The Physical Environment
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Chapter Review

Assess your understanding of concepts related to this chapter by answering the questions below. Click the question to reveal the correct answer.
The effectiveness of habitat occupation depends in part on the means of transportation. Animals must use their own locomotion, while plants disperse by wind, running water, ocean currents, and animals. Thus, climate and topographic barriers are more of an impediment to animals than plants. For either, continental drift poses a significant barrier to diffusion. The separation of continents has isolated plants and animals in the past thus preventing their complete occupation of a suitable habitat.
Photosynthesis is the process where by green plants convert carbon dioxide and energy into oxygen and stored carbohydrates. Respiration is the burning of stored chemical energy. Transpiration is the loss of water through the stomata of plant leaves.
A habitat is the specific, physical location of an organism. Habitats can be identified at different spatial scales. A niche is the function or occupation, of a life-form within a community. An organism's niche incorporates the physical (habitat), chemical, and biological factors that maintains the health and vitality of the organism. An organism's interaction with the abiotic factors of its environment (heat and moisture) defines its niche.
The tropical rain forest has the largest net primary production of all biomes.
Plants have adapted to dry conditions by evolving deep roots to extract water held deep beneath the surface. Some plants have extensive near surface root systems to catch infiltrating water, or thick fleshy leaves. Others have thick bark and or short waxy leaves to reduce transpiration. Plants go dormant during dry periods, drop their leaves, or have no leaves at all. They instead have thick moisture retentive, photosynthetic skin.
Is the evolutionary process that tends toward a stable, diverse plant community (climax community). Each  community prepares the environment for that which succeeds it.
The limiting factor to growth in low latitudes is moisture. The limiting factor to growth in high latitudes is energy (solar radiation).
A food chain is the sequence of consumption and energy transfer through an ecosystem. A food chain consists consists of different trophic levels which are the position of an organism in a food chain. At the base is the primary producers that convert solar energy into organic energy. Above the producers are the consumers that ingest live plants (primary consumer) or prey on other consumers (secondary consumer). Decomposers such as, bacteria, molds, and fungi make use of energy stored in already dead plant and animal tissues.
Plant communities affect soil type when organic material decomposes into the soil altering soil moisture retention, infiltration capacity, soil structure and soil chemistry. Trees shade the forest floor, reducing incident solar radiation and lowering temperatures of both the soil and the air. Reduced incident light decreases evaporation keeping soils moister beneath the forest canopy. These impacts affect animal habitats and the diversity of animal species which are associated with these plant communities.
Net biomass productivity is the difference between gross productivity (production of plant material by photosynthesis) and respiration. Net productivity is closely related to a number of environmental factors like climate, soils, and available nutrients. Net biomass production will be highest where there is an ample supply of moisture to meet the needs of plants. Biomass productivity is also high where soils are rich in nutrients and have a positive soil moisture balance. Forest, especially tropical forest have high net biomass productivity while deserts have low productivity.

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For Citation: Ritter, Michael E. The Physical Environment: an Introduction to Physical Geography.
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