Grade 11 Biology - Evolution

Evolution

changes in DNA of a species over time

Natural Selection

The environment selects which individuals produce the most.

Artificial Selection

When humans decide which individuals will breed

Adaptation

A change in protein synthesis giving an advantage to an organism but not a change in DNA

vestigial structures

A structure in an organism that has lost all or most of its original function.

Gene pool

The total collection of alleles in a population

Convergent Evolution

the evolution of similar traits in distantly related species eg. whales and sharks

Divergent Evolution

evolution of one or more closely related species into different species; resulting from adaptations to different environmental conditions.

Coevolution

process in which two or more species evolve in response to changes in each other

Eg. agouti and brazil nut

Lamarck

inheritance of acquired characteristics- proved incorrect

Galapagos Islands

Islands where Darwin notice adaptive radiation

Cuvier

a palaeontologist who proposed the theory of catastrophism

Lyell

a geologist who proposed the theory of uniformism

Macroevolution

large scale evolutionary changes including the formation of new species

Microevolution

Small changes in gene frequencies within one generation of a population/species.

Allopatric Speciation

Occurs when the population is divided by a physical barrier into two subpopulations

Genetic Drift

changes to an allele's frequency as a result of chance; such changes are more pronounced in small populations

Gene Pool

All of the alleles in all the individuals that make up a population

Alleles

a specific form of a gene

Mutation

A change in DNA

homologous structures

Similar anatomical structures with different functions

Disruptive Selection

a type of natural selection in which two extreme forms of a trait are selected

Stabilizing Selection

Natural selection that favours average individuals in a population

Directional Selection

occurs when natural selection favours one of the extreme variations of a trait

Adaptive Radiation

Evolution from a common ancestor that results in many diverse species adapted to different environments

Cladistics

a method of determining evolutionary relationships based on the presence or absence of recently evolved traits

Analogous structures

Similar functions with different anatomical structures

terestrial

Living on land

punctuated equilibrium

The theory that species evolve during short periods of rapid change

adaptive radiation

An evolutionary pattern in which many species evolve from a single ancestral species

Fossils

Traces of organisms that existed in the past

Embryology

The branch of zoology studying the early development of living things.

founder effect

When a portion of an original population breaks off and forms a new population

bottleneck effect

a population is reduced drastically from an event

gradualism

species evolve by the accumulation of many small changes over a long time period

punctuated equilibrium

The theory that species evolve during short periods of rapid change

behavioral adaptation

A change in the way an animal acts and responds to its environment.

Pre-zygotic

before fertilization

Post-zygotic

after fertilization

Behavioural

Two species have different courtship behaviours. eg. Songbirds

temporal

mating at different times. eg.frogs

Habitat

Species occupy different environments

gametic isolation

When sperm can't fertilize the eggs.

Zygotic Mortality

Fertilization, but no zygote

hybrid inviability

fertilized egg cannot progress past an early embryo

hybrid infertility

hybrid offspring are sterile or have low fertility