Unit One Study Guide Flashcards
Microevolution
Changes that occur within a species and the characteristics of a population
Macroevolution
Changes that occur as a result of cumulative microevolutionary events over long periods of time and result in the origin of new species
Explain how mutations contribute to evolution and their importance.
Source of new alleles in a pop.
Founder Effect
when individuals from a population relocate and bring only a fraction of the genes available in the gene pool with them
Bottleneck Effect
when a population is decreasing, therefore there are only a few genotypes that contribute to the next generation.
Genetic Drift
Genetic drift is a change in allele frequency due to chance
Sexual Selection
When individuals pair up according to phenotype or genotype
Biological Species Concept
If two organisms breed and produce viable fertile offspring, they are the same species.
Reproductive Isolation
when a species cannot successfully reproduce or reproduce at all due to a variety of factors including behavioral, geographical, or genetic barriers.
prezygotic (before fertilization) barriers to reproduction?
Habitat Isolation- physical separation prevents members of two species from mating (can be allopatric or sympatric)
Temporal Isolation- differences in timing of mating seasons prevents members of different species from mating and producing offspring
Behavioral Isolation- differences in behavior, mating rituals, or calls prevents members of different species from mating
Mechanical Isolation- differences in reproductive anatomy prevents members of different species from mating
Gametic Isolation- differences in gametes prevents mating ( ex. Biochemical differences in signaling between sperm and egg)
postzygotic barriers to reproduction??
Reduced viability: the hybrid organism does not develop as it should and survival rate is low
Reduced fertility: the hybrid organism is unable to reproduce due to chromosomes not matching and meiosis failing.
Hybrid Breakdown: While the first generation of the hybrid may have been able to produce and live, the second generation is less viable and sterile
Allopatric Speciation (“other” “homeland”):
Geographically isolate populations
Caused by geologic events or processes
Evolves by natural selection & genetic drift
Ex. Squirrels on N/S rims of Grand Canyon
Sympatric Speciation (“together” “homeland”)
Combine populations within same geographic area
Gene flow between subpopulations blocked by polyploidy, habitat differentiation, sexual selection
Ex. Polyploidy in 80% of plants (oats, cotton, potatoes, wheat)
prezygotic barriers to reproduction?
Habitat Isolation- physical separation prevents members of two species from mating (can be allopatric or sympatric)
Temporal Isolation- differences in timing of mating seasons prevents members of different species from mating and producing offspring
Behavioral Isolation- differences in behavior, mating rituals, or calls prevents members of different species from mating
Mechanical Isolation- differences in reproductive anatomy prevents members of different species from mating
Gametic Isolation- differences in gametes prevents mating ( ex. Biochemical differences in signaling between sperm and egg)
prezygotic barriers to reproduction?
Habitat Isolation- physical separation prevents members of two species from mating (can be allopatric or sympatric)
Temporal Isolation- differences in timing of mating seasons prevents members of different species from mating and producing offspring
Behavioral Isolation- differences in behavior, mating rituals, or calls prevents members of different species from mating
Mechanical Isolation- differences in reproductive anatomy prevents members of different species from mating
Gametic Isolation- differences in gametes prevents mating ( ex. Biochemical differences in signaling between sperm and egg)
prezygotic barriers to reproduction?
Habitat Isolation- physical separation prevents members of two species from mating (can be allopatric or sympatric)
Temporal Isolation- differences in timing of mating seasons prevents members of different species from mating and producing offspring
Behavioral Isolation- differences in behavior, mating rituals, or calls prevents members of different species from mating
Mechanical Isolation- differences in reproductive anatomy prevents members of different species from mating
Gametic Isolation- differences in gametes prevents mating ( ex. Biochemical differences in signaling between sperm and egg)
Taxonomy