Natural Selection: Life's Way of Stayin' Alive: Crash Course Biology #13

What are adaptations in biology?

• Traits that help organisms survive and reproduce.

• Changes in an organism's behavior due to learning.

• Features that are only found in animals.

• Traits that are always harmful to an organism.

Which statement best describes the relationship between genotype and phenotype?

• Genotype is the observable trait, while phenotype is the genetic information.

• Genotype is the genetic information, and phenotype is its actual expression in the real world.

• Both genotype and phenotype refer to the internal functions of an organism.

• Genotype and phenotype are interchangeable terms for an organism's inherited traits.

What is the first essential condition for natural selection to take place in a population?

• All individuals in the population must be identical.

• There must be a variety of traits among individuals in the population.

• Traits must be acquired during an individual's lifetime.

• The environment must remain completely stable over time.

Which physical traits helped anole lizards survive strong hurricane winds?

• Bigger toes and longer front legs

• Smaller toes and shorter back legs

• Bigger toes and shorter back legs

• Longer tails and stronger front legs

In a forest experiencing stabilizing selection, which type of pine tree is most likely to thrive?

• Very short trees that use less energy

• Very tall trees that get more sunlight

• Trees of medium height that balance light and energy needs

• Trees with the most needles for photosynthesis

What happens to a population of trees under directional selection when resources like water become scarce?

• The population becomes taller on average.

• The population becomes shorter on average.

• The population develops a wider range of heights.

• The population remains the same height on average.

What is an example of an evolutionary trade-off for male howler monkeys?

• Having a loud voice or having big testicles

• Having long tails or strong arms for climbing

• Having sharp teeth or good eyesight for finding food

• Having thick fur or being fast runners to escape predators