Unit 2.3 Test Retake

When a volcano erupting under the ocean near Iceland grew tall enough to be visible above the ocean surface, the Island of Surtsey was born. When the volcanic matter had cooled one of the first species that came in on the wind was spores of lichen, an algae/fungi organism that performs chemical weathering by secreting a mild acid on the bare rock. Lichen is an important pioneer species because it is able to:

• break down rock to form soil

• grow into a much larger plant

• conduct water up to its leaves

• survive any predator

The role of a pioneer species in primary succession is to change a bare habitat into one that is suitable for other organisms. A species that is responsible for primary succession in an ecosystem is MOST likely able to —

• survive any predator.

• migrate during the winter.

• live at high altitudes.

• get energy from the sun and photosynthesize.

Using the diagram, which section shows the greatest amount of sustainability?

• when grasses and weeds begin to grow because there is large population of each

• when flowering plants and shrubs appear because insects will also appear

• when the Pine Forest appears because trees will provide homes to mammals

• when slow growing trees such as oak and hickory appear because there will be the greatest amount of biodiversity.

How does biodiversity contribute to the sustainability of an ecosystem?

• The presence of more species with different adaptations makes it more likely that some organisms will survive an ecological disaster.

• Greater genetic variation within species makes it more likely that some individuals will survive a disease outbreak.

• The presence of a variety of herbivore species that can feed on a large number of different producer species helps ensure abundant prey for predators in the ecosystem.

• All of the above

The food webs model relationships among the organisms in two ecosystems. Which ecosystem would be more likely to survive if a disease killed the grasses?

• The forest ecosystem, because most of the animals can eat other organisms

• The grassland ecosystem, because several predators compete for food

• The forest ecosystem, because it has three top predators

• The grassland ecosystem, because it has many herbivores

The diagram below shows an example of ecological succession. How can you tell that this is an example of secondary succession rather than of primary succession?

• No plants exist when the process begins.

• Soil is present at the beginning of the process.

• The process ends with the growth of large trees.

• The sizes of the plants generally increase over time.

Some plants have stems that can hold water and have almost no leaves, which reduces water loss. In which type of biome would this be important?

• grassland

• rainforest

• swamp

• desert

Deforestation, pollution, and over hunting can all result in—

• increase in biodiversity.

• reduction in biodiversity.

• no effect on biodiversity.

• a state of equilibrium.

The table below identifies the number of the most common plants for 4 ecoregions in Texas. Based on the information provided, which of the following best describes the most diverse (Diverse = has variety) ecoregion?

• Q

• R

• S

• T

The table describes the number of the most common plants for ecoregions in Texas. Which statement can best be supported by the information?

• Ecoregion Q has a lot of animals that eat the plants.

• Ecoregion R has a variety of biotic factors that support the abiotic factors.

• Ecoregion S has poor soil quality and extremely high precipitation.

• Ecoregion T has the abiotic factors to support the greatest variety of plant life.