60 terms

Freeman chapters 25-28

Gonzaga University Biology 101
gene flow
movement of alleles from one population to another
DNA polymerase makes an error, the base sequence changes, the protein coded by the sequence may be different
Biological species concept
the definition of a species as a population or group of populations that are reproductively isolated from other groups
disadvantages of biological species concept
what about species that reproduce asexually? it can only be applied to populations that overlap geographically
prezygotic isolation
individuals of different species are prevented from mating
postzygotic isolation
offsprings of matings between members of different species do not survive or reproduce
mechanical isolation
morphology prevents breeding
behavioral isolation
different mating behaviors
genetic isolation
breeding occurs, but gametes don't match
hybrid inviability and infertility
offspring die or can't reproduce
morphospecies concept
distinguishing features are most likely to arise if populations are independent and isolated from gene flow
phylogenetic species concept
reconstruct the evolutionary history of populations
monophyletic group
an ancestral population plus all of its descendants
trait found in certain groups of organisms that exists in no others, "unique forms"
populations that live in discrete geographic areas and have distinguishing features
population colonizes a new habitat and forms a new population
physical barrier splits a population into subgroups that are physically isolated
allopatric speciation
speciation that begins with physical isolation via dispersal or vicariance
sympatric speciation
speciation of populations that live in the same time and place
ecological isolation
species use different habitats
temporal isolation
species breed at different times
phylogenetic trees
document the evolutionary relationships among organisms and are estimated from data
mass extinction
environmental catastrophes that rapidly eliminate species and have occurred repeatedly throughout the history of time
phylogenetic inference
studies of living specimens, fossils, DNA, RNA, protein, and genetics
calculate a statistic that summaries similarity
identify synapomorphies, shared derived traits...closely related taxa should share the most
ancestral trait
a characteristic that existed in an ancestor
derived trait
a modified form of the ancestral trait, found in a descendant
convergent evolution
similarities evolve independently
similar traits due to shared ancestry
similar traits but independent evolution
background extinction
average rate of extinction caused by gradual change, competition, new diseases
End-Permian extinction hypothesized causes
intense global warming, oceans became anoxic, sea level dropped dramatically, low O2 and high CO2 levels in the atmosphere
ecological opportunity
new or novel resources become available
morphological innovation
evolution of key trait
sticky layer outside of cell wall (polysaccharide or protein)
attachment pili (protein appendages)
motility, high velocity potential
membrane folding
increases surface area for chemical reactions
prokaryotes use them to battle harsh environments
uptake of foreign DNA from surroundings
phage construction error. horizontal gene transfer
combining DNA with other bacteria
bacteria that cause disease
first organisms to perform oxygenic photosynthesis, became chloroplast
unique prokaryotic adaptations
diverse metabolic pathways, cell walls, surface adaptations, membrane folding, reproductive strategies
adaptive radiation
The diversification of a group of organisms into forms filling different ecological niches
spherical, very tiny. endosymbionts--they live as parasites inside animal cells
diverse morphology, some are multicellular, use every metabolic pathway except oxygenic photosynthesis, E. coli is a member, became mitochondria
live in virtually every habitat, including extreme environments. no known parasitic
3.5 bya
prokaryotic photosynthesis
2.7 bya
eukaryotic cells/oxygen increases
2.2-2.1 bya
cambrian explosion, animals appear
550 mya
400 mya
300 mya
200 mya
150 mya
dinosaurs go extinct
65 mya
200,000 ya