#14 Biological Evolution

Adaptation

any trait that can be passed on to subsequent generations that increases the organism’s ability to survive in its environment and reproduce more often

Competition

when organisms living in the same community use the same limited resources, but those resources are not enough to fill the needs of every individual organism

Intraspecific competition

competition between two or more individuals of the same species

Interspecific competition

competition between two or more individuals of different species

Direct competition

competition between two or more individuals where the individuals fight one another for the same resource

Indirect competition

competition between two or more individuals where the individuals use the same resource but do not interact with each other directly

Fitness

how well an individual survives and produces offspring in its environment

Natural selection

the process that results in an organism having favorable adaptations to its environment, which are passed on through reproduction, thus changing the genetic makeup of future generations

struggle for existence

the competition for vital resources between members of a population

Gene flow

the transfer of genes from one population to another due to the migration of individuals into or out of a population

Chromosomes

a strand of DNA that has been wrapped around protein to make it fit into a smaller volume

Allele

a version of a particular gene

Gene pool

the genetic information of a population of interbreeding organisms

Genetic recombination

an exchange of DNA having the same genes between homologous chromosomes that results in new combinations of alleles from multiple genes on the same chromosome

homologous chromosomes

chromosomes that contain the same genes at the same locations

Jurassic period

a period from about 200 million years ago to 145 million years ago during which dinosaurs were the predominant form of life on land

Meiosis

a type of cellular division used in sexual reproduction to produce sex cells, also known as gametes, that have half the number of chromosomes of body cells and a different genetic makeup due to genetic recombination

Mutation

a change in genetic information caused by a change in the sequence of DNA

recombinant chromosomes

chromosomes that have undergone genetic recombination and have new combinations of alleles

competitive exclusion

a process by which one species outcompetes another species trying to use the same resources in the same environment, reducing the number of individuals of the other species present in that environment

resource partitioning

when two or more species divide up a resource so they can both coexist in the same environment without having to use the same resources to survive

bottleneck effect

a dramatic reduction in the size of a population that results in a decrease in genetic variation 

evolution

change in the genetic makeup of a population over time

Founder effect

the effect on the resulting gene pool that occurs when a new isolated population is founded by a small number of individuals possessing limited genetic variation relative to the larger population from which they have migrated

Gene flow

the movement of alleles, or versions of genes, from one population to another

Genetic drift

evolution caused by random events

Reproductive success

an individual’s ability to survive and produce offspring that are viable, fertile, and successful

Selection

a process in evolution, like natural selection or artificial selection, in which only certain individuals reproduce and pass on their DNA to the next generation

Selective mating

a process of selection in which individuals will only mate with certain individuals based on their characteristics

Vector

an organism that transmits a substance from one organism or source to another

Reproductive isolation

inability of members of a population to interbreed successfully with other members of the population, due to separation caused by geographic, behavioral, genetic, or other barriers

Speciation

formation of new and distinct species as a result of evolution

altruistic behavior

behavior exhibited by individuals within a group that potentially reduces the fitness of that individual but enhances the fitness of other members of the group

Kin selection

the process by which individual animals choose to protect and care for their closest relatives, even if the decision to do so causes them harm