exam 3 Flashcards
hierarchical organization
- aristotle
- species fall into natural groups, some better than others
- humans above animals, men above women
fixity of species
- working scientific theory
- empirical evidence, philisophical ideas
- discrete boundaries between species based on how things look
- species do not change over time, no extinction
natural theology
- all creation is due to activities of a Christian God
- discover nature = discover God
foundation of darwin and wallace
- darwin’s HMS Beagle voyage: lots of different organisms in different islands, fossils, similar behavior
- studied finches in the galapagos islands
- darwin’s voyage of the beagle notes 1838
- wallace writes him a letter from malaysia in 1858
- darwin’s origin of species 1859
success of an organism
survive and reproduce
components/postulates of natural selection
- individual members of population vary
- traits are passed from parent to offspring
- some individuals fail to survive and reproduce
- survival and reproduction are not determined by chance (but by advantageous traits)
evidence of natural selection: artificial selection
if we can do it with dogs and produce, why can’t nature do it
evidence of natural selection: comparative anatomy
organisms from different ancestries have same froms/structures
vestigial structures
a structure that no longer provides a function, but did for ancestors. also referred to as evolutionary baggage
convergent evolution
natural selection causing non-homologous structures that serve similar functions
analogous structures
structures with similar functions/appearance but different internal anatomies
evidence of natural selection: embryology
species with similar embryos likely have common ancestors, stages of development show different groups
evidence of natural selection: geographic distribution
similar species in different locations evolve differently (ex. mammals and marsupials)
evidence of natural selection: progression of fossil forms
shallower fossils more closely resemble modern organisms
neodarwinian synthesis
- reconciles natural selection with mendelism (mendel rediscovered early 1900s)
- inheritance is particulate (DNA)
- differential proliferation of phenotypes (advantageous)
- natural selection changes gene frequencies
- more successful genotype = more successful offspring (survival and reproduction)
population
all individuals of same species living in a given geographical area
gene
discreet segment of DNA that codes for a particular trait
gene pool
all the genes (and their alleles) of a population
allele frequency
relative proportion of each allele in the population
- 25 individuals, 50 alleles, 20/50 are B dark fur alleles, allele freq. = 40%
- if a species is not evolving, that frequency will not change
conditions for hardy-weinberg principle
- no mutations
- no gene flow
- very large population
- completely random mating
- no differential fitness
gene flow
movement of alleles to and from other populations
genetic drift
a random event that removes some alleles from a small population
genetic drift: bottleneck
when an event causes a population to suddenly become very small
genetic drift: founder effect
isolated colonies founded by a small population
adaptation vs. trait
a trait is only considered and adaptation if it influences the success of an organism in its environment
competition
interactions among individuals who attempt to utilize a limited resource
coevolution
when species exert selection pressures on each other and thus mutually affect one another’s evolution (usually predator-prey)
directional selection
favors individuals on one extreme
- ex. peacock tails
stabilizing selection
favors individuals with the average trait, reduces variation
- ex. newborn baby weight
disruptive selection
favors individuals with either extreme of a trait
- can lead to speciation
species
groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
- doesn’t account for organisms that reproduce asexually or extinct populations
pre-mating isolating mechanisms: geography
can’t mate if you can’t meet
pre-mating isolating mechanisms: ecology
different populations use different resources (ex. ground vs. tree lizards)
pre-mating isolating mechanisms: temporal
different populations unable to mate due to time season (ex. trees and pollen)
pre-mating isolating mechanisms: behavior
different displays and courtship to attract mates (ex. birds w/ different songs)
pre-mating isolating mechanisms: mechanical
reproductive organs not compatible (ex. size, pollinated flowers, etc)
post-mating isolating mechanisms: gametic incompatibility
mating occurs, but fertilization does not
post-mating isolating mechanisms: hybrid inviability
hybrids don’t survive or are less successful than parents
post-mating isolating mechanisms: hybrid infertility
hybrids survive but cannot reproduce
allopatric speciation
two populations geographically separated
sympatric speciation
population isolation without geographic separation (ecological niche differences)
adaptive radiation
many speciation events in a short time of which the order cannot be determined, populations invade a variety of new habitats
localized distribution
if species are too localized, they are very threatened by environment change
specialization/overspeciation
if species are too adapted to their specific environment, they are very threatened by environment change
interactions with other species
when new species are introduced to the environment quickly it can lead to extinction for others
- predation
- increased competition
taxonomy
the naming of organisms
2 part name
Genus species
- genus always capitalized, species always lowercase
- italicized digitally, underlined hand written
phylogeny
classification based on evolutionary history
systematics
discovering evolutionary relationships
- clade: family tree of groups of organisms, based on evolutionary events
hierarchal system
domain, kingdom, phylum, class, order, family, genus, species
trivial classifications
organizing system of convenience that doesn’t reflect beyond the single criteria of classification
non-trivial classification
organizing system that reflects something in addition to the criterion on which it is organized (more than one criteria)
monophyletic taxon
most recent common ancestor and all of its decendents
polyphyletic taxon
does not include the common ancestor of all members of the taxon
paraphyletic taxon
includes the most recent common ancestor, but not all of its decendents
