BIO PHOTO TIME :D

to attract insects

height difference:

nectar to attract insects

 phototropism

Apple :)

worked with Qing

soure: qinglovesbiology.blogspot.com

3.4

3.4 Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation

Pollen grains land on the stigma. Tubes grow down the plant and it is species specific, which means that the pollen would germinate only if it lands on the same kind of plant. They grown down to the ovule.

1)     The male nucleus travels down the pollen tube into the ovule à fertilisation. It forms the zygote, which grows into an embryo.

2)     Outside the ovule is the testa, the seed coat.

3)     Inside the ovule is the cotyletons, the food store for the seedlings. The food is supplied until the first leaf grows.

4)     The wall of the ovary thickens (lots of energy is put into this). It contains sugar and protein. This turns into the fruit of the plant.

Lily VS Grass

Adaptation: structure enables function, efficiency

- Sepals à Petals à Stamen à Carpel

GRASS

- Plants invest to produce more pollens

- Risky reproduction strategy

- Feathery stigma à large surface area

- Pollens: large surface area, light, wing like features

- The grass is not investing energy in making nectarine guide lines and scent. Save energy

LILY

- Plants invest to attract insects:

  - The lines in the petals that bees can see: nectarine guide

- Scent: chemical travels to bring the bee to the flower

- Sepals mutated to look like petals à greater chance of attracting more insects (bright, colourful, we are assuming that insects see colour)

Vector for pollination is the wind, insects…etc

Water, bird, animals,

3.3b

3.3b Describe the structures of a wind-pollinated flower and explain how it is adapted for pollination

Wind-pollinated flower

Once again, pollen needs to be transferred from the anther to stigma, but this time by wind (air).

Adaptations:

- Pollen grains are lightweight with some kind of wing features so that they can move throug the air more efficiently.

- Anthers will be exposed to the wind.

- Stigma has a large surface area, featherlike structure to catch the pollen grains as they pass through the air

- The petals have no colour in petals, no scent and no nectarine because there is no need to attract insects. This is a waste of energy for grass.

3.3a

3.3 Describe the structures of an insect-pollinated flower and explain it is adapted for pollination

Insect-pollinated flower

Pollen needs to be transferred from the anther to another flower’s stigma.

Pollen is a small structure that contains the male nuclei.

This transfer takes place by insects.

It is important for the first flower to attract insects and have a reason to go to the second flower.

Pollen transfer from one plant to another: cross pollination

In a single flower, there are other ways to attract insects:

1)     Signals to the insects: coloured petals, scents – insects detect the molecules and are attracted

2)     Value to the insect going to the flower: food – nectarine à fructose and pollen itself

Stamen: male part of the plant – anther, filament. The stalk underneath the anther is filament. The anther produces pollen grains.

Carpel: Female part – stigma (pollen grains fall here), style (connects stigma to the ovary), ovary (contain eggs – ovules)