Science Living Things and Their Habitats Year One
Science Living Things and Their Habitats Year One Science | Year 5 | Living Things and Their Habitats | Making New Plants 1 | Lesson 1
Aim • I can describe how some plants reproduce. Success Criteria I can identify the function of the parts of a flower. I can describe ways that plants are pollinated in order to reproduce.
Reproduction In this lesson, you will learn more about sexual reproduction in plants. Living things that use this type of reproduction have cells called gametes. These are split into male gametes and female gametes. In some living things, the male and female are separate, but in other living things one organism contains both male and female gametes. In plants, the male gametes are contained in the pollen and the female gametes are called ovules. When a male gamete and a female gamete join it is called fertilisation. Sexual reproduction produces offspring that are similar to both parents, but not identical to either.
The male part of the flower is the stamen. This is made up of the filament and the anther. The anther is where the pollen is produced. The female part of the flower is the carpel. This is made up of the stigma, the style and the ovary. If pollen lands on the stigma, travels down the style and arrives in the ovary, a new seed will be produced. This is called FERTILISATION
How does the pollen get to the stigma? This process is called POLLINATION
Insects in Pollination • Insects don't pollinate on purpose; it's just something that happens as they collect nectar from flowers to feed on. Insects are incredibly important when it comes to pollination. Here are some facts to prove it: • Honey bees account for 80% of all insect pollination. • Nearly all chocolate relies on midges pollinating the cocoa plant, which might make them seem slightly less annoying!
The Pollination Process 1. The flower petal’s bright colours and fragrant scents attract insects. 1. The insect arrives on the flower to collect nectar. This nectar is a sweet liquid which makes perfect insect food. 1. As the insect is gathering the nectar, it rubs against the anthers, which rub pollen onto the insect. 1. After the insect is done feeding on the flower’s nectar, it gets hungry and gets attracted by another flower`s bright colours.
The Pollination Process 5. As the insect feeds on the nectar in this new flower, the pollen stuck to the insect from the first flower rubs off onto the female parts of the second flower (the stigma). 5. Part of this pollen travels down the style and then into the ovary. 5. The tiny piece of pollen joins onto an ovule in the ovary. The plant has now been fertilised. 5. The ovary of the flower turns into seeds which will then be dispersed so that new plants will be able to grow somewhere else.
Wind Pollination • While some plants use insects to help them transport their pollen, others rely on wind. These plants are usually less colourful as they do not need to attract insects. The wind carries pollen from one plant to another. Rice is an example of a wind-pollinating plant. • This is a less coordinated way of pollinating, as it relies on a huge amounts of pollen being blown in any direction, depending on the wind. • Wind pollinating plants can cause some people to experience hay fever during the spring and summer due to the large amounts of pollen in the air.
Self Pollination • Some plants self-pollinate. They transfer the pollen grains from the anther to the stigma on the same flower. These plants do not need a pollinator, such as an insect, in order to reproduce. • Only a few plants self-pollinate. Examples include peanuts, orchids, peas and sunflowers.
Insect or Wind? In pollination, pollen from the stamen is transferred to the stigma. A pollen tube then grows down through the style to the ovary. The pollen travels down the pollen tube and fuses with an ovule in the ovary. This is fertilisation. Although flowers contain both the male gametes (in pollen) and the female gametes (ovules), most plants cannot fertilise themselves. They rely on other ways of transferring the pollen to the stigma; this starts the pollination and fertilisation process. Two ways that flowers can be pollinated are by insect or by the wind. Learn the parts of the flower.
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