Allele Frequency
What is an allele?
One or two alternative versions of a gene.
What is the difference between an allele and a trait? Give an example.
An allele is a version of a gene, while a trait is the observable characteristic influenced by that gene.
Example: The allele for blue eyes or brown eyes; the trait is eye color.
What is genetic drift?
a change in allele frequencies due to change.
Define natural selection.
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
Define mutation.
What is allele Frequency?
Proportion of a specific allele in a population. Measures how common an allele is.
A plant has the genotype Tt for height. Identify the alleles and the trait.
Alleles: T and t
Trait: Plant height
How does genetic drift differ from natural selection in evolution?
Natural selection causes evolution based on the fitness of an organism. Genetic Drift causes evolution by random chance.
What role does variation play in natural selection?
Genetic variation provides the diversity needed for natural selection to act, allowing environmental pressures to favor individuals with beneficial traits.
All mutations are bad.
false
What is the difference between a dominant and a recessive allele?
Dominant alleles are expressed over recessive alleles.
Is eye color an allele or a trait? Justify your answer.
Eye color is a trait.
The alleles are the gene versions (e.g., blue, brown, green) that determine which form of the trait is expressed.
What is the founder effect?
A small group of individuals breaks off from a larger population to establish a new population, with different allele frequencies than the original population.
Who came up with the theory of Natural Selection?
Charles Darwin
How do mutations drive evolution?
They introduce new genetic variations that can be acted on by natural selection.
How can natural selection affect allele frequency?
If natural selection favored a specific allele, the allele frequency would increase overtime.
If it is not a favored allele, the allele frequencies will decrease.
In humans, the gene for earlobe attachment has two alleles: free (E) and attached (e). What trait does this gene influence?
Trait: Earlobe attachment (whether earlobes are free or attached)
are large or small populations more susceptible to genetic drift
Small Populations
What would happen if an environment changes drastically and none of the organisms in the environment have favorable adaptations?
Extinction
What is natural selection's role in mutation?
Natural selection can favor beneficial mutations and eliminate harmful ones over time.
Describe how allele frequencies can be used in evolutionary biology.
The change in allele frequencies can be used to indicate the evolution of a population.
Explain how different alleles of the same gene can produce different traits.
Different alleles code for variations of a protein, which can change the phenotype.
Example: One allele for pea flower color codes purple, another allele codes white, producing different traits.
Explain how genetic drift can lead to a loss of genetic variation in a population.
Due to random chance, certain alleles can disappear from the population entirely.
How is genetic variation an important part of Natural Selection?
Genetic variation is important because having differences allows some organisms to better adapt and change easier than other organisms.
When do mutations pass to the next generation?
During reproduction