AP State Syllabus AP Board 7th Class Science Solutions Chapter 13 Seed Dispersal Textbook Questions and Answers.
AP State Syllabus 7th Class Science Solutions 13th Lesson Seed Dispersal
7th Class Science 13th Lesson Seed Dispersal Textbook Questions and Answers
Improve Your Learning
What happens if seeds are not dispersed?
- Seeds dispersal is essential for the survival of plants.
- If seeds are not dispersed, there will be competition with the mother plant for air, water and minerals.
- Most of the seeds won’t germinate.
- If seed dispersal is not there, we can’t see different plants in different areas.
- If seed dispersal is not there, we can see only a few plants in our surroundings.
How are the seeds dispersed in caltropis?
- Caltropis seeds are dispersed through wind.
- Caltropis seeds have light and hairy structure at one end.
- They travel with wind and settle at a suitable place to germinate.
Why do most of the coconut trees grow along the seashore?
- Coconut fruit floats on water and moves from one place to another.
- The outer covering of the coconut seed has empty spaces filled with air and are fibrous.
- This is the reason for coconut fruit to float on water.
- When the coconut fruit reaches ground it germinates there.
- That’s why usually coconut trees grow along the seashores.
Do you find any relationship between the weight of the seeds and the dispersal mechanism? Discuss with suitable examples.
- I find relationship between the weight of the seeds and the dispersal mechanism.
- For example: Seeds of caltropis.
a) These are light and have hairy structure at one end.
b) So they travel with wind and settle at a suitable place to germinate.
c) Milkweed, cotton seeds etc., are all dispersed by wind.
- Another example: coconut fruit
- a) The outer covering of the seed has empty spaces filled with air and are fibrous.
b) The coconut fruit floats in water and reaches the ground somewhere. There it germinates.
c) Seeds of lotus is another example.
- Another example: Neejn fruit.
a) Birds like Bulbuls, Mynahs, crows eat the outer fleshy part gets digested in the food canal and the seed coats of them become tender.
b) They are then dispersed to other places as bird droppings.
- Similarly animals, Human beings carry the seeds to other places.
Ravali said “Dispersal of seed is very important in nature”. Is she correct? Why do you support her?
Yes, It is correct I support her because
- The seeds of a plant should be dispersed to different places for the plants of the – same species to be grown there.
- As a result of this dispersal, there will not be competition for space, air and other nutrients between the mother plant and daughter plants.
- Plants Of any species will not be populated at one particular place but will be distributed to different places.
Collect the information in the following table and discuss the reasons.
|Agents of dispersal||Name of the seed / Fruit|
|By wind||Caltropics, Milk weed|
|By water||Coconut fruit, water plants|
|By animal||Seeds of grass plants|
|By bird||Neem fruits|
|By man||Tomatoes, sugarcane, wheat, pulses etc.|
|By any other||Bhendi, Mustard, Kankambaram|
Some seeds like soap nuts have very hard shell? Why is it so?
- Soap nuts will be transported to different places by any means.
- During the transport, the seed must be intact without any damage.
- Some birds may swallow it and come out as a dropping on the way of their flight. It is in a very hard shell, the seed is not damaged.
Nowadays people want to eat sprouts. List out the reasons why they take sprouts as food.
- Sprouts contain many nutrients needed for human body.
- Sprouts do not contain harmful contents that cause damage to the health of human beings.
- Sprouts give not only energy but also health to human beings.
- These are the main reasons for people to eat sprouts now-a-days.
Collect some seeds sow them in a particular place in your school garden. Observe how many days each type of seed takes to germinate. Tabulate your observations.
The student can do it.
Collect Tadi seeds and make a model. Display them in your School.
The student can do it with the help of the teacher.