Survivorship Curves (College Board AP® Environmental Science): Exam Questions

Which line on the graph represents the survivorship of a K-selected species?

Elephants are keystone species that give birth to an average of 1 calf every four to five years. Females nurse their calves for about four years and teach them how to stand, swim and find food. Elephants are known for being fierce protectors of their calves. Which of the following curves best represents the survivorship of elephants? 

Which line on the graph represents the survivorship of a species in which survivorship is independent of age?

Bullfrogs engage in external fertilization by releasing sperm as the female lays eggs, producing up to 20,000  offspring in a single breeding event. Which line of the graph represents the survivorship of a bullfrog?

American bison are large, grazing mammals with long lifespans and slow reproduction rates. Bison typically give birth to a single calf after a gestation period of about nine months, Mothers provide extensive care and protection, which significantly reduces juvenile mortality. Which of the following best identifies the American bison?