Intro to Evolution: What We Can Learn From a Giraffe's Neck: Crash Course Biology #11

What kind of animal did whales evolve from approximately 50 million years ago?

• A fish-like creature

• A four-legged land mammal

• A bird

• An insect

What does biological evolution describe?

• Dramatic changes in an organism over its lifetime.

• Heritable changes in populations over time.

• The process of an organism becoming perfect.

• How organisms learn new behaviors.

Which statement accurately describes genetic mutations?

• They happen on purpose to make an organism better.

• They are always harmful to an organism.

• They are random changes that can be passed to offspring.

• They only occur in response to environmental changes.

What is the primary purpose of an adaptation in an organism?

• To make the organism "more evolved" than others.

• To achieve a perfect form for the species.

• To help the organism survive in its specific environment.

• To allow the organism to choose its traits.

The recurrent laryngeal nerve in a giraffe takes a very long, roundabout path from the brain to the larynx, looping around the heart. What does this example suggest about evolution?

• Evolution always leads to the most efficient biological designs.

• Evolution can result in complex, but not always perfectly optimized, structures.

• Giraffes are less evolved than humans because their nerves are longer.

• The length of a nerve is directly related to an animal's intelligence.

Morning glory flowers in Mexico are mostly blue, but in the southeastern U.S., they show a variety of colors. This difference doesn't seem to give them any advantage or disadvantage. What does this suggest about genetic variation?

• All genetic variations provide a clear benefit or harm to an organism.

• Genetic variations only happen when an organism needs to adapt to a new environment.

• Some genetic variations can occur randomly without an immediate impact on survival or reproduction.

• The color of a flower is always determined by its geographic location.

All living things share a universal genetic code. How does this shared code benefit humans in medicine?

• It allows humans to communicate directly with other organisms.

• It enables scientists to transfer genes from one organism to another to produce useful substances like insulin.

• It proves that all diseases affect all living things in the same way.

• It means that all organisms have the exact same DNA sequence.

The bones in a human arm, a cat's paw, a whale's flipper, and a bat's wing have a similar basic structure, even though they are used for different activities. What does this similarity suggest?

• These animals all live in similar environments.

• These animals evolved independently but developed similar structures by chance.

• These animals share a common ancestor from which these structures were inherited and then adapted.

• These structures are vestigial and no longer serve any purpose.