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š¬ Think about it
Think of your family at home. You depend on each other and on things like water and electricity. Living things in nature do the same. They depend on each other and on air, water and soil. Let us see these connections.
What two kinds of interactions happen in a habitat?
- Living things (biotic) depend on non-living things (abiotic) to survive.
- Plants and animals also depend on each other.
- So there are biotic-abiotic interactions and biotic-biotic interactions.
- Both are important for survival in any habitat.
Biotic ↔ Abiotic
Biotic ↔ Biotic
Between living and non-living parts
Between two living things
Earthworms live in moist soil
A frog eats insects
A fish lays eggs in water
A water snake eats fish
In this Activity, we will identify and describe interactions between biotic and abiotic components shown in a pond scene.
Materials needed
The pond figure (Fig. 12.5), notebook and Table 12.3.
Procedure
1. Look at the pond figure carefully.
2. Use Criterion 1 — interactions between biotic and abiotic components.
3. Use Criterion 2 — interactions between two abiotic components.
4. Use Criterion 3 — interactions among biotic components.
5. Relate your learning to your observations.
6. Record them in Table 12.3 at the right places.
2. Use Criterion 1 — interactions between biotic and abiotic components.
3. Use Criterion 2 — interactions between two abiotic components.
4. Use Criterion 3 — interactions among biotic components.
5. Relate your learning to your observations.
6. Record them in Table 12.3 at the right places.
Table 12.3 — Interactions of biotic and abiotic components in a habitat
| Criterion 1: Interactions between biotic and abiotic components | Criterion 2: Interaction between two abiotic components | Criterion 3: Interaction among the biotic components |
|---|---|---|
| Earthworms live in moist soil. | The day temperature is high due to bright sunlight. | A frog eats insects. |
| Many microbes are present in the pond. | Water is evaporating fast due to the sunlight. | A water snake eats fish. |
| A fish lays eggs in water. | Air current blows slowly on the water surface creating gentle waves. | Frogs and fish may compete for small insect larvae. |
| Plants take water and nutrients from the soil. | The soil near the pond is moist. | A fish lays eggs in water near vegetation to protect them from other fish or frogs. |
Observation
Some interactions are between living and non-living things. Some are between two non-living things. Some are between two living things.
Explanation
The biotic and abiotic components interact to form an ecosystem. These interactions support life processes like nutrition, respiration and reproduction.
ā Summary
- Three criteria used
- Biotic-abiotic links
- Abiotic-abiotic links
- Forms an ecosystem
What is an ecosystem?
- Biotic and abiotic components in a habitat interact together.
- This interacting system is called an ecosystem.
- Organisms use abiotic parts for food, shelter and protection.
- So ecosystems can be large or small.
Example:
A small pond, a forest, or even one large banyan tree can be an ecosystem.
What are the two main types of ecosystems?
- Aquatic ecosystems include ponds, rivers and lakes.
- Terrestrial ecosystems include forests, farms and large trees.
- Farmland is a human-made ecosystem.
- So ecosystems can overlap and interact with each other.
Aquatic ecosystem
Terrestrial ecosystem
Found in water
Found on land
Ponds, rivers, lakes
Forests, farms, large trees
How do biotic and abiotic parts depend on each other?
- Sunlight, carbon dioxide and water help plants make food.
- Soil gives nutrients; air gives oxygen for respiration.
- In turn, plants release oxygen and hold soil in place.
- So the dependence works both ways.
In this Activity, we will study a forest ecosystem and classify organisms by what they eat.
Materials needed
The forest figure (Fig. 12.1b), internet or library, and Table 12.4.
Procedure
1. Study the forest picture carefully.
2. Spot the organisms listed in Table 12.4.
3. Using the internet or library, find out what each one eats.
4. Record whether each feeds on plants, animals, both, or makes its own food.
2. Spot the organisms listed in Table 12.4.
3. Using the internet or library, find out what each one eats.
4. Record whether each feeds on plants, animals, both, or makes its own food.
Table 12.4 — Eating habits of different organisms
| Name of the organism | Performs photosynthesis | Feeds on plants and plant products | Feeds on animals | Feeds on both plants and animals |
|---|---|---|---|---|
| Deer | No | Yes — Grass and leaves of plants | No | No — Only on plants |
| Hare | No | Yes — grass and leaves | No | No |
| Vulture | No | No | Yes — dead animals | No |
| Bengal Fox | No | Yes — fruits | Yes — small animals | Yes |
| Bird (Shikra) | No | No | Yes — small birds, insects | No |
| Squirrel | No | Yes — nuts, seeds | No | No |
| Mouse | No | Yes — grains | Yes — insects | Yes |
| Mushroom | No | No — grows on dead matter | No | No |
| Tree | Yes | No — makes own food | No | No |
Observation
Some organisms make their own food. Some eat only plants, some only animals, and some eat both.
Explanation
Plants make food and are called producers. Others depend on them and are called consumers. This tells us the feeding habits of each organism.
ā Summary
- Forest organisms studied
- Plants are producers
- Others are consumers
- Feeding habits found
What are producers, consumers, herbivores, carnivores and omnivores?
- Producers (autotrophs) make their own food, like plants.
- Consumers (heterotrophs) cannot make food and eat others.
- Herbivores eat only plants; carnivores eat only animals.
- Omnivores eat both plants and animals.
| Type | What it eats | Example |
|---|---|---|
| Producer (autotroph) | Makes its own food | Green plants |
| Herbivore | Only plants | Deer, hare |
| Carnivore | Only animals | Leopard |
| Omnivore | Plants and animals | Crow, fox, mouse |
Important Points
- An ecosystem forms when biotic and abiotic parts interact.
- Ecosystems can be aquatic or terrestrial.
- Auto means self; troph means food. Hetero means other.
ā Test Yourself
-
What is an ecosystem?
View Answer
A system where biotic and abiotic components interact with each other. -
Name the two main types of ecosystems.
View Answer
Aquatic (water) and terrestrial (land). -
Why are plants called producers?
View Answer
Because they make their own food by photosynthesis. -
What is a herbivore?
View Answer
An organism that eats only plants, like a deer. -
Give an example of an omnivore.
View Answer
A crow, fox or mouse — they eat both plants and animals.
Important Definitions
- Ecosystem — biotic and abiotic components of an area interacting together.
- Producer (autotroph) — an organism that makes its own food, like a plant.
- Consumer (heterotroph) — an organism that depends on others for food.
- Herbivore — an animal that eats only plants.
- Carnivore — an animal that eats only animals.
- Omnivore — an animal that eats both plants and animals.
š NCERT Question 7 — Observe two different places
Observe a park and a roadside. List their living and non-living parts and compare the two ecosystems.
View Answer →
