Pollination

1. Pollination

2. Pollination • Pollination is the transfer of pollen from the male anther to the female stigma.

3. Importance of Pollination • Sexual reproduction is important for evolution as it produces variable offspring, creating diversity and variation among populations (shuffling of genes). • Variation is required for Natural Selection to occur. • Sexual reproduction is advantageous to an organism only if it happens with someone other than itself!

4. Sexual Reproduction • In animals it’s easy because you have separate male and female individuals. • In flowering plants it’s not so easy, because most flowers have both male and female parts in them, called perfect flowers. • Flowering plants have evolved special ways to prevent inbreeding.

5. Function of Flowers • Flowers are designed to attract pollinators with colorful petals, scent, nectar and pollen.

6. Avoiding Self-Pollination • Timing – male and female structures mature at different times. • Morphological – structure of male and female organs prevent self-pollination (dioecious plants). • Biochemical – chemical on surface of pollen and stigma/style that prevent pollen tube germination on the same flower.

7. Methods of Pollination • Plants use one of two methods for pollination: • Wind Pollination • Animal Pollination

8. Wind Pollination • Gymnosperms and some flowering plants (grasses, trees) use wind pollination. • Flowers are small, inconspicuous and grouped together. • Not a very efficient method (too chancy and wasteful).

9. Animal Pollinators • Many flowering plants rely on animals for cross-pollination: • Insects – bees, wasps, flies, butterflies, moths. • Birds – hummingbirds, honey creepers. • Mammals – bats, mice, monkeys.

10. Pollen • The shape and form of pollen is related to its method of pollination… • Insect-pollinated specieshave sticky or barbedpollen grains. • Wind-pollinated speciesis lightweight, small andsmooth (corn pollen).

11. Co-evolution • Co-evolution involves a change in the genetic composition of one organism triggered by a genetic change in another. • Animal-flowering plant interaction is a classic example of co-evolution: • Plants evolve elaborate methods to attract animal pollinators. • Animals evolved specialized body parts and behaviors that aid plant pollination.

12. Bees • Beessee yellow, blue and UV light. • Flowers have developed “honey guides” and bee landing platforms. • Bees are the most important group of flower pollinators.

13. Butterflies and Moths • Also guided by sight and smell. • Butterflies can see red and orange flowers. • Usually shaped as a long tube because of insect’s proboscis – to get nectar. • Moth-pollinated flowers are usually white or pale, with sweet, strong odor – for night pollination.

14. Flies and Beetles • Flies like flowers that smell like dung or rotten meat. • Lay their eggs there, but larvae die due to lack of food. • Beetles pollinate flowersthat are dull in color, buthave very strong odor

15. Birds • Birds have a good sense of colour, they like yellow or redflowers. • Birds do not have a good sense of smell, so bird-pollinated flowers usually have little odor. • Flowers provide fluid nectar.

16. Mammals • Bats pollinate at night, so flowers are white. • Mouse-pollinated flowers are usually inconspicuous, and open at night.

17. Why Pollinate ? • Pollinators get a food reward for moving pollen to another flower. • Nectar– a sugary solution produced in special flower glands called nectaries. • Nectar concentration matches energy requirements of the pollinator: bird and bee pollinated flowers have different sugar concentrations.

18. Why Pollinate ? • Pollen – is high in protein, some bees and beetles eat it. • Flowers can produce two kinds of pollen: • Normal • Sterile but tasty

19. Getting Attention • Plants advertise their pollen and nectar rewards withcolours, scents and honey guides.

20. Plant Mimicry • Some plants take advantage of the sex drive of certain insects… • Certain orchids look like female wasps, and even smell like them! • Males try to mate with them,and in the process theypollinate the plant • The orchid gets pollinated,but the male wasp only getsfrustrated!

21. Plant Mimicry • Some plants take advantage of the sex drive of certain insects. • Certain orchids look like female wasps, and even smell like them.

22. Plant Mimicry • Males try to mate with them, and in the process they pollinate the plant. • The orchid gets pollinated, but the male wasp only gets frustrated.