Post on 29-Jan-2023
SESSION 2020-21 CLASS 5 SCIENCE
Chapter 1
Plant Life
Introduction:
Plants are one of the most essential living organisms on the earth.
They are immensely beneficial to both animals and human beings.
All living things have a limited life span, therefore to continue
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their existence they produce their own kind and multiply in
number.
Reproduction:
Plants mainly reproduce through seeds. Besides many plants also
reproduce through other parts such as stem eg. Potato, ginger,
root eg. Sweet potato, leaves eg. Bryophyllum.
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I. Outer covering of seed called see-coat
II. Inside seed coat one or two cotyledons are present.
III. Between these cotyledons a baby plant (embryo) is
present.
Cotyledons store food
utilized for growth. Two types of seeds are there dicot eg. Gram
and peas and monocot seeds eg. Maize seeds.
Germination:
In favourable condition i.e water, air temperature, seeds, grow
in young plants called sapling.
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Dispersal of seed:
Seeds scattered or spread across to get enough sunlight , air ,
nutrients , and space to grow into saplings . This process is
called dispersal of seeds .
Seeds disperse through air , water , animal or explosion .
Wind :
The seeds i.e. light in weight and have hairs or wings and are
carried away easily by wind ex - Cotton , hiptage ,madar
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Water :
Plants that grow along river banks or seas are dispersd by
water as these fruits contains fibrous outer covering or husk , or
spongy and can be easily carried away by water ex – coconut ,
lotus
Animals :
Some seeds and fruits have hooks or spikes and they stick to
animals body . ex – Xanthium , speargras
Birds eat fruits and drop some part to ground that later
germinates – Guava , apple
Explosion :
Some fruits like okra, pea become dry and burst. This causes the
seeds scattered away in all directions.
Agriculture:
Growing crops on large scale for commercial use. Plants which
grown in fields for food and raw material are called crops. These
are of two types Kharif crops and Rabi crops.
Farmers must follow certain methods to get good yield as quality
of seed, type of soil, climate, use of fertilizers, manur, nutrient,
pesticides, insecticides at different stages, and removing weeds
etc. After harvesting grains should be properly stored.
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Flow chart of agricultural practices
Exercises:
Fill in the blanks :-
1. Coconut is dispersed by water .
2. Seeds germinates and grow into a seedlings.
3. Mustard and sesame are oil producing crops.
4. Seeds of Cotton and hiptage plants are dispersed by wind.
Write true or false :-
1. Sweet potato grows through stem cutting. Flase
2. All plants can reproduce through seeds. False
3. Weeds are unwanted plants which grow along with the crop.
True
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4. Insecticides and pesticides are sprayed after crops are
harvested. False
Short answer type question :-
Q.1. Define the term.
1. Reproduction- The process by which living things produce
young ones of their own kind.
2. Agriculture- Method of growing crops on large scale for
commercial purpose.
3. Transplantation- Process of transferring the seedlings from
nursery to main fields.
4. Dispersal of seed- The process of spreading seeds to different
location away from mother plant by various agents.
Q.2. What are the three main parts of seeds?
Ans. The three main parts of the seed are seed coat, embryo, and
cotyledons.
Q.3. What is germination? Name three conditions needed for
germination.
Ans. The process of transformation of a seed into a seedlings.
Proper amount of water, air and temperature are the conditions
needed for germination.
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Large answer type question :-
Q.4. Why is dispersal of seed necessary? Write names of agents
of seed dispersal.
Ans. Dispersal of seed is necessary to provide seedlings enough
sunlight, air, nutrients and space to grow.
Agents that help in seed dispersal are:
1. Wind – Cotton, hiptage
2. Water – Coconut, lotus
3. Animals- Xanthium, spear grass
4. Explosion – Pea, okra
Q.5. Differentiate between Kharif and Rabi crops.
Ans. Kharif crops- Crops which grow in summer season are called
Kharif crops ex- Rice , maize , jowar , bajra
Rabi crops -Crops which grow in winter season are called Rabi
crops ex- Wheat , peas , mustard
Q.6. Write few points of obtaining good and healthy crop.
Ans. Farmers can grow healthy crops by following certain tips ;
1. Seed must be of good quality .
2. Proper distances should be maintained between seeds while
sowing.
3. Adequate amount of water , manures and fertilizers should
be provided at different stages.