Interdependence

A scientist named Joseph Connell studied two species of barnacles on the shore of a Scottish island. In the area between the average tide and the neap high tide, he found that the population of Species A was smaller than that of Species B. He removed Species B from one area but left both Species A and B in a similar area. The graph below shows the results of this study. Based on these data, which hypothesis was Connell most likely testing?

• The populations of both species of barnacles increase more in warm water than in cool water.

• Barnacles grow larger when they are isolated from other species.

• The two species of barnacles compete with each other for resources.

• The two species of barnacles are closely related to each other.

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

The graph below shows the percent of seeds from two plant species that sprout when grown in water containing different amounts of salt. Which of the following best summarizes the effect of saltwater on these plant species?

• Species 1 can sprout only in freshwater, and Species 2 can sprout only in saltwater

• Both species can sprout in freshwater and saltwater, but Species 2 can sprout in a higher salt concentration than Species 1.

• Both species need salt in their water, but Species 2 needs more salt than Species 1.

• Species 1 can sprout only in water with a low salt concentration, but Species 2 is not affected by the salt concentration.

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NGSS.MS-LS1-5

NGSS.MS-LS2-1

Which organisms in the food web shown above compete for the same food source in this environment?

• Grasshoppers and snakes

• Hawks and frogs

• Frogs and snakes

• Decomposers and grasses

Tags

NGSS.MS-LS2-1

This diagram shows the variety of organisms that live in different tide zones. Mussels are common organisms that compete for space in intertidal (middle) tide zones. If all of the mussels were removed from zone A, which organisms would likely compete for the space in Zone A?

• Periwinkle and Limpets

• Sea lettuce and Chiton

• Sea urchins and Hermit crabs

• Rock louse and Periwinkle

Tags

NGSS.MS-LS2-1

Which types of native organisms do feral hogs most likely compete with for food sources?

• Carnivores and producers

• Herbivores and carnivores

• Producers and decomposers

• Decomposers and herbivores

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

Giant salvinia is an aquatic plant that floats on water and reproduces rapidly. When these plants die, decomposition by bacteria affects oxygen levels in the water. As more plants die, less oxygen is available in the water. Students observe a pond covered by giant salvinia. Which statement is the best prediction the students can make about the immediate future of the pond?

• The depth of the water in the pond will increase.

• Fish populations in the pond will begin to decrease.

• The amount of bacteria in the pond will suddenly decrease.

• The number of different types of plants around the pond will increase.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

A scientist added bacteria and a nutrient medium that could support the growth of the bacteria to a sterilized petri dish. No other materials were added. The graph models growth of the bacteria over time. Which of these most likely explains why the bacterial population stopped growing?

• The bacteria competed for nutrients and died after all the nutrients were consumed.

• The bacteria did not reproduce in the system, and eventually each individual died at the end of its life cycle.

• The bacteria mutated from photosynthetic to carnivorous organisms and consumed one another until all the individuals were dead.

• The bacteria became diseased and were unable to survive in the closed system.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

NGSS.MS-LS2-4

The strangler fig is a vine that starts out as a seed in the tree canopy of the rain forest. It drops its roots down from the canopy to the forest floor.

By sprouting in the rain-forest canopy, the strangler fig seedling is exposed to more

• sunlight

• soil

• nutrients

• consumers

Tags

NGSS.MS-LS1-5

Four students were asked to create a graph representing a typical predator–prey relationship. Which graph shows a situation in which the number of predators in a population depends on the number of prey?

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NGSS.MS-LS2-2

NGSS.MS-LS2-4

How does this chemical help black walnut trees compete with plants growing nearby?

• By attracting herbivores to the other plants

• By suppressing the growth of the other plants

• By increasing the photosynthesis rates in the other plants

• By limiting the amount of water available to the other plants

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4