Biology Chapter 3 Flashcards

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Questions and Answers

All of life on Earth exists in a region known as ______.

the biosphere

Groups of different species that live together in a defined area make up a(an) _______.

community

What are autotrophs?

Organisms that use energy they take in from the environment to convert inorganic molecules into complex organic molecules.

The series of steps in which a large fish eats a small fish that has eaten algae is a ________.

food chain Signup and view all the answers

Which of the following organisms is a decomposer?

Earth worms Signup and view all the answers

The total mass of living tissue at each trophic level can be shown in a(an) _________.

biogeochemical cycle Signup and view all the answers

Nutrients move through an ecosystem in ________.

biogeochemical cycles Signup and view all the answers

In the nitrogen cycle, what do bacteria that live on the roots of plants do?

Change nitrogen gas into ammonia. Signup and view all the answers

Which biogeochemical cycle does NOT involve a stage where the chemical enters the atmosphere?

Phosphorus cycle Signup and view all the answers

When an ecosystem is limited by a single nutrient that either is scarce or cycles very slowly, this substance is called a(an) _________.

limited nutrient Signup and view all the answers

What is the definition of ecology?

The scientific study of interactions among organisms and between organisms and their environment. Signup and view all the answers

Name the different levels of organization within the biosphere, from smallest to largest.

Individual, population, community, ecosystem, biome, and biosphere. Signup and view all the answers

How do scientists use modeling to study ecological changes?

Models help gain insight into complex phenomena such as the effects of global warming on ecosystems. Signup and view all the answers

How is sunlight important to most ecosystems?

Sunlight is the main energy source for life on Earth. Signup and view all the answers

What is chemosynthesis?

The process by which some organisms, such as certain bacteria, use chemical energy to produce carbohydrates. Signup and view all the answers

Distinguish between autotrophs and heterotrophs. Give an example of each.

Autotrophs can produce their own food; examples include plants and algae. Heterotrophs obtain energy from food; examples include herbivores and carnivores. Signup and view all the answers

What is a decomposer? Provide an example.

An organism that breaks down and obtains energy from dead organic matter. Example: Bacteria, fungi, worms. Signup and view all the answers

Which group of organisms is always found at the base of the food chain or food web?

Autotrophs (producers) Signup and view all the answers

What is an ecological pyramid? Describe the three different types of ecological pyramids.

An ecological pyramid shows the relative amounts of energy or matter at each trophic level. The three types are biomass pyramids, numbers pyramids, and energy pyramids. Signup and view all the answers

Why is the transfer of energy and matter in a food chain only about 10 percent efficient?

Organisms use most of the energy they consume for life processes, and some is released into the environment as heat. Signup and view all the answers

What is a biogeochemical cycle?

A repeating series of processes that passes the same molecules around again and again within the biosphere. Signup and view all the answers

List two ways in which water enters the atmosphere in the water cycle.

Evaporation, transpiration. Signup and view all the answers

Explain the process of nitrogen fixation.

Bacteria that live in the soil and on plant roots called legumes convert nitrogen gas into ammonia. Signup and view all the answers

What are some similarities between the carbon cycle and the nitrogen cycle?

In both cycles, the atmosphere is a major reservoir, and both involve plants as transformers of the nutrients. Signup and view all the answers

What is meant by 'nutrient limitation'?

If a nutrient is in short supply, the ecosystem's growth will be limited. Signup and view all the answers

Study Notes

Key Terminology

Biosphere: The global sum of all ecosystems; where all life exists.
Community: A group of different species living together in a defined area.

Autotrophs and Heterotrophs

Autotrophs: Organisms that convert inorganic molecules into organic ones using energy from the environment (e.g., sunlight).
Heterotrophs: Organisms that obtain energy by consuming other foods; includes herbivores, carnivores, and omnivores.

Food Chains and Ecosystem Dynamics

Food Chain: A series of steps illustrating energy transfer, such as a large fish eating a small fish that has consumed algae.
Decomposers: Organisms like earthworms that break down dead organic matter to obtain energy.

Nutrient Cycling

Biogeochemical Cycles: Nutrients move through ecosystems through cycles, including carbon, nitrogen, and phosphorus cycles.
Nitrogen Cycle: Involves bacteria that convert nitrogen gas into ammonia, essential for plant growth.
Phosphorus Cycle: The only cycle that does not have a gas phase, so it does not involve atmospheric entry.

Trophic Levels and Energy Transfer

Ecological Pyramid: A diagram showing energy or matter at each trophic level; includes biomass and numbers pyramids.
Energy Transfer Efficiency: Typically about 10% of energy is transferred between trophic levels; much is used for life processes or lost as heat.

Importance of Sunlight

Sunlight: The primary energy source for ecosystems, essential for sustaining life processes.

Nutrient Limitation

Limited Nutrient: A single nutrient that restricts growth in an ecosystem if it is scarce or cycles slowly.

Ecosystem Organization

Levels of Organization: Ranges from individual organisms to ecosystems and biomes.
Ecology: The scientific study of interactions among organisms and their environment.

Water Cycle

Water Entry: Water enters the atmosphere via evaporation and transpiration.

Modeling in Ecology

Ecological Models: Used by scientists to understand complex phenomena such as global warming and its effects on ecosystems.

Similarities in Nutrient Cycles

Carbon and Nitrogen Cycles: Both involve the atmosphere as a major reservoir and the role of plants in transforming nutrients.

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Description

Test your understanding of key concepts from Biology Chapter 3 with these flashcards. Each card focuses on essential terms and definitions related to ecosystems and living organisms in the biosphere. Perfect for students looking to reinforce their knowledge in biology.