Environmental factors that might result in random yearly variations in the rates of survival and birth within a population include changes in temperature, precipitation, food availability, predation, and disease. Changes in temperature can affect the availability of food sources, the ability of organisms to reproduce, and the ability of organisms to survive. Changes in precipitation can affect the availability of food sources, the ability of organisms to reproduce, and the ability of organisms to survive. Changes in food availability can affect the ability of organisms to reproduce and the ability of organisms to survive. Changes in predation can affect the ability of organisms to reproduce and the ability of organisms to survive. Changes in disease can affect the ability of organisms to reproduce and the ability of organisms to survive.
