Changes in Species & Darwin's Theory of Evolution

Flashcards on Darwin's Theory of Evolution and related concepts

Charles Darwin

Sailed on the HMS Beagle to the Galapagos Islands and developed the theory of evolution based on observations of finches, tortoises, and other species.

Lamark

Believed in inheritance of acquired traits

Wallace

Studied distribution of species in terms of biography.

Malthus

Proposed human population is growing faster than food supply

Artificial Selection

Humans selectively breed organisms (humans choose 'favorable' traits).

Natural Selection

Nature chooses 'favorable' traits.

Overproduction

Produce more offspring than needed.

Competition

Offspring compete for food and space.

Variation

Characteristics within a species vary.

Adaptations

Because of variation some individuals will be better adapted to survive and reproduce

Natural Selection

The environment selects plants or animals with the best traits and they become the parents of the next generation.

Speciation

Over a long period of time, many adaptations accumulate and unfavorable ones disappear that the original species has changed so much that a new species has formed.

Coevolution

Change in one organism in response to a change of another – common in predator/prey relationships.

Analogous structures

Share the same function but not same structure – so organisms not evolutionarily related.

Vestigial structures

No longer of use and have accumulated mutations that make them smaller.

Pseudogenes

Copies of nearly identical DNA that don’t function, not translated or transcribed – so not subjected to natural selection thus they accumulate mutations faster than functional genes.

Microsatellite

Short repeated nucleotide sequences common place for mutation causing increased variation so increased survival in new environments

Embryology

Organisms with common ancestors have similar patterns of development. Also similar genes are evidence of common ancestor.

Speciation

Formation of a new species by separating the gene pools – reproductive isolation. We know that two species are different if they are not able to reproduce a fertile offspring.

Allopatric speciation

Geographic isolation, physically isolate populations

Sympatric speciation

New species develop in the same area so another form of reproductive isolation occurs ex. behavioral isolation – different mating rituals, times or physical characteristics

Polyploidy

Duplication of chromosomes – creates new species. Can only reproduce asexually or sexually with other polyploids

Adaptive radiation

Rapid increase in speciation when organisms avoid competition by adapting to different habitats

Convergent Evolution

Unrelated organisms develop similar traits due to similar environment

Divergent Evolution

Related organisms use structures in alternative ways in a new environment

Coevolution

Ecologically closely connected organisms evolve together

Gradualism

Speciation occur through accumulation of many gradual and fairly constant changes

Punctuated Equilibrium

Short period of rapid change followed by a period of stasis. It is explained by the numerous gaps in the fossil record.