Grade Six Science
Hello Boys and Girls!
How are you and your studies coming along? Continue doing lots and lots of revision. It helps in the raising of your level of performance.
What did we look at last week? Do you remember? We looked at different types of fruits. Did you use lots of fruits during the past week? Fruits are so good for you. Name two vitamins that we can get from eating fruits.
Now let’s find out how seeds are dispersed or scattered. Discuss your thoughts on this topic with a friend.
Seed dispersal is the movement or transport of seeds away from the parent plant. Plants need to disperse seeds away from themselves to stop overcrowding and to create new sets. The seeds have different ways of being dispersed as you found out. Here are some ways in which seeds are dispersed:
Wind: Some fruits are adapted to catching the wind and the seeds being blown away.
Water: Some fruits are waterproof and can float. Coconuts, palm tree seeds and mangrove seeds are examples.
Animals: Lots of fruits are liked by animals. When an animal eats these fruits the little seeds are not digested, and pass through the animal unharmed.
Bursting: Some fruits suddenly burst open, throwing the seeds in all directions. This is also known as explosive mechanism. Peas are an example.
Humans: Humans also deliberately distribute seeds.
Shaking: When it is windy some plants shake and the tiny seeds are thrown out through tiny holes.
Catching a lift: Some fruits have tiny hooks on them. These little hooks catch on passing animals if they brush against the plant, and get carried away.
Drop and Roll: The casing of the fruits split when they land on the ground. The fruit then rolls away from the tree.
Look carefully at the pictures below.
Now what happens to those seeds after they have been dispersed? That’s the big question. I’m sure that you know the answer.
I know you have done this many times in your various classes. Yes, for germination to occur, the seed must have
- water / moisture - sunlight/ warmth - air
Germination is the process whereby a seed develops into a young plant.
Did you observe the following stages? ● The seed swells: It takes in water. ● The seed coat bursts, ● The radicle pushes through the seed coat into the soil.
● Primary roots begin to develop. The cotyledons are rising above the ground.
● The seedling that is emerging begins to straighten out. ● Primary leaves begin to unfold. The stem gets stronger.
● The tree leaves completely emerge and the cotyledons eventually dry up and fall off.
Let’s look at pictures of the stages of germination that you can see below.