CHAPTER- 2 DIVERSITY IN THE LIVING WORLD
NOTES
1. When we look around us, we see that all around, there are different types of trees, birds, animals, etc. These all are diverse.2. Some animals live on the land, while others live on trees. Birds live on trees. Fish live in water, and some creatures like frogs live both on land and in water.
3. There is also diversity in the food eaten by animals and in the types of their movements.
4. The diversity of plants and animals found in a particular region is part of that region’s biodiversity. Every member of a region’s biodiversity has a unique role. For example, trees provide food and shelter to certain birds and animals, and animals help in seed dispersal after eating fruits.
5. Trees– Some plants are very tall and their stems are thick, hard, brown, and woody. Their branches begin to grow at some height above the ground from the stem. Such plants are called trees. Example– the guava tree.
6. Shrubs– Some plants do not have stems as tall as trees. These types of plants have many brown, woody stems that branch out close to the ground. These stems are hard but not as thick as the stem of a tree. Such plants are called shrubs. Example– the rose plant.
7. Herbs– Some plants are small in size and have soft, green stems. These are called herbs. Example– the tomato plant.
8. Climbers– Some plants have weak stems and need support to grow upward; such plants are called climbers.
9. Creeping plants– Some plants grow by spreading over the surface of the ground, and they are called creeping plants.
10. Veins– You can see thin lines on the leaves of plants. These thin lines are called veins. The pattern formed by the veins is called venation.
11. Reticulate Venation– In some leaves, you can see a net-like pattern of veins on either side of the thick central vein. This pattern is called reticulate venation.
12. Parallel vein arrangement– You can see that in some leaves, the veins run parallel to each other. This pattern is called a parallel vein arrangement.
13. Taproot– In some plants, there is a main root from which small lateral roots emerge. Such roots are called taproots.
14. Fibrous root– In some plants, the roots appear as clusters of thin roots of similar size that emerge from the base of the stem. Such roots are called fibrous roots.
15. Cotyledon– In some seeds, the seed inside the seed coat is divided into two parts. Each part is called a cotyledon.
16. Like plants, animals also differ greatly from one another.
- Different animals have different types of movement. Animals can fly, run, crawl, walk, or jump/leap.
17. The plants and animals found in one type of region are different from the plants and animals found in other types of regions.
18. Deserts– Dry deserts are extremely hot during the day and very cold at night. The fleshy stems of plants found in deserts can store water and help the plants withstand the hot conditions of these regions.
19. Adaptation– Plants and animals found in a particular region have their own specific characteristics that enable them to survive there. These specific characteristics, which allow plants and animals to live in a particular area, are called adaptations.
20. Habitat– The place where plants and animals live is called their habitat. A habitat plays an important role in forming the biodiversity of a region.
21. The habitat of plants and animals that live on land is called a terrestrial habitat.
Examples- Forests, grasslands, deserts, and mountainous regions.
22. The habitat of plants and animals that live in water is called an aquatic habitat.
Examples- Ponds, lakes, etc.
23. Some animals, like frogs, can live both in water and on land. These are called amphibians.
24. Damage to the habitats of plants and animals deprives them of their homes, food, and other resources. This leads to a loss of biodiversity.
Let us enhance our learning
Question-1. Here are two types of seeds. What differences do you find among the roots and leaf venation of their plants?
Answer- In figure (a), wheat seeds are shown, and in figure (b), wheat and kidney bean seeds are shown. The following differences are observed in the roots and venation of their leaves:
Roots-
- Wheat: It is a monocotyledonous plant, whose roots are fibrous roots.
- Kidney bean: It is a dicotyledonous plant, whose roots are tap roots.
Venation of leaves-
- Wheat: The venation of its leaves is parallel, where the veins in the leaves run in a parallel manner.
- Kidney bean: The venation of its leaves is reticulate, in which the veins form a net-like pattern in the leaves.
Question-2. Names of some animals are given below. Group them based on their habitats. Write the names of aquatic animals in the area marked 'A' and terrestrial animals in the area marked 'B'. Enter the names of animals living in both habitats in part 'C'.
Horse, Dolphin, Frog, Sheep, Crocodile, Squirrel, Whale, Earthworm, Pigeon, Tortoise.
Answer- Section 'A' (Aquatic Animals)
- Dolphin
- Whale
Section 'B' (Terrestrial Animals)
- Horse
- Sheep
- Squirrel
- Pigeon
- Earthworm
Section 'C' (Animals of both habitats)
- Crocodile
- Frog
- Tortoise
Question-3. Manu's mother maintains a kitchen garden. One day, she was digging out radish from the soil. She told Manu that radish is a kind of root. Examine a radish and write what type of root it is. What type of venation would you observe in the leaves of radish plant?
Answer- The radish root is a taproot, which is formed from a main root and smaller roots that branch out from it. These types of roots go deep into the soil, providing strength to the plant. The leaves of the radish plant have a reticulate venation, where the veins of the leaves spread out like a net. Several smaller veins branch out from the main vein. This venation is found in dicot plants, and it helps in the transportation of nutrients and water within the plant.
Question-4. Look at the image of a mountain goat and a goat found in the plains. Point out the similarities and differences between them. What are the reasons for these differences?
Answer- Similarities-
- Both goats are four-legged mammalian creatures.
- Both bodies are covered with hair.
- Both goats depend on plants and graze.
Difference-
- The body of a mountain goat is covered with thick and long hair, which helps keep it warm in cold mountainous regions.
- The goat found in plains has fewer and shorter hairs on its body, which help it cope with the heat.
Reasons for the differences-
- The mountain goat lives in cold and high regions, so it has more hair on its body to protect itself from the cold.
- The goat of the plains lives in warm and flat regions, so it has fewer hairs on its body to protect itself from the heat.
Question-5. Group the following animals into two groups based on any feature other than those discussed in the chapter- Cow, Cockroach, Pigeon, Bat, Tortoise, Whale, Fish, Grasshopper, Lizard.
Answer- These animals can be divided into two groups based on their lifestyle and habitat-
1) Aquatic animals and semi-aquatic animals-
- Whale– lives in water.
- Fish– lives in water.
- Turtle– lives on both water and land, a semi-aquatic animal.
2) Terrestrial and aerial animals-
- Cow– lives on land.
- Cockroach– lives on land.
- Pigeon– flies in the sky but lives on land.
- Bat– capable of flying but stays in caves or trees during the day.
- Grasshopper– lives on land.
- Lizard– lives on land.
Question-6. As the population grows and people want more comfortable lives, forests are being cut down to meet various needs. How can this affect our surroundings? How do you think we can address this challenge?
Answer- Negative effects of deforestation:-
- Climate change– Deforestation increases the amount of carbon dioxide in the atmosphere, leading to global warming and climate change.
- Loss of biodiversity– Deforestation is destroying the habitats of wildlife, due to which many species may become extinct.
- Soil erosion– Trees hold the soil together. Deforestation increases soil erosion, which leads to floods and a decrease in soil fertility.
- Loss of water resources– Deforestation also affects water resources, leading to a decrease in rivers, lakes, and groundwater levels.
Solution to the problem:-
- Afforestation– Emphasis should be placed on planting more trees and regenerating deforested areas.
- Awareness campaigns– Educating people about the importance of forests and their conservation.
- Recycling and reduced usage– People should be encouraged to recycle resources and use them less so that the demand for forest products decreases.
Question-7. Analyse the flowchart. What can be examples of 'A' and 'B'?
Answer- Example of A– If a plant has leaves with a reticulate venation pattern, it will be a dicotyledonous plant. Examples – Rose, Mango, etc.
Example of B– If a plant has no leaves, or if it has leaves but they do not have a reticulate venation pattern, it may be a monocotyledonous plant or a leafless plant. Examples – Wheat, Maize, etc.
Thus, the examples of A and B can be classified based on the characteristics of the plants as follows.
Question-8. Raj argues with his friend Sanjay that "Gudhal (hibiscus) plant is a shrub." What questions can Sanjay ask for clarification?
Answer- Sanjay can ask the following questions for this:-
- What is the stem of the hibiscus plant like?
- How tall does the hibiscus plant grow?
- Is the hibiscus plant short and spreading, or does it grow quite tall?
- Does the hibiscus plant have a single stem, or does it have many branches?
- In what type of soil and location does the hibiscus plant grow?
Through these questions, Sanjay can understand why the hibiscus plant can be seen as a shrub.
Question-9. Based on the information in the table, find out examples of these plants for each group.
B) What other similarities do Plants of Group B have?
Answer- Similarities among the plants in Group A-
- Venation of leaves: Reticulate venation, where the veins in the leaves spread like a network.
- Examples: Radish, Kidney bean, etc.
- Flower structure: The number of floral parts is generally four or five.
- Roots: The main root grows deep into the soil, from which smaller roots emerge.
Similarities among the plants in Group B-
- Venation of leaves: Parallel venation, where the veins in the leaves are arranged in a parallel pattern.
- Examples: Wheat, Grass, etc.
- Flower structure: The number of floral parts is generally three.
- Roots: The roots do not grow deep but are of uniform thickness and spread across the soil.
Question-10. Observe the labelled part of a duck in the picture given below. What differences do you observe in the feet of the duck compared to the other birds? Which activity would the duck be able to perform using this part?
Answer- By looking at the feet of the duck (A) in the picture, you can see that its feet have a webbed structure, which is different from the feet of other birds.
Difference– The duck’s feet have webbing between the toes, which helps it swim in water. Other birds, like the pigeon (B), do not have such webbed structures because they are mainly adapted for flying and walking on land.
Activity– The duck uses its webbed feet for swimming. These feet act like paddles in the water, allowing the duck to move easily. Because of this feature, the duck belongs to the category of aquatic birds, and swimming in water is one of its main activities.
