These DAV Class 6 Science Notes and DAV Class 6 Science Chapter 1 Notes – Our Environment act as excellent revision resources, particularly in preparation for board exams.
Our Environment Class 6 DAV Notes
→ Environment: The surrounding in which a living being lives is called its environment. Environment can be divided into two types:
- Biotic Environment: The living beings in an environment are the components of biotic environment.
- Abiotic Environment: The non-living things make the abiotic environment. For example: air. water, soil, light, temperature, etc.
→ Components of Biotic Environment: Following are the main components of biotic environment:
→ Producers: Green plants are called producers because they prepare their own food. The process by which green plants prepare their food is called photosynthesis. During photosynthesis, green plant takes energy from sunlight, carbon dioxide from air and water from soil. Then the plant uses them in the presence of chlorophyll to make food. Glucose is the food which a green plant makes and oxygen gas is also formed during this process.
→ Consumers: Animals depend on green plants for food. An herbivore directly takes food from green plants, while a carnivore indirectly takes food from green plants. So, consumers can be divided into two main categories, viz. primary consumers and secondary consumers.
→ Decomposers: When animals and plants die, their dead remains are broken into simple substances. This process is called decomposition. Fungi and bacteria carry out decomposition and hence are known as decomposers. Decomposition is necessary for returning the raw materials to the environment.
→ Biodegradable Materials: Materials which can be broken down into simple substances by microorganisms are called biodegradable materials. Example: paper, cloth, vegetable, fruit peels, etc.
→ Non-biodegradable Materials: Materials which cannot be broken down into simple substances by microorganisms are called non-biodegradable materials. Example: glass, iron, tin, plastic, etc.
→ Compost: The farm and kitchen waste turns into a dark brown or black soil-like substance. This is called compost. Compost contains simple substances. Compost is highly beneficial for soil fertility.
→ Vermicompost: Compost made with the help of earthworms is called vermicompost. Vermicompost is excellent, nutrient-rich, organic fertilizer and soil conditioner.
→ Components of Abiotic Environment
→ Water: Water is required by all living beings for various biological activities. Living beings cannot survive without water.
→ Rainwater Harvesting: Rainwater harvesting is a method in which rainwater is collected and stored for later use. This is useful for places which get scanty rainfall and often have to suffer from shortage of water. Rainwater from rooftop can be collected in an underground tank. This water can be treated so that it can be safely used. Rainwater harvesting can also be used for recharging the groundwater.
→ Air: Air is also essential for all living beings. All living beings need oxygen for respiration. Without air, we cannot survive for more than a few seconds. Oxygen and many other gases, which are present in air, are important for our survival.
→ Light: Sun is the ultimate source of light for us. Green plants utilize solar energy during photosynthesis. Thus, all of us get food because of sunlight. Different plants and animals behave differently to light. Some animals are active during day, while some others are active during night.
→ Temperature: The degree of hotness or coldness is expressed in terms of temperature. The temperature on the earth is neither too high nor too low. This is just ideal to support life. Moderate temperature is good for living beings, but some living beings are live at very hot or very cold places as well.
→ Soil: Soil is important for plants because they grow on soil. Soil provides a base for green plants. Additionally, soil is a reservoir of water and minerals for plants. Soil is also home to many creatures.
Interaction In The Environment
→ Food Chain: Plants and animals interact with each other for food. This relationship can be shown by a flow chart which is called food chain. Food chain shows the transfer of energy from plants to other living beings. This is also known as energy chain.
Grass (Producer) → Deer (Primary consumer) → Lion (Secondary consumer)
→ Mineral Cycle: The bodies of all living beings are made up of many minerals. These minerals are obtained from the abiotic environment. When a living being dies, these minerals are returned to the environment, through decomposition. Thus, a continuous cycle is formed between the abiotic and biotic environment. This cycle is called mineral cycle.
→ Balance between Oxygen and Carbon Dioxide: Animals and plants take in oxygen and give out carbon dioxide during the process of respiration. The burning of coal, wood and petrol also adds carbon dioxide to the atmosphere. But during the process of photosynthesis, plants use up carbon dioxide and give out oxygen. In this way a balance is maintained between the amount of oxygen and carbon dioxide in the atmosphere.
→ Environment: The surrounding of a living being is called its environment.
→ Biotic: The living beings make the biotic component of environment.
→ Abiotic: The non-living things make the abiotic component of environment. Microorganisms: The living beings which are so small that they cannot be seen by naked eyes are called microorganisms.
→ Producer: Green plants are called producers because they prepare their own food and that food is utilized by all other living beings.
→ Primary consumer: Herbivores are called primary consumers.
→ Secondary consumer: Carnivores are called secondary consumers.
→ Photosynthesis: The process by which green plants prepare their food is called photosynthesis.
→ Carbohydrate: Compounds of carbon, oxygen and hydrogen. Carbohydrate is the main food made by green plants.
→ Chlorophyll: The green pigment present in green parts of plants. Chlorophyll is necessary for photosynthesis.
→ Chloroplast: The green coloured plants which contain chlorophyll. Chloroplast is the site of photosynthesis.
→ Autotrophs: Organisms which make their own food are called autotrophs.
→ Heterotrophs: Organisms which depend on other organisms for food are called heterotrophs. Decomposition: The process of changing dead remains of plants and animals into simple substances is called decomposition.
→ Decomposer: The organisms which carry out decomposition.
→ Scavengers: Some animals eat dead bodies of animals and thus clear the dead remains. These animals are called scavengers, e.g. vulture, jackal, crow, etc.
→ Biodegradable: Materials which can be decomposed by microorganisms are called biodegradable.
→ Non-biodegradable: Materials which cannot be decomposed by microorganisms are called non-biodegradable.
→ Compost: The dark soil like material which is obtained after decomposition of farm or kitchen waste is called compost.
→ Vermicompost: Compost which is prepared with the help of earthworms is called vermicompost.
→ Rainwater Harvesting: Collection and storage of rainwater for future use and for groundwater recharge is called rainwater harvesting.
→ Groundwater: The water which is available below the surface of earth is called groundwater. Nocturnal Animal: Animals which remain active during night are called nocturnal animals. Diurnal Animal: Animals which remain active during day are called diurnal animals. Temperature: The measure of degree of coldness or hotness is called temperature. Terrestrial Animals: Animals which live on land.
→ Aquatic Animals: Animals which live in water.
→ Terrestrial Plants: Plants which grow on land.
→ Aquatic Plants: Plants which grow in water.
→ Food Chain: The chain of living beings through which food is transferred from green plants to animals is called food chain.
→ Energy Chain: The chain of living beings through which energy from sunlight is transferred to various living beings is called energy chain. Food chain and energy chain are the same.
→ Mineral Cycle: The continuous cycle through which minerals are supplied from abiotic environment to biotic environment and back to the abiotic environment is called mineral cycle.