Chapter 2 Important Questions: Diversity in the Living World

✔ Correct Answer: (c) Tomato

Tomato is a herb because it is a small plant with a soft and green stem. Mango is a tree, while Rose and Hibiscus are shrubs.

✔ Correct Answer: (a) Venation

Venation refers to the arrangement or pattern of veins on a leaf. Veins are the thin lines visible on leaves that transport water and nutrients.

✔ Correct Answer: (d) Grass

Grass leaves show parallel venation, where veins run parallel to each other. Hibiscus, mustard, and chickpea are dicot plants that show reticulate venation.

✔ Correct Answer: (b) Taproot and reticulate venation

Plants with two cotyledons are dicots. Dicot plants typically have a taproot system and reticulate (net-like) venation in their leaves. $\text{Dicot} \Rightarrow \text{Two cotyledons} + \text{Taproot} + \text{Reticulate venation}$

✔ Correct Answer: (c) Pond

A pond is an aquatic habitat — a place in water where plants and animals live. Deserts, forests, and grasslands are all terrestrial (land-based) habitats.

✔ Correct Answer: (b) Adaptations

Adaptations are special features that help organisms survive in their specific environment. For example, the conical shape of a deodar tree helps snow slide off easily in the mountains.

✔ Correct Answer: (c) Frog

Amphibians are animals that can live both in water and on land. Frogs are the classic example of amphibians. Whales and dolphins are purely aquatic, while tortoises are primarily terrestrial.

✔ Correct Answer: (b) One hump and long legs with wide hooves

Camels of the hot desert have one hump to store food and long legs with wide hooves to walk on sandy desert without sinking. Cold desert camels (Ladakh) have two humps and shorter legs.

✔ Correct Answer: (c) Rose

A shrub is a plant that is not as tall as a tree, has many woody stems branching close to the ground, and a hard but not very thick stem. The rose plant fits this description perfectly.

✔ Correct Answer: (b) Are community-protected treasures of biodiversity

Sacred groves are undisturbed patches of forest protected by local communities. No one is allowed to harm animals, cut trees, or disturb these areas, making them rich reserves of biodiversity.

Dicotyledons (Dicots). When a seed like chickpea is split after soaking, it separates into two halves called cotyledons. Plants producing such seeds are called dicots. $\text{Dicot seed} = 2 \text{ cotyledons (e.g., chickpea)}$

Taproot. A taproot is the primary root of a plant from which smaller side roots branch out. Examples of plants with taproots include mustard and hibiscus, which are dicot plants.

Biodiversity. Biodiversity describes the richness of different species of plants and animals living in a region. Each member of the biodiversity plays a unique role in the ecosystem.

Creepers. Creepers are plants with weak stems that cannot stand upright and instead grow along the surface of the ground. Examples include pumpkin and watermelon plants.

Habitat. A habitat provides an organism with food, water, air, shelter, and other needs for survival. For example, the habitat of a camel is the desert, and the habitat of a fish is water.

False. Monocot plants have parallel venation in their leaves (where veins run parallel to each other), not reticulate venation. Reticulate venation is a feature of dicot plants. $\text{Monocot} \Rightarrow \text{Parallel venation} + \text{Fibrous roots}$

False. A rose plant is classified as a shrub, not a tree. It has multiple woody stems that branch close to the ground and is not as tall or as thick-stemmed as a tree.

True. Amphibians are animals that are adapted to survive in both aquatic and terrestrial environments. Frogs are the most common example of amphibians.

True. When habitats are destroyed, plants and animals lose their homes, food sources, and other resources. This leads directly to a loss of biodiversity, as seen in the declining populations of the Bengal Tiger and Great Indian Bustard.

True. The thick and fleshy stems of cactus are an adaptation to store water in the desert, where very little water is available. This helps the cactus survive the extreme hot and dry conditions.

Mustard has a taproot; grass has fibrous roots; hibiscus (a dicot) shows reticulate venation; monocot plants show parallel venation.

Each organism has specific adaptations suited to its habitat.

The root system labeled 'X' is a Taproot system. In a taproot system, there is one prominent main root (the taproot) from which smaller side roots arise. Examples of plants with this root system include mustard and hibiscus (dicot plants).

Leaf 'P' shows Reticulate Venation. In reticulate venation, the veins form a net-like pattern on both sides of a thick central midrib. This type of venation is found in dicot plants such as hibiscus and chickpea.

Biodiversity is the variety of plants and animals found in a particular region, each playing a unique role in the ecosystem. For example, trees provide food and shelter to birds, while animals help spread seeds after eating fruits — showing mutual dependence. $\text{Biodiversity} = \text{Variety of living organisms in a region}$

Herbs are small plants with soft, green stems (e.g., tomato), while shrubs are taller than herbs with multiple hard, woody stems that branch close to the ground (e.g., rose).

Venation is the pattern of veins on a leaf. The two types are: (1) Reticulate venation — net-like pattern, found in hibiscus; (2) Parallel venation — veins run parallel, found in grass and banana. $\text{Venation} = \text{Pattern of veins on a leaf}$

A cotyledon is each part of a seed when it is split into two after soaking (as seen in chickpea). A dicot seed has two cotyledons (e.g., chickpea), while a monocot seed has only one thin cotyledon (e.g., maize). $\text{Dicot} = 2 \text{ cotyledons}, \quad \text{Monocot} = 1 \text{ cotyledon}$

Adaptations are special features that enable plants and animals to survive in their particular habitat. Example — Plant: The conical shape of a deodar tree allows snow to slide off easily in mountainous regions. Animal: The wide hooves of a hot-desert camel prevent it from sinking in sand.

Terrestrial habitats are land-based environments (e.g., forests, deserts), while aquatic habitats are water-based environments (e.g., ponds, oceans).

Generally, plants with reticulate venation have a taproot system (dicots), while plants with parallel venation have a fibrous root system (monocots). $\text{Reticulate venation} \Rightarrow \text{Taproot} \quad ; \quad \text{Parallel venation} \Rightarrow \text{Fibrous roots}$

Salim Ali (1896–1987) was an Indian scientist who travelled across India to observe and document the diversity of birds, their habitats, and travel routes. He is called the 'Birdman of India' because of his landmark contributions, including a 10-book series on birds of the Indian Subcontinent, and his efforts to conserve bird-rich regions like Keoladeo National Park.

Sacred groves are undisturbed patches of forests protected by local communities, where no one is allowed to cut trees or harm animals. They are important because they serve as community-protected treasures of biodiversity, sheltering numerous plants, animals, and medicinal plant species.

Key Points:

• Project Tiger (1973): Initiated to protect the declining population of the Bengal Tiger by conserving its natural habitat.

• Cheetah Reintroduction Project (2022): Initiated to restore the population of the Cheetah in India, as it had become locally extinct.

Grouping makes it easier to understand and study the diversity of plants and animals by organising them based on their similarities and differences. Just as arranging books in groups helps find them easily, grouping living organisms helps scientists study and compare them systematically. $\text{Grouping} = \text{Arranging organisms by common features}$

Key Points:

In plants, these three features are closely linked:

$\text{Dicot} \Rightarrow \text{2 cotyledons} + \text{Taproot} + \text{Reticulate venation}$

$\text{Monocot} \Rightarrow \text{1 cotyledon} + \text{Fibrous roots} + \text{Parallel venation}$

Chickpea is a dicot with taproots and reticulate venation. Maize (wheat) is a monocot with fibrous roots and parallel venation.

Key Points:

• Deodar tree (Mountain habitat): It has a conical shape and flexible, sloping branches that allow snow to slide off easily during heavy snowfall, preventing the branches from breaking.

• Cactus plant (Desert habitat): It has thick and fleshy stems that store water, enabling it to survive in hot deserts where water is very scarce. Its leaves may be modified to reduce water loss.

Both plants show how adaptations are directly shaped by the environmental conditions of their habitats.

Key Points:

Plants are grouped based on height, stem type, and branching pattern:

Thus, by observing the height, texture of the stem, and point of branching, we can easily classify a plant into one of these three groups.

Key Points:

• Humps: The single hump of the Rajasthani camel stores food for scarce desert conditions. The two humps of the Ladakhi camel provide extra food storage for cold winters when food is scarce.

• Legs/Hooves: Long legs and wide hooves of the hot-desert camel prevent sinking in sand, while shorter legs of the cold-desert camel help navigate mountainous terrain.

Key Points:

When habitats are damaged, plants and animals lose their homes, food sources, and other resources, leading to a decline in their populations and ultimately loss of biodiversity. Human activities such as deforestation and dam construction destroy natural habitats.

Conservation efforts in India:

1. Project Tiger (1973) — to protect the Bengal Tiger from extinction.

2. Cheetah Reintroduction Project (2022) — to restore cheetah populations.

Sacred groves also serve as community-protected biodiversity reserves across India.

Grouping of Plants — A Detailed Study

1. Based on Stem

Plants are classified into three groups based on their stem:

Climbers (need support to climb) and creepers (grow along the ground) are also special groups.

2. Based on Leaf Venation

$\text{Venation} = \text{Pattern of veins on a leaf}$

• Reticulate venation: Net-like pattern on both sides of a midrib. Found in hibiscus, chickpea.

• Parallel venation: Veins run parallel. Found in grass, banana, maize.

3. Based on Root Type

• Taproot: One main root with side roots. Found in mustard, chickpea.

• Fibrous roots: Bunch of similar thin roots from stem base. Found in grass, wheat.

4. Based on Seeds (Cotyledons)

$\text{Dicot} = 2 \text{ cotyledons} \quad ; \quad \text{Monocot} = 1 \text{ cotyledon}$

5. The Relationship

$\text{Dicot} \Rightarrow \text{2 cotyledons} + \text{Taproot} + \text{Reticulate venation}$

$\text{Monocot} \Rightarrow \text{1 cotyledon} + \text{Fibrous roots} + \text{Parallel venation}$

This systematic grouping helps scientists study and understand plant diversity more easily.

Habitats and Biodiversity

Definition of Habitat

$\text{Habitat} = \text{The place where a plant or animal lives and gets its needs fulfilled}$

A habitat provides food, water, air, shelter, and other necessities for survival.

Terrestrial Habitats

Habitats on land are called terrestrial habitats.

Aquatic Habitats

Habitats in water are called aquatic habitats.

Amphibians like frogs can live in both terrestrial and aquatic habitats.

Why Does Biodiversity Vary?

Biodiversity varies from region to region because of different environmental conditions such as temperature, water availability, and terrain. Each organism develops adaptations suited to its environment:

• Desert plants store water (cactus).

• Mountain trees are conical to shed snow (deodar).

• Desert camels have humps to store food and wide hooves to walk on sand.

$\text{Different conditions} \Rightarrow \text{Different adaptations} \Rightarrow \text{Different biodiversity}$

This explains why a pond, a desert, and a mountain all support entirely different communities of plants and animals.

Root Systems in Plants

Diagram Description

Draw the following two diagrams side by side:

(A) Taproot System:

• Draw one thick, prominent central root growing downward.

• Show several smaller side roots (lateral roots) branching off from the main root.

• Label: Taproot (main central root), Lateral roots (side roots), Stem base (at the top).

• Write example: Mustard / Chickpea

(B) Fibrous Root System:

• Draw a cluster of many thin roots of similar size all arising from the base of the stem.

• No single dominant root should be visible.

• Label: Fibrous roots (many thin equal roots), Stem base (at the top).

• Write example: Grass / Wheat

Activity: Relating Root Type with Leaf Venation

Materials needed: Saplings of lemongrass, marigold, sadabahar (periwinkle), chickpea, and wheat.

Steps:

1. Carefully uproot each sapling and wash the roots with water.

2. Observe and record whether each plant has a taproot or fibrous roots.

3. Observe the leaves of each plant and record whether the venation is reticulate or parallel.

4. Record observations in a table.

Conclusion:

$\text{Taproot} \Leftrightarrow \text{Reticulate venation (Dicots)}$

$\text{Fibrous roots} \Leftrightarrow \text{Parallel venation (Monocots)}$

This activity confirms that there is a definite relationship between root type and leaf venation, which is linked to whether a plant is a monocot or dicot.

Adaptations and Biodiversity Conservation

Definition of Adaptation

$\text{Adaptation} = \text{Special features that help an organism survive in its specific habitat}$

Adaptations develop over time in response to the environmental conditions of a habitat.

(i) Camel in the Hot Desert

(ii) Deodar Tree in the Mountains

• Conical shape: Allows snow to slide off easily without damaging branches.

• Flexible and sloping branches: Bend under snow load without breaking.

• These adaptations help the tree survive in regions with heavy snowfall.

(iii) Fish in Water

• Streamlined body: Reduces water resistance and allows smooth movement.

• Fins: Help the fish steer, balance, and propel itself through water.

$\text{Streamlined body} + \text{Fins} \Rightarrow \text{Efficient swimming}$

Loss of Biodiversity

When habitats are damaged due to deforestation or human activities:

• Plants and animals lose their homes, food, and shelter.

• Species populations decline or become extinct (e.g., Bengal Tiger, Great Indian Bustard, Cheetah).

Conservation Efforts

We must protect biodiversity to ensure that our planet remains full of life and that all plants and animals can survive and thrive for future generations.