To succeed in the SAT’s you must know the following about plants: The three main parts of a plant Photosynthesis Flowers and fertilisation Seed dispersal Pollination Conditions for plants to grow Germination Lifecycle of a plant
Plants and trees have three main parts: 1. Head/Leaves 2. Trunk (trees) or stem (flowers) 3. Roots
Starting at the bottom: ROOTS This is the part of the plant that anchors (fixes) it into the ground so that it doesn't fall over. The roots also absorb water and minerals from the soil.
The water and nutrients are then transported up through the roots. Roots grow underground and seek out water and nutrients.
Stems have four main functions which are: The Stem / Trunk 1. Support for the leaves, flowers and fruits. -Without the stem / trunk the plant would not stand up against the wind and all of the leaves, flowers and fruits would be stuck on the ground.
The Stem / Trunk 2. The stem carries water and minerals from the roots to these parts. This is the part of the plant that links the roots to the leaves and flowers.
The Stem / Trunk 3. The stem allows access to sunlight The stem / trunk pushes the leaves, fruits and flowers towards the sunlight ready for photosynthesis
The Stem / Trunk 4. The stem stores water and nutrients for the plant to use later. -This is to you storing food in your stomach.
The head of the plant is often either: Leaves or Flowers …or both!
The Leaf • Catching and storing rain water • Photosynthesis (Click here for an explanation) Back to leaves and flowers
Photosynthesis is when plants create oxygen so that we can breathe! It’s like a big recipe. Ingredients: Sunlight (caught by the leaves), Water (caught by the roots and leaves) Carbon Dioxide (a gas in the air caught by the leaves) The plant takes these “ingredients” and makes: Oxygen (So that we can breathe!) and Glucose (A sugary food that the plant eats) That’s photosynthesis!
PHOTOSYNTHESIS Just remember… + CARBON DIOXIDE + (Gas) (Water) (Sunlight) =
Photosynthesis creates: Back to contents page Back to leaves and flowers GLUCOSE OXYGEN This is a sugary food that the plant eats. It is the only living organism on this planet that makes food for itself. This is why it is at the beginning of every food chain! This allows us all to breathe. Can you see why plants are important now?
Flowers Stigma Stamen Petal Back to contents page To pollination
Boys only! Boys only! The Stamen TheMALEside of the flower that growspollen. Boys only! Boys only!
Anther Pollen pieces Filament The Stamenis the male part of a flower. Each stamen generally has a stalk called the filament, and, on top of the filament, an anther. The anther holds lots of pollen. Go back to flower
The Stigma Girls only Girls only The FEMALE part of the flower where the pollen needs to get to! Girls only Girls only
Go back to flower Style: If pollen passes through the style and to the ovary a seed will start to grow. Found in the middle of the flower thestigma is sticky and catches pollen and is connected to a tube called the style which leads downwards to the plantsovary. If pollen enters into the ovary a seed will start to grow. This is known asfertilisation. Stigma Ovary
Petals do a similar job to leaves. They catch rain and sunlight. They are also bright sweetly scented and attract insects to them. Back to flower Flower Petals Continue
SEED DISPERSAL Seed dispersal happens when seeds are spread out over a wide area so that all of the new plants have enough room to grow. • Seeds are dispersed (spread out) in four different ways: • Animals • Explosion • Water • Wind Back to contents page Why is seed dispersal important for plants?
Back to seed dispersal Some seeds are dispersed by explosion. Peas have a seedpod that dries and splits, flinging the seeds over a wide area.
Back to seed dispersal Some seeds are dispersed by the wind. Grasses have fine, light seeds with 'whiskers' that are blown long distances by the wind.
Back to seed dispersal The seeds are dispersed by water. Coconuts have a thick outer coat and are designed to float in water
The seeds are dispersed by animals. Seeds are dropped far away from the parent bush. Holly has brightly coloured fruit to attract birds that eat them. Some seeds stick onto passing animals and later fall off. Insects such as ants can carry seeds away from trees. Back to seed dispersal
What if the seeds were not spread out? • As plants grow above the ground so do the roots in the soil. This is not good for two reasons: • There will not be much space for the trees and their roots will become tangled. • Each tree will be fighting for the water and nutrients in the soil. Most of the trees will not be able to find enough water and will starve. Back to seed dispersal
Pollination is where pollen travels from the stamen to the stigma Who helps flowers become pollinated?
Some plants are pollinated by insects. The large colourful petals and the nectar attract insects to the flowers. The plant's pollen then sticks to the insects and they carry it to the next plant they visit. Back to contents page
Leaves grow towards sunlight -How a seed “grows up” to become a plant. Stem develops Seed Roots develop
Germination A seed becoming a plant Back to contents page
The life cycle of a plant Back to contents page
Plants don't grow well if they don't get the right raw materials. If any of these raw materials are not included the plant will turn yellow and then wilt and die.
A plant is so clever it will grow to where ever sunlight is. Back to contents page