Plants and Flowers Around The School

Flowers are colourful and have a sweet scent to attract insects. Some of the leaves have larger surface areas than others. Moreover, some plants are able to live in water.

Photo Credit: Michelle :)

Fruit + Seeds / Dissection of an Apple

- After the seeds have fertilized, they either become a seed pod or a fruit in order to reproduce.

 Dissection of an Apple:

- Apples are the colour red because of the need to attract animals. 

Animal eats the apple --> The seed remains in the animals system --> The animal "does its business" and inside the poo lies the seed --> The seed starts to grown again after some time.

 Example of Seed Pods:

 Example of Fruits:

3.4 Plant Fertilisation

- The pollen grains germinate: a tube begins to grow downwards. (note: the pollen tubes will only complete if they are from the same species)
- The tube goes all the way down and around into the yellow ovule
- Traveling down the pollen tubes are the male nucleus which goes into the ovule
1. Pollen nucleus will fertilise the ovule --> formation of Zygote and this will grow into the embryonic plant.
2. Outside the ovule forms the Testa (seed coat).
3. Formation of cotyledons = food stores for the seedling which will support the plant until it develops its first set of leaves.
4. Plant will put a lot of energy (sugars, protein) into the walls of the ovary / carpel. It will build up and form the fruit.

Dissection of a Lily

Carpel:

• Ovary - contains eggs called ovules 
• Style - connects the ovary to the stigma
• Stigma - where pollen grains fall

Stamen:

• Anther - contains and produces pollen
• Filament - supports the anthers

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• Petals - bright and colourful to attract the insects
• Sepals - adapted to look like petals to increase the chances of insects being attracted to the flower. 

3.3b Wind Pollination

- Wind pollination = the transfer of pollen from the anther to the stigma through air carried by the wind
- adaptation:
        - light weight pollen grains (e.g. wing feature)
        - anthers will hang clear from flower structure = sticking out so that they are exposed to the wind
        - stigmas will be exposed, have a large surface area (feather-like structure) to catch the pollen grains as they pass            through air on the wind and caught onto the stigma structure.
        - no colour is needed to attract the insects, no scent, no nectaries

3.3a Insect Pollination

- Process of pollinating flower = there has to be a transfer of pollen (pollen - small structure containing the male nuclei) from the anther to the stigma of another flower
- The transfer of this takes place by insects. Therefore, necessary for the first flower to attract the insect
- When pollen goes from one plant to another = cross pollination
- adaptation to attract insect:
     - signals: colour petals, scents
     - value: food = nectaries / fructose, pollen (as protein)
- stamen = male part of the plant composed of the anther which produces the pollen grains
- anther and filament form the stamen
- female part: stigma - where pollen grains fall, style - connects stigma to ovary, ovaries - which contain eggs called ovules.
- The whole female structure is called the carpel
- The stamen is the male part