this unit has 3 different vocabulary sections that I have split up into 3 knowts!
speciation
when a group of species separates from other members of its species and develops its own unique characteristics until it can no longer be considered the same species
adaptive radiation
one common ancestor species evolves into many diverse forms
hybrid inviability
hybrids fail to develop or to reach sexual maturity
hybrid breakdown
offspring of hybrids are weak or infertile
hybrid sterility
hybrids fail to produce functional gametes
reproductive barrier
a biological feature of organisms that prevents interbreeding among closely related species
punctuated equilibrium model of speciation
when a group evolves forward after long periods without change or with very little change and then remains without much change for another period of time
gradualism model of speciation
species diverge over time in small, steady steps
behavioral isolation
there is little to no sexual attraction between the different species
gametic isolation
male and/or female gametes die before uniting or fail to unite
reproductive isolation
the inability of a species to breed successfully with related species due to geographical, behavioral, physiological, or genetic barriers
temporal isolation
mating or flowering occurs at different seasons or times of day
mechanical isolation
structural differences in genitalia or flowers prevent copulation or pollen transfer
habitat isolation
populations live in different habitats and do not meet
biological species concept
a species is a group of populations whose members have the potential to interbreed and produce fertile offspring
if members of one species do mate with members of another species, the offspring will not be fertile
genealogical species concept
a group of organisms whose members are all more closely related to each other than they are to any organisms outside the group
morphological species concept
based on observable and measurable phenotypic traits
ecological species concept
based on ecological resource use, focusing on unique adaptations to particular role in a biological community (niche)
allopatric speciation
geographic isolation can lead to speciation
sympatric speciation
new species can form in the same geographic area if reproductive isolation occurs
phylogenetic species concept
a set of organisms with a unique genetic history. molecular data helps define species in terms of unique genetic markers