Lecture 5: Adaptation and Evolution Flashcards
what is evolution
A process that changes populations of organisms over time.
How dose evolution occur?
Through changes in gene frequency over time, within a population
What are the two required components for evolution?
Evolution requires Phenotype variation among individuals that is heritable
What are Genetic Differences?
Variation as a result of differences in genome
What is Phenotypic Plasticity?
Variation as a result of environmental influences
What is a phenotype?
An attribute of an organism such as its behavior, morphology, or physiology.
What is a genotype?
The set of genes an organism carries
What is genetic drift?
Extremely important in smaller populations,
it is where Random processes result in the loss of genetic variation in mating, fecundity, mortality, inheritance
What is a Genetic bottle neck?
A reduction in genetic diversity in a population due to a large reduction in population size.
What is the founders effect?
When a small number of individuals leave a large population to colonize a new area and bring with them only a small amount of genetic variety.
What is natural selection?
The differential reproduction and survival of individuals in a population due to environmental influences
What is the first rule of natural selection?
There are many more offspring produced than can be supported by the environment (competition)
What is the second rule of natural selection?
Traits vary among individuals within a population and may be heritable
What is the overall basis of natural selection?
Some heritable traits give individuals an advantage in the environment.
Such as advantageous traits, conferring higher fitness.
All of these traits will slowly become more common.
What are adaptations?
Traits that have been selected for through natural selection
What is directional selection?
When the mean population shifts from one direction to another through some animals showing advantageous adaptations
What is stabilizing selection?
Selection that sees the average population having the favorable trait (mean in the center)
What is disruptive selection?
Selection that spits a population in half, with the center mean being the smallest population.
What is a Species?
Biological species concept
Group of actually or potentially interbreeding population, which are reproductive isolated from such groups”
What is Speciation?
Physical and ecological processes interact with selection and random processes such as drift to produce species.
True or false:
Morphology is best way to identify species.
True
What is the biological species concept?
The idea that organisms that can interbreed are members of the same species.
What are the two major forms of reproductive isolation?
Prezygotic
&
Postzygotic
What are some examples of Prezygotic reproductive barriers?
4
- The inability to find a mate (Ecological)
- The organisms not being fertile at the same time (temporal)
- Give & recivie mating cues (behavioral)
- the parts cannot go together ( mechanical)
What are examples of postzygotic reproductive barriers?
- the Zygote & embryotic development is impossible (Hybrid inviability)
- Production of grandchildren is impossible (hybrid sterility)
What is Allopatric specication?
- Barrier creates geographically isolated populations
What is Parapatrc speciation?
Population expands into new habitat within range of parent species
What is sympatric speciiation?
Genetically distinct populations form within barrier or spatial isolation.
What causes Sympatric spceiation?
Disruptive selection leading to associative mating
