Chapter 18

Question 1

Adaptive Feature

Answer 1

An inherited feature that helps an organism survive and reproduce in its environment.

Question 2

Mutation

Answer 2

A genetic change.

Question 3

Variation

Answer 3

Differences between individuals of the same species.

Question 4

Adaptation

Answer 4

The process, resulting from natural selection, by which populations become more suited to their environment over many generations.

Question 5

Gene Mutation

Answer 5

A random change in the base sequence of DNA.

Question 6

Continuous Variation

Answer 6

Shows a complete range of phenotypes within a population, between 2 extremes influenced by genes and environment (e.g., height, body mass).

Question 7

Discontinuous Variation

Answer 7

Distinct categories with no intermediates, typically caused by one or few genes (e.g., blood group).

Question 8

Natural Selection

Answer 8

Survival and reproduction of organisms with advantageous characteristics, passing on those traits to offspring.

Question 9

Artificial Selection

Answer 9

Human-guided breeding to enhance desirable traits in organisms.

Question 10

Xerophytes

Answer 10

Examples of Adaptations: Needle-shaped leaves, sunken stomata, and thick waxy cuticles to reduce water loss.

Question 11

Hydrophytes

Answer 11

Examples of Adaptations: Air spaces in roots and leaves for buoyancy, stomata on the upper epidermis for gas exchange, one on lower.

Question 12

Antibiotic Resistance in Bacteria

Answer 12

A mutation that enables bacteria to become resistant antibiotic treatment, which is then passed to offspring because they survive longer.