-
how to evolution advance according to ernst mayr?
by speciation, which is the production of new gene complexes capable of ecological shifts
-
what is the keystone of evolution according to Mayr
species
-
taxonomists
science of defining groups of biological organisms on shared characteristics and giving names to those groups
-
are species real?
yes individuals cluster in morphospace corresponding to geno and phenotypic space.
-
what can help us find ancestor
morphology and molecular clock (rate of decay)
-
what example in class showed organisms that were only distinguishable on the basis of karyotype
agrodiaetus butterflies
-
what is the natural category in the taxonomic hierarchy?
species
-
hierarchy from species
genus, family, order
-
what did darwin think of species
extension of the spectrum of variation seen within species (rhetorical necessity)
-
what was the problem with Darwin's definition of species?
there is usually a disconnect between variation within a species and variation among species
-
species paradox
darwin taught us to think of species as dynamic, changing entities, yet seeking to create an all embracing species concept, we place boxes around changing things
-
what is dobzhansky's definition of species
group of organisms barred from interbreeding with other similar groups by its physiological properties (sterility of hybrids or incompat of parents)
-
mayr's definition of species
species are reproductively isolated from other groups
-
problems with BSC
- not work with fossils
- or asexual species
- ring species
- varying degrees of reproductive isolation
-
what is an example of ring species
phylloscopus warblers
-
alternative species concepts
- cluster of organisms that is distinct from other lineages and within which there is a common ancestor (phylogenetic)
- ecological (occupies the same zone)
-
what is different about alternative species concept and BSC?
alternative emphasize outcomes of history. BSC emphasizes process
-
in practice what do we rely on for distinguishing species
morphology
-
prezygotic barriers
- ecological
- temporal
- sexual/behavioral
- mechanical
- gametic incompatibility
-
example of ecological reproductive isolation
ladybugs (yasutomii and niponica)
-
behavioral isolation ex
green lacewings
-
mechanical barrier ex
- genital arch in males of drosophila
- baculum of walrus requires mechanically fitting species
-
postzygotic barriers?
hybrid inviability and sterility
-
biometrical characteristics
techniques that rely on measurable physical characteristics
-
the new synthesis
not all traits are expressed, expressed in discrete units, though wide varieties
-
allopatric
physical barrier
-
peripatric
specie moves to island
-
parapatric
pineapple and apple hence specie isolated based on food preference
-
sympatric
blue dino wants to mate with red dino
-
pup fish in death valley
example of allopatric
-
what is an ecological niche
all elements that allow organism to survive
-
what is the principle of competitive exclusion by G.F. Gause
two species occupying the same habitat can coexist only if they are not competing for the same resource
-
vicariance
physical barrier
-
dispersal
go to nearby island (birds and wind dispersed plants are better at it)
-
-
deteriministic
according to dispersal abilities
-
disharmony
ecosystems incomplete (not many species), susceptive to freak events
-
example of sympatric
palm trees flower at different times as a result of volcano. even though they could interbred
|
|
