Mechanism of Evolution
What are mutations?
Random changes in DNA that create new alleles.
What are structures that we do not need?
What is allopatric speciation?
A type of speciation where a physical barrier separates two populations.
What was Hardy?
A mathematician.
What is osmosis?
The movement of a solvent from a high to low concentration or the movement of a solute from a low to high concentration.
What is non-random mating?
When organisms prefer specific traits over other traits.
Which layers are the oldest and youngest when determining the age of fossils?
Top: Youngest
Bottom: Oldest
What is a zygote?
An egg cell that gets fertilized.
What is random mating?
When there is no preferences over certain traits.
What is the type of bell curve which favors one extreme trait over another?
Directional.
What is natural selection?
Process where individuals with more advantageous traits are more likely to survive and reproduce.
What do early stages of embryos tell us.
Suggests they share a common ancestor and developmental pathways.
What are the prezygotic barriers?
Behavorial isolation: Different mating rituals.
Temporal isolation: Different mating time periods.
Mechanical isolation: Incompatible reproductive structures.
What was Weinberg?
A physician.
Disruptive.
What is gene flow?
An intentional movement of alleles between populations due to migration.
Which animal do humans share most of their DNA with?
Chimpanzees.
What are the two prezygotic barriers?
1. Hybrids are sterile
2. Hybrids do not survive long.
What is hardy-weinberg equilibrium?
A mathematical relationship between allele frequencies and genotype frequencies.
What is the type of bell curve in which it favors moderate traits?
Stabilizing.
What is the bottleneck and founder effect?
A sudden reduction in the population size due to a change in the environment.
When a few individuals become isolated from a larger population.
What is the difference between analogous and homologous structures?
Analogous: Structures that are physically different but share the same function.
Homologous: Structures that are physically similar but often have different functions.
What is the difference between sympatric and parapatric speciation?
Sympatric: Same location
Parapatric: Adjacent locations; may include a central area where they interbreed.
What needs to happen in a population to achieve hardy-weinberg equilibrium?
No mutation, no genetic drift, no gene flow, no natural selection, and random mating.
What are types of selection pressures?
1. Human influence
2. Predation
3. Environmental changes
4. Competition