Evolution Flashcards
(14 cards)
Define convergent evolution.
Different organisms in similar habitats become more alike in appearance and behavior, though they do not share a common ancestor; results in analogous structures.
Define divergent evolution.
Many species evolve from a common ancestor and colonize new environments with unoccupied ecological niches; results in homologous structures.
What are the four kinds of reproductive isolation?
1) geographic (physical barriers, allopatic)
2) Niche differentiation (ecological isolation and different habitats, sympatic)
3) altered behavior (e.g. nocturnal and diurnal)
4) altered physiology (only in plants, chromosomal mutations and polyploidy)
How has evolution led to biodiversity?
- changes are passed down to offspring over generations
- changes affect entire population, not individuals
- cumulative changes combine to create a significant change
Name six pieces of evidence for evolution.
1) fossil records
2) embryos and comparative anatomy (homologous and analogous structures)
3) biochemical studies and common DNA
4) biogeography (distribution and patterns of organisms on earth)
5) antibiotic resistance (change over time)
6) artificial selection
What are the two types of evolution?
1) small-scale: change in gene frequency from one generation to the next (microevolution)
2) large-scale: descent of different species from a common ancestor (macroevolution)
Name the six main ideas of Darwin’s theory.
1) overproduction
2) competition over resources
3) variation
4) adaptation
5) natural selection
6) speciation (formation of new species)
Define fitness.
The measure of an organism’s ability to survive and produce more offspring than other members of the population; how good a genotype is at making offspring versus another genotype.
Define adaptation.
A change in structure to carry out a function more efficiently, and to survive better
1) appearance
2) structure
3) physiology
4) behavior
5) mode of life
What are three types of adaptations?
1) structural (physical characteristics, e.g. blowholes, needles on cacti)
2) physiological (chemical changes, e.g. snake venom, skunk glands)
3) behavioral (e.g. migration, courtship rituals)
What are the three modes of natural selection?
1) stabilizing (average trait value), limits evolution
2) directional (at one extreme due to environment)
3) disruptive/diversifying (both extremes), distinct subpopulations
Name the five conditions for the Hardy-Weinburg Equilibrium.
1) no mutation
2) no em/immigration
3) large population with many alleles
4) random reproduction
5) no natural selection
What are the five factors that alter genetic variation in a gene pool?
1) natural selection/fitness
2) em/immigration
3) genetic drift (bottleneck, founder), change in gene pool due to random chance
4) non-random mating (best fitness)
5) mutations
Define evolution.
The cumulative change in heritable characteristics of a population over time.
