Ecological Stability

Which of the following describes climax community?

• Type of succession in which no ecosystem previously existed.

• Gradual change in an ecosystem over time.

• A final and stable ecological community.

• The relationship between two species in which both compete for a resource.

Which of the following is an example of secondary succession?

• Hardened rock from a volcanic eruption has mosses that begin to grow.

• An old field that was once farmland is no longer cultivated and begins to regrow weeds and shrubs.

• A newly formed sand dune with one pioneer species.

• None of the above.

Which of the following accurately depicts a climax community?

• An uninhabited rock begins to grow a species of moss.

• An ecosystem is filled with various trophic levels of organisms and reaches a point of stability.

• In the 1950’s, the wolves in Yellowstone National Park were overhunted and they were no longer present in this ecosystem.

• The different species of finches throughout the Galapagos Islands were geographically separated and developed different types of beaks.

Tags

NGSS.MS-LS2-3

What is the role of a keystone species in an ecosystem?

• They are the first to colonize a new habitat in primary succession.

• They define and maintain the ecological structure of the community.

• They are involved in the recycling of nutrients by decomposing organic material.

• They primarily modify the habitat to make it less hospitable for other species.

Tags

NGSS.MS-LS2-2

NGSS.MS-LS2-4

Which of the following would have the highest species richness?

• An ecosystem with 30 species with varying numbers of each population.

• An ecosystem with 15 species with 2 populations dominating in size.

• An ecosystem with 25 species with roughly the same amount of individuals in each population.

• An ecosystem with 5 highly specialized species with equal amount of individuals in each population.

Tags

NGSS.MS-LS2-5

Which of the following is correct about secondary succession?

• It occurs where no ecosystem previously existed.

• It occurs where an ecosystem already existed.

• It requires more time than primary succession.

• It requires the same amount of time as primary succession.

Which of the following is an example of a pioneer species?

• A species of birds that inhabit an ecosystem as the population of pollinators increase.

• A species of moss that begins to grow on recently exposed rock.

• A tree that grows up over other trees in an ecosystem and prevent them from receiving sunlight and nutrients.

• The wolves in Yellowstone National Park act as a keystone species.

What typically initiates secondary succession in an ecosystem?

• The introduction of a new species into the area.

• A significant alteration such as a fire or flood.

• The gradual evolution of species over millennia.

• The removal of top predators from the food chain.

Tags

NGSS.MS-LS2-4

Why are bees considered a keystone species?

• The honey they make supports the bear population

• They pollinate flowers that produce fruit which supports the ecosystem

• They sting when threatened

• They live in hives

Tags

NGSS.MS-LS2-2

NGSS.MS-LS2-4

NGSS.MS-LS2-5

Based on the graph shown, how can you tell sea otters are a keystone species?

• as the sea otter population decreases, biodiversity increases

• as sea otter population increases, biodiversity increases

• changes in the sea otter population have little effect on biodiversity 

• the sea otter population dereases due to the presence of urchins

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4