The above is a labelled diagram of an insect pollinated flower. You can tell that it is pollinated by an insect because of the large petals. In reality it would probably have a bright colour, pleasant smell and nectar to attract the pollinator.
What do all the bits do?
The anther and filament together are called the stamen. They are the male part of the flower.
The stigma, style and ovary are jointly called the carpel (or pistil). This is the female part of the flower.
The anthers produce pollen. The pollen contains the male gamete or sex cell.
The ovary contains the egg. This is the female gamete.
Pollen from one flower must come into contact with the stigma of another flower of the same species. This process is called pollination.
When the male and female gametes join (or fuse) we say that the flower has been fertilised.
The male and female gametes fuse to form the zygote. This develops into the embryo.
When a flower has been fertilised the stigma, style, stamens and petals fall off so that the plant can put all of its resources into developing the fruit.
The pollen can be transferred from flower to flower in two different ways.
By wind as in grasses or ragweed
By animals such as bees or hummingbirds
.
The fruits need to be dispersed so that the new young plants don’t compete with their parents for nutrients in the soil, light and space.
Seeds can be dispersed in a variety of ways. For example…
By birds or other animals eating the fruit and egesting the indigestible seeds (eg cherry)
By the wind blowing the seeds (eg dandelion)
By water (eg coconut)
By explosions (eg Himalayan balsam)
.
Questions…
- Suggest one way in which a wind pollinated plant may differ from an insect pollinated plant.
- Why do insect pollinated plants produce less pollen than wind pollinated plants?
- What three conditions are usually necessary for seeds to germinate?
- What is the function of (a) xylem and (b) phloem?
- Himalayan balsam is an “invasive non-native plant” in the UK. Name another example of an invasive species (can be from anywhere in the world).
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