection
Recombination.