Genetics and ecosystems official content key terms

Allele

Different forms of a gene that can exist at a specific locus on a chromosome.

Dominant

An allele that expresses its phenotype even in the presence of a recessive allele.

Dominant

An allele that expresses its phenotype even in the presence of a different allele.

Heterozygous

A genotype with two different alleles for a particular gene.

Homozygous

An organism with two identical alleles for a specific trait.

Heterozygous

An organism with two different alleles for a specific trait.

Multiple alleles

A situation where a gene has more than two alleles, leading to a variety of possible genotypes and phenotypes, such as in the ABO blood group system.

Phenotypic ratio

The ratio of different phenotypes produced in the offspring from a genetic cross, reflecting the expression of alleles.

Observed frequency

The actual number of occurrences of a particular phenotype in a sample.

Expected frequency

The predicted number of occurrences of a particular phenotype based on theoretical ratios.

Population

A group of organisms of the same species that can potentially interbreed in a specific area and time.

Carrying Capacity

The maximum number of individuals of a species that an environment can sustainably support.

Gene Pool

The total collection of genes and their alleles in a population.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population.

Genetic Drift

A mechanism of evolution that refers to random changes in allele frequencies in a population, particularly in small populations.

Gene Flow

The transfer of genetic material between populations, which can alter allele frequencies and affect genetic diversity.

Allele frequency

The relative frequency of an allele at a genetic locus in a population, expressed as a fraction or percentage.

Genotype frequency

The proportion of a specific genotype among all individuals in a population.

Allele

Different forms of a gene that can exist at a specific locus on a chromosome, contributing to genetic variation.

Phenotype

The physical expression of an organism's genotype, influenced by both genetic and environmental factors.

Adaptation

A trait that enhances the survival and reproductive success of an organism in its environment.

Fitness

The relative ability of an organism to survive and reproduce in a specific environment.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Fitness

The ability of an organism to survive and reproduce in its environment, often measured by the number of offspring produced.

Genetic Drift

A mechanism of evolution that involves random changes in allele frequencies in a population, especially significant in small populations.

Founder Effect

A phenomenon that occurs when a small group of individuals establishes a new population, leading to reduced genetic diversity compared to the original population.

Geographic isolation

A form of reproductive isolation where physical barriers prevent populations from interbreeding.

Temporal isolation

A form of reproductive isolation where species breed at different times, preventing mating.

Community

A group of different species living together in a particular area and interacting with each other.

Carrying Capacity

The maximum population size that an environment can sustain indefinitely without being degraded.