Populations and Resources Chapter 3

Elephants eat grass. What is the consumer population?

• Elephants

• Grass

• Both are the consumer population

• Neither are the consumer population

Tags

NGSS.MS-LS2-1

Scientists have been studying the size of three populations in a grassland. In this ecosystem, lizards eat fireflies, and fireflies eat gnats (a type of insect). The data showed that all three populations were stable. Then the lizard population decreased suddenly. What will most likely happen to the size of the firefly population as a result?

• increase. The smaller lizard population will need fewer energy storage molecules so they will eat fewer fireflies. This will lead to fewer deaths than births in the firefly population.

• increase. The smaller lizard population will leave more energy storage molecules available for the firefly population to reproduce more. This will lead to more births in the firefly population.

• stay the same. The size of its resource population did not change, so the amount of energy storage molecules available for the fireflies did not change. There will be the same number of births and deaths in the firefly population.

• decrease. A decrease in any population causes a decrease in the sizes of all other populations in the ecosystem.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS2-2

In Australia, both opossums and foxes eat rats. The sizes of the populations have been stable for the last 12 years, but recently the size of the opossum population increased. What will likely happen to the fox population?

• increase. An increase in the size of any population leads to an increase in the sizes of all other populations in an ecosystem.

• stay the same. Opossums and foxes do not eat each other, so the number of births and deaths in the fox population will stay the same.

• decrease. The larger opossum population will leave fewer energy storage molecules for all other populations in the ecosystem, so the fox population will reproduce less. This will lead to fewer births than deaths in the fox population.

• decrease. Fewer energy storage molecules will be available to the fox population from the smaller rat population, so the fox population will reproduce less. This will lead to fewer births than deaths in the fox population.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS2-3

A population of bluefish lives in the Gulf of Mexico. Over the last 50 years, the size of the bluefish population has decreased. What best explains the decrease in the size of the bluefish population?

• A lot of bluefish died and no new bluefish were born.

• More bluefish were born than died.

• Fewer bluefish were born than died.

• The bluefish population is always decreasing because bluefish are always being eaten.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Scientists have been studying the size of three populations in a region. In this ecosystem, lions eat wild pigs, and wild pigs eat frogs. The data showed that all three populations were stable. Then the frog population decreased suddenly. What will likely happen to the size of the wild pig population as a result?

• increase. The smaller frog population will need fewer energy storage molecules so there will be more energy storage molecules available to the wild pig population. This will lead to more births in the wild pig population.

• decrease. The smaller frog population will provide fewer energy storage molecules for the wild pig population, so the wild pig population will reproduce less. This will lead to fewer births than deaths in the wild pig population.

• decrease. A decrease in any population causes a decrease in the sizes of all other populations in an ecosystem.

• stay the same. The size of their consumer population did not change, so the number of deaths in the wild pig population did not change. There will be the same number of births and deaths in the wild pig population.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

In North America, both bears and eagles eat trout. The sizes of the populations have been stable for the last 9 years, but recently the size of the eagle population decreased. What will likely happen to the bear population?

• stay the same. Eagles and bears do not eat each other, so the number of births and deaths in the bear population will stay the same.

• increase. The smaller eagle population will leave more energy storage molecules for all other populations in the ecosystem, so all populations will reproduce more. This will lead to more births in the bear population.

• increase. More energy storage molecules will be available to the bear population from the larger trout population, so the bear population will reproduce more. This will lead to more births than deaths in the bear population.

• decrease. A decrease in the size of one population leads to a decrease in the sizes of all other populations in an ecosystem.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS2-2

Competition occurs when two species share the same ______.

• habitat

• food source

• both of the above

• neither of the above

Tags

NGSS.MS-LS2-4

In a rainforest, both spiders and frogs eat flies. The sizes of the populations have been stable for the last 10 years, but recently the size of the frog population decreased. What will likely happen to the spider population?

• increase. The smaller frog population will leave more energy storage molecules for all other populations in the ecosystem, so all populations will reproduce more. This will lead to more births in the spider population.

• increase. More energy storage molecules will be available to the spider population from the larger fly population, so the spider population will reproduce more. This will lead to more births than deaths in the spider population.

• stay the same. Frogs and spiders do not eat each other, so the number of births and deaths in the spider population will stay the same.

• decrease. A decrease in the size of one population leads to a decrease in the sizes of all other populations in an ecosystem.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS2-2

When a populations is known to be STABLE, it:

• there are more deaths

• there are more births

• stays mostly the same, over time

• horses live there

An indirect effect is:

• the result of one cause leading to an effect that causes one or more other effects

• the result of one cause stopping a desired effect

• the result of more than one cause leading to the death rate of a population

• when there is a direct relationship between one organism and the next