Hank lists the different types of natural selection and explains each of them. He accompanies each type of selection with examples. He also briefly covers artificial selection, also known as selective breeding.
Key Words: Phenotype, Genotype, Modes of Selection, Directional Selection, Stabilizing Selection, Disruptive Selection, Sexual Selection, Directional Sexual Selection, Artificial Selection
Hank provides background information on the biologist who contributed to evolutionary history: Charles Darwin. He also explains the four principles of Darwin's idea of natural selection, which are variation, heritability, struggle for existence, and survival and reproduction rates.
Key Words: Genetic Drift, Fitness, Variations of Phenotype, Heritable, The Struggle for Existence, Survival and Reproduction Rates
Beakman explains that giraffes have long necks so they can eat leaves out of trees. He mentions that heredity has caused them to all have long necks. He then pretends to be Charles Darwin, who explains how natural selection caused the long necks in giraffes.
In a test to become an astronaut, candidates must demonstrate their ability to blow bubbles for an extended period of time. Candidates will be chosen to move forward based on their performance in this test, as it indicates their ability to withstand the challenging conditions of the role.