Genetic Variation
What is genetic variation and why is it important for evolution?
Differences in DNA among individuals; it provides material for natural selection.
Who first described the process of natural selection?
Charles Darwin and Alfred Russel Wallace.
What is an adaptation?
A trait that increases an organism's chance of survival and reproduction.
What does Ro represent in disease studies?
The average number of people infected by one person.
What is an environmental pressure?
A factor that influences which traits are advantageous.
Name one source of genetic variation in populations.
Mutations or sexual reproduction.
What does 'survival of the fittest' mean?
Organisms best adapted to their environment survive and reproduce.
Give an example of an adaptation in humans related to disease.
ERAP2 gene variant for plague resistance.
If Ro > 1, what happens to the disease?
It spreads in the population.
Give an example of an environmental pressure from history.
The Black Death or cholera outbreaks.
True or False: All variations are visible traits.
False
What happens to traits that provide an advantage over time?
They become more common in the population.
How does adaptation relate to evolution?
Adaptations accumulate, leading to population changes over time.
Why do scientists use graphs in studying evolution?
To visualize changes in trait frequency over time.
How does climate change act as an environmental pressure?
It alters habitats, favoring certain traits.
What does heritable mean in the context of traits?
Traits can be passed from parents to offspring.
Name one factor that influences natural selection.
Environmental conditions.
True or False: Evolution occurs in individuals.
False; it occurs in populations.
What does a steep upward trend in a trait graph indicate?
Rapid increase in that trait's frequency.
True or False: Environmental pressures always cause extinction.
False; they can lead to adaptation.
Give an example of a hidden variation that affects survival.
Immune system gene variants like ERAP2.
Explain why not all individuals with advantageous traits survive.
Chance events and other factors affect survival.
Why is the ERAP2 gene considered evidence of rapid evolution?
Its frequency changed significantly after the Black Death.
How does probability relate to survival of traits?
Traits that improve survival have higher chances of being passed on.
Explain how malaria influenced human evolution.
It led to the spread of the sickle cell trait in some populations.