Week #4 Flashcards
Who suggested the Biological Species Concept (BSC)?
Ernst Mayr
What is the Biological Species Concept (BSC)?
groups of interbreeding natural populations which are reproductively isolated from other such groups produce viable offspring
Ex. wholphin
What are some criticisms of the Biological Species Concept?
Difficult to apply concept to pops. that are geographically separated; Many species hybridize in captivity; Many organisms are asexual; Fossils?
What are the 4 main species concepts?
Biological, Ecological, Phylogenetic, Evolutionary
What is Ecological Species Concept?
A group of organisms adapted to a specific set of resources, or niche, in their environment
What is Phylogenetic Species Concept?
A “tip” on phylogeny; smallest set of organisms that share an ancestor and can be distinguished from other such sets
What is Evolutionary Species Concept?
A single image of ancestor-dependent populations that maintains its own identity from other lineages
What is a subspecies?
A biological classification that ranks below species; designates a population of a particular geographic region genetically distinguishable from other such populations of the same species
What are the 5 types of prezygotic reproductive isolation?
Temporal Isolation, Habitat/Ecological Isolation, Behavioral Isolation, Mechanical Isolation, Gametic Barrier
What is Temporal Isolation?
Species have different breeding schedules
What is Habitat/Ecological Isolation?
Members of species move or are otherwise separated
What is Behavioral Isolation?
Certain actions or behaviors impacts reproduction
What is Mechanical Isolation?
Their reproductive structures simply do not fit together
Ex. bees, pollen, and flowers
What is Gametic Barrier?
Differences in their gamete cells (eggs and sperm) prevent fertilization
Ex. sperm and egg are not capable of fertilization
What are the 2 types of postzygotic reproductive isolation?
Hybrid Inviability and Hybrid Sterility
What is Hybrid Inviability?
An embryo is produced, but cannot survive development
What is Hybrid Sterility?
Different species can produce a viable offspring, but that offspring cannot reproduce
Ex. Mules
What is speciation?
Formation of two species from one original species
What are the two ways speciation occurs?
Anagenesis and Cladogenesis
What is anagenesis?
When population of entire species changes on genetic level WITHOUT a split; ancestral population goes extinct
A.K.A. - phyletic evolution, evolution, gradualism
What is cladogenesis?
Species splits into two genetically-distinct populations adapted to different ecosystems &/or survival strategies; both species may survive
What are the types of speciation occurs?
Allopatric and Sympatric
What is Allopatric speciation?
Involves geographic isolation
Think: different lakes, different fish, same species
Ex. elephants
What is Sympatric speciation?
Occurs in the same geographical area; Reproductive Isolation
Think: same lake, different fish, same species
What is gradualism?
Changes in species is slow and gradual, occurring in small periodic changes
What is punctuated equilibrium?
Occurs in spurts of relatively rapid change with long periods of non-change; stabilizing and oscillating selection responsible for stasis
What is Adaptive Radiation?
A clade (group of related species) that has evolved into numerous, diverse forms
