DIVERSITY IN THE LIVING WORLD – Class 6 - Science
SUMMARY
Meaning of Diversity
Diversity means variety, and the living world shows a vast variety of plants, animals, and microorganisms.
Need for Classification
Because of the countless number of living beings on Earth, scientists classify them into groups to make their study easier and more systematic. Classification is based on body structure, mode of nutrition, habitat, and methods of reproduction.
Major Groups of Living Things
Plants are autotrophs as they make their own food through photosynthesis. Examples are trees, shrubs, herbs, algae, mosses, and ferns. Animals are heterotrophs as they depend on other organisms for food. Examples include insects, birds, fishes, and mammals. Microorganisms are very small organisms that cannot be seen with the naked eye. Examples are bacteria, fungi, protozoa, and viruses.
Habitats of Organisms
Living organisms occupy different habitats. Some live on land like lions, tigers, and elephants, while some live in water like fishes and lotus. Amphibians like frogs live both on land and water, and aerial organisms like birds and bats live mostly in air.
Adaptations
To survive in their habitats, organisms show adaptations. A camel stores water in its body to live in deserts, fishes have gills to breathe in water, and cactus plants store water and have spines instead of leaves to reduce water loss.
Importance of Diversity
Diversity in living organisms is very important as it maintains balance in nature through the food chain and oxygen cycle. It also provides humans with food, medicines, clothing, and shelter, and adds beauty to life and the environment.
SHORT Q&A (1 MARK EACH)
Q: What does diversity mean?
A: Diversity means variety.
Q: Give an example of diversity in plants.
A: Trees, shrubs, herbs, algae, mosses.
Q: Give an example of diversity in animals.
A: Insects, birds, fishes, mammals.
Q: Why is classification needed?
A: To study organisms easily and systematically.
Q: On what basis are organisms classified?
A: Body structure, nutrition, habitat, and reproduction.
Q: What are autotrophs?
A: Organisms that make their own food.
Q: Name one autotroph.
A: Green plants.
Q: What are heterotrophs?
A: Organisms that depend on others for food.
Q: Name one heterotroph.
A: Animals.
Q: What are microorganisms?
A: Very small living organisms not visible to naked eyes.
Q: Name two microorganisms.
A: Bacteria and fungi.
Q: What is a habitat?
A: The place where an organism lives.
Q: Give an example of a terrestrial animal.
A: Lion.
Q: Give an example of an aquatic plant.
A: Lotus.
Q: Which animal can live both on land and in water?
A: Frog.
Q: Give one example of an aerial animal.
A: Bird.
Q: What adaptation helps camel survive in deserts?
A: It stores water and fat in its body.
Q: What adaptation helps fish breathe in water?
A: Gills.
Q: What adaptation helps cactus survive in deserts?
A: It stores water and has spines instead of leaves.
Q: What helps birds to fly?
A: Wings and hollow bones.
Q: What are amphibians?
A: Animals that live on land and in water.
Q: Name one amphibian.
A: Frog.
Q: Why are plants called autotrophs?
A: Because they prepare their own food by photosynthesis.
Q: Why are animals called heterotrophs?
A: Because they depend on plants and other animals for food.
Q: Which organism causes diseases like malaria?
A: Protozoa.
Q: Which microorganism is used in making bread?
A: Yeast.
Q: Which microorganism helps in fixing nitrogen in soil?
A: Rhizobium.
Q: Which gas is given out by plants during photosynthesis?
A: Oxygen.
Q: What is the importance of diversity?
A: It maintains balance in nature.
Q: What is the food chain?
A: The sequence of organisms where one is food for another.
Q: Which organisms are at the beginning of a food chain?
A: Green plants.
Q: Which organisms are at the end of the food chain?
A: Carnivores.
Q: Which living things decompose dead organisms?
A: Fungi and bacteria.
Q: Why are decomposers important?
A: They recycle nutrients in nature.
Q: Name one aquatic animal.
A: Fish.
Q: Name one terrestrial plant.
A: Mango tree.
Q: What do we call living organisms that cannot make their own food?
A: Heterotrophs.
Q: What do we call living organisms that can make their own food?
A: Autotrophs.
Q: Which group of living organisms includes viruses?
A: Microorganisms.
Q: How does diversity add beauty to life?
A: By making the environment colorful, balanced, and rich in variety.
LONG QUESTIONS AND ANSWERS
Q: What is diversity? Explain its importance in the living world.
A: Diversity means the presence of different types of plants, animals, and microorganisms in nature. It shows the variety of life forms found on Earth. It is important because it balances nature, maintains the food chain, provides us food, shelter, oxygen, and keeps ecosystems healthy. Without diversity, life would not be possible.
Q: What is classification? Why is it necessary in science?
A: Classification is the process of grouping organisms into categories based on similarities and differences. It is necessary because it helps us to study millions of organisms easily, identify unknown organisms, understand their relationships, and avoid confusion in naming them.
Q: Explain the difference between autotrophs and heterotrophs with examples.
A: Autotrophs are organisms that prepare their own food by photosynthesis, e.g., green plants. Heterotrophs cannot make their own food and depend on others, e.g., animals. Autotrophs are producers and form the base of the food chain, while heterotrophs are consumers and depend directly or indirectly on plants.
Q: What are microorganisms? Explain their beneficial and harmful roles.
A: Microorganisms are tiny living organisms not visible to the naked eye, such as bacteria, fungi, protozoa, algae, and viruses. Beneficial roles include making bread (yeast), fixing nitrogen (Rhizobium), making antibiotics (penicillin). Harmful roles include causing diseases (malaria by protozoa, cholera by bacteria) and spoiling food.
Q: What is a habitat? Describe different types of habitats with examples.
A: Habitat is the natural home of an organism. Major types are:
Terrestrial (land) – lion, camel
Aquatic (water) – fish, lotus
Aerial (air) – eagle, parrot
Amphibians (land + water) – frog
Habitats provide organisms with food, shelter, and favorable conditions to survive.
Q: Explain how animals are adapted to live in different habitats.
A:Camel stores water and has long legs for deserts
Fish have gills and fins for swimming in water
Frogs have moist skin and lungs for both land and water
Birds have wings and hollow bones for flying
These adaptations help organisms survive in their respective habitats.
Q: What is the food chain? Explain with an example.
A: A food chain is the sequence of organisms in which one organism is food for another. Example:
Grass → Grasshopper → Frog → Snake → Eagle
Here, grass is the producer, grasshopper is a herbivore, frog is a carnivore, and eagle is the top consumer. It shows how energy flows from plants to animals.
Q: What are decomposers? Explain their role in nature.
A: Decomposers are microorganisms like bacteria and fungi that break down dead plants and animals. They recycle nutrients into the soil, clean the environment by decomposing waste, and make the soil fertile. Without decomposers, the Earth would be filled with dead matter.
Q: Compare terrestrial and aquatic plants with examples.
A:Terrestrial plants grow on land, e.g., mango tree, neem. They have roots in soil and normal leaves.
Aquatic plants grow in water, e.g., lotus, hydrilla. They have thin or spongy leaves, hollow stems, and floating ability.
Both are adapted to survive in their own environments.
Q: Explain the special features of desert plants and animals.
A:Desert plants like cactus store water in stems, have spines instead of leaves, and waxy coating to reduce water loss.
Desert animals like camels store fat in humps, can survive without water for many days, and have long eyelashes to protect from sand.
These adaptations help them survive in extreme heat.
Q: Explain the importance of plants in maintaining diversity.
A: Plants are producers that provide food, oxygen, and shelter. They form the base of the food chain. Forests and grasslands give habitat to animals. They also prevent soil erosion, purify air, and balance carbon dioxide. Without plants, animals and humans cannot survive.
Q: Describe the role of animals in maintaining ecological balance.
A: Animals help in pollination, seed dispersal, maintaining food chains, and balancing populations. Herbivores prevent overgrowth of plants, carnivores control herbivore numbers, and decomposers recycle waste. Each animal has a role in keeping nature balanced.
Q: What are amphibians? Explain their adaptations with examples.
A: Amphibians are animals that can live on land and in water, e.g., frog, salamander. They have moist skin for breathing in water, lungs for land, webbed feet for swimming, and strong hind legs for jumping. These features help them survive in dual habitats.
Q: Explain why diversity is important for human beings.
A: Diversity provides food, medicine, clothing, and shelter. It gives oxygen, wood, and raw materials. It maintains the food chain and ensures ecological balance. It also adds beauty, tourism opportunities, and cultural richness to human life.
Q: How do aquatic animals survive in water? Explain with examples.
A: Aquatic animals like fish have gills for breathing oxygen dissolved in water, fins for swimming, and streamlined bodies for easy movement. Whales and dolphins have lungs but come to the surface to breathe. These adaptations help them live in water.
Q: Explain the relationship between producers, consumers, and decomposers.
A: Producers (plants) make food, consumers (animals) eat plants or animals, and decomposers (fungi, bacteria) break down dead organisms. Together, they form a cycle of energy flow and nutrient recycling. This relationship maintains balance in the ecosystem.
Q: How does diversity help in survival of species?
A: Diversity gives organisms different food sources, habitats, and survival strategies. If one species disappears, others can still maintain the balance. Variety also helps in adaptation to changing environments. This ensures the survival of life on Earth.
Q: Explain with examples how microorganisms are useful in daily life.
A:Yeast is used in making bread and cakes
Lactobacillus makes curd from milk
Rhizobium fixes nitrogen in soil
Penicillin is an antibiotic made from fungi
Some algae are used in food supplements
Thus, microorganisms are essential in food, medicine, and agriculture.
Q: Explain how microorganisms can be harmful to humans.
A: Some microorganisms cause diseases like malaria, cholera, and tuberculosis. Viruses cause flu and COVID-19. They spoil food, contaminate water, and damage crops. They spread quickly and affect health, economy, and environment.
Q: What are the differences between plants and animals?
A:Plants are autotrophs, animals are heterotrophs
Plants do not move, animals move freely
Plants prepare food, animals depend on plants or other animals
Plants have cell walls, animals do not
Plants release oxygen, animals release carbon dioxide
Q: Explain the role of bacteria in nature.
A: Bacteria help in nitrogen fixation, decomposition, making curd, and producing antibiotics. Some bacteria cause diseases like cholera and typhoid. Thus, bacteria are both useful and harmful but play an important role in nature.
Q: How do birds adapt to flying?
A: Birds have wings, hollow bones, light bodies, and strong chest muscles. Their feathers reduce air resistance. They have sharp eyesight and beaks suited for eating different foods. These adaptations make them excellent fliers.
Q: Explain the adaptations of polar animals.
A: Polar animals like polar bears and penguins have thick fur or feathers, a layer of fat (blubber), and white body color for camouflage. They can store food and survive extreme cold conditions. These features help them live in icy regions.
Q: How does the food chain show interdependence of organisms?
A: A food chain links plants, herbivores, and carnivores. If one link is broken, the whole chain is disturbed. Example: If plants disappear, herbivores will die, then carnivores too. It shows all organisms depend on one another for survival.
Q: Explain why decomposers are called recyclers of nature.
A: Decomposers break down dead matter into nutrients like nitrogen, phosphorus, and carbon. These nutrients return to the soil and are used by plants again. This recycling keeps the environment clean and fertile, making decomposers recyclers of nature.
Q: How are desert plants different from normal plants?
A: Desert plants like cactus have thick stems for water storage, spines instead of leaves, deep roots, and waxy coverings to reduce water loss. Normal plants have broad leaves, shallow roots, and do not store much water.
Q: Explain why frogs are called amphibians.
A: Frogs are called amphibians because they can live both in water and on land. They breathe with gills in their early stage (tadpole) and with lungs as adults. They have moist skin, webbed feet, and strong legs to survive in both habitats.
Q: How do humans depend on biodiversity?
A: Humans get food, medicine, clothing, shelter, and oxygen from biodiversity. Forests give wood, rivers give fish, animals give milk and meat, and plants give fruits and vegetables. Without biodiversity, human survival would not be possible.
Q: Explain why every organism is important in nature.
A: Each organism has a role: plants give oxygen and food, herbivores eat plants, carnivores control herbivore numbers, decomposers recycle waste. If one is removed, the balance is lost. Every organism contributes to the survival of life on Earth.
Q: Write a note on the beauty of diversity in life.
A: Diversity makes our planet colorful and beautiful. Different flowers, birds, animals, and landscapes add charm to nature. It provides balance in the environment and richness in culture, food, and traditions. Diversity makes life meaningful and worth living.
MCQS
Which term means variety among living organisms
a) Similarity
b) Diversity
c) Unity
d) Adaptation
Answer b) Diversity
The scientific method of grouping organisms is called
a) Evolution
b) Classification
c) Reproduction
d) Nutrition
Answer b) Classification
Plants are called
a) Heterotrophs
b) Parasites
c) Autotrophs
d) Carnivores
Answer c) Autotrophs
Which organisms depend on others for food
a) Plants
b) Autotrophs
c) Animals
d) Algae
Answer c) Animals
The process by which green plants prepare food is
a) Respiration
b) Digestion
c) Photosynthesis
d) Fermentation
Answer c) Photosynthesis
Organisms that cannot be seen with the naked eye are called
a) Plants
b) Microorganisms
c) Animals
d) Amphibians
Answer b) Microorganisms
Bacteria, fungi, protozoa, and viruses are examples of
a) Microorganisms
b) Mammals
c) Birds
d) Amphibians
Answer a) Microorganisms
Animals that live on land are called
a) Aquatic
b) Terrestrial
c) Amphibians
d) Aerial
Answer b) Terrestrial
Frogs can live both on land and in water, so they are
a) Amphibians
b) Mammals
c) Aerial animals
d) Aquatic animals
Answer a) Amphibians
Birds and bats are mostly
a) Amphibians
b) Aerial animals
c) Aquatic animals
d) Terrestrial animals
Answer b) Aerial animals
Camel stores water in its body to live in
a) Mountains
b) Desert
c) Forest
d) River
Answer b) Desert
Fishes breathe with the help of
a) Lungs
b) Gills
c) Skin
d) Trachea
Answer b) Gills
The cactus has spines instead of leaves to
a) Store food
b) Attract animals
c) Reduce water loss
d) Make oxygen
Answer c) Reduce water loss
Which plant stores water in its stem
a) Mango
b) Lotus
c) Cactus
d) Neem
Answer c) Cactus
The lotus plant grows in
a) Forest
b) Desert
c) Water
d) Mountains
Answer c) Water
Which one is a heterotroph
a) Neem tree
b) Lotus plant
c) Lion
d) Algae
Answer c) Lion
Which of these is NOT a microorganism
a) Bacteria
b) Fungi
c) Protozoa
d) Elephant
Answer d) Elephant
Classification makes the study of organisms
a) Difficult
b) Easier
c) Complicated
d) Boring
Answer b) Easier
Living beings that get food from other living beings are
a) Autotrophs
b) Producers
c) Heterotrophs
d) Decomposers
Answer c) Heterotrophs
Which of the following is an aerial animal
a) Cow
b) Dog
c) Pigeon
d) Crocodile
Answer c) Pigeon
A fish lives in
a) Land
b) Desert
c) Water
d) Air
Answer c) Water
Amphibians can
a) Live only in air
b) Live only on land
c) Live both on land and water
d) Live only in desert
Answer c) Live both on land and water
Which one is a terrestrial animal
a) Tiger
b) Fish
c) Frog
d) Pigeon
Answer a) Tiger
Viruses are very
a) Big
b) Small
c) Green
d) Colourful
Answer b) Small
Diversity in living things is important because it maintains
a) Sports
b) Balance in nature
c) Factories
d) Machines
Answer b) Balance in nature
The balance in nature is maintained through
a) Food chain and oxygen cycle
b) Sports and games
c) Clothes and houses
d) Cars and trains
Answer a) Food chain and oxygen cycle
Humans depend on plants and animals for
a) Medicines
b) Food
c) Shelter
d) All of these
Answer d) All of these
Microorganisms are usually studied with
a) Telescope
b) Microscope
c) Binoculars
d) Naked eye
Answer b) Microscope
Which of these helps in recycling dead matter in nature
a) Bacteria and fungi
b) Lions and tigers
c) Birds and bats
d) Fish and frogs
Answer a) Bacteria and fungi
The study of variety of living things is known as
a) Chemistry
b) Diversity
c) Biology
d) Physics
Answer c) Biology
