Ch 11. Species and Races Flashcards
species
group whose members have the greatest resemblance. each has 2 part name
2 part name of species
1st: indicates genus, a broader group
2nd: specific to species within genus
biological species
consistent definition to determine differences between species
reproductively isolated
can interbreed and produce fertile offspring, but cant reproduce with other species
gene pool
sum total of all alleles within a species. makes an impermeable container for gene pool. change in frequency can only happen within a species
prefertilization barriers
failure to mate/produce an embryo
spatial isolation
prefert. different species dont come in contact
behavioral isolation
prefert. ritual mating behaviors differ
mechanical isolation
prefert. incompatible sex organs
temporal isolation
prefert. timing of readiness to reproduce is diferent
gamete incompatibility
prefert. proteins on egg that allow sperm to bind dont work for another species
postfertilization barriers
fertilization occurs, but hybrid cant reproduce
hybrid inviability
postfert. zygote cant complete development because genetic instructions incomplete
hybrid sterility
postfert. hybrid cant produce offspring because chromosome number is odd. (mule)
speciation
evolution of species from an ancestral form. isolated population diverge in traits. divergance can lead to reproductive isolationa nd formation of a new species. 3 steps necessary
3 necessary steps for speciation
- isolation of gene polls of subgroups/populations of the species
- evolutionary changes in gene pools of 1 or both of isolated population
- evolution of reproductive isolation between population, preventing future gene flow
founder hypothesis
diversity of unique species on oceanic islands and isolated bogs, caves, and lakes resulted from colonization by 1 species that rapidly speciated, taking advantage of many different resources. allopatric or sympatric.
allopatric
isolation due to geographic barrier
sympatric
separation of gene pool even when near each other
polyploidy
process of chromosome duplication. if occurs in hybrid, fertility may be possible again. mostly in plant and some insects and frogs.