vocab 1
differential survival and reproductive success among a group of organisms due to differences in the inherited traits or characteristics of the organisms
natural selection
a process by which the heritable characteristics of a population change such that the organisms in the population become better able to survive and reproduce in their environment
adaptation
What is a resource?
A source or supply that can be used to benefit organisms.
How does overproduction of offspring contribute to natural selection?
Because more offspring are produced than can survive, individuals with favorable traits are more likely to live and reproduce.
How do polygenic traits show continuous variation in a population?
Polygenic traits are controlled by multiple genes, producing a wide range of phenotypes.
What is adaptation, and how does it increase fitness?
An adaptation is an inherited trait that increases an organism's fitness by helping it survive and reproduce.
Defenition of phenotype...
The physical expression of a gene or set of genes; the appearance of an organism.
How do selective pressures affect populations?
Selective pressures favor individuals with beneficial traits, increasing their chances of survival and reproduction.
How does differential survival lead to changes in populations over time?
Individuals with beneficial traits survive and reproduce more, making those traits more common.
How does gene flow affect genetic variation in a population?
Gene flow introduces new alleles into a population, increasing genetic variation.
How does variation in a population support natural selection?
Variation provides differences in traits that natural selection can act on.
Explain survival of the fittest
The continued existence of organisms that are better adapted to their environment, with the extinction of others that are not
How does competition for limited resources drive natural selection?
Organisms with advantageous traits are more likely to survive when resources are limited.
How can environmental changes act as a selective pressure?
Environmental changes may favor certain traits, causing organisms with those traits to survive and reproduce more.
How do genetic drift and natural selection differ?
Genetic drift changes allele frequencies by chance, while natural selection changes them based on advantageous traits.
the ecological role played by an organism
niche
explain variation
the occurrence of an organism, behavior, trait, or gene in more than one form
What are the two types of genetic drift?
1:bottleneck effect 2:founder affect
When do polygenic traits occur?
Polygenic traits occur when natural selection acts on traits, or phenotypes, that are controlled by multiple genes, and each gene has some contribution to the overall result.
How can reproductive isolation lead to speciation?
Reproductive isolation prevents populations from interbreeding, which can lead to the formation of new species.
the divergence of populations or subpopulations of the same species to the point that they can no longer interbreed and generate fertile offspring
speciation
How can mutations introduce variation into a population?
Mutations create new alleles that may produce new traits in a population.
stasis, speciation, adaptive radiation, extinction
There are three basic ways that natural selection can influence the distribution of phenotypes for polygenic traits in a population. What are they?
Stabilizing selection, Directional selection, Disruptive selection
What are three ways natural selection can influence polygenic traits?
Directional selection, stabilizing selection, and disruptive selection.