Ch.18 intro to darwinian

Convergent evolution

Organisms evolved similar characteristics because of exposure to similar environmental challenges

Homologous

Two different RELATED species share a COMMON ancestor with different adaptations of common ancestral features

Homoplasy

Two different, UNRELATED species that DO NOT share a COMMON ancestor share similar traits

Macroevolution

Major evolutionary changes that occur over a long period of time resulting in large phenotypic changes as the formation of new species

Microevolution

More minor evolutionary changes that occur over just a few generations (allele level)

Modern synthesis

An explanation of evolution that incorporates many aspects of biology such as molecular genetics phylogeny, natural selection, mutations

Population

A group of individuals of the same species

Species

A group of successfully interbreeding organisms that also produce fertile offspring that interbreed

Vestigial structure

Remnants of structures that were present and functional in the ancestral organisms

Natural selection

Mechanism where organisms with best chance of survival pass on three genes

Evolution

Gradual change in traits over time accumulations of heritable changes

Things about evolution

1. Organisms survive because of changes that have occurred in gene pool

2. They do not change to survive

3. Changes may not result in a more complex or ordered state

4. Natural selection favors genetic change supporting survival

Diverge to the point of becoming different

Evolution in time relative

Modifications can occur in just a few generations

Major thing of biological species

• interbreeding

• Producing fertile offspring

Population

Group of individuals of one species

• live in same geographic area at same time

Leonardo da Vinci

Fossils as extinct animals/organisms

• geologist studying fossils

Hutton

Gradualism - earth’s features were formed by slow continuous period of times

Cuvier

Punctuated equilibrium

• catastrophes resulted in mass extinctions

• New species fill voids

Malthus

Geometric vs arithmetic growth

• favorable variations for survival tend to be preserved, unfavorable ones eliminated

Jean baptiste de Lamarck

Traits acquired during one’s lifetime passed to offspring natural phenomenon involved and evolutionary changes occurs

Darwin proposed evolution based on 4 observations

Variation, overproduction, limits on population growth, and differential reproductive success

Variation

Characteristics not same in all individuals

Overproduction

More offspring produced than can survive

Limits on population growth

Number of survivors limited by competitions for resources

Differential reproductive success

Most favorable combination of characteristics likely to serve and reproduce

Fossil record

Lineage - connections between living and dead

DNA analysis changing historical relationships

Other evidence - preserved footprints and embryos

Fossilization

Depends upon “rapid covering and preservation”

• favored by water environments, bogs and tar pits

Not favored

• Dry environments, rainforests

Body structure impacts fossilization

• more hard body parts then soft parts

Influenced by social structure can give false impressions