topic 5 Flashcards
theory of evolution
proposed by charles darwin, explains gradual change/diversification of species
- descent with modification because of natural selection
natural selection
the process where organisms which enhanced traits are more likly to survive and reproduce
pre darwin fossils
fossils found in different strata are different than today’s organisms, so species mustve gone extinct
georges cuvier theory
catastrophism theory, no evolution, species are different now because old ones are dead
jean-baptiste lamarck
disappearance of species over time because of the inheritance of acquired characteristics
where/what did darwin study
finches on the galapagos islands
observations of finches
similar, but not identical features becayse of common ancestry (beak shape)
artificial selection
modification of species because of selection of desired traits
observations for natural selection
individuals in a population vary in their inherited traits (genetic diversity), populations produce more offspring than the environment can support (competition for resources)
inferences for natural selection
individuals with preferable inherited traits are more likely to survive and reproduce, the unequal ability to do so leads to that accumulation of advantageous traits over generations
genotypic variation
difference in DNA among individuals in a population, heritable trait, genotypes are NOT directly subject to natural selection (some traits not expressed)
phynotypic variation
variability in observed traits of a population, determined by interaction of environmental factors and genotypes
qualifications for natural selection
must be expressed in the phenotype and heritable (caused by genotype)
selective agents
environmental factors that affect survival/reproduction
selective pressures
when a selective agent consistently causes differences in survival
medium ground finch example
substantial variation in beak depth, drought caused dependency on larger tougher seeds, individuals with larger beaks more likely to survive/pass on traits, average beak size increases
adaptation
inherited characteristic that improves its chances for survival
natural selection
the processes where individuals with certain inherited traits survive more BECAUSE of those traits
