quiz 2 prep Flashcards
(33 cards)
decribe plato’s typological thinking
Plato believed all creatures and life were unchanging and static, that everyone was made by god perfectly, and there was no extinction, no new species; this is called typological thinking
describe aristotle’s scale of nature
Aristotle believed that all beings were unchanging and made by god but that there was a hierarchy and humans were the best, closest to only god; called “the great chain of being”
describe lamarckian evolution
lamarck believed that evolution started at the bottom of the chain by spontaneous generation and organisms move up the chain over time, making larger more complex species
mechanism: inheritance of acquried characters:
individual organisms could change their phenotype during their life to adjust to their environment and then pass on those changes to their offspring
describe darwin and wallace’s theory of natural selection
darwin and wallace believed that nature itself selected for certain traits in organisms that made it so that certain phenotypes had a higher fitness and eventually the selected phenotype had a higher frequency than others
describe artificial selection
artificial selection is the process by which humans choose the surviving and reproducing organism, such as making vegetables or breeding dogs
summarize the criteria that defines natural selection
natural selection occurs on a population, there must be variation, the variation must be heritable, and there must be more off spring produced than can survive, competition for resources, and differential reproductive success
compare terms used in evolution w/ their everyday use in english
evolution is a theory-but not a guess, a well observed phenomena backed up by thousands of hypotheses and data, fitness is ability to reproduce, whereas in everyday use it is strength or cardiovascular health
what was darwin’s journey on the HMS beagle?
around south america, where he dug up fossils and observed and collected specimen int he Galapagos and argentina, long journey where he discovered and observed for his studies
how did the finches on the galapagos islands help darwin articulate his theory of natural selection?
the finches each had traits that benefitted them on their respective island and their needs, the variation in traits was observed
why is it inaccurate to say natural selection changes individuals?
natural selection does not change individuals, it changes phenotypic frequency overtime in a population. Traits that are more favorable and increase fitness become more popular, but individual changes only mean variation is present
why is it inaccurate that natural selection is goal directed?
natural selection is not goal directed because the environment and earth is always changing. the “goal” is simply reproducing and those conditions are ever changing
why is it inaccurate to say that natural selection leads to perfection?
natural selection never leads to perfection because variation must always be present for selection to occur, and the environment and favorable traits for fitness will always change
typological thinking
what was the prevailing viewpoint before darwin?
that the earth was relatively young and the number of species never changed, aristotle’s scale of nature was popular, naturalists at the time tried to joint traditional beliefs with evidence of change
3 conditions for natural selection
variation, heritability, differential reproductive success
modes of natural selection
directional, stabilizing, disruptive, balancing
intersexual selection
selection for traits that enhance the reproduction of the
intrasexual selection
selection by competition between organisms of the same sex for reproduction
asymmetry of sex
the way females put more energy into creating eggs and raising them whereas males are only limited by mating
sexual dimorphism
when sexes of a species have completely different looks that are visible
what leads to sexual dimorphism?
the selection of traits by sexual selection
genetic drift on genetic variation
effect of genetic drift on fitness
how does sampling error cause genetic drift?
