UNIT 7 Organisms & Their Environment

A group of ecosystems that share similar climates and typical organisms

• biome

• ecosystem

• interrelated

• interdependent

• interaction

The more diverse an ecosystem is --

• the more threatened its populations are

• the more similar the species will be

• the more sustainable it is

• the fewer varieties of species are present

Which of the following situations contributes to the sustainability of an ecosystem?

• Increase in biodiversity

• Decrease in biodiversity

• Extinction of a population from the ecosystem

• Removal of many populations of organisms

Which of the following sequences most likely represents ecological succession on a recently abandoned wheat field?

• grasses → flowering plants → shrubs → native trees

• native trees → shrubs → flowering plants → grasses

• shrubs → grasses → native trees → flowering plants

• flowering plants → native trees → shrubs → grasses

A hurricane hits a coastal prairie and destroys the habitat. Years later, there is an appearance of small plants with rapidly spreading roots.

This vegetation describes —

• a microhabitat

• primary succession

• secondary succession

• biodiversity

When forest fires destroyed many of the pine trees in Bastrop State Park, the burned areas began secondary succession. What is the role of succession in this example?

• Creating new soil by chemical and physical weathering of rocks

• Restoring the ecosystem through grass, shrub, and tree stages

• Changing the landscape to be more fire resistant in the future

• Opening the land for new uses like farming and raising livestock

How does secondary succession help restore equilibrium to a region destroyed by a flood?

• It increases the number and types of species

• It brings back species from extinction

• It stops the other flood from occurring

• It decreases the rate of evolution

a stable ecological community that has reached equilibrium

• ecological succession 
• climax community
• secondary succession
• pioneer speciles

A flower bed is created at a school so flowers can be planted in the autumn.

Over the summer, the flower bed is ignored. Which of the following should the students expect to find when they come back to school?

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In2011,firesinBastropCounty,Texaswerethemostdamaging wildfires in Texas history. The fire spread through the pine trees and scorched nearly 5,700 acres of Bastrop State Park. The majority of the Houston toad’s habitat was lost, and the Lost Pines Forest was greatly affected.

As ecological succession began, which of these most likely appeared in

the Bastrop forest area first?

• Shrubs and trees

• Newly developed topsoil

• Weeds and grasses

• Lichens on fallen trees