Biology Chapter 13: Our Environment

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Questions and Answers

What role does ozone (O3) play in the atmosphere?

It serves as a habitat for airborne species.

It is a source of oxygen for organisms.

It shields the Earth from ultraviolet radiation. (correct)

It provides nutrients to soil ecosystems.

Which process leads to the formation of ozone in the atmosphere?

Decomposition of organic matter releasing oxygen.

UV radiation splitting molecular oxygen into free oxygen atoms. (correct)

Combination of nitrogen and hydrogen molecules.

Chemical reactions of carbon dioxide with sunlight.

What has been the trend of ozone levels in the atmosphere since the 1980s?

Ozone levels have remained constant.

Ozone levels have increased significantly.

Ozone levels have fluctuated continuously.

Ozone levels have decreased sharply. (correct)

How does human activity contribute to air pollution?

Through the emission of greenhouse gases. (B) Signup and view all the answers

What is a direct consequence of increased UV radiation reaching the Earth's surface?

Increased skin cancer rates in humans. (D) Signup and view all the answers

Which of the following is NOT considered a method to reduce pesticide intake?

Doing away with gardening practices. (D) Signup and view all the answers

What is the primary function of decomposers in the ecosystem?

To recycle nutrients back into the soil. (A) Signup and view all the answers

Which trophic level would primary consumers occupy in a food chain?

Second trophic level. (D) Signup and view all the answers

What happens to energy as it moves through different trophic levels?

It diminishes progressively. (C) Signup and view all the answers

What is biological magnification?

The accumulation of harmful chemicals in organisms at higher trophic levels. (B) Signup and view all the answers

How do harmful chemicals often enter the food chain?

From pesticides absorbed by plants and aquatic organisms. (D) Signup and view all the answers

Which of the following can contribute to the accumulation of pesticide residues in food items?

The use of non-degradable chemicals in agriculture. (C) Signup and view all the answers

Why is the energy captured by autotrophs not available to them again?

Due to the loss of energy in metabolic processes. (A) Signup and view all the answers

What type of food items are commonly found to contain pesticide residues?

Grains, fruits, vegetables, and meats. (B) Signup and view all the answers

What is a consequence of water pollution related to pesticide usage?

Transfer of harmful chemicals to various food chains. (D) Signup and view all the answers

Why might some states ban certain food products?

Due to concerns about pesticide levels in food. (A) Signup and view all the answers

What characterizes biodegradable substances?

They decompose by the action of bacteria or saprophytes. (C) Signup and view all the answers

Which statement is true about non-biodegradable substances?

They are not broken down by biological processes. (C) Signup and view all the answers

What are the potential impacts of biodegradable substances on the environment?

They can enrich the soil as they break down. (D) Signup and view all the answers

How do non-biodegradable substances generally affect the ecosystem?

They may harm various members of the ecosystem. (B) Signup and view all the answers

What are some recent developments in the field of plastics?

Biodegradable plastics that may still be harmful to the environment. (D) Signup and view all the answers

Which of the following is NOT a method of waste management discussed?

Dumping waste in landfills without processing. (A) Signup and view all the answers

Why is it important to learn about biodegradable and non-biodegradable substances?

To understand their long-term effects on the environment. (C) Signup and view all the answers

What percentage of sunlight energy do green plants typically convert into food energy?

1% (A) Signup and view all the answers

What is a common outcome of improper disposal of non-biodegradable waste?

Reduction of soil quality. (C) Signup and view all the answers

How much energy is converted from food consumed by primary consumers into their own body mass?

10% (D) Signup and view all the answers

Why do food chains generally consist of only three or four steps?

Significant energy loss at each trophic level (C) Signup and view all the answers

What do the greatest number of individuals in an ecosystem typically represent?

Producers (D) Signup and view all the answers

What is the primary characteristic of energy flow in an ecosystem?

Unidirectional flow (B) Signup and view all the answers

What term best describes the complex interconnections of food relationships in an ecosystem?

Food web (B) Signup and view all the answers

What is the main reason for the loss of energy during energy transfer in ecosystems?

Energy is converted to heat (B) Signup and view all the answers

In the context of trophic levels, which statement is true?

Energy availability decreases with each trophic level. (D) Signup and view all the answers

Which of the following constitutes a food-chain?

Grass, goat, and human (A) Signup and view all the answers

What is a consequence of killing all the organisms in one trophic level?

Other levels will collapse due to interdependence (D) Signup and view all the answers

Which of the following is an example of a biodegradable item?

Fruit-peels (C) Signup and view all the answers

What happens as energy transfers from one trophic level to the next?

There is a loss of energy (A) Signup and view all the answers

Which option is NOT an environment-friendly practice?

Using disposable plastic utensils (A) Signup and view all the answers

What impact do chemicals like CFCs have on the ozone layer?

Endanger the ozone layer (C) Signup and view all the answers

How can individuals help reduce the problem of waste disposal?

Composting organic waste and recycling materials (A) Signup and view all the answers

What are chlorofluorocarbons (CFCs) primarily used for?

As refrigerants and in fire extinguishers (B) Signup and view all the answers

What major action did the United Nations Environment Programme (UNEP) take in 1987?

Forged an agreement to freeze CFC production (B) Signup and view all the answers

Which of the following actions is NOT recommended for managing garbage produced?

Keeping waste material away from moisture (A) Signup and view all the answers

What type of materials generally remain unchanged over long periods of time when buried?

Plastic products (C) Signup and view all the answers

Why do specific enzymes break down only particular substances?

Enzymes have a specific action (C) Signup and view all the answers

In the recommended garbage observation activity, what should you do with the collected waste?

Bury it in soil after covering with 15 cm of soil (A) Signup and view all the answers

What can be inferred about the changes in waste materials over time?

Some materials change their form and structure faster than others (B) Signup and view all the answers

What happens if coal is consumed according to the principles of digestion?

The body does not extract any energy (D) Signup and view all the answers

Study Notes

Chapter 13: Our Environment

All living organisms (plants, animals, microorganisms, humans) and their physical environment interact, forming ecosystems.
Ecosystems consist of biotic (living) components (organisms) and abiotic (non-living) components (physical factors like temperature, rainfall, wind, soil, minerals).
Examples of ecosystems include gardens, forests, ponds, lakes, and crop fields (human-made).
Organisms are grouped as producers, consumers, or decomposers based on how they obtain sustenance.
Producers make organic compounds (sugars, starches) from inorganic substances using sunlight (photosynthesis). Green plants and some bacteria are producers.
Consumers feed on producers or other consumers (herbivores, carnivores, omnivores, parasites).
Decomposers break down dead organisms and waste products into simple inorganic substances, which are used by plants. Bacteria and fungi are decomposers.
An aquarium is a human-made ecosystem.
Food chains show a sequence of organisms feeding on one another. A trophic level represents a step in the food chain.
Producers are the first trophic level. Primary consumers eat producers. Secondary consumers eat primary consumers. Tertiary consumers eat secondary consumers.
Food webs show interconnected food chains in an ecosystem.
Energy flows in a one-way direction through a food chain. Energy is lost during each transfer.
The 10% rule states that only about 10% of the energy at one trophic level is available to the next level.
Chemicals can accumulate along food chains; larger organisms accumulate greater amounts. This is called biological magnification.
Hazardous materials in the environment can have harmful effects on living things, accumulating in higher trophic levels.
Ozone (O₃) at higher levels of the atmosphere protects Earth from harmful UV radiation. CFCs (chlorofluorocarbons) deplete ozone, causing an environmental problem.
Waste disposal is an environmental problem.
Biodegradable materials break down naturally by biological processes.
Non-biodegradable materials do not break down easily, stay in the environment for extended periods, and can cause environmental problems.
Activities such as waste disposal and use of chemicals impact ecosystems.
Methods to reduce environmental impact can include proper waste management, reducing consumption of non-biodegradable products, and practicing sustainable habits.

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Description

Explore Chapter 13 on Our Environment, where you'll learn how living organisms interact with their physical surroundings to form complex ecosystems. Delve into the roles of producers, consumers, and decomposers in these environments, and uncover examples of both natural and human-made ecosystems. Test your understanding of ecological principles through this engaging quiz.