Natural Selection and Adaptation Concepts

Dr. Sammy, an entomologist, explains how adaptation is linked to the environment and how populations respond to environmental changes through natural selection. The video covers three types of selection: directional, disruptive, and stabilizing, with examples of each. Directional selection is illustrated with snow voles adapting to climate change, disruptive selection with dung beetles showing bimodal size distribution, and stabilizing selection with gall flies balancing between wasp and bird predation.

What is the primary driver of adaptation in populations?

• Random chance

• Human intervention

• Natural selection

• Genetic mutation

How does climate change affect the body size of snow voles?

• It favors larger body sizes

• It has no effect on body size

• It favors smaller body sizes

• It causes random changes in body size

What is the main advantage of large snow voles?

• They are more agile

• They have better survivorship

• They reproduce faster

• They consume less food

Which selection pattern is characterized by favoring one extreme trait?

• Directional selection

• Random selection

• Disruptive selection

• Stabilizing selection

In disruptive selection, which traits are favored?

• Random traits

• Extreme traits

• Moderate traits

• No traits are favored

How do small dung beetles increase their chances of mating?

• By forming alliances with other males

• By growing larger horns

• By digging backdoor entrances

• By fighting larger males

What is the main characteristic of stabilizing selection?

• Favoring extreme traits

• Favoring moderate traits

• Random selection of traits

• No selection pressure

Why are medium-sized galls favored in the presence of both wasps and birds?

• They are less visible to predators

• They provide more food

• They are easier to build

• They are less likely to be attacked by both wasps and birds

What role does natural selection play in a changing environment?

• It stops genetic diversity

• It becomes irrelevant

• It promotes new adaptations

• It slows down evolution

What is the effect of environmental change on trait distribution?

• It remains constant

• It becomes more diverse

• It often changes

• It becomes less diverse