4.2 Speciation U4 Flashcards
What is speciation?
the formation of a new & distinct species
via evolution
separates & develops unique characteristics
What are the types of species concepts?
Biological
Morphological
Recognition
Cohesion
Ecological
Evolution
Pluralistic
What is Biological Species Concept?
Reproductive Isolation
not necessarily easy to apply
hat is Morphological Species Concept?
Phenotypic Differences(fossil species)
What is Recognition Species Concept?
Mating recognition
What is Cohesion Species Concept?
Persistence of discrete phenotypes
What is Ecological Species Concept?
Filling of ecological niches
Competition for resources
What is Evolution Species Concept?
Evolutionary lineages
What is Pluralistic Species Concept?
Combinations of the others as appropriate
What are the types of selection on polygenic traits?
Normal
Stabilizing
Directional
Disruptive
What Normal distribution on polygenic traits?
Bell shaped trend
What is Stabilizing Selection on polygenic traits?
removes extreme variations
narrows width of distribution
What is Directional Selection on polygenic traits?
favors one extreme
shifts right or left
What is Disruptive Selection on polygenic traits?
favors both extremes
creates a bimodal distribution
What is allopatric speciation?
Gene flow is interrupted due to geographical isolation
What is sympatric speciation?
Speciation that occurs in populations that live in the same geographic area
Isolating Mechanisms- Pre Zygotic?
Temporal
Ecological
Behavioural
Mechanical
Geographic Isolation
Isolating Mechanisms- Post Zygotic?
Hybrid Inviability
Hybrid Infertility
Hybrid Breakdown
Isolating Mechanisms- Pre Zygotic: Temporal? ex
Occurs when two species mate at different times of year
Frogs live in same pond but breed during different seasons
Isolating Mechanisms- Pre Zygotic: Ecological? ex
Occurs when two species occupy different habitats
Lions and tigers can interbreed, but occupy different habitats
Isolating Mechanisms- Pre Zygotic: Behavioral? ex
Occurs when two species have different courtship behaviours
Certain groups of birds will only respond to species-specific mating call
Isolating Mechanisms- Pre Zygotic: Mechanical? ex
Occurs when physical differences prevent copulation/pollination
Certain breeds of dog are morphologically incapable of mating due to size
Isolating Mechanisms- Pre Zygotic: Geographic Isolation? ex
Seperated by physical barriers
Kaibab Squirrel and Abert Squirrel live on diff sides of the grand canyon
Isolating Mechanisms- Post Zygotic: Hybrid Inviability? ex
Hybrids are produced but fail to develop to reproductive maturity
Certain types of frogs form hybrid tadpoles that die before they can become a frog
Isolating Mechanisms- Post Zygotic: Hybrid Infertility? ex
Hybrids fail to produce functional gametes(sterility)
Mules are sterile hybrids resulting from mating between a horse and a donkey
Isolating Mechanisms- Post Zygotic: Hybrid Breakdown? ex
F1 hybrids are fertile, but F2 generation fails to develop properly
The offspring of hybrid copepods have less potential for survival or reproduction
What is macroevolution?
Large-scale transformation in a taxonomic group, including the evolution of new species
What is Microevolution?
Only deals with allele frequencies changing within a specific population
What does extinction influence?
Can influence speciation and other evolutionary patterns
What is Mass Extinction?
Many species become extinct in a short time period
What is adaptive radiation?
Single ancestral species diverges into several different forms adapted to slightly different environments
What is the tempo of evolution? ex
Rate of evolution is variable
What is Gradualism?
slow and steady
What is Punctuated Equilibrium?
Periods of equilibrium disrupted by periods of rapid change
What is coevolution?
Evolution of at least two species in a mutually dependent manner
