Class 7 Science - Chapter Reproduction in Plants NCERT Solutions | Describe the various ways by which seeds
Describe the various ways by which seeds are dispersed.
Seed dispersal takes place by various agent that is responsible for cross pollination; and this means to scatter seeds over a large area. The seeds of some of the plant disperse as seeds and some are dispersed in the form of fruits because they contain seeds inside them. There are various methods of seed dispersal that have been categorised into two main categories: Abiotic (like wind, gravity, water etc.) and Biotic (animal pollinators like insects).
Anemophily (wind pollination): It is the mode of transfer of pollen grains from anther to stigma through the agency of wind. The flowers that are wind pollinated are anemophilous. These flowers contains some adaptations like flowers are colourless, odourless and nectar-less; pollen grains are small, dry, dusty and sometimes saccate so that they can blow away easily to the long distances etc.
Hydrophily (water pollination): It is the mode of transfer of pollen grains from anther to stigma occurs through the agency water. The flowers that are water pollinated are hydrophilous flowers. These flowers contains some adaptations like flowers are small, colourless, odourless and nectar-less; pollen grains are unwettable, stigma are long and sticky etc. Dispersal by water takes place in some aquatic plants which is very rare and in some that grows near a water body. For example: Zostera, Hydrilla, Ceratophyllum etc.
Entomophily (insects pollination): It is the animal pollinator or biotic category in which the transfer of pollen grains from anther to stigma occurs through the agency of insects. The flowers that are insect pollinated are entomophilous flowers. These flowers contains some adaptations like flowers are usually large, brightly coloured and slowly to attract insect pollinators etc. The most common insect pollinators are as follows: moths, flies, butterflies, bees, beetles etc.
Dispersal by Humans: Human beings also help in dispersal of seeds during the farming.
There are much more methods for the dispersal of seeds like Ornithophily (pollination by birds), Chiropterophily (pollination by bats) etc.
More Questions From Class 7 Science - Chapter Reproduction in Plants
- Q:-
Sketch the reproductive parts of a flower.
- Q:-
Match items in Column I with those in Column II:
Column I Column II
(a) Bud (i) Maple
(b) Eyes (ii) Spirogyra
(c) Fragmentation (iii) Yeast
(d) Wings (iv) Bread mould
(e) Spores (v) Potato
(vi) Rose - Q:-
How does the process of fertilisation take place in flowers?
- Q:-
Describe the different methods of asexual reproduction. Give examples.
- Q:-
Explain the difference between self-pollination and cross-pollination.
- Q:-
Explain what you understand by sexual reproduction.
- Q:-
State the main difference between asexual and sexual reproduction.
- Q:-
Tick the correct answer:
(a) The reproductive part of a plant is the
(i) leaf (ii) stem (iii) root (iv) flower(b) The process of fusion of the male and the female gametes is called
(i) fertilisation (ii) pollination
(iii) reproduction (iv) seed formation(c) Mature ovary forms the
(i) seed (ii) stamen
(iii) pistil (iv) fruit(d) A spore producing plant is
(i) rose (ii) bread mould
(iii) potato (iv) ginger(e) Bryophyllum can reproduce by its
(i) stem (ii) leaves
(iii) roots (iv) flower - Q:-
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
Popular Questions of Class 7 Science
- Q:-
State similarities and differences between the laboratory thermometer and the clinical thermometer.
- Q:-
State differences between acids and bases.
- Q:-
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food - Q:-
Name the elements that determine the weather of a place.
- Q:-
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———. - Q:-
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants - Q:-
Why does an athlete breathe faster and deeper than usual after finishing the race?
- Q:-
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates - Q:-
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge. - Q:-
Why do organisms need to take food?
Recently Viewed Questions of Class 7 Science
- Q:-
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge. - Q:-
Will the compass needle show deflection when the switch in the circuit shown by Fig.14.24 is closed?
- Q:-
Why is blood needed by all the parts of a body?
- Q:-
What is meant by the following terms?
(i) Rearing (ii) Shearing (iii) Sericulture - Q:-
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
- Q:-
A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(i) 100 km (ii) 25 km
(iii) 15 km (iv) 10 km - Q:-
Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, _________. - Q:-
Draw a diagram of the human excretory system and label the various parts.
- Q:-
Fill in the blanks:
(a) Cleaning of water is a process of removing ____________.
(b) Wastewater released by houses is called ____________.
(c) Dried ____________ is used as manure.
(d) Drains get blocked by ____________ and ____________. - Q:-
Study the following statements about ozone:
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its proportion in air is about 3%.Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four
- All Chapters Of Class 7 Science
- All Subjects Of Class 7