Name: _______________________________________ Date: _____________ Period: ________
Chapter 2-3 Practice Problems
1. Why is an ecological pyramid smaller at the top than at the bottom?
An ecological pyramid, which represents the amount of energy in each tropic level of an
ecosystem, is smaller on top because energy is lost as it flows from one level to the next.
2. What portion of Earth is included in the biosphere?
The biosphere forms a thin layer around Earth and includes only the portion of Earth
that includes life. It is a couple kilometers below the ocean’s surface and a couple
kilometers above the Earth’s surface.
3. How can you recognize the predator and the prey in a predation relationship?
The organism that pursues another organism to consume it is the predator. The
organism that is pursued and eaten is the prey.
4. How do individuals relate to populations in the organization of the biosphere?
Individuals are the lowest level of organization. Each is a single organism. Populations
are the next level of organization. Individuals of a single species that share the same
geographic location make up populations.
5. Compare and contrast mutualism and parasitism.
They are both forms of symbiosis. In mutualism, two or more organisms live closely
together and benefit each other. In parasitism, one organism benefits at the expense of
the other organism.
6. Why are green plants or algae good indicators of the distribution of living organisms in
an area?
Most organisms depend on green plants or algae for survival. Therefore, organisms that
depend on a particular plant or alga will be found living in the same areas as the plant or
alga.
7. Why are detritivores an important part of the ecosystem?
Detritivores decompose organic material in an ecosystem and return nutrients to the
soil, air, and water. This decomposition is needed to make nutrients available for reuse
by other organisms.
8. What is the function of nitrogen fixation?
Nitrogen fixation captures and converts nitrogen into a form that is usable by plants.
9. Summarize the long-term cycle of phosphorus.
Phosphorus is a component of some rocks. Weathering or erosion of rock that contains
phosphorus slowly adds phosphorus to the soil and water in the long-term cycle.
10. What are some strategies that humans could use to remove carbon dioxide from the
atmosphere? Explain.
During photosynthesis, autotrophs take in carbon dioxide. Planting forests, setting aside
regions for shallow water algae growth, and preserving tropical forests are ways of
removing excess carbon dioxide from the atmosphere.
11. Why is secondary succession faster than primary succession?
Secondary succession is faster than primary succession because soil exists, seeds might
be present, some species might be present, and there may be seeds and animals in
undisturbed nearby areas.
12. What are the three zones of Earth that are based on latitude?
Tropical, polar, and temperate
13. Why are mountains and polar regions not considered terrestrial biomes?
Mountains and polar regions are not considered terrestrial biomes because although
mountains are found throughout the world, their climate characteristics and plant and
animal life vary depending on elevation, while polar regions are ice masses and not true
land areas with soil.
14. Which zone of Earth is heated the most by the sun?
Tropical zone (or equatorial zone)
15. What is the difference between weather and climate?
Weather is the specific condition of the atmosphere at a specific time and place. Climate
applies to a large region, and it is a region’s average weather conditions, such as
temperature and precipitation, over many years.