AP Bio - Evolution Unit

Artificial Selection

Modification of other species through selective breeding with desired traits

Natural Selection

Process by which organisms better suited to their environment have a higher chance of survival and passing on their traits to the next generation

Evolution

Descent with modification ; process by which species accumulate differences form their ancestors as they adapt to different environments over time

Adaptation

Inherited characteristics that enhances chances of survival or reproduction

Homology

Similarities from common ancestry

• Homologous structures — same structure, different function

• Vestigial structures — remnants of features that served important functions in ancestors, but serve no current purpose today

Ancestral characters

Characters that remained since common ancestor

Derived characters

Characters that changed since common ancestor

Morphological

(In cladograms) uses structural traits as basis of organization

Molecular

(In cladograms) uses the basis of amino acids (DNA ←→ RNA) to determine the type of organism it is

Population

Group of individuals living in the same area

Gene Pool

All alleles for loci in population

Hardy-Weinberg Equilibrium

Describes a population that isn’t moving

Founder Effect

Genetic drift caused by individuals that leave to start a new population

Bottleneck effect

Genetic drift caused by drastic reduction in population size due to sudden environmental change

Gene flow

Movement of alleles between populations

Reproductive Isolation

Isolation that prevents different species can’t mate with each other

Prezygotic barriers

Barriers that blocks mating or fertilization (prevents mating from happening in the first place)

Habitat Isolation

Prezygotic barrier made possible with species occupying different habitats

Temporal Isolation

Prezygotic barrier made possible with different breeding times throughout the year

Behavior Isolation

Prezygotic barrier made possible with different courtship rituals

Mechanical Isolation

Prezygotic barrier made possible due to morphological differences

Gametic Isolation

Prezygotic barrier made possible due to sperm’s inability to fertilize the egg

Postzygotic barriers

Barriers that prevent hybrid zygote from developing into a fertile adult (prevents hybrid offspring from continuing development after mating)

Reduced hybrid viability

Postzygotic barrier where hybrid offsprings die off early

Reduced hybrid fertility

Postzygotic barriers where hybrids are sterile (unable to have gametes)

Hybrid breakdown

Postzygotic barriers where 1+ generations are successful but eventually die out

Allopatric speciation

Speciation that results due to the species from being geographically isolated

Sympatric speciation

Speciation that results from being not geographically isolated

• isolated by their niches

• occurs from mutations (polyploidy)

  • occurs from sexual selection

Obligate aerobes

Organisms that require O₂ for cellular respiration

Obligate anaerobes

Organisms that get poisoned by O₂

Facultative Anaerobes

Organisms that can switch between using O₂ or not