Biology: The Biosphere: Earth's Life-Supporting Systems
Exploring how air, water, land, and living things interact
Biology: The Biosphere: Earth's Life-Supporting Systems
Exploring how air, water, land, and living things interact
Biology - Grade 6-8
- 1
Define the biosphere in your own words. Include at least two examples of places where living things can be found.
Think about all the parts of Earth that can support organisms.
The biosphere is the part of Earth where life exists. It includes places such as forests, oceans, soil, lakes, and even areas high in the atmosphere where tiny organisms or spores may be found. - 2
Name the four major Earth systems and briefly describe how each one helps support life.
The atmosphere provides gases such as oxygen and carbon dioxide and helps regulate temperature. The hydrosphere provides water. The geosphere provides land, soil, and minerals. The biosphere includes all living things and their interactions. - 3
A pond ecosystem includes fish, algae, insects, mud, sunlight, water, oxygen, and bacteria. Sort these items into biotic and abiotic factors.
Biotic means living. Abiotic means nonliving.
The biotic factors are fish, algae, insects, and bacteria because they are living or were once living. The abiotic factors are mud, sunlight, water, and oxygen because they are nonliving parts of the ecosystem. - 4
Explain how energy usually enters most ecosystems and how it moves through a food chain.
Energy usually enters most ecosystems as sunlight. Producers such as plants or algae use sunlight to make food, and then energy moves to consumers when they eat producers or other consumers. - 5
Write a food chain with at least four parts that could exist in a grassland ecosystem. Label the producer and the consumers.
Start with a plant because plants are producers.
One possible food chain is grass to grasshopper to frog to hawk. The grass is the producer, and the grasshopper, frog, and hawk are consumers. - 6
Why are decomposers important in the biosphere? Give one example of a decomposer.
Decomposers are important because they break down dead organisms and wastes, returning nutrients to the soil or water. An example of a decomposer is a fungus, bacterium, or earthworm. - 7
Describe one way the atmosphere and biosphere interact.
Think about breathing and photosynthesis.
The atmosphere and biosphere interact when animals breathe oxygen from the air and release carbon dioxide. Plants also take in carbon dioxide from the atmosphere and release oxygen during photosynthesis. - 8
Describe one way the hydrosphere and biosphere interact.
The hydrosphere and biosphere interact because living things need water to survive. For example, fish live in water, and land plants absorb water through their roots. - 9
A forest is cut down to build homes. Identify two possible effects this change could have on the local biosphere.
Think about food, shelter, soil, and air.
Cutting down a forest can remove habitats, causing some animals to move away or die. It can also reduce the number of plants that produce oxygen, store carbon, and help prevent soil erosion. - 10
Explain why biodiversity can make an ecosystem more stable.
Biodiversity can make an ecosystem more stable because many different species can fill different roles. If one species decreases, other species may still provide food, pollination, decomposition, or other important functions. - 11
Use the water cycle to explain how water moves between the hydrosphere, atmosphere, geosphere, and biosphere.
Include evaporation, precipitation, and living things in your answer.
Water evaporates from oceans, lakes, and soil into the atmosphere. It falls as precipitation onto land and water, soaks into the ground, and is used by plants and animals. Plants can also release water vapor back into the atmosphere through transpiration. - 12
Carbon moves through Earth's systems. Describe how carbon can move from the atmosphere into the biosphere and then back into the atmosphere.
Carbon can move from the atmosphere into the biosphere when plants take in carbon dioxide during photosynthesis. It can move back into the atmosphere when organisms respire, when decomposers break down dead matter, or when materials burn. - 13
A drought affects a lake ecosystem. Predict how the drought could affect producers, consumers, and abiotic factors in the lake.
A drought means there is less available water than usual.
A drought could lower the water level and increase water temperature, which are abiotic changes. Producers such as algae and aquatic plants may have less habitat or fewer nutrients. Consumers such as fish, insects, and birds may have less food, less oxygen, or less space to live. - 14
Compare a habitat and a niche. Use an example of an organism in your explanation.
A habitat is the place where an organism lives, while a niche is the role the organism has in its ecosystem. For example, a bee's habitat may be a meadow, and its niche includes collecting nectar and pollinating flowers. - 15
A student says, "Humans are separate from the biosphere because we use technology." Explain why this statement is incorrect.
Consider what humans need to survive.
This statement is incorrect because humans are living organisms and are part of the biosphere. Humans depend on Earth's systems for air, water, food, materials, and a stable climate, even when they use technology.