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๐ฌ Think about it
Think about a busy market. Many sellers, many buyers, all in one place. A pond is like that too. Many fish, many frogs, many plants live together. Let us see how we group all these living things.
What is a population?
- In a pond you see many fish of the same kind.
- This group of the same kind, living together, is a population.
- So a population is one type of organism in a habitat at a given time.
Example:
All the mango trees growing in one orchard form a population of mango trees.
In this Activity, we will count organisms in a small marked area to understand the population of each type.
Materials needed
String to mark the area, a ruler, notebook and Table 12.2.
Procedure
1. Divide students into four to five groups.
2. Each group may identify any two organisms, plant(s) or animal(s).
3. Mark an area of 1 m × 1 m in your school garden.
4. Identify four organisms in this area, and count their numbers.
5. Record the number of the organisms in Table 12.2.
6. Compile the data from all groups.
2. Each group may identify any two organisms, plant(s) or animal(s).
3. Mark an area of 1 m × 1 m in your school garden.
4. Identify four organisms in this area, and count their numbers.
5. Record the number of the organisms in Table 12.2.
6. Compile the data from all groups.
Table 12.2 — Number of particular organisms at a given space and time
| Name of organism | Population (Number of individual organisms) |
|---|---|
| Plant 1: | 20 |
| Plant 2: | 05 |
| Animal 1: | 8 |
| Animal 2: | 3 |
Observation
In the example, there is a population of 20 plants of one type and only 5 plants of another type in the same 1×1 m² area.
Explanation
A population is a group of the same type of organisms in a habitat at a given time. Counting them shows how big each population is.
โ Summary
- Small area marked
- Organisms counted
- Numbers recorded
- Population found
What is a community?
- Different populations sharing the same habitat form a community.
- So plants, animals and microbes together make the community.
- These organisms interact and depend on one another.
Population to Community
One kind of organism
↓
Population
Many of the same kind together.
↓
Community
Different populations sharing a habitat.
What happens if a habitat has only one type of organism?
- All of them would need the same things — food, water, space.
- So there would be heavy competition between them.
- That is why resources may become scarce.
๐ก Ever heard of ...
- A flower has a stalk, green sepals and coloured petals.
- It has two reproductive parts — carpels (female) and stamens (male).
- Stamens release yellow dust-like pollen grains.
- Wind, water, insects, bats and birds carry pollen to carpels.
- This process is called pollination.
- It is essential for the formation of fruits and seeds.
Important Points
- A population is the same kind of organism at a given time.
- A community is made of many populations in one habitat.
- The organisms in a community depend on one another.
โ Test Yourself
-
Define a population.
View Answer
A group of the same kind of organism living together in a habitat at a given time. -
What forms a community?
View Answer
Different populations sharing the same habitat together. -
Which is bigger, a population or a community?
View Answer
A community is bigger, because it contains many populations. -
What is pollination?
View Answer
The carrying of pollen from stamens to carpels, which helps form fruits and seeds. -
Why is having only one type of organism a problem?
View Answer
They all need the same resources, causing competition and scarcity.
Important Definitions
- Population — a group of the same kind of organism in a habitat at a given time.
- Community — different populations sharing the same habitat.
- Pollination — the carrying of pollen from stamens to carpels of flowers.
๐ NCERT Question 1 — Refer to the given diagram
Look at the diagram and pick the wrong statement about population, community and ecosystem.
View Answer →
