Living Beings and Their Surroundings

Living Beings and Their Surroundings: Complete CBSE Class 6 Science Notes

Introduction to Living Beings and Their Surroundings

Our planet Earth is home to diverse environments, from the freezing Himalayan mountains to the scorching Rajasthan deserts, and from lush forests to vast oceans. Each of these surroundings supports unique forms of life that have adapted remarkably to survive in their specific conditions. Understanding how living beings interact with their surroundings is fundamental to studying biology and appreciating the incredible diversity of life on Earth.

This comprehensive guide covers everything students need to know about living beings, their habitats, and the fascinating adaptations that allow organisms to thrive in different environments.

What Are Living Things?

Definition

Living things are organisms that require food, water, and air for their survival. They exhibit specific characteristics that distinguish them from non-living things. All plants and animals are living things, also called organisms. The scientific study of living things is called biology.

What Are Non-Living Things?

Non-living things do not require food, water, or air for their survival. Examples include tables, chairs, rocks, and books. These objects exist but do not show the characteristics of life.

Characteristics of Living Things

Living organisms share several fundamental characteristics that define life:

1. Need for Food

All living things need food to stay alive and obtain energy. Plants make their own food through photosynthesis, while animals obtain food by consuming plants or other animals. Without food, air, and water, living things cannot survive.

2. Growth

Growth means an increase in size over time. All living things grow from smaller forms to larger ones:

• A seed grows into a plant
• A baby grows into an adult
• Young animals become larger and more mature

3. Movement

Movement is one of the most important signs of life:

• Animals can move from one place to another or move body parts
• Plants are fixed in soil but can move parts of their body such as leaves, flowers, shoots, and roots toward stimuli like sunlight, water, or gravity

4. Response to Stimuli

Living things respond to changes in their surroundings. These changes are called stimuli.

Examples of stimuli include:

• Heat
• Light
• Touch
• Sound
• Smell
• Taste
• Water
• Chemicals

Example: The Mimosa plant (touch-me-not plant) folds its leaves when touched. Here, the touch is the stimulus, and folding leaves is the response.

5. Respiration

Respiration is the chemical process in which food combines with oxygen to release energy. All living things undergo respiration to obtain energy from food. Breathing is the process of taking air into the lungs and expelling it. Breathing provides oxygen needed for respiration.

Different organisms breathe differently:

• Humans and mammals: Use lungs
• Fish: Use gills to absorb oxygen dissolved in water
• Earthworms: Breathe through their thin, moist skin
• Plants: Exchange gases through tiny pores called stomata on their leaves

6. Excretion

Excretion is the removal of waste substances from the body. All living things excrete:

In Animals:

• Carbon dioxide (during breathing)
• Urea, unwanted water, and salts (in urine)
• Solid wastes (in feces)

In Plants:

• Waste products are stored in leaves, bark, and fruits
• Plants get rid of wastes by shedding leaves, peeling bark, and dropping fruits

7. Reproduction

Reproduction is the process by which living organisms produce new members of their species. This ensures the survival of species on Earth.

Different methods of reproduction:

• Animals: Some give birth to young ones (humans, dogs), others lay eggs (birds, fish)
• Plants: Reproduce through seeds, tubers, or other methods

8. Definite Life-Span

All living things have a definite life-span (the duration of life):

• Humans: Average 60-70 years
• Some insects: Only a few hours
• Tortoises: More than 100 years

Differences Between Living and Non-Living Things

Living Things	Non-Living Things
Need food, air, and water	Do not need food, air, or water
Grow in size	Do not grow
Can move on their own	Cannot move on their own
Respond to stimuli (sensitive)	Do not respond to stimuli
Reproduce themselves	Do not reproduce
Respire and release energy from food	Do not respire
Excrete waste materials	Do not excrete
Have a definite life-span and eventually die	Exist indefinitely

What is a Habitat?

Definition

A habitat is the place or surroundings where a plant or animal lives. It provides everything an organism needs for survival, including food, water, shelter, and suitable climate.

Examples of Habitats

• Deserts
• Mountain regions (hills)
• Forests
• Grasslands
• Gardens
• Fields
• Soil
• Ponds
• Lakes
• Rivers
• Oceans (seas)
• Sea-shores

Types of Habitats

Habitats are broadly classified into two main categories:

1. Terrestrial Habitats (Land-Based)

Terrestrial habitats are land-based environments where plants and animals live.

Examples:

• Deserts
• Mountains (hills)
• Forests
• Grasslands
• Gardens
• Fields
• Homes

2. Aquatic Habitats (Water-Based)

Aquatic habitats are water-based environments where plants and animals live.

Examples:

• Ponds
• Rivers
• Lakes
• Swamps (waterlogged ground)
• Oceans (seas)

Components of a Habitat

Every habitat consists of two types of components:

1. Biotic Components (Living)

Biotic components include all living things in a habitat:

• Plants
• Animals
• Micro-organisms (bacteria, fungi)

2. Abiotic Components (Non-Living)

Abiotic components include all non-living things in a habitat:

• Soil
• Rocks
• Air
• Water
• Sunlight
• Temperature

Important: A habitat includes not just these components but also the interactions between biotic and abiotic components.

What is Adaptation?

Definition

Adaptation is the presence of specific body features or certain habits that enable a plant or an animal to live in a particular habitat. Organisms develop these special features over time to survive better in their environment.

Adaptations help organisms:

• Obtain food and water
• Protect themselves from predators
• Cope with extreme temperatures
• Reproduce successfully

Adaptations in Terrestrial Habitats

1. Desert Habitat

Deserts are waterless areas covered with sand, having little or no vegetation, extremely hot during the day, and very dry.

Adaptation in Desert Animals

Example: Camel

Camels are remarkably adapted to survive in hot, dry deserts:

1. Long legs: Keep the body away from hot sand
2. Water storage: Can drink large amounts of water and store it in the body
3. Water conservation: Passes small amounts of urine, dry dung, and does not sweat much
4. Fat storage in hump: Can break down stored fat to obtain water during emergencies
5. Large, flat feet: Help walk easily on soft sand without sinking

Other desert animals:

• Desert rats and snakes: Live in burrows during hot daytime; come out during cool nights; excrete very little urine to conserve water

Adaptation in Desert Plants

Example: Cactus

Cactus plants have special features for desert survival:

1. Modified leaves: Leaves are modified into thin spines (thorns) to reduce water loss through transpiration
2. Green stem for photosynthesis: The green stem (not leaves) carries out photosynthesis
3. Water storage: Stems store water
4. Thick waxy cuticle: Covers the stem to prevent water loss through evaporation

2. Mountain Habitat

Mountains are very high hills with extremely cold and windy conditions.

Adaptation in Mountain Plants

Mountain trees survive cold and windy conditions through:

1. Cone shape: Allows rain and snow to slide off easily without damaging branches
2. Needle-like leaves: Small leaves lose very little water in windy conditions
3. Deciduous trees: Broad-leaved trees shed leaves before winter to prevent water loss when soil water is frozen

Adaptation in Mountain Animals

Example: Yak

Yaks are large oxen covered with long silky hair:

• Long hair: Protects from cold and keeps the body warm

Example: Mountain Goat

Mountain goats are well-adapted for mountain life:

1. Long hair: Protects from cold
2. Strong hooves: Hard and rough feet enable running up rocky mountain slopes for grazing

3. Forest and Grassland Habitat

Forests are large areas covered mainly with trees and plants. Grasslands are large areas covered with grass used for grazing, with few trees or hiding places.

Adaptation in Forest/Grassland Animals

Example: Lion (Predator)

Lions are adapted for hunting:

1. Strong, fast, and agile: Can hunt and kill prey like deer
2. Long, sharp claws: Help catch prey
3. Front-facing eyes: Enable correct judgment of prey location for catching
4. Light brown color: Helps hide in dry grassland while hunting (camouflage)

Example: Deer (Prey)

Deer are adapted for escaping predators:

1. Side-facing eyes: Enable all-round vision to see predators in all directions
2. Big ears: Provide excellent hearing to detect predator movements
3. Fast and agile: High speed helps escape from predators
4. Brown color: Helps hide in dry grasslands (camouflage)
5. Strong teeth: For chewing hard plant stems

Adaptations in Aquatic Habitats

1. Ocean Habitat

Oceans are very large areas of sea with saltwater.

Adaptations in Ocean Animals

Example: Fish

Fish are perfectly adapted for life in water:

1. Streamlined body: Head, trunk, and tail merge to form a shape that moves easily through water with least resistance
2. Gills: Special breathing organs that absorb oxygen dissolved in water
3. Slippery scales: Protect the body and help in easy movement through water
4. Strong tail: Used for swimming
5. Flat fins: Help change direction and maintain body balance in water

Other adaptations:

• Many sea animals have streamlined bodies for easy movement
• Most sea animals have gills for breathing underwater

2. Ponds, Lakes, and Rivers

These are freshwater aquatic habitats.

Adaptations in Aquatic Plants

Types of aquatic plants:

1. Floating plants: Float on water surface (Example: Water lettuce, Water hyacinth)
2. Partly submerged plants: Partially in water (Example: Water lily, Lotus)
3. Completely submerged plants: Entirely underwater (Example: Hydrilla)

Adaptations:

1. Very short, small roots: Main function is to hold the plant in place
2. Soft, hollow, light stems: Have large air-filled spaces for buoyancy
3. Narrow, ribbon-like leaves: Can bend in flowing water without obstructing flow (in submerged plants)

3. Animals Adapted to Water and Land

Example: Frog

Frogs can live both in water and on land:

1. Webbed back feet: Thin skin between toes works like paddles for swimming in water
2. Strong back legs: Enable hopping (jumping) and catching prey on land

Quick Reference 

Concept	Definition	Examples
Living Things	Organisms that need food, water, and air	Plants, animals, humans
Non-Living Things	Things that don't need food, water, or air	Rocks, chairs, tables
Habitat	Place where an organism lives	Desert, forest, ocean, pond
Terrestrial Habitat	Land-based habitat	Desert, mountains, grasslands
Aquatic Habitat	Water-based habitat	Ocean, river, pond, lake
Adaptation	Special features for survival in a habitat	Camel's hump, fish's gills
Biotic Components	Living parts of habitat	Plants, animals, microorganisms
Abiotic Components	Non-living parts of habitat	Soil, water, air, sunlight
Respiration	Process of releasing energy from food using oxygen	Breathing in all organisms
Excretion	Removal of waste from body	Urine, sweat, carbon dioxide

Common Exam Questions:

• Define living things and their characteristics
• Differentiate between terrestrial and aquatic habitats
• Explain specific adaptations (camel, fish, cactus)
• Describe the components of a habitat
• List differences between living and non-living things

Conclusion

Understanding living beings and their surroundings is fundamental to appreciating the incredible diversity of life on Earth. Every organism, from the smallest insect to the largest whale, has developed remarkable adaptations that allow it to thrive in its specific habitat. By studying these adaptations and the relationships between organisms and their environments, we gain insights into the delicate balance of nature and the importance of protecting diverse habitats for the survival of all species.

Remember that all living things share common characteristics, yet each has unique features suited to its environment. This knowledge forms the foundation for further studies in biology and environmental science.