Nutrition In Living Organisms | Class 7 Science, Chapter 4, Maharashtra State Board, Question Answers
Q. 1. Classify according to food-type.
Tiger, cow, vulture, bacteria, deer, goat, human, fungus, lion, sparrow, buffalo, frog, cockroach, tick.
Answer:
- Carnivores: tiger, Lion
- Herbivores: cow, deer, goat, buffalo
- Scavengers: vulture
- Decomposers: fungus, bacteria
- Carnivores: sparrow
- Insectivores: frog Parasitic: tick
- Omnivores: human, cockroach
Q. 2. Match the pairs.
| Group ‘A’ | Group ‘B’ |
| 1. Parasitic plant | a. Mushroom |
| 2. Parasitic plant | b. Lichen |
| 3. Saprophytic plant | c. Drosera |
| 4. Symbiotic plant | d. Cuscuta |
Answer:
| Group ‘A’ | Group ‘B’ |
| 1. Parasitic plant | d. Cuscuta |
| 2. Parasitic plant | c. Drosera |
| 3. Saprophytic plant | a. Mushroom |
| 4. Symbiotic plant | b. Lichen |
Q. 3. Answer the following questions in your words.
Q. (a) : Why do living organisms need nutrition?
Ans: Living organisms need nutrition due to the following:
(a) To supply the energy required for doing work.
(b) Growth and development of the body.
(c) To replace the damaged cells and repair tissues.
(d) To fight diseases.
Q. (b): Explain the process of production of food in plants.
Ans: The process of production of food in plants are as follows:
➻ Plants can produce their own food for the growth.
➻ With the help of sunlight and chlorophyll, using water and nutrients from the soil and carbon dioxide from the air, plants make their food in their leaves.
➻ This process is called as photosynthesis.
In this process plants give out oxygen and take in carbon dioxide.
Q. (c): What is meant by parasitic plants? Name their different types with examples of each.
Ans: The plants that grow on the body of other plants to obtain food are called as parasitic plants.
There are two types of parasitic plants:
- Hemiparasites: e.g. Loranthaceae, cuscuta
- Holoparasites: e.g. Rafflesiaceae.
Q. (d): Explain the various steps of nutrition in animals.
Ans: Steps of nutrition in animals are as follows:
- Ingestion: Food is taken into the body.
- Digestion: Conversion of food into simple soluble forms.
- Absorption: Transfer of soluble food to the blood.
- Assimilation: Utilization of absorbed food by cells and tissues for energy production, growth and repair.
- Egestion: Removal of waste products and undigested food from body.
Q. (e) : Name some unicellular organisms in which all life processes take place within their unicellular body.
Ans: Unicellular organisms like amoeba, euglena, paramoecium in which all life processes take place within their unicellular body.
Q. 4. Give reasons.
(a) Insectivorous plants are attractively coloured.
Ans: Insectivorous plants are attractively colored to attract the insects towards them.
The bright colors help these plants catch insects with their droplets of a sticky substances which they use for food.
The Drosera burmanii are the plants consume insects to fulfill their need for nitrogen.
(b) Butterflies have a long tube-like proboscis.
Ans: Butterflies have a long tube-like proboscis to help them drink nectar from flowers.
The proboscis works like a straw, allowing them to reach deep inside flowers to get the sweet nectar.
This helps butterflies get the food they need to survive.
Q.5: Prepare and complete the flowchart according to type of nutrition
Ans:
Q.6: Think and answer.
Q. (a) We prepare a variety of foodstuffs and dishes at home. Are we then autotrophic organisms ?
Ans: No, we are not autotrophic organisms.
➻ Autotrophic organisms, like plants, make their own food by using chlorophyll, sunlight, water, and carbon dioxide from the air.
➻ We prepare food at home using ingredients that come from plants and animals.
➻ This means we depend on other living things for our food, so we are heterotrophic organisms.
Q. (b) Which organisms are greater in number – autotrophs or heterotrophs ? Why ?
Ans: Autotrophs are greater in number than heterotrophs.
➻ This is because autotrophs, like plants, make their own food and are found everywhere, from forests to oceans.
➻ They form the base of the food chain, providing energy for all other living things.
➻ Without autotrophs, heterotrophs, which depend on them for food, couldn’t survive.
Q. (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: Heterotrophs are fewer in deserts because there is not much food and water available.
➻ In the sea, there is plenty of food and water, so many more heterotrophs can live there.
➻ The ocean has a lot of plants and other organisms that provide food, making it a better place for heterotrophs to survive.
Q. (d) What damage or harm do ectoparasitic and endoparasitic animals cause ?
Ans: Ectoparasitic animals, like ticks and fleas, live on the outside of other animals.
➻ They suck the blood of the animal and can cause itching, irritation, and spread diseases.
➻ Endoparasitic animals, like worms, live inside the bodies of other animals and can make them sick by taking their nutrients and damaging their organs.
➻ Both types of parasites can harm the health of their hosts.
Q. (e) Why is plant food not produced in any other parts of the plant except the green ones ?
Ans: Plant food is not produced in any other parts of the plant except the green ones because
➻ Only the green parts have chlorophyll.
➻ Chlorophyll is the substance that helps plants use sunlight to make food through a process called photosynthesis.
➻ Without chlorophyll, the plant cannot make its own food. That’s why only the green parts, like leaves, produce food.
Additional Question answer:
Q.1: Fill in the blanks.
Q.1 Leaves have microscopic openings called ……………. .
Answer: Stomata
Q.2. The ……………. transports minerals and water from roots to all aerial parts of the plant.
Answer: xylem
Q.3. The ……………. transports the food from the leaves to other parts of the plant.
Answer: phloem
Q.4. ……………. are made from carbon, hydrogen, oxygen.
Answer: Carbohydrates
Q.5. ……………. are made from carbon, hydrogen and oxygen and nitrogen.
Answer: proteins
Q.6. Micro-organisms like ……………. are present in soil.
Answer: azotobacter
Q.7. The scientist ……………. identified Drosera plant in Sri Lanka in 1737.
Answer: Johannes Burman
Q.8. Removal of waste products and undigested food from the body is called …………….
Answer: Egestion
Q.9. Amoeba moves with the help of ……………. .
Answer: pseudopodia
Q.10.Animals that obtain their food from both plants and animals are called ……………. .
Answer: Omnivores
.
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