Abiotic and Biotic Review

Which factor is most responsible for limiting the number of giraffes in a savanna ecosystem?

• the amount of rainfall

• the temperature of the environment

• the presence of other herbivores like zebras

• the number of trees with leaves at a height only giraffes can reach

What happens when an ecosystem exceeds its carrying capacity?

• The population will continue to grow.

• Some individuals will die or migrate to another location.

• The ecosystem will expand to accommodate more individuals.

• Resources will become more abundant to support the growing population.

How does the availability of water affect the competition among organisms in a desert ecosystem?

• It reduces competition because water is always available.

• It increases competition, as water is a limited resource.

• It has no effect on competition because all organisms are adapted to low water levels.

• It increases the number of organisms that can survive without water.

What is the effect of nutrient-poor soil on plant populations?

• It leads to a decrease in plant populations due to increased competition.

• It supports larger populations with less competition.

• It has no effect on plant populations since all plants need the same nutrients.

• It causes plants to grow faster to reach the nutrients they need.

Which scenario would cause a significant change in an ecosystem’s stability?

• a sudden increase in the population of a top predator

• a long period of consistent and mild weather

• a steady supply of water and sunlight

• a severe and long drought that depletes all water sources

Select ALL that describe biotic factors in an ecosystem.

• a herd of deer grazing in a meadow

• the amount of sunlight received by plants

• the temperature of the water in a pond

• fungi decomposing a fallen tree

• bacteria breaking down dead organic matter in the soil

Select ALL that are abiotic factors in an ecosystem.

• the oxygen content in a lake

• the acidity level (pH) of the soil

• the moisture level of the air in a rainforest

• a population of fish in a river

• a forest of pine trees

How do changes in abiotic factors, such as temperature or water availability, influence the carrying capacity of an ecosystem? Use scientific reasoning to explain your answer.

• They have no effect on the carrying capacity.

• They can increase or decrease the carrying capacity.

• They only decrease the carrying capacity.

• They only increase the carrying capacity.

Use scientific reasoning to describe how human activities, such as deforestation or pollution, can change the balance of biotic and abiotic factors in an ecosystem.

• Human activities have no impact on ecosystems.

• Human activities can only affect biotic factors.

• Human activities can change both biotic and abiotic factors.

• Human activities only affect abiotic factors.