Theory of Evolution by Natural Selection

Natural selection is often described as "survival of the fittest." Based on the video, which scenario best exemplifies this concept?

• A population of insects reproduces rapidly, outnumbering predators.

• A species of birds evolves larger wings to fly longer distances in search of food.

• A predator species hunts down weaker prey, leaving the strongest to escape.

• A plant species thrives in a dry environment due to its ability to store water.

The video highlights the tortoises of the Galápagos Islands. Why do the shells and neck lengths of tortoises vary across the islands?

• Each island has predators that influenced shell shape through defense adaptations.

• Tortoises migrated between islands, leading to blending of physical traits.

• The availability of vegetation at different heights influenced shell shape and neck length.

• Climate differences caused changes in the tortoises’ genetic material.

The work of other scientists influenced Darwin's theory of evolution. For example, Thomas Malthus contributed to Darwin's understanding of natural selection by:

• Explaining how acquired traits are passed on to offspring over generations.

• Demonstrating how populations grow faster than their resources, leading to competition.

• Proposing that all species have a common ancestor based on fossil evidence.

• Conducting experiments on artificial selection in domestic animals and plants.

DNA evidence is mentioned in the video as crucial for understanding evolutionary relationships. Which statement best explains why DNA comparisons are powerful evidence?

• DNA shows that all species are identical on a molecular level.

• DNA provides a record of the mutations that have occurred in a species.

• Similar DNA sequences in different species indicate shared ancestry.

• DNA evolves independently of physical traits, providing unbiased data.

The video discusses vestigial structures. Which of the following is an example of such a structure, and what does it imply about evolution?

• The wings of a bat, indicating adaptation for flight.

• The pelvis of a whale, suggesting an ancestor that walked on land.

• The sharp teeth of carnivores, adapted for meat consumption.

• The gills of fish, showing their aquatic origins.