7C Change in Populations not Individuals

Male guppies found in areas without predators are more colorful than the ones found in locations with large predator populations. A population of adult guppies originating from an area with a large number of predators is transferred to a nearby area with few predators. Which of these is most likely to happen over a few generations?

• the mortality rate of the guppies will increase

• offspring will stop competing for resources

• there will be an increase in mutations in the offspring

• there will be an increase in the number of colorful guppies

The diagram shows light and dark-colored beetles that live on a tree. Which result is most likely to occur to the beetle population due to predation over time?

• the number of light-colored beetles in the population will increase

• there will be more dark-colored beetles than light-colored beetles

• the number of light-colored beetles will decrease

• the dark-colored beetles will move to a different type of tree

The quiver tree grows in desert areas in southern Africa. In recent decades average temperatures have been rising in southern Africa. Scientists predict that this warming trend will continue. Quiver trees in the hottest parts of their range near the equator are dying, but quiver trees at high elevations or in parts of the range that are farther from the equator are growing and reproducing. Which of these best explains what is happening to the quiver tree population in southern Africa?

• individual quiver trees are unable to adjust to the rising temperatures, and only those in cooler parts of the range will survive

• the quiver tree species is unable to survive rising temperatures throughout its range. The species is likely to undergo rapid extinction

• Individual quiver trees can quickly adapt to rising temperatures. Individual trees will change their method of seed dispersal in cooler parts of the range.

• The quiver tree species will survive by producing offspring suited for warmer temperatures