Sexual reproduction • The mixing of genetic material from two parents to produce offspring • Offspring are genetically different from parents
Plants • Flowers are the sexual reproductive structures in plants
Lily flower • Ecological strategy: • Insect pollinated flower targeting bees in particular
Lily advantages The reward and display make it very likely that pollen from one lily plant will reach another lily plant
Lily flower • Draw flower, note projections and markings on petals.
Lily flower • Stigma protrudes in front of stamens so insect touches stigma and deposits pollen from another flower first!
Adaptations for pollinator • Spikes on petals force pollinator past anthers on way to nectary
Adaptations for pollinator • Stigma is above anthers so pollinator deposits pollen from another flower before it gets pollen from this flower
Adaptations for pollinator • Anthers are large so pollen eating bees won’t destroy them, enough pollen for bee and cross pollination
Adaptations for pollinator • Highly scented nectar because bees have a good sense of smell.
The flower at the right shows how UV markings may guide insect to nectary past anthers
disadvantages • Huge energy cost (nectar and showy flower) • Insects can’t fly in bad weather • Relies mainly on bees so if they become extinct then no cross pollination.
Adaptations for environment • Grow in sheltered environments • Bloom in warm season spring or summer • Petals won’t get ruined by wind • Cold blooded insects need warmth to fly • Bees can’t fly in windy weather, bad weather • Longer days for more time to pollinate
Your turn - Questions • Describe the difference in function between the sepals and the petals. • The Stamen is the male reproductive structure consisting of the anther and the filament, Describe how the pollen in the anther may get distributed. • Describe two ways a flower encourages cross pollination from a bee or bird. • Describe why there is some distance between the stigma and the ovary. • Name some adaptations angiosperms have made to increase their chance of survival. • Name some disadvantages of the way angiosperms reproduce.
Answers • The sepals protect the young flower bud whereas the petals are to attract pollinators. • Wind blows pollen from the flowers anther to other flowers stigma. • Bees or other animals such as birds collect nectar and in the process transfer pollen to other plants. • The nectar in flowers smell good to attract animals that assist in cross pollination
Answers-Adaptations • Spikes on petals force pollinator past anthers on way to nectary. • Stigma is above anthers so pollinator deposits pollen from another flower before it gets pollen from this flower • Anthers are large so pollen eating bees won’t destroy them, enough pollen for bee and cross pollination • Highly scented nectar because bees have a good sense of smell • The flower has UV markings that guide the insect to the nectary past the anthers • Pollen is spikey to stick to insect hairs
Answers cont.. • The bees love nectar so encourage them to come back to the flower and pollinate it and other flowers. • The stigma needs to be up high so it can be pollinated and the ovary needs to be somewhere less exposed so that it can be protected.
Answers-Disadvantages • Huge energy cost (nectar and showy flower) • Insects can’t fly in bad weather • Relies mainly on bees so if they become extinct then no cross pollination.
Question-Homework • Discuss the advantages and disadvantages of the reproductive system of an angiosperm.