Introduction
Our environment includes everything around us such as air, water, land, plants, animals, and human beings. It provides all the natural resources necessary for survival. A healthy environment is essential for life on Earth. However, due to pollution and careless human activities, the environment is getting damaged. This chapter teaches us about the importance of the environment and why we should protect it.
Chapter 1: Our Environment – Detailed Answers
A. Fill in the blanks
- Plastic is non-biodegradable because it cannot be broken down into simpler substances naturally by microorganisms.
- We should say ‘No’ to plastic bags and instead use paper bags or cloth bags to protect the environment.
- The flowers of the Morning Glory plant bloom at sunrise and close after sunset.
- Polar bears and penguins are animals that are found only in very cold regions.
- The processes of respiration and photosynthesis help in maintaining the balance of carbon dioxide and oxygen in the atmosphere.
B. True or False
- Herbivores can prepare their own food.
False
Herbivores cannot make their own food. They depend on plants for their food. - Fungi and bacteria are organisms that can be easily seen by the human eye.
False
Fungi and bacteria are very small organisms and most of them can only be seen with the help of a microscope. - The sunflower faces the east in the morning.
True
Sunflowers turn towards the sun and face east in the morning. - Camels do not have sweat glands.
True
Camels have very few sweat glands, which helps them survive in the hot desert. - Soil is an important biotic component of our environment.
False
Soil is a non-living part of the environment, so it is an abiotic component.
C. Tick the correct option
- Biotic environment includes:
Producers, consumers as well as decomposers - The group of organisms which use light for making food are called:
Autotrophs - Decomposers include:
Bacteria as well as fungi - Which of the following is not biodegradable?
Aluminium foil - Vermicomposting is done by:
Worms - An animal that is not affected much by the heat of the desert is:
Camel
D. Brief Answers
1. Why should we segregate different types of wastes?
We should segregate different types of waste because it helps in proper waste management and protects the environment from pollution. Biodegradable waste such as vegetable peels and leaves can be used to make compost, while non-biodegradable waste such as plastic and glass can be recycled separately. This process reduces the amount of garbage and helps in keeping the surroundings clean and healthy.
2. Write the meaning of the term ‘vermicomposting’.
Vermicomposting is the process of making compost from kitchen and garden waste with the help of earthworms. The worms break down the waste into nutrient-rich compost, which can be used as manure for plants. It is an eco-friendly way to recycle organic waste and improve soil fertility.
3. Which component of air gets used up during photosynthesis?
During photosynthesis, plants use carbon dioxide from the air to prepare their food. In this process, plants release oxygen into the atmosphere, which is essential for living organisms.
4. Suggest any five activities that can help to save the environment.
We can save the environment by doing the following activities:
- Plant more trees to increase greenery and reduce pollution.
- Use cloth or paper bags instead of plastic bags.
- Segregate waste into biodegradable and non-biodegradable materials.
- Save water by avoiding wastage and using rainwater harvesting.
- Follow the habit of reducing, reusing, and recycling materials.
These activities help in reducing pollution and conserving natural resources.
5. How does nature maintain a balance between the amounts of oxygen and carbon dioxide in the atmosphere?
Nature maintains the balance of oxygen and carbon dioxide through the processes of photosynthesis and respiration. During photosynthesis, green plants absorb carbon dioxide and release oxygen. During respiration, animals and humans inhale oxygen and exhale carbon dioxide. In this way, the amount of these gases remains balanced in the atmosphere.
E. Detailed Answers
1. Distinguish between:
(a) Autotrophs and Heterotrophs
| Autotrophs | Heterotrophs |
|---|---|
| Autotrophs are organisms that can prepare their own food using sunlight, water, and carbon dioxide. | Heterotrophs are organisms that cannot make their own food and depend on other organisms for food. |
| Green plants are examples of autotrophs. | Animals and human beings are examples of heterotrophs. |
(b) Decomposers and Scavengers
| Decomposers | Scavengers |
|---|---|
| Decomposers break down dead plants and animals into simpler substances. | Scavengers feed on dead animals. |
| They help in recycling nutrients back into the soil. | They help in cleaning the environment by eating dead organisms. |
| Examples: bacteria and fungi | Examples: vultures and crows |
2. Difference between biodegradable and non-biodegradable materials
| Biodegradable Materials | Non-Biodegradable Materials |
|---|---|
| These materials can be broken down naturally by microorganisms. | These materials cannot be broken down naturally by microorganisms. |
| They do not remain in the environment for long. | They remain in the environment for a long time and cause pollution. |
| Examples: paper, cloth, vegetable waste | Examples: plastic, glass, aluminium foil |
3. How does decomposition of dead animals turn out to be useful?
The decomposition of dead animals is useful because it helps in recycling nutrients in nature. When animals die, decomposers such as bacteria and fungi break down their bodies into simple substances. These substances mix with the soil and make it fertile. Plants absorb these nutrients from the soil for growth. In this way, decomposition helps maintain the balance of nature.
4. Why is rainwater harvesting a ‘ray of hope’ for overcoming the present scarcity of water in cities?
Rainwater harvesting is called a ‘ray of hope’ because it helps in collecting and storing rainwater for future use. In cities, where water shortage is becoming a serious problem, rainwater harvesting can reduce dependence on groundwater and municipal water supply. It also helps in raising the groundwater level and ensures the availability of water during dry periods. Therefore, it is an effective solution to overcome water scarcity.
5. Why do buffaloes cool themselves in water during summer?
Buffaloes cool themselves in water during summer because they have dark-colored skin and very few sweat glands. Their black skin absorbs more heat from sunlight, making them feel hotter. Since they cannot sweat much, they sit in water or mud to lower their body temperature and stay cool.
Value-Based Question
Values conveyed by Shuchi’s mother
Shuchi’s mother teaches important values such as confidence, honesty, creativity, and environmental awareness. She encourages Shuchi to reuse old newspapers to make paper bags instead of using plastic bags. This teaches the importance of recycling and caring for the environment while also developing useful skills.
Summary of The Chapter
Environment means the surroundings in which living organisms live. It includes both living things like plants, animals, and humans, and non-living things like air, water, and soil.Here is a summary of the key points from Chapter 1, “Our Environment”:
- Environment Components:
- The environment consists of biotic (living) components like plants, animals, and humans, and abiotic (non-living) components like air, water, soil, light, and temperature.
- Biotic Environment:
- Producers (Plants): Green plants prepare their own food through photosynthesis using sunlight, carbon dioxide, water, and minerals. They are called autotrophs.
- Consumers (Animals): Animals depend on plants for food and are classified as herbivores (primary consumers), carnivores (secondary consumers), and omnivores (feed on both plants and animals).
- Decomposers (Microorganisms): Organisms like fungi and bacteria break down dead plants and animals into minerals, recycling nutrients back into the soil. Scavengers like vultures and crows consume dead animals, helping keep the environment clean.
- Biodegradable vs. Non-Biodegradable Materials:
- Biodegradable materials (e.g., paper, cloth) can be decomposed by microorganisms, while non-biodegradable materials (e.g., plastic) cannot and harm the environment.
- Waste Management:
- Segregating biodegradable and non-biodegradable waste is essential for environmental health. Biodegradable waste can be composted, while non-biodegradable waste should be disposed of properly.
- Vermicomposting uses worms like redworms to speed up the composting process, producing nutrient-rich organic fertilizer.
- Abiotic Environment:
- Water: Essential for survival, used for drinking, cooking, irrigation, and other activities. Rainwater harvesting is a sustainable method to collect and store rainwater for later use.
- Air: A mixture of gases, including oxygen, nitrogen, and carbon dioxide, which are vital for respiration and photosynthesis.
- Light: Sunlight is the ultimate source of natural light, essential for photosynthesis and life on Earth. Plants and animals respond to light in various ways.
- Temperature: Affects the distribution and activities of living organisms. Different organisms have varying tolerance ranges for temperature.
- Soil: Provides water and minerals to plants and serves as a habitat for soil organisms.
- Interaction in the Environment:
- Plants and animals are interdependent through food chains, which show the transfer of energy from producers to consumers.
- The mineral cycle involves the recycling of nutrients between biotic and abiotic components.
- Balance of Oxygen and Carbon Dioxide:
- Nature maintains a balance between oxygen and carbon dioxide through respiration, combustion, and photosynthesis.
- Dynamic System:
- The environment is a dynamic system where biotic and abiotic components continuously interact with each other.
Key concepts such as food chains, the mineral cycle, waste management, and the importance of maintaining environmental balance are emphasized throughout the chapter.
The environment supports life by providing:
- Clean air to breathe
- Water to drink
- Food to eat
- Land to live on
Components of Environment
The environment has two main components:
1. Biotic Components
These are the living things in the environment such as:
- Plants
- Animals
- Human beings
- Microorganisms
2. Abiotic Components
These are the non-living things such as:
- Air
- Water
- Soil
- Sunlight
Both biotic and abiotic components depend on each other for balance in nature.
Importance of Environment
The environment is important because it:
- Provides natural resources
- Maintains ecological balance
- Supports plant and animal life
- Gives us fresh air and water
Without a healthy environment, life on Earth would not be possible.
Human Impact on Environment
Human activities are harming the environment in many ways:
- Pollution: Air, water, and land pollution make the environment dirty.
- Deforestation: Cutting trees reduces oxygen and harms wildlife.
- Wastage of resources: Overuse of water and energy leads to scarcity.
These activities disturb the natural balance of the environment.
How to Protect Our Environment
We can protect our environment by:
- Planting more trees
- Saving water
- Reducing pollution
- Recycling waste
- Avoiding plastic use
Small steps can make a big difference in keeping the Earth clean and safe.
Conclusion
Our environment is precious and essential for life. It is our duty to protect it from pollution and destruction. By caring for nature and using resources wisely, we can ensure a healthy future for all living beings.