Natural Selection and Human Traits Flashcards
What is balancing selection?
A type of selection that maintains two or more alleles in a population.
How does sickle cell anemia provide a fitness advantage?
Heterozygous individuals are resistant to malaria.
What mutation causes sickle cell anemia?
A point mutation in the beta-globin gene (HBB).
Why is sickle cell anemia more common in Africa?
It offers a survival advantage in malaria-endemic regions.
What type of selection is lactase persistence an example of?
Directional selection.
How do evolutionary trees help in studying human evolution?
They show relationships between populations and the origins of traits.
What is the most genetically diverse human population?
African populations.
What does mitochondrial DNA reveal about human origins?
All humans share a common ancestor in Africa.
What drives convergent evolution in traits like lactase persistence?
Similar environmental pressures.
How does malaria influence human evolution?
It selects for traits like the sickle cell allele that confer resistance.
How does the geographic distribution of sickle cell anemia reflect natural selection?
It is more prevalent in malaria-prone regions, where heterozygotes have a survival advantage.
What is the relationship between sickle cell anemia and malaria?
Heterozygous carriers of the sickle cell allele (HbA/HbS) are resistant to malaria.
Why is the sickle cell allele prevalent in certain regions?
Natural selection favors the allele in malaria-endemic areas due to its protective advantage.
What is balancing selection?
A type of natural selection that maintains genetic variation, such as in the sickle cell trait.
