Need Flashcards
Components of hardy Weinberg
- Very large population
- No gene flow between populations
- No mutations
- Random mating
- No natural selection
Biological species
A species is a group of populations whose members have the potential to interbreed in nature and produce fertile offspring
Morphological species
Classifying species based on observable and measurable physical traits such as shape, size, and other features of morphology (form)
Ecological species
Identifies species in terms of their ecological niches, focusing on unique adaptations to particular roles in a biological community
Phylogenetic species
A species is the smallest group of individuals that shares a common ancestor and that forms one branch on the tree of life
Prezygotic barriers
Temporal isolation, habitat isolation, behavioral isolation, mechanical isolation, gametic isolation
Postzygotic barriers
Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
Temporal isolation
Mating or flowering occurs at different seasons or times of day
Habitat isolation
Populations live in different habitats and do not meet
Behavioral isolation
There is little or no sexual attraction between different species
Mechanical isolation
Structural differences in genitalia or flowers prevent copulation or pollen transfer
Gametic isolation
Male and/or female gametes die before uniting or fail to unite
Reduced hybrid viability
Hybrids fail to develop or to reach sexual maturity
Reduced hybrid fertility
Hybrids fail to produce functional gametes
Hybrid breakdown
Offspring of hybrids are weak or infertile
Allopathic speciation
When the initial block to gene flow is a geographic barrier that isolated a population
Sympathetic speciation
A new species arises within the same geographic area as a parent species
Ways sympatric speciation can happen
Parent species doubles DNA but doesn’t replicate, then splits and doubles again. Ends up with 4n
Species A has two chromosomes in gamete, species B has three, they unite and double chromosomes. Ends up with added A and B chromosomes
Adaptive radiation
The evolution of many diverse species from a common ancestor
Punctuated equilibrium
Long periods of little change, or equilibrium, punctuated by abrupt episodes of speciation
Gradualism
Slow, gradual changes in a species
Phylogeny
The evolutionary history of a species or group of species
Convergent evolution
Species from different evolutionary branches may come to resemble one another if they live in similar environments and natural selection favors similar adaptations
Order of size things levels
Species, genus, family, order, class, phylum, kingdom, domain
Parsimony
The quest for the simplest explanation for observed phenomena
Three-domain system
Two domains of prokaryotes: bacteria and archaea
One domain of eukaryotes: eukarya
Primary succession
When ecological succession begins in a virtually lifeless area with no soil
Secondary succession
Occurs where a disturbance has destroyed an existing community but left the soil intact
Carbon goes from earth into air
Carbon goes from air into earth
(Cellular) respiration
Photosynthesis
