Understanding Populations: How Populations Change in Size

Understand population dynamics: birth, death, growth, and limiting factors.

Write a definition of population in your own words. How Populations Change in Size Over time, the growth rates of populations change because birthrates and death rates increase or decrease. Growth rates can be positive, negative, or zero. For a population’s growth rate to be zero, the average number of births must equal the average number of deaths. A population would remain the same size if each pair of adults produced exactly two offspring, and each of those off-spring survived to reproduce. If the adults in a population are not replaced by new births, the growth rate will be negative and the population will shrink. After Reading the above selection answer the questions below. The average number of deaths is greater than the average number of births Negative Population Growth The average number of deaths equals the average number of births Zero Growth Rate The average number of births is greater than the average number of deaths Positive Growth Rate Suppose that every year, one half of the population has two offspring per person, and the other half has none. If all members of the population die after a year, what is the resulting growth rate? Explain your answer. Sequencing Information Sequence the statements below to illustrate zero population growth. Match the statement with the correct order in the sequence. The population size returns to what it was in year x. 4 Two adults produce two offspring in year x. 1 The offspring, as adults, reproduce one offspring each. 2 The parents die. 3 Correctly fill in the equation to show population growth. Copy and paste the following words: Deaths, Births, Change in Population Size Change in Population Size Births Deaths Label the type of graph below. Copy and paste one of the following terms: Exponential Growth or Logistic Growth Exponential Growth Label the parts of the graph below. Copy and paste the following words Population Crash, Carrying Capacity, Exponential Growth, Runs out of resources, Population stabilizes Carrying Capacity Exponential Growth Runs out of resources Population Crash Population stabilizes Define limiting resource and explain its effect on a population's size.