Unit Seven: Natural Selection- essential knowledge

What is natural selection

mechanism of evolution

How is evolutionary fitness measured

reproductive success

What does natural selection act on

phenotypic variations in poopulations

How does environmental change impact populations

applying selective pressures

How do humans affect variation in other species

artificial selection

When does convergent evolution occur

when similar selective pressures result in similar phenotypic adaptions in different populations or species

By which random occurrences does evolution occur

mutations, genetic drift (bottlenecks and founder effect), migrations/gene flow

How can differences in populations of the same species increase

reduction of genetic variation

What is the flow of evolution through mutation

mutation to genetic variation to phenotypes to natural selection

When is the Hardy-Weinberg model used and what are the conditions

used for describing and predicting allele frequencies in a nonevolving population. condition: large population size, absence of migration no net mutations, random mating, absence of selection

What is the Hardy-Weinberg equation

p² + 2pq +q² = 1

What is evidence of evolution in a population

changes in allele frequencies

Which populations are most susceptible to random environmental impact

small populations

Where is evolution supported

geography, geology, physical, biochemical, mathematical data

How can fossils be dated

age of surrounding rocks, rate of carbon 1-4 decay, geographical data

What do morphological homologies represent

features shared by common ancestry

What provides evidence for evolution and common ancestry

comparison of DNA nucleotide sequences and/or protein amino acid sequences

What evidence supports the relatedness of organisms in all domains

structural and functional evidence

What structural evidence indicates common ancestry in all eukaryotes

membrane-bound organelles, linear chromosomes, genes with introns

What continuous evolutionary support is there within populations

genomic changes over time, continuous changes in the fossil record, resistance to antibiotics, pesticides, herbicides, chemo drugs, development of pathogens

at do phylogenetic trees and cladograms model

phylogenetic trees- relationship between lineages, amount of change over time
cladograms- relationship between lineages

How are phylogenetic trees and cladograms created

analyzing loss or gain of genetic traits within a species population

Which type of data is best for phylogenetic trees and cladograms

molecular data

What can phylogenetic trees and cladograms show

speciation

Where can phylogenetic trees and cladograms be constructed from

morphological similarities of living or fossil species in DNA or protein sequences

What do phylogenetic trees and cladograms represent

constantly revised hypotheses

When does speciation occur

two populations become reproductively isolated from eachouther

What are species

a group capable of interbreeding and exchanging genetic information to produce viable, fertile offspring

What is punctuated equilibrium versus gradualism

punctuated equilibrium- rapid evolution after long stasis
gradualism- evolutions over hundreds thousands of years or more

When does divergent evolution occur

new habitats results in phenotypic diversification

What are the two forms of speciation

sympatric or allo patric

what maintains reproductive isolation and prevent gene flow between populations

prezygotic and postzygotic mechanisms

How can niches be affected by extinction

creates new spaces of explotation

How does genetic diversity influence populations survavial

diversity increases ability to responded to environmental changes

What is geological evidence for the origins of life

formed 4.6 billion years ago (bya) with hostile environmens until 3.9 bya with early fossils at 3.5 bya