cont lecture 21
isolation by distance
populations breed with those in close proxy (results in variation across range of species)
ring species
connected series of populations wherein each interbreed with closely sited populations, bit for which there are least 2 "end" species (literal "ends" (arroheads) CANT interbreed, but species along the vector length can)
ecological speciation
selection for different ecological traits indifferent niches create reproductive barriers
magiv traits
traits that simultaneously confer divergent local adaptation and act as reproductive barriers (tldr: 2 for 1)
islands allow for alloatric speciation
it literally hard to go between distant islands
colonization speciation
we also see that as organism tend to colonize differing islands, they speciate
(pace of speciation) Drosophila
in natural conditions, we see that it takes hundreds to thousand of years for them to speciate (typically linked with some factor f reproductive isolation)
(pace of speciation) Allopolyploid
when an individual has two or more complete sets if chromosomes from different species
example of Allopolyploid
plants can produce sterile hybrids that still undergo genome duplication that can then undergo normal meiosis (tldr: supha fast speciation)
cryptic species
comprise of multiple taca that are grounded under the same name because they look nearly the same morphologically, however different species genetically (however, in microbes the distinction between species can rely upon if their 16s rRNA genes vary by more than 3%)
horizontal gene transfer
many unicellular organisms may accrue a litany of new genomes throughout their lifespan; makes it very hard to identify what is a new species
stbale ecotype model
long-lived population of genetically related individuals that share the same set of adaptation for a niche