Plant Reproduction

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Plant Reproduction
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Sexual reproduction

• The mixing of genetic material from two parents
  to produce offspring
• Offspring are genetically different from parents

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Plants

• Flowers are the sexual reproductive structures in
  plants

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Draw and Label this diagram!
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Lily flower

• Ecological strategy
• Insect pollinated flower targeting bees in
  particular

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Lily advantages

• The reward and display make it very likely that
  pollen from one lily plant will reach another
  lily plant

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Lily flower

• Draw flower, note projections and markings on
  petals.

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Lily flower

• Stigma protrudes in front of stamens so insect
  touches stigma and deposits pollen from another
  flower first!

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Adaptations for pollinator

• Spikes on petals force pollinator past anthers on
  way to nectary

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Adaptations for pollinator

• Stigma is above anthers so pollinator deposits
  pollen from another flower before it gets pollen
  from this flower

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Adaptations for pollinator

• Anthers are large so pollen eating bees wont
  destroy them, enough pollen for bee and cross
  pollination

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Adaptations for pollinator

• Highly scented nectar because bees have a good
  sense of smell.

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• The flower at the right shows how UV markings may
  guide insect to nectary past anthers

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• Pollen is spikey to stick to insect hairs

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disadvantages

• Huge energy cost (nectar and showy flower)
• Insects cant fly in bad weather
• Relies mainly on bees so if they become extinct
  then no cross pollination.

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Adaptations for environment

• Grow in sheltered environments
• Bloom in warm season spring or summer
• Petals wont get ruined by wind
• Cold blooded insects need warmth to fly
• Bees cant fly in windy weather, bad weather
• Longer days for more time to pollinate

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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.

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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

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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 wont
  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

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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.

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Answers-Disadvantages

• Huge energy cost (nectar and showy flower)
• Insects cant fly in bad weather
• Relies mainly on bees so if they become extinct
  then no cross pollination.

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Advantages, disadvantages niche
Advantages Disadvantages Other / Niche
Gametes separate. Targeted pollination allowing high number of gametes produced to fertilise. High energy adaptations. Bees cant fly in bad weather (extinction?). Blooms seasonally, in sheltered environments. Pollen sticky and spikey. Smell and UV, Wind and pollinators required.
Dominant sporophyte life cycle Not dependant on gametophyte for survival
Nourishing zygote Zygote is protected by the plant. Seed made to provide energy for young zygote. Pollen tube required for fertilisation. Energy required to make seed. Can withstand harsh environments as seed can provide nutrients.
Vascular tissue Sporophyte can survive dry periods Can survive in variety of environments
Seeds Can withstand harsh conditions before germinating when more favourable. Lots of energy needed to make seeds. Can grow in variety of environments
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Label the diagram a-k
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Question-Homework

• Discuss the advantages and disadvantages of the
  reproductive system of an angiosperm.