Evolution Flashcards
Oparin and Haldane
suggested first organic molecules came from early atmospheric gases
Miller and Urey
confirmed Oparin and Haldan’es theory
dating of fossils: relative
layers of strata
dating of fossils: absolute
radiometric dating
Precrambrian era
90% of Earth’s history
We are in which era?
Cenozoic era
Spontaneous generation
life from nonllife
Theory of biogensis
life from life
Endosymbotic theory
prokaryotes engulfed other prokaryotes to form eukaryotes
a population of organisms can change over generations if individuals having certain heritable traits leave more offspring than others
Natural Selection
trait shaped by natural selection that increases an organism’s reproductive success
Adaptation
change in the genetic composition of a population over time
Evolution
Microevolution
pertains to evolutionary change within a population
Hardy-Weinberg Equilibrium
population that is not changing genetically
Assumptions under Hardy-Weinberg Equilibrium (there are 5)
- population is large
- mating is random
- no migration
- mutations can be ignored
- Natural selection is not acting on the population
Genetic drift
change in the gene pool of small population due to chance
Gene flow
gain or loss of alleles due to immigration or emigration
Non random mating
certain individuals are preferred by the opposite sex
Types of genetic drift:
Bottleneck effect
a change in a populations allele frequencies due to a substantial reduction in a population size
ex-earthquake
Types of genetic drift:
Founder effect
Colonization of a new location by a small number of individuals and the random change that occurs in a small colony
ex-amish
Polymorphism: morph
2 or more contrasting phenotypic alleles for a trait
ex: king snake; blood type
Polymorphism: cline
graded change in inherited traits in geographic continuum
Heterozygote advantage
promotes variability and larger gene pool
Endangered species
generally, low variability
Neutral variability
No apparent selective advantage for reproductive success; not subject to natural selection
Types of natural selection: stabilizing-
favors intermediate variants
Types of natural selection: directional-
shifts the phenotype frequency in one direction or another. Acts as one phenotypic extreme. Common during environmental change
Ex-peppered moths
Types of natural selection: diversifying-
favors both extremes over intermediates
speciation
change of a species over time into another
macroevolution
evolutionary change at or above the level of species
Prezygotic isolating mchanisms
prevent reproductive techniques
Habitat isolation
one on land, other on water
Behavioral isolation
different mating songs
Mechanical isolation
sex organs are incompatible
temporal isolation
species reproduce during different seasons or times of day
Postzygotic
fertilization has occurred but hybrid offspring can’t reproduce
Divergent evolution
formation of a new species from new habitat
Convergant evolution
2 unrelated species in similar niches but geographically far apart, having similar adaptations
Homologous structure
our arm vs bat arm
Analogous structure
bee vs bird wing
Coevolution
Mutualistic relationship between 2 species
ex-flower and pollinator
Rate of speciation
most evolution proceeds slowly but sometimes a dramatic event occurs
gradualism
slow change
punctuated equilibrium
dramatic event that causes change
