Year 9 Science – Plants revision notes

A revision sheet & some quick summary notes to take for Year 9 Science – Plants topic! You can use these to study for your end-of-topic test, and to revise for the end-of-year exams!

Adaptations for certain plants to survive

Eg: Mangroves have saplings on the tree itself so that when they’re ready they just drop down into the sea. They already have a base root developed because they were prepared. This is what adaptation has shown us. This helps them so when they drop down they don’t get pulled out by the tide, but actually stick to the ground.

(When the mangrove seed drops, it is carried by the tide to another place so that its mother doesn’t ‘strangle’ it or take its food.)

How does photosynthesis work?

Photosynthesis is the process that plants go through to keep them alive. This is a part of their adaptation because without it, they would be dead as they have no other source of food, so they make their own using sunlight, carbon dioxide and water. The process of collecting what they need is: first they collect water using the little hairs on their roots, and the water gets transferred through a pipe inside the plant called the Xylem. They collect sunlight and the carbon dioxide in the air using their leaves. One of their adaptations is to open their leaves out for more surface area so they could absorb more sunlight. They have pores called stomata on the bottom of the leaves to absorb the carbon dioxide. These small holes operate by opening and closing so they lose minimal water. They then carry out ‘photosynthesis’ to make glucose. They use glucose as their food which they turn into energy to keep carrying out photosynthesis and respiration, and to store the excess glucose as starch in their roots, as they don’t use all of it in one go. Another way to put all this is that plants absorb light energy using the chlorophyll in their leaves, which also makes the leaves green. They use it to react carbon dioxide with water to make a sugar called glucose.

Process of Reproducing

Sexual reproduction in flowering plants involves the production of male and female gametes, and the transfer of the male gametes to the female ovules in a process called pollination (the process of the two parts forming creates a zygote). After pollination occurs, fertilization happens and the ovules grow into seeds within a fruit or a flower. Wind and water help the pollination process, but I would say that the animals pollinating helps this process the most. The birds and insects want to eat the sweet nectar, so when they land on a flower they put their head in it and get the sticky pollen caught on them, and when they go to the next plant the pollen comes off the animal and sticks to the stigma where it then eats travels down the pollen tube and the two gametes meet.

Seed dispersal

Helicopter (maple) leaves are really cool. They have an adaptation so that when the seeds in the leaves are ready they fall off the tree, because of how the leaves are shaped (they look like propellers) they fly around in the wind and don’t land directly under the dominant tree. They land far away from the adult tree so there is no competition between the two. Another one is the grapple leaf. The grapple leaf is as it sounds. Their dispersal method requires things like animals eg birds, dogs or even us humans to brush against them and they cling on to us as we transport the seeds, and they land wherever. Berry plants have an adaptation for dispersal too. They make yum berries to get the birds and/or animals eat them and because the little seeds in the berries are indigestible, when the animal excretes (poo) they release all the seeds. The poo also acts as a fertiliser in a way. This is also a way of transportation.

Sorry for the short summaries, started late on this topic but I will make sure to cover everything for your next topic. Enjoy the free notes!

Made by Andrew Mom


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