2 Plant Reproduction Reproduction in Flowering Plants and Conifers The process of pollinationThe reproductive cells in these plants are the eggs and pollen produced at particular times of the year.The eggs remain on the plants. The pollen is transferred to the egg.
3 Strategies to ensure pollen transfer Because plants are fixed in one location they have evolved strategies to ensure their pollen grains are transferred.Pollen may be transferred by the following means;Insects (beetles, flies, bees, butterflies)Birds of many speciesMammals (bats, small rodents, honey possums)
4 Strategies to ensure pollen transfer Wind pollinationPollen of all conifers and some flowering plants is carried by the windPollen carried by the wind is small, smooth and very lightFlowering plants that are wind pollinatedDo not have brightly coloured flowersHave pollen producing organs (stamens) exposed to the windHave feathery stigmas to catch passing pollen grainsWind pollination is affected by climate
5 Strategies to ensure pollen transfer Most flowering plants are pollinated by insects, birds or mammalsAnimals that are the carriers of pollen are called vectorsFlowering plants attract and reward their vectors
6 Which vector? Insect-pollinated flowers Blue or purple or yellow as these colours are visible to insectsMay have a platform shape for landingMay have a scent to mimic something to attract an insect. Eg rotting meat
7 Which vector? Insect-pollinated flowers Usually have nectaries inside the flower producing sugar-rich nectar attracting insectsOften have ultraviolet reflecting white or yellow dots or lines to signal the presence of flowers (insects can see UV radiation)
8 Which vector? Insect-pollinated flowers Stamens are often arranged to that insects must push through them to reach the nectariesThe pollen grains are often larger than wind pollinated flowers and sticky
9 Which vector? Insect-pollinated flowers Flowers pollinated by nocturnal insects often have a strong scent to attract; this scent is strongest at night. Eg Grevilia Leucopteris (smelly socks)Some flowers mimic the shape of the female of the insect species to attract
10 Which vector? Bird-pollinated flowers Often red or orange or yellow – these colours recognised by birds as suitable sources for foodGenerally not scented – vision not smell importantOften petals form a tubular shapeUsually have nectaries inside the flower at the base
11 Which vector?When birds access the nectaries they dislodge the pollen from the stamen inside the floral tube and it coats the back of their head
12 Dispersing plant offspring In flowering plants and conifers spread of the next generation of plants occurs through a seed (embryo resulting from fertilisation of egg by pollen)In flowering plants the seeds are enclosed by fruitIn conifers the seeds are naked.
13 Dispersing plant offspring Seeds or fruits may move or be moved by;Sailing in the windDrifting on water currents (water proof coat)Hitchhiking on animals (hooks or spines to attach)Hitchhiking in animals (bright coloured berries, etc. Eaten – resistant to digestive enzymes)