Ch. 15 Book Vocab Part 2 Flashcards
(15 cards)
Gene flow
individuals or gametes migrate from one population to another
genetic drift
genetic makeup of population may change due to random events
prezygotic isolation
occuring before fertilization
postzygotic isolation
occuring after fertilization
name prezygotic barriers
geographic isolation, ecological isolation, and mechanical isolation
name postzygotic barriers
zygot death, sterility in hybrid plants, low fitness in hybrids
geographic isolation
the same population is separated and becomes so genetically different that the populations cannot interbreed
ecological isolation
species can be sympatric (occupy overlapping ranges of territory) without exchanging genes
mechanical isolation
structures of reproduction must fit one another to produce offspring
example: orchid reproductive structures
allopolyploid
a polyploid generated from an interspecific cross
autopolyploid
polyploid formed from a single species, intraspecific hybrids
autotetraploid
four copies of every chromosome are present, which can associate in groups of two, three, or four at meiosis
can cause unbalanced gametes
apomixis
a form of asexual propagation, the production of seeds without fertilization
organic evolution
accumulation of genetic changes in pops of living orgs through many changes/drivers
epigenetics
study of heritable changes in gene expression not due to mutation
Can be accompolished by blocking gene expression via the addition of methyl groups to DNA; Can be reversed when gene products are needed
Occurs during development, typically reset during sexual reproduction; Can be carried across generations; May be short term adaptation that allows org to switch between phenotypes to respond changing environments
