Evolutionary Biology

Evolution Deffinition- change in the gene pool overtime

gene pool- traits of the population

macroevoltuion- large changes in a species over a long time

microevolution- small amount of time, changes in alleles or gene frequencies

Darwin Theory of Evolution Requires:

• Inheritance: offspring inherit parents traits

• Organisms with highest fitness survive:

  • Fitness: the ability to survive & reproduce in an environment

  • This does NOT NESSISARILY the biggest or strongest

• There is Variation between species

• OVERPRODUCTION: more organismims are produced than will survive

Darwin’s Conclusion: Individuals who inherit characteristics most fit for theri environment are more likey to leave more offspring than less fit individuals. This is calles natural selection.

Natural Selection: Individuals that have physical or behavioral traits that better suit their environment are more likely to survive and will reproduce more successfully than those that do not have such traits

• acts on a range of phenotypes (gene pool) in a population

• This does not act on idividuals, Orangisums CANNOT WILL themselves to evolve

Can we see evolution in real time? Yes, through bacteria

Artificial Selection: Humans select for/against particular traits when breeding animals and plants, create desired changes over time

Evidence of evolution: various structures/data give us evidencethat evolution has happened and is occuring

• Homologus structures: Related structres that are inherited from a common ancestors. (same relation, position, or structure)

• Analogus structres= same job, very different structre

• other evidence of evolution:

  • fossils

  • similarity of proteins/DNA between species

  • similarity of embryo deveolpment between species

Benifit of sexual reproduction to evolution: sexual reproduction can often speed up evoltuion becuase offspring have increased GENETIC VARIATION

Benifit of mutation: Mutations can also cause genetic variation- if a mutation arises that is benifitial for a particular environment, it will be passed onto the offspring & become widespread (becomes adaptation)

Adaptations: inherited characteristic that increases organismums chance for survival

ARE NOT CAUSED OVER THE LIFE OF THE ORGANISUM- cannot AQUIRE adaptations

• adaptations become common in a species (becuase of natural selection). The more common it is, the more adapted the species is

• behavioral adaptations: living in herds, mating behaviors

• Physcial adaptations: large horns, camoflage, poision

Isolation types

• Isolation= organisums of the smae species get spearated(isolated), which can lead to new species

• Geographical isoltaion: greographic/geologic event that separtes a group

• Habitat isoltaion: different members of a species end up living different habitat

• Reproductive isolation:

  • Gametic isolation-gamets don’t fertilize each other

  • temporal isolation: individuals mate at different times in the year

  • Behavioral isolation and sexual selection: different mating behaviros

Genetic drift: changes in gene frequencies ina population, cuases evolution

• bottleneck effect: population gets dramatically smaller due to natural disaster, loss of habitat, or hunting

  • causes: loss of genetic diveristy

• Founder effect: a small subset of population breaks off and starts a new colony

  • also decreases genetic diverity