BIOLOGY: Topic 4 Flashcards
Define microevolution.
A change in allele frequency in a population or species across generations focus is on variation within populations and evolutionary change over shorter periods time periods.
What are the four processes that can cause microevolution?
Genetic Drift
Mutation
Gene flow
Natural selection
The decrease in fitness as a consequence of inbreeding is called ____________ ____________.
inbreeding depression
What are deleterious alleles?
(Typically) Recessive alleles that decrease an individual’s general fitness. Typically a result of inbreeding since the chances of carrying these alleles increases among relatives.
What is heterozygote advantage?
At some loci (regions of a chromosome), heterozygotes have higher fitness than either homozygote. Inbreeding decreases heterozygosity hence lowering fitness due to the fact that inbreeding increases homozygosity.
What is mutation?
Mutation is a mechanism of microevolution, it is a change genetic information of an organisms DNA. It arises from errors in DNA replication or recombination. It causes genetic variety and therefore can cause evolution since it can also change allele frequency. It is random in occurence, meaning it is non-Lamarkian (not in a specific order or for a specific reason).
What are the two scales of mutations? What’s the difference?
Large and small scale. Small scale involves the substitution/insertion/deletion of one or more nucleotides while large scale involves mutations in the entire chromosomal structure.
What are two types of small scale mutations?
Substitution or Insertion/Deletion
What are the two outcomes of substitution mutation?
Either it’s a silent mutation and the amino acid is not affected, or its a replacement mutation and the amino acid is affected.
What is insertion/deletion?
One or more nucleotides are added or removed, which can alter the reading frame (frameshift), generally producing severe consequences.
What is ‘Gene flow’?
It’s migration. The movement of alleles between populations, analogous to mutation as it introduces and removes alleles to a given population.
True or false: Gene flow is more effective at influencing microevolution than mutation.
True! Cuz the rates of gene flow» mutation rates.
What are pros and cons to gene flow?
Cons: Lower local adaptation
Pros: Promote adaptation by helping spread beneficial alleles.
True or false: A large contributing factor to genetic drift is the finiteness of a population.
True! The smaller a population is, the higher the affect of genetic drift.
Give an example of genetic drift:
- A forest fire that wipes out a percentage of birds
- Palestinian children getting massacred by Israeli coward soldiers
- COVID wiping out 7 million people
