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00:00Hi kids! Today we will learn various means of seed dispersal. So let's start!
00:10Kids, we learned that pollination is a process by which pollens are transferred
00:17from the anther, that is the male part of the flower, to the stigma, which is the
00:23female part of the flower, and thereby enabling fertilization and reproduction.
00:31Now let's see how pollination occurs or how pollens reach stigma. There are
00:39several ways by which pollens can reach stigma of carpel. It can be through
00:46insects, bees, animals, birds, wind, or even water. The process by which pollens,
00:57after reaching the stigma of pistil, reaches the ovules present in ovary is
01:03called fertilization, which leads to the formation of seeds. And these seeds are
01:11sown in mud to grow new plants. In our garden, we sow seeds of different plants
01:21to grow non-flowering plants, flowering plants, and fruit trees. When a seed is
01:29sown, it requires enough sunlight, mineral, salts, water, space, and air to grow into
01:39a new plant. If many seeds are sown at the same place or close to each other,
01:47there would be a tough competition among seeds for necessities, that is soil, water,
01:56space, mineral, salts, and sunlight. And the strongest or fittest seeds win the
02:06fight for survival or the fittest seeds would grow. Examples? Many seeds fall from
02:13the trees and there begins a competition among the seeds and even between seeds
02:20and the parent tree for soil, water, space, mineral salts, and sunlight. So, plants
02:30need to produce a large number of seeds as all seeds will grow into new plants.
02:36Only a few ones will grow into new plants. Some seeds are eaten away by birds or
02:45animals. Some are destroyed by wind or rain. Some seeds are even eaten by human
02:53beings. So, seeds need to spread as far as possible from the parent tree or plant
02:59and also at places where there's enough space for the seed to germinate or grow.
03:05And this process of spreading seeds away from the parent plant is called seed dispersal.
03:14There are many means of seed dispersal. Let's learn about them.
03:21Wind. Some plants have very small and lightweight seeds. Such seeds are spread
03:31or dispersed by wind. Small and light seeds fly away with wind to distant places. Seeds
03:39can float on the breeze or alternatively they can flutter to the ground. The classic examples
03:47of these dispersal mechanisms include dandelions, which have feathery pappas attached to their
03:54seeds so they can disperse to very long distances. Maples, which have winged seeds,
04:04flutter to the ground. An important constraint in case of wind dispersal is that a lot of seeds
04:13must be produced by the plant. As likelihood of a seed landing in a site suitable for germination
04:21is very less. Water. Many aquatic and some terrestrial plants use seed dispersal through
04:30water. Seeds can travel for extremely long distances depending on the specific mode of
04:38water dispersal. The water lily is an example of such a plant. Water lilies flowers make a fruit
04:50that floats in the water for a while and then drops down to the bottom to take root on the
04:57floor of the pond. The seeds of the palm trees can also be dispersed by water. If they grow near
05:06oceans the seeds can be transported by ocean currents over long distances allowing the seeds
05:14to be dispersed as far as other continents. Mangrove trees live right in the water. Their
05:24seeds fall from the tree and grow roots as soon as they touch any kind of soil. During low tide
05:32they might fall in soil instead of water and start growing right where they fell. If the water level
05:41is high however they can be carried far away from where they fell and the mangrove trees often make
05:49little islands as dirt and other things collect in their roots making little bodies of land.
05:56Animals can disperse plant seeds in several ways. Seeds may get attached to animal fur. Birds and
06:06animals can consume seeds which are dispersed by means of waste removed from their body. Birds and
06:14mammals are the most important seed dispersers but a wide variety of other animals including
06:21turtles and fish also can transport seeds. Ants. Ants carry seeds into their colonies and feed on
06:31some of them and leave some seeds in an underground chamber and there they can germinate into new
06:38plants. So there is a relationship between animals and plants. Plants provide food to animals and
06:48animals help disperse the seeds of plants to distant and different locations and help them
06:55grow into new plants. Many rodents such as squirrels and rats may also disperse seeds by
07:04hoarding the seeds in their hidden holes which remain well protected from other seed predators
07:10and some are left uneaten and grow into new plants. Humans may disperse seeds by various
07:20means like seeds may get attached to human clothes, shoes, and vehicles and get transported to distant
07:29locations. In some plants seeds are spread by popping open their fruits suddenly. When they
07:38are ripe that is fruits explode suddenly when they are ripe and this explosion spreads the
07:45seeds away from the parent plant to distant locations. Examples. Peas. The pea suddenly
07:55splits open violently and makes the seeds fly out of the pod in all directions. So kids today we
08:04learned a lot about how plants disperse or spread their seeds to distant locations in order to grow
08:12new plants and how animals and plants depend on each other and how water and wind too helps
08:21plants disperse their seeds. Now you may go ahead and take a quiz to learn more. Bye-bye!