Flower StructureObjectives:

*State the functions of different parts of a flower**Describe the structures of insect and wind pollinated flowers

*** Compare the adaptations of flowers and pollens of insect and wind pollinated flowers

Nectary

Sepal Petal Stamen Carpel

Protects the flower in bud

Bright colour and scent for attracting pollinating agents Many have nectary at base to make nectar for feeding insects.

Male organ. Anther is where the pollens Pollen is the male sex cell (gamete).

are made and the filament holds up the anther so the flowers can be pollinated easily

Female organ. Ovary contains the ovule s which has female gametes. Stigma is where the pollen lands, style connects the ovary to the stigma

Insect pollinated Wind pollinated

Petals

Nectaries

Stamen

Pollen

Carpels

Produces sugary nectar to attract insects

No nectary

Large brightly coloured and scented to attract insects

Small, green inconspicuous flowers , no scent

Anthers hang outside so wind can blow away large quantities of pollen

Made in large quantity as a lot can get wasted, smooth and light

Feathery long stigma positioned outside the flower which act as nets to catch as much pollen as possible

Sticky short stigma positioned inside the flower for insects to rub against it.

Sticky, spikey,

Anthers inside so insects can rub against them

Pollination

Objectives:*Define self and cross pollination**Name agents of pollination*** Discuss significance of self and cross pollination

1. Pollination occurs when pollen grains from the stamen land on the stigma of the carpel

2. Fertilisation occurs when the male sex cell in the pollen fuses with the female sex cell in the ovule

Sexual reproduction in flowersSexual reproduction in flowersSexual reproduction in flowersSexual reproduction in flowers

Sexual reproduction in flowers

Sexual reproduction in flowersSexual reproduction in flowersSexual reproduction in flowersSexual reproduction in flowers

Sexual reproduction in flowers

Self Pollination Cross Pollination

Advantages 1. No pollinating insects needed

2. Plants growing in isolation from others of the same species can still get pollinated

3. Well adapted to the same environment as their parents

4. Pollination is more successful

1. Variation due to exchange of genetic material

2. Dispersed away from each other leading to no intraspecific competition

3. Well adapted to change in environment due to variation upon which natural selection can operate

4. Well suited for evolution

Disadvantages 1. Very little variation unless there is a mutation which may not be expressed

2. Very limited chance of evolution

3. Intraspecific competition

1. Dependant on pollinating insects

2. Plants in isolation will not be able to reproduce

3. Pollination is a question of chance