CBSE Notes Class 6 Science Chapter 6 The Living Organisms: Characteristics and Habitats

The world around us is filled with a diverse range of objects, which can be categorized into living and non-living things. Living things require food, water, and air to survive. This includes all animals, humans included, as they all depend on these essentials for life. In contrast, non-living things do not need food, water, or air to exist. For example, items like tables and chairs are considered nonliving because they do not require any of these resources for survival.

1.0Characteristics of Living Things 

The characteristics of living things include:

1. Nutrition:  Living things require food, air, and water.

2. Growth:  They have the ability to grow.

3. Movement: Living organisms can move independently.

4. Sensitivity: They can respond to stimuli or changes in their environment.

5. Respiration:  Living things respire, releasing energy from food.

6. Excretion:  They eliminate waste materials from their bodies.

7. Reproduction: Living organisms can reproduce and produce offspring.

8. Life Span: They have a defined life span, after which they eventually die.

2.0Habitat

• All living organisms, including plants and animals, tend to inhabit environments that best meet their needs. 
• The location where a plant or animal resides is referred to as its habitat. 
• A habitat offers essential resources such as food, water, air, light, shelter for protection, and a space for breeding for the organisms living there.

1. Terrestrial habitats 

• A land-based habitat is known as a terrestrial habitat. Examples of terrestrial habitats include deserts, mountains (or hills), forests, grasslands, gardens, fields, soil, and homes.

2. Aquatic Habitats 

• A water-based habitat is referred to as an aquatic habitat. 
• Plants and animals that reside in water are considered to inhabit an aquatic environment. 
• Examples of aquatic habitats include ponds, lakes, rivers, swamps (areas with waterlogged ground), and oceans (or seas).

Components of a Habitat

• Biotic components refer to the "living" elements within a habitat.  These include plants, animals, and microorganisms that coexist in that environment.
• Abiotic components refer to the "nonliving" elements in a habitat. These include various factors such as soil, rocks, air, water, sunlight, and temperature.

3.0Adaptations 

• A living organism can thrive in a specific habitat if its body is adapted to the conditions of that environment. 
• To survive in their surroundings, plants and animals develop special characteristics or features. 
• These specific body traits or behaviors that enable an organism to live successfully in a particular habitat are referred to as adaptations.
• Some of the important terrestrial habitats are 
• Deserts  
• Mountain regions 
• Forests (or Grasslands)

1. Deserts 

• Desert rats and snakes survive in hot, water-scarce deserts through key adaptations:
• They live in burrows, staying underground during the day to avoid heat and water loss, as the burrows remain cool. 
• They emerge only at night, when it's cooler, to search for food.

Adaptation in Desert Plants

• Desert plants have several adaptations to survive in hot, dry environments:
• Their leaves are often absent, very small, or modified into spines to reduce water loss through transpiration.  
• The stems take on the role of leaves, conducting photosynthesis.  
• Stems are adapted for water storage and covered with a thick waxy layer (cuticle) to minimize water loss.  
• Many desert plants have long roots that extend deep into the soil to absorb water.

2. Mountain Regions

Adaptation in Mountainous Plants

• Mountain regions experience heavy rainfall and cold winters, often with snowfall that can damage plants. Trees in these habitats have developed several adaptations to survive:
• Cone-Shaped Structure : Mountain trees typically have a cone shape with sloping branches, allowing rain and snow to slide off easily, preventing damage to branches and leaves.
• Needle-Like Leaves: Many mountain trees feature small, needle-like leaves that minimize water loss in windy conditions. These leaves have a thick waxy coating that reduces transpiration and protects against rain and snow damage.

Animals living in mountainous regions are well-adapted to the cold environment.

• Yaks: They have long hair that keeps them warm by protecting them from the cold.
• Mountain Goats: Their long hair also helps them stay warm, and they have strong hooves to navigate rocky slopes easily.
• Snow Leopards: With thick fur covering their body, feet, and toes, snow leopards are well-equipped to endure extremely cold and snowy conditions.

3. Adaptations in Lions and Deer for Forest Habitat

Lion Adaptations

• Claws:  Lions have long, strong claws that can be withdrawn to prevent wear, aiding in catching prey.
• Eyesight:  Positioned at the front of its head, lion eyes provide depth perception for locating prey.
• Coloration:  The light brown color helps lions blend into dry grasslands while hunting.

Deer Adaptations

• Vision: With eyes on the sides of its head, deer can see in all directions, helping detect predators.
• Hearing:  Large ears enhance the deer's ability to hear approaching threats.
• Speed: Quick movement allows deer to escape predators like lions.
• Coloration:  The brown color helps deer remain concealed in dry grasslands.
• Teeth:  Strong teeth are adapted for chewing tough plant materials found in forests.

Aquatic Habitats 

• The important aquatic habitats are 
• Oceans - Many sea-animals have streamlined bodies to help them move in sea -water easily. 
• Ponds, lakes, and rivers are examples of "freshwater" aquatic habitats. The plants that thrive in these water environments are referred to as aquatic plants.

Adaptations in aquatic plants (or water plants):

• Aquatic plants exhibit various adaptations to thrive in their environments. Here are some key adaptations:
• Root Structure: Aquatic plants have short, small roots primarily designed to anchor them in place. They can absorb water and dissolved minerals directly through their stems, branches, and leaves since all parts are immersed in water.
• Stem Composition:  The stems of aquatic plants are soft, hollow, and lightweight, with large air-filled spaces. This allows them to remain buoyant in the water, eliminating the need for strong stems.
• Leaf Structure: Submerged aquatic plants possess narrow, ribbon-like leaves that can bend with the flow of water in rivers and streams, preventing obstruction of the current.