4.2 Describing Populations Answer Key

Question: Population size

Answer: describes the number of individual organisms present in a given population at given time

Question: Population density

Answer: describes the number of individuals within a population in a certain area

Question: Population distribution

Answer: describes how organisms are arranged within an area

Question: Age structure

Answer: describes the relative numbers of organisms of each age within a population

Question: Age structure diagram

Answer: visual tools scientists use to show the age structure of populations

Question: Sex ratio

Answer: proportion of males to females

Question: When a population size ___________ or remains steady, this is often a sign of healthy population

Answer: increases

Question: If a population size begins to _________ rapidly, this can be a signal that extinction is coming

Answer: declines

Question: Instead of counting each organism individually, ecologists use __________ methods to estimate population sizes

Answer: sampling

Question: A population’s destiny describes how

Answer: crowded the population is