speciation - exam 4 Flashcards
biological species concept
a group of individuals that have the potential to interbreed & produce fertile offspring
limitations of biological species concept
- extinct forms of life – we don’t know if they could interbreed
- asexual reproduction & self-fertility
- potential to interbreed – isolated in nature, but breed when put together?
ring species
all populations can interbreed except the 2 “ends” of the ring
1 or 2 species?
reproductive isolation
biological factors that impede reproduction
prezygotic reproductive barriers - no mating attempted
temporal isolation
habitat isolation
behavioral isolation
prezygotic reproductive barriers - mating attempted, no zygote formed
mechanical isolation
gametic isolation
mechanical isolation
morphological features prevent successful mating
gametic isolation
gametes do not unite
specific recognition molecules needed
post zygotic barriers
mating & fertilization occur, zygote forms
hybrid inviability
hybrid sterility
hybrid breakdown
hybrid inviability
hybrid development impaired
hybrid id frail & doesn’t complete development
hybrid sterility
hybrid cannot reproduce
infertile
hybrid breakdown
1st generation hybrids fertile
2nd generation hybrids not fertile
what can reproductive barriers lead to
speciation
not interacting –> evolving separately
allopatric speciation
geographic separation leads to no gene flow
natural selection & genetic drift
reproductive isolation
sympatric separation
speciation without geographic isolation
reproductive barrier evolves first
