chapter 24
what is a prezygotic barrier?
prevents members from different species from mating to produce a zygote
habitat isolation
behavioral isolation
temporal isolation
mechanical isolation
genetic isolation
what is polyploidy?
the presence of extra sets of chromosomes due to accidents in cell division
Down syndrome
what is reinforcement?
barriers occur when hybrids are less fit than their parent species
overtime the rate of hybridization decreases
natural selection increases the reproductive isolation between two populations of a species
what is a postzygotic barrier?
the offspring is not viable
reduced hybrid viability
reduced hybrid fertility
hybrid breakdown
baby can be produced but cannot continue to reproduce
what is autopolyploid and alloploid?
autopolyploid- individual with more than two chromosome sets derived from one species
alloploid- species with multiple sets of chromosomes dervied from different species
what is fusion?
if gene flow is great enough, the parent species can fuse into a single species
what is the morphological species concept?
defines a species by structural features
applies to sexual and asexual species
what is habitat differentiation?
sympatric speciation can also result from the appearance of new ecological niches
a new habitat forms and species begin to prefer the new habitat over the old one
what is stability?
extensive gene flow from outside the hybrid zone can overwhlem selection for increased reproductive isolation inside the hybrid zone
offspring is less fit than the parents
what is allopatric speciation?
gene flow is interputted by a geographical barrier, seperating the two species
what is a hybrid zone?
a region in which members of different species mate and produce hybrids
what is a speciation rate?
result changes in few or many genes which can happen at a slow or fast pace
what is sympatric speciation?
species are able to be around other species but continue to only mate with their same species
what are the three possible outcomes in a hybrid zone?
reinforcement
fusion
stability