Part 9: Evolution Flashcards
Natural selection
Operates in an individual level, driving force of evolution
Evolution
Change in a population over time
Charles Darwin
Dele oped theory of evolution in 1800s
Jean-Baptiste de Lamarck
Proposed theory that acquired traits were passed down to future generations, later proven wrong
Paleontology
Study of fossils
Biogeography
Study of distribution of flora and fauna in the environment
Flora
Plants
Fauna
Animals
Embryology
Study of the development of an organism
Comparative anatomy
Study of anatomies of various animals and how they are similar and different
Homologous structures
Structures on different species that have similar functions and structures, point to a common ancestor
Analogous structures
Structures that have the same function, but not structure, and are said to have evolved separately from each other
Molecular biology
Proves evolution because of similarities in DNA across species
Genetic variability
No two individuals have identical sets of alleles, except identical twins
Random mutation
Brought about genetic variation
Directional selections
One of the phenotypes was favored at one of the extremes of the normal,distribution
Stabilizing selection
Organisms with extreme traits are eliminated from a population
Disruptive selection
Extreme traits are favored, and common traits are elected against
Species
Final distinction in binomial nomenclature naming system, separated by ability to reproduce (ie, if two organisms count or won’t reproduce, they are different species)
Speciation
Emergence of a new species
Divergent evolution
Occurs in closely related species with different behaviors and/or traits, when individuals of a species mutate enough to no longer be called the same species
Convergent evolution
When two unrelated and dissimilar species come to have similar traits, often because they have been exposed to similar selective pressures
Allopathic speciation
A population becomes separated from the rest of the species so they can’t interbreed
Sympathetic speciation
When new species develop, but not as a result of geographical barriers
Hardy-Weinberg Law
Even with all the shuffling of genes that occurs, the relative frequencies of of genotypes in a population will prevail over time; can only be true if population is large, no mutations occur, there is no immigration of emigration, there is random mating, and there is no natural selection
Hardy-Weinberg Equations
Phenotypes: p+q=1
Genotypes: p^2+2pq+q^2=1
Genetic drift
Changes in the allele frequencies of a population
