Question

Read the following about the agents of seed dispersal.
a. Xanthium and urena by animals
b. Drumstick and maple by wind
c. Groundnut and areca nut by birds
d. Madar and sunflower by insects.
Select the alternative which includes all the correct statements.
A. a and b
B. a and c
C. c and d
D. b and c

Answer 1

Hint:- Seed dispersal is the process of dispersal or transport of seeds from the parent plant. As the plants are fixed at a place by roots, so their movement is limited. Therefore, seed dispersion requires different methods.

Complete Answer:-
In seed dispersion, propagules are transported mainly through two ways known as biotic and abiotic vectors. The abiotic vector includes non-living medium for seed dispersion such as wind, while the biotic vectors include living medium for transport of seed such as insects, birds, and animals. There are five modes of dispersion of seeds i.e. water, gravity, ballistic, wind, and animals.
The dispersion of seed involves detachment of the diaspore from the parent plant body. Dispersal of seed by wind is a primitive method in which seeds float with the wind and thereby, reach the ground. The most common examples of wind dispersion are dandelions, drumsticks, and maples, in which the seeds are winged or feathery.
The dispersion of seeds by animals occurs mostly through mammals. For dispersal through animals, seeds have hooks, spines, mucus, or barbs on their outer surface to get attached to the animals. Common examples of seed dispersal through animals are Urena, beggar tick, and Xanthium.

Thus the correct option is (A) a and b.

Note: For dispersion of seeds through the wind, the seed should have some characteristic features such as the seed should be light-weight or winged so that it can float with the wind to travel long distances. This adaptation of seeds to be dispersed by wind is known as anemochory. Similar to this, for dispersion of seed through animals, seeds are modified in their structure, such as spiny. These adaptations are known as zoochory.