Populations and Evolution Flashcards
What is a population in biological terms?
A population is a group of organisms of the same species living in the same area at the same time, capable of interbreeding and producing fertile offspring.
What is the gene pool of a population?
The gene pool is the total collection of genes and alleles present in a population at a given time, including all genetic variations.
What is genetic variation within a population?
Genetic variation refers to differences in the genetic makeup of individuals within a population, leading to different traits and alleles.
What is natural selection?
Natural selection is the process by which individuals with advantageous traits are more likely to survive, reproduce, and pass on their beneficial alleles to the next generation.
How does natural selection lead to evolution?
Natural selection causes evolution by increasing the frequency of beneficial alleles in a population, leading to the gradual change in the population over generations.
What is stabilizing selection?
Stabilizing selection favors individuals with traits close to the population mean, reducing genetic variation and maintaining the status quo.
What is directional selection?
Directional selection occurs when an extreme phenotype is favored, leading to a shift in the population’s traits in one direction.
What is disruptive selection?
Disruptive selection occurs when extreme phenotypes are favored over intermediate ones, potentially leading to the formation of two distinct subgroups within a population.
What is sexual selection?
Sexual selection is a type of natural selection where certain traits increase an individual’s chances of attracting mates and reproducing, such as bright plumage in birds.
What is artificial selection?
Artificial selection is the process by which humans selectively breed organisms with desirable traits, often to enhance food production, appearance, or other characteristics.
What is genetic drift?
Genetic drift is the random fluctuation in allele frequencies in a population due to chance events, which can significantly impact small populations.
How does genetic drift affect small populations?
In small populations, genetic drift can cause alleles to become fixed or lost quickly, reducing genetic variation and potentially leading to inbreeding.
What is the founder effect?
The founder effect is a type of genetic drift that occurs when a small group of individuals establishes a new population, leading to a reduced gene pool.
What is the bottleneck effect?
The bottleneck effect is a type of genetic drift where a population’s size is drastically reduced, leading to a loss of genetic diversity and changes in allele frequencies.
What is speciation?
Speciation is the process by which new species arise from a single ancestral species, often due to reproductive isolation.
What is reproductive isolation?
Reproductive isolation occurs when two populations of the same species can no longer interbreed, leading to the development of distinct species.
What are the types of reproductive isolation?
The two main types of reproductive isolation are prezygotic (before fertilization) and postzygotic (after fertilization), such as temporal, behavioral, and mechanical isolation.
What is allopatric speciation?
Allopatric speciation occurs when a population is geographically isolated, preventing gene flow and leading to the formation of new species.
What is sympatric speciation?
Sympatric speciation occurs when new species arise within the same geographic area, often due to ecological or behavioral differences that prevent interbreeding.
What is adaptive radiation?
Adaptive radiation is the rapid diversification of a single ancestral species into a variety of different forms, each adapted to a specific environmental niche.
What is a hybrid zone?
A hybrid zone is an area where two closely related species interbreed, producing hybrid offspring, which can provide insights into speciation processes.
What is the role of mutations in evolution?
Mutations introduce new genetic variations into a population, which may be beneficial, neutral, or harmful, and provide the raw material for natural selection.
What is gene flow?
Gene flow is the movement of alleles between populations due to migration or interbreeding, which can introduce new genetic material and reduce genetic differences.
What is the Hardy-Weinberg principle?
The Hardy-Weinberg principle states that allele frequencies in a population will remain constant in the absence of evolutionary influences, such as selection or mutation.
