Evolution

Geographic Isolation

When a population is physically separated; causes new subspecies to be created because new gene pools are created

Speciation

When new species are created from a pre-existing species because of geographic isolation

Animals produce more offspring than can survive and many that survive may not produce offspring; all species have genetic variation; there is competition (Exists within and among species); survival of the fittest; decent with modification

What are the 5 parts of The Theory of Natural Selection

Food, water, shelter, space (FWSS)

What do animals among species(Not of the same species) compete for?

Food, water, shelter, space, mates (FWSSM)

What do animals within species compete for?

Survival of the fittest

Some organisms are more suited to their environment as a result of variations in the species

Fitness

The ability of an organism to survive and reproduce in its environment

Decent with modification?

the idea that all animals physical characteristics have been modified from their ancestors

adaptation

an inherited characteristic that increases an organisms chance for survival

Biodiversity

the variation of animals within a species

Evolution

A genetic change in a population over time

Fossil

Remains or traces of an animal that lived long ago

Fossil Remain

A physical part of an organism that lived long ago

Fossil Traces

An imprint left by an organism that lived long ago

Homologous Structure

physical parts of an organism that is similar to other organisms but serves a different function

Vestigial Structures

physical parts of an organism that no longer serve a purpose

If the animal has the same structure as another animal with a similar still functioning structure, then they are related; an organisms evolutionary past

What do vestigial structures show?

A common ancestor

What do similar looking embryos of different species show?

animals are somewhat related; may share a common ancestor

What do similarities in amino acids show?

evolutionary relationships

What does a cladogram show?

Biogeography

geographic distribution of similar living species

Geographically separated species may have a common ancestor

What does biogeography show?

Population

Number of individuals of the same species that live together in one area

Biotic Potential

The size of a population if nothing stopped it

Limiting factors (FWSS)

What controls population growth?

Carrying capacity

The maximum number of organisms that an environment can support

Natural disasters, climate, food, water, shelter, space, population size

What can change carrying capacity?

Stage D; there is always genetic variability in a species

In what stage is genetic variation shown on this graph?

Stage A; potential to increase is at its maximum before carrying capacity is reached

In what stage is the ability to increase the greatest?

Stage C: Competition is at its height after carrying capacity is reached

In what stage is competition at its greatest?

Stage C: When carrying capacity is reached, only the organisms with the best variations survive

In what stage is survival of the fittest at its greatest?

Stage C: The organisms with the best traits survive and reproduce, then pass down their traits to their offspring

In what stage is descent with modification at its greatest?

Variation

What must be present in a population for evolution to occur?

Crossing over and gene mutations

Where does variation come from?

Divergent evolution

One ancestral species causes multiple descendant species to be born

When evolution occurs

When genetic equilibrium is disrupted?

Natural Selection, Migration, Genetic Drift, Isolation, Mutation, and sexual selection

What are the 6 causes of genetic equilibrium being disrupted?

Stabilizing; eliminates extremes of a trait, causing a reduction of variation in a species

What kind of natural selection is this?

Directional; moves the average of a trait to the left or right

What kind of natural selection is this?

Disruptive; selects against the average and favors the extremes

What kind of natural selection is this?

Gene flow

The movement of alleles from one population to another changes allele frequencies in each area; is caused by immigration and emigration

Isolation

A type of divergent evolution; can be geographic or behavorial; can lead to speciation

Genetic Drift

A chance occurrence that changes allele frequency (Hurricanes and tornadoes)

Sexual Selection

Certain physical traits attract mates, allowing the traits to be passed on

Allele

A sequence of nucleotides; determines physical traits (Ex: AGG)