Natural Selection and Hardy-Weinberg Equilibrium

These flashcards cover key concepts from the lecture on natural selection, Hardy-Weinberg equilibrium, and various evolutionary principles.

Natural Selection

The non-random difference in reproductive output among replicating entities, often due to survival differences in a specific environment.

Bacterial Operons

A group of genes that are regulated together; includes inducible operons like lac operon and repressible operons like trp operon.

Lac Operon

An inducible operon that promotes transcription of genes involved in digesting lactose when lactose is present.

Trp Operon

A repressible operon that inhibits transcription in the presence of tryptophan.

Allele Frequency

The proportion of a specific allele among all allele copies in a population.

Hardy-Weinberg Equilibrium

A principle stating that allele and genotype frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.

p and q

p represents the frequency of the dominant allele while q represents the frequency of the recessive allele in a population.

Genetic Drift

The change in allele frequency due to random sampling events, particularly in small populations.

Convergent Evolution

The evolution of similar structures in different species due to similar environments, leading to analogous structures.

Divergent Evolution

The evolution of different traits in species that share a common ancestor, resulting in homologous structures.

Directional Selection

A type of natural selection that favors phenotypes at one end of the phenotypic spectrum.

Disruptive Selection

A type of natural selection that favors individuals at both extremes of the phenotypic spectrum.

Stabilizing Selection

Natural selection that favors average phenotypes and selects against extreme variations.

Phenylketonuria (PKU)

A human metabolic disorder that results in mental retardation if untreated, inherited in an autosomal recessive pattern.

2pq

The equation representing the frequency of heterozygous individuals in a population according to Hardy-Weinberg.

Allelic Frequency Calculation

Using the Hardy-Weinberg equation to calculate frequencies and percentages of alleles and genotypes in a population.

Mutations

Changes in the DNA sequence that can create genetic variation essential for evolution.