bio-evolution Flashcards
Evidence of evolution - comparative morphology
Homologous structures - similar ancestor, now have diff functions
Analogous structures- Same function, different origin
Vestigial structures- useless to us now, helpful to the ancestors
Convergent evolution- when distant populations can develop similar structures (analogous)
Evidence of evolution- fossils
The deeper (older) you go the simpler the organisms, and the more dissimilar from modern organisms Some species exhibit evolution in body structure over time
Evidence of evolution- embryology
Vertebrate embryos all look similar in early stages of development
Evidence in evolution- biochemistry and genetics
Genetic similarities between organisms genetic codes
All organisms share similar basic biochem processes (DNA as genetic blueprint, rna and ribosomes for translation, roughly same set of 20 amino acids to build proteins, use atp for energy)
natural selection
Only the “fittest” are those that survive long enough to reproduce and pass on the adaptations / beneficial mutations that helped them survive long
Hardy-Weinberg principle
Under some conditions the frequencies of alleles and genotypes in a sexually reproducing population remain constant from one generation to the next
Equations
Psqaured+2pq+qsquared = 1
P+q=1
P=??
Q=??
P=dominant allele frequency
Q= recessive allele frequency
Five factors that contribute to evolutionary change
Mutations Gene flow Nonrandom mating Small population size Natural selection
Genetic drift
Random change in allele frequencies over time , brought about by chance alone
Causes of genetic drift
Founders effect
Population bottleneck
Population bottleneck
Drastic reduction in population size brought about by overhunting or natural catastrophes
Change allele frequencies and reduce genetic variation
Founder effect
Small number of individuals leave a large population and stables a new isolated population
Darwins finches
Finches that travel from mainland Ecuador to the Galápagos Islands – some of them must adapt to a new resource in order to survive
Assortative mating
A preference for mates that are similar in appearance
How bacteria become resistant / pests become immune to pesticide
Those that have a beneficial mutation will survive long enough to reproduce and pass the mutation to their offspring
Selective breeding (artificial selection)
On,y choosing the “best” traits for breeding
Inbreeding
Continued breeding of similar individuals
Equilibrium population
Idealized population in which allele frequencies don’t change from generation to generation
Sexual selection
Type of natural selection that favors traits that help one find a mate
Why are unfavorable (to survival) traits appealing to female mates
Female mates think, wow they can survive even though they have bad survival qualities
Directional selection
On extreme is favored in the environment and the are the main ones to continue reproducing so the species will evolve in that direction
Stabilizing selections
Environment favors the average phenotype
Disruptive selection
An area has more than one resource, so two opposite extremes are favored and evolved to
