get people to leave a area
evolutionary forces is most likely to decrease variation between populations
Global Warming
Populations increase and decrease because people leave one country (emigration) and enter another (immigration). A rise or fall in either the birth rate or death rate in a country can also cause populations to increase or decrease.
After carrying capacity, populations decrease.
A decrease in the availiable water
plankton populations decreasing
people die or leave to a different place
Food availability is a determining factor.
Food availability is a determining factor.
The hawk population increases and the other populations decrease.
Food availability is a determining factor.
Plankton population decrease plankton making less oxygen