Speciation and patterns of evolution Flashcards
What is Speciation?
Speciation is the process by which new species arise due to genetic divergence and reproductive isolation.
What are the two main types of speciation?
Allopatric speciation (due to geographic isolation) and sympatric speciation (without physical barriers).
What is Reproductive Isolation
A set of mechanisms that prevent different species from interbreeding and producing viable, fertile offspring.
What are the two main types of reproductive isolation?
Pre-zygotic isolation (before fertilization) and post-zygotic isolation (after fertilization).
What is Evolutionary Adaptations?
A heritable trait that increases an organism’s fitness in its environment.
How does natural selection drive adaptation?
Natural selection favors individuals with beneficial traits, leading to their increased frequency in a population.
What is Allopatric and Sympatric Speciation
A population is geographically separated, leading to genetic divergence and new species formation.
How does sympatric speciation occur?
Speciation occurs within a shared habitat due to factors like polyploidy, behavioral isolation, or temporal isolation.
What is Coevolution?
The process by which two or more species evolve in response to each other’s adaptations.
Give an example of coevolution.
Flowers evolving specific shapes to match their pollinators, like hummingbirds and tubular flowers.
What is Microevolution
Small-scale evolutionary changes within a population over a short time, such as allele frequency shifts.
What is macroevolution?
Large-scale evolutionary changes that lead to the emergence of new species over long time periods.
Pre-zygotic isolation
Barriers that prevent fertilization from occurring, such as behavioral or temporal isolation.
Post-zygotic isolation
Barriers that occur after fertilization, leading to inviable or infertile offspring.
Geographic isolation
Physical separation of populations, preventing gene flow and leading to speciation.
Hybrid inviability
When hybrid offspring fail to develop or survive to adulthood.
Hybrid infertility
When hybrid offspring cannot reproduce (e.g., mules).
Gametic isolation
Incompatibility between gametes of different species, preventing fertilization.
Divergent evolution
When related species evolve different traits due to different environmental pressures.
Environmental pressures
Factors like climate, predators, and food availability that drive natural selection.
Natural selection
The process where organisms with favorable traits survive and reproduce more successfully.
Adaptive radiation
The rapid evolution of multiple species from a common ancestor to occupy different niches.
Gene flow
The movement of alleles between populations, increasing genetic diversity.
Polyploidy
The presence of extra sets of chromosomes, which can lead to new species in plants.
Behavioral isolation
Differences in mating behaviors prevent interbreeding between species.
Temporal isolation
Species reproduce at different times, preventing interbreeding.
Microevolution
Small genetic changes within a population over a few generations.
