Interactions in Ecosystem

Competition becomes more important as the number of individuals ______ or the availability of resources _________.

• increases, decreases

• increases, increases

• decreases, increases

• decreases, decreases

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Barnacles are marine organisms that live attached to surfaces as adults. A scientist studies two barnacle species that live on rocks on a coast in Scotland. In some rocky areas Species A is found alone. In other rocky areas Species B is found alone. In still other rocky areas both species are found together. The diagram below shows the two barnacle species on rocks in their habitats.

If Species B were removed from the rocky areas it shares with Species A, Species A would most likely inhabit —

• Zone I only

• Zones I and II only

• Zone III only

• Zones I, II, and III

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4

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.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

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

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-LS2-3

NGSS.MS-LS2-4

A group of scientists studied some trees in a pine forest. In the densely forested areas, the trees were within 1 m of each other. The scientists observed that these trees had dead branches near the ground. They measured the height above the ground at which the first living branches were found on different-sized trees in the forest. Then they repeated this procedure on the same kind of trees in an open meadow. This graph summarizes the scientists’ data.

Which inference is best supported by these data?

• Pine trees in a dense forest can grow taller than pine trees in an open meadow.

• Pine trees in a dense forest compete for sunlight with the surrounding trees.

• Pine trees in a dense forest are part of a less-complex food web than pine trees in an open meadow.

• Pine trees in a dense forest have more living branches than pine trees in an open meadow.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

NGSS.MS-LS2-4

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?

• 
• 
• 
• 

Tags

NGSS.MS-LS2-2

NGSS.MS-LS2-3

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-LS2-2

After researching the diets of several birds inhabiting a nearby pond, a student goes on a field investigation to observe the feeding habits of the birds. The student records information from research and observations in the table. The student observes a great blue heron catching fish near the edge of the pond. Based on the information the student collected, which bird will compete with the great blue heron for the same hunting spots and similar prey?

• The mallard, because it hunts for fish while wading near the edge of the pond

• The pied-billed grebe, because it dives in open water to get crayfish on the bottom of the pond

• The great egret, because it hunts in water near the edge of the pond for fish and other prey

• None of these

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2