Variation and Selection

Flashcards on variation, selection, and adaptation in biology.

__ is the differences between individuals of the same species.

Differences between individuals of the same species

__ variation is a range of phenotypes between two extremes.

A range of phenotypes between two extremes

__ variation has a limited number of distinct phenotypes with no intermediates

Limited number of distinct phenotypes with no intermediates

__ can result in change in a characteristic or even the appearance of a brand- new characteristic in the gene pool

Mutations

Mutation is __

A change in the base sequence of DNA

In meiosis, __.

Homologous chromosomes exchange genes, and separate from one another, so the gametes which are formed are not all exactly the same.

Fitness is __

The greater its chance of surviving to adulthood and reproducing.

Process of __ is the process resulting from natural selection, by which populations become more suited to their environment over many generations.

The process resulting from natural selection, by which populations become more suited to their environment over many generations.

__ selection is the greater chance of passing on of genes by the best adapted organisms.

It is the greater chance of passing on of genes by the best adapted organisms.

__ is the change in adaptive features over time, as the result of natural selection.

The change in adaptive features over time, as the result of natural selection.

Selection __ is when individuals produce more offspring than their environment can support, and some die because of factors such as predation, food shortage or disease

Individuals produce more offspring than their environment can support, and some die because of factors such as predation, food shortage or disease

Development of __-resistant bacteria is when some bacteria mutate, change their DNA, and become resistant to antibiotics by producing thick cell walls for protection or produce enzymes to digest antibiotic

Some bacteria mutate, change their DNA, and become resistant to antibiotics by producing thick cell walls for protection or produce enzymes to digest antibiotic

__ selection is made by humans to produce varieties of animals and plants with desirable traits that would have an increased economic importance and increases the world's food supply.

Made by humans to produce varieties of animals and plants with desirable traits that would have an increased economic importance and increases the world's food supply.

Adaptation of __ to water loss, include

Have hairs on their leaves, very long branched roots to increase rate of absorption, thick waxy cuticle to prevent water loss by evaporation, stomata are sunken or present in groove, leaves reduced to spines to reduce water loss by transpiration, swollen green stem to perform photosynthesis and store water.

Adaptation of __ include

Stomata on upper surface to allow CO2 uptake or on both surfaces, little lignin in Xylem (Leaf is supported by water), thin Cuticle, roots don’t attach to ground (Floating)

__ is a random change in allele frequencies within a population.

Genetic drift

__ is the movement of genes into or out of a population due to migration.

Gene flow

The concept of __ describes the maximum reproductive capacity of an organism.

Biotic potential

A __ is a group of individuals of the same species that live in the same area and interact with each other.

Population

__ is a type of selection that favors individuals at both extremes of the phenotypic range.

Disruptive selection

__ is an evolutionary process that leads to speciation, resulting in new species from a common ancestor.

Divergent evolution

A __ is a gradual accumulation of adaptations in a population over time.

Adaptive radiation

The term __ refers to structures that have similar functions but evolve independently in different species.

Analogous structures

An __ is a trait that enhances the survival or reproductive success of an organism.

Adaptation

The __ is a measure of the genetic variation within a population.

Genetic