9_3 ECO Q A PDF Past Paper

1. Who were Charles Darwin and Gregor Mendel? Charles Darwin: Developed the concept of natural selection. Gregor Mendel: Discovered the principles of inheritance through experiments with pea plants. 2. What were the four components required in Darwin’s concept of natural sele...

1. Who were Charles Darwin and Gregor Mendel? Charles Darwin: Developed the concept of natural selection. Gregor Mendel: Discovered the principles of inheritance through experiments with pea plants. 2. What were the four components required in Darwin’s concept of natural selection? Four Components of Darwin's Natural Selection: Organisms produce offspring like themselves. Variation exists among individuals, and some of it is heritable. More offspring are produced than can survive. Individuals with advantageous traits are more likely to survive and reproduce. 3. What is heritability? Heritability: The proportion of phenotypic variation in a population that is due to genetic variation. 4. What is Hardy-Weinberg Equilibrium? Hardy-Weinberg Equilibrium (HWE): A principle stating allele and genotype frequencies remain constant from generation to generation in the absence of evolutionary forces. 5. What are allele and genotype frequencies under HWE? Allele and Genotype Frequencies under HWE: Allele frequencies: p+q=1p + q = 1p+q=1 Genotype frequencies: p2+2pq+q2=1p^2 + 2pq + q^2 = 1 p2+2pq+q2=1 6. What are the 5 assumptions (and associated violations) of HWE? Assumptions of HWE: No mutation  No gene flow Large population size (no genetic drift) Random mating No natural selection 7. What is the difference between a population bottleneck and a found event? Population Bottleneck vs. Founder Event: Bottleneck: A large population is drastically reduced in size, leading to loss of genetic diversity. Founder Event: A new population is established by a few individuals, carrying only a fraction of the original genetic variation. 8. What are three different types of natural selection on phenotypes? Three Types of Natural Selection on Phenotypes: Directional Selection: Favors one extreme phenotype. Stabilizing Selection: Favors average phenotypes. Disruptive Selection: Favors two or more extreme phenotypes over the average. Notes: In order for natural selection to work, we need: variation within populations