Rev 4 Flashcards
What is the dominant allele for tail length in wild hamsters?
L
‘L’ represents long tailed hamsters.
What is the recessive allele for tail length in wild hamsters?
l
‘l’ represents short tailed hamsters.
What is the allelic frequency?
A ratio of alleles in a population
It indicates how common an allele is in a gene pool.
What is the Genotypic Ratio for the given hamster population?
Calculated from the genotypes present
Requires specific genotype counts from the data.
What is the Phenotypic Ratio for the given hamster population?
Calculated from the phenotypes present
Requires specific phenotype counts from the data.
What is a test cross?
A cross between a homozygous recessive and an unknown genotype
Used to determine the genotype of an individual with a dominant phenotype.
What is the F1 Genotypic Ratio from a cross between a heterozygous long-tailed hamster and a short-tailed hamster?
1 Ll : 1 ll
This ratio is derived from the Punnett square results.
What is genetic equilibrium?
A state where allele frequencies remain constant over generations
Indicates no evolutionary change.
List 5 key conditions for maintaining genetic equilibrium.
- Large population size
- No mutations
- No migration
- Random mating
- No natural selection
These conditions prevent changes in allele frequencies.
List six pressures that can disrupt a population’s gene pool.
- Natural selection
- Genetic drift
- Mutation
- Migration
- Non-random mating
- Environmental changes
These factors can lead to evolution.
What is the Hardy-Weinberg Principle?
A principle that describes the conditions under which allele frequencies remain constant
It serves as a model for understanding genetic equilibrium.
What is selective mating?
The process where mates are chosen based on specific phenotypes
This can lead to changes in allele frequencies.
What happens to the frequency of a favored phenotype allele over time?
It usually increases
This occurs despite the conditions for genetic equilibrium being rarely maintained.
How can differential migration alter allelic frequencies?
Immigration increases allele frequency, emigration decreases it
Movement of individuals can change the genetic makeup of a population.
What is the process called when a small group is separated from the main population?
Founder effect
This can lead to reduced genetic diversity.
What effect does natural selection have on competing alleles?
It favors the allele that enhances survival and reproduction
This leads to changes in allele frequencies over time.
Why are most mutations not successful in the gene pool?
They often do not confer an advantage for survival or reproduction
Many mutations are neutral or harmful.
Describe Random Genetic Drift.
A process where allele frequencies change by chance in small populations
It can lead to loss of genetic variation.
What happened to the allelic frequencies for the ‘Penny’ gene in class?
They shifted from the original 0.5:0.5 ratio
This demonstrates the impact of random sampling.
Name the three biggest drivers of evolution.
- Natural selection
- Genetic drift
- Mutation
These forces significantly impact allele frequencies.
What is a gene pool?
The total collection of genes in a population
It includes all alleles for every gene present.
