Week 10 Flashcards
(21 cards)
What is population genetics?
Describes microevolutionary change
It has greatly expanded our understanding of evolution.
What is the common ancestor concept in evolution?
All life on Earth is related to a common ancestor
This includes humans, beetles, plants, bacteria, etc.
What does natural selection promote?
Traits and behaviors that increase an organism’s chances of survival and reproduction
It eliminates traits that reduce fitness.
What is a phenotype?
An individual’s observable characteristics, e.g., height, eye color, physiology, behavior
Examples include color blindness and lactose intolerance.
What is a genotype?
An individual’s genetic make-up
Can be described from all of an individual’s genetic material or from a subset.
Define locus and allele.
Locus = location of a particular gene; Allele = version of a particular gene
Plural of locus is loci.
What is the Hardy-Weinberg equilibrium (HWE)?
A population’s allele and genotype frequency are stable unless an evolutionary force is acting
It serves as a baseline to compare actual population dynamics.
What are the assumptions of Hardy-Weinberg equilibrium?
- Natural selection is not acting
- There is no mutation or gene flow
- Population size is infinite
- Random mating (panmictic)
Changes in allele frequencies indicate evolutionary forces at play.
What is genetic drift?
Random evolutionary change that can eliminate an allele from a population by chance
It occurs more rapidly in small populations.
What is a bottleneck in genetic drift?
A temporary reduction in population size that wipes out genetic variation
It can lead to continued random evolution.
What is the founder effect?
A specific type of bottleneck where new populations are founded by a subset of the original population
Newly founded populations may have different allele frequencies than the original.
What is gene flow?
The movement of genes from one population to another
It can be high among plants due to pollen movement.
What are mutations?
New mutations introduce novel genotypic and phenotypic variation
They can be small or large changes.
What is non-random mating?
Some individuals are more or less likely to mate than others
This can lead to variations in mating success.
Define intersexual selection.
When one sex chooses the mate they will have
Mostly, it is the female who chooses the male.
Define intrasexual selection.
When individuals of the same sex compete for mates
Winning individuals have higher fitness.
What is sexual dimorphism?
Trait manifests differently in males and females
Often results from sexual selection.
What are the types of natural selection?
- Stabilizing selection
- Directional selection
- Diversifying selection
Each type impacts the distribution of phenotypes within a population.
What is frequency-dependent selection?
Favours phenotypes that are either common or rare
Example: Male common side-blotched lizards have different patterns based on their frequency.
Fill in the blank: Natural selection selects — it cannot _______.
[create]
Fill in the blank: Fitness is measured as _________.
[reproductive success]
