Background: The theory of evolution by natural selection was proposed at about the same time by both Charles Darwin and Alfred Russel Wallace, shown in Figure below , and was set out in detail in Darwin's 1859 book On the Origin of Species . Natural selection is a process that causes heritable traits that are helpful for survival and reproduction to become more common, and harmful traits, or traits that are not helpful or advantageous for survival to become more rare in a population of organisms. This occurs because organisms with advantageous traits are more "fit" to survive in a particular environment and have "adapted" to the conditions of that environment. These individuals will have greater reproductive success than organisms less fit for survival in the environment. This will lead to an increase in the number of organisms with the advantageous trait(s) over time. Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment. Natural selection is one of the cornerstones of modern biology.

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which group of antelope is more adapted to the environment?
Answer: group A

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which group of antelope is less adapted to the environment?
Answer: group B

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which group of antelope will have greater reproductive success?
Answer: group A

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which group of antelope will have lower reproductive success?
Answer: group B

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which traits in the antelope will become more common over time, long necks and strong teeth or short necks and weak teeth?
Answer: long necks and strong teeth

Situation: In sub-Saharan Africa there are two predominant groups of antelope present. The first group of antelope, group A, have long necks and strong teeth. The second group of antelope, group B, have shorter necks and weaker teeth. Because of their longer necks and stronger teeth, the antelope from group A are more easily able to pick fruit and leaves from the tall trees in the region compared to antelope from group B.

Question: Which traits in the antelope will become less common over time, long necks and strong teeth or short necks and weak teeth?
Answer: short necks and weak teeth