7th Grade Science: S2 Exam

Over 50 years, the size of the panther population in the southeastern United States increased. What best explains the increase in the size of the panther population?

• Fewer panthers were born than died.
• More panthers were born than died.
• A lot of panthers were born and none of them died.

A resource population is the population that.....

• is eaten by others
• eats others

Recently the tiger population has increased. What will likely happen to the worm population?

• increase. The larger tiger population will lead to fewer wild pigs. The smaller wild pig population will need fewer energy storage molecules to reproduce, so they will eat fewer worms. This will lead to more births than deaths in the worm population.
• stay the same. Tigers do not eat worms, so the number of births and deaths in the worm population will stay the same.
• decrease. The larger tiger population will leave fewer energy storage molecules available in the ecosystem for the worm population, so there will be fewer births in the worm population.

Energy storage molecules are:

• molecules required only for the birth rate
• potatoes
• a molecule organisms use to stabilize a population
• a molecule that organisms can use to release the energy needed to survive

Recently the size of the aphid population decreased. What will likely happen to the anteater population?

• stay the same. Anteaters do not eat aphids, so the number of births and deaths in the anteater population will stay the same.
• decrease. Fewer energy storage molecules will be available to the anteater population from the smaller ant population, so the anteater population will reproduce less. This will lead to fewer births than deaths in the anteater population.
• increase. The smaller aphid population will leave more energy storage molecules available in the ecosystem for the anteater population, so there will be more births in the anteater population.

A population of deer lives in Canada. Over 50 years, the size of the deer population decreased. What best explains the decrease in the size of the deer population?

• A lot of deer died and no deer were born.
• Fewer deer were born than died.
• More deer were born than died.

An ecologist is a scientist who studies....

• The life cycles of viruses and their hosts.
• The interactions between living things and their environments.
• The types of rocks and soil in an area.
• The phase of different substances.

The grasshopper population decreased suddenly. What will likely happen to the size of the rat population as a result?

• stay the same. The size of their consumer population did not change, so the number of deaths in the rat population did not change. There will be the same number of births and deaths in the rat population.
• increase. The smaller grasshopper population will need fewer energy storage molecules so there will be more energy storage molecules available for the rat population to reproduce. This will lead to more births in the rat population.
• decrease. The smaller grasshopper population provides fewer energy storage molecules for the rat population, so the rat population will reproduce less. This will lead to fewer births than deaths in the rat population.

In the last 50 years, the size of the squirrel population has stayed the same. What must be true about the squirrel population during the last 50 years?

• The number of squirrels that were born was the same as the number of squirrels that died.
• No squirrels were born and no squirrels died.
• The squirrels did not have any baby squirrels during these years.

In this food web, which of the following animal(s) are part of the resource population?

• Coyote
• Deer
• Wolf