Nutrition in Living Organisms - Standard 7 - General Science - Balbharati
Nutrition in Living Organisms
Exercise
Q. 1 Classify according to food-type.
tiger, cow, vulture, bacteria, deer, goat, human, fungus, lion, sparrow, buffalo, frog, cockroach, tick.
Ans.
| Herbivores | Cow, Deer, Goat, Buffalo |
| Carnivores | Tiger, Lion, Frog |
| Omnivores | Human, Cockroach, Sparrow |
| Scavengers | Vulture |
| Decomposers | Bacteria, Fungus |
| Parasites | Tick |
Q. 2 Match the pairs.
| Group 'A' | Answers |
|---|---|
| Parasitic plant | Cuscuta |
| Insectivorous plant | Drossera |
| Saprophytic plant | Mushroom |
| Symbiotic plant | Lichen |
Q. 3 Answer the following questions in your own words.
(a) Why do living organisms need nutrition?
Ans. Living organisms need nutrition because it provides them with the energy and essential substances they need to stay alive and carry out their everyday functions. Nutrition helps organisms grow, repair their bodies, and stay healthy. It's like fuel for our bodies, just like how a car needs petrol or diesel to run smoothly. Without proper nutrition, living organisms would not have the energy or building blocks they need to survive and thrive.
(b) Explain the process of production of food in plants.
Ans. Plants also need food for their growth. They can produce their own food. With the help of sunlight and chlorophyll, plants make their food in their leaves, using water and nutrients from the soil and carbon dioxide from the air. This process is called photosynthesis.
(c) What is meant by parasitic plants? Name their different types with examples of each.
Ans. Some animals depend upon other animals for food. They can obtain the food only from animals on whom they are dependent. This is called as parasitic nutrition. Some animals live on the body surface of other animals and obtain their food by sucking their blood. This is called ectoparasitic nutrition and such animals are called ectoparasites, for example, louse, bed-bug, tick, etc. Animals like tapeworm and roundworms live inside the body of other animals and obtain their food. This is endoparasitic nutrition and these animals are known as endoparasites.
(d) Explain the various steps of nutrition in animals.
Ans. 1. Ingestion - Food is taken into the body.
(e) Name some unicellular organisms in which all life-processes take place within their unicellular body.
Ans. 1. Amoeba 2. Euglena 3.Paramoecium
Q. 4 Give reasons.
(a) Insectivorous plants are attractively coloured.
Ans. Insectivorous plants have bright colors to attract insects to make them think it's a flower or fruit they can land on.
(b) Butterflies have a long tube-like proboscis.
Ans. Butterflies have long tube-like proboscises to reach deep into flowers and extract nectar as their main food source.
Q. 5 Prepare and complete the flowchart according to type of nutrition.
Ans.
Q. 6 Think and answer.
(a) We prepare a variety of foodstuffs and dishes at home. Are we then autotrophic organisms?
Ans. No, preparing and consuming a variety of foodstuffs and dishes at home does not make you an autotrophic organism. Autotrophic organisms are those that can produce their own food through processes like photosynthesis (plants) or chemosynthesis (certain bacteria). Humans and other animals are heterotrophic, which means they obtain their food by consuming other organisms or organic matter.
(b) Which organisms are greater in number - autotrophs or heterotrophs? Why?
Ans. Autotrophs use sunlight or inorganic compounds to produce their own food, which is then consumed by heterotrophs. Since they can directly convert energy from the sun into organic matter, they are more efficient at capturing and storing energy than heterotrophs, which rely on consuming other organisms. This energy transfer through the food chain means that there need to be more autotrophs to support the energy needs of the heterotrophic population higher up in the food chain. Consequently, autotrophs typically outnumber heterotrophs in most ecosystems.
(c) The number of heterotrophs found in desert regions is smaller. However, they are found in greater numbers in the sea. Why is this so?
Ans. Deserts have fewer creatures because they're hot and dry, making it hard to find food and water. The sea has more creatures because it's full of water and food. Sea creatures are adapted to life in water, while desert creatures have special ways to survive, like storing water or being active at night. Deserts also have more competition for limited resources, making it tough for many creatures. In the sea, there are different places to live, from the surface to the deep sea, so more creatures can fit into these niches. The environment and resources in these places determine how many creatures can live there.
(d) What damage or harm do ectoparasitic and endoparasitic animals cause?
Ans. 1. Physical Harm: Parasites can bite, burrow, or irritate the host's skin.
(e) Why is plant food not produced in any other parts of the plant except the green ones?
Ans. Plant food, in the form of glucose and other sugars, is primarily produced in the green parts of the plant, such as leaves, because these parts contain chloroplasts. Chloroplasts are the organelles responsible for photosynthesis, the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen.
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