FINAL EXAM Flashcards
Directional Selection
An exceptional phenotype that has higher reproduction and survival.
Example of Directional Selection
Finches with larger beaks survived more than those without larger beaks
Disruptive Selection
Average phenotypes have lower reproduction and survival compared to extremes
Permian Period
- Prokaryotes appeared in Paleozoic, later 3 landmasses join to form Pangea
- Mesozoic era. Dinosaurs, birds, flowering plants. Pangea breaks up and drifts north. North America and Africa parted
- End of Mesozoic. Pangea broke up, North America and Eurasia still connected
Cretaceous Period
- Cenozoic. Antarctica and Australia separate
Stabilizing Selection
Extreme phenotypes have lower rates of production and survival. Average phenotype becomes more common
Morphological Species
Based on differences in color, structure, proportions, etc.
Biological Species
A group of actually or potentially interbreeding populations that produce fertile offspring
Allopatric Speciation
Occurs when populations are geographically isolated. Aka geographic speciation
Examples of allopatric speciation
Mountains, rivers, uplifts, etc.
Sympatric Speciation
Production of new species within a population or within dispersal range of a population
Aspects of sympatric speciation (3)
- Often occurs in a patchy environment
- Pre-mating reproductive isolation occurs before population shifts to a new source or habitat
- Induces evolution of a specialization to exploit and unused or novel resource
Aspects of sympatric speciation (3)
- Often occurs in a patchy environment
- Pre-mating reproductive isolation occurs before population shifts to a new source or habitat
- Induces evolution of a specialization to exploit and unused or novel resource
Polyploidy
Abrupt or instantaneous speciation
Types of polyploidy
- 2N + 2N = 4N tetraploid offspring
- 2N + 1 = 3N triploid offspring
- Many agricultural plants do this
Adaptive Radiation
Evolutionary diversification of a species derived from a common ancestor
When does adaptive radiation usually occur?
Aften organisms colonize an island group or new environment
Steps in adaptive radiation
- Physical access to new environment
- Species must be able to exploit new environment
- Enough genetic variation to establish itself under selective pressures of climate in new environment and competition from other species present
Parallel evolution
Adaptive changes in organisms with common evolutionary heritage
Convergent evolution
Development of similar characteristics in unrelated species living in different areas but similar environmental conditions
Population Definition
Group of individuals of the same species living at the same place at the same time
Type I survivorship curve
Juvenile survival is high and most mortality occurs among older individuals
Type II survivorship curve
Individuals die at an equal rate, regardless of age
Type III survivorship curve
Die at higher rate as juveniles and then at much lower rates later in life