Unit 10: Speciation

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