Can you work out what these are trying to say?. Plant Reproduction.
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Transcript of Can you work out what these are trying to say?. Plant Reproduction.
Sexual Reproduction in PlantsLink to the Edexcel Syllabus3.3 Describe the structures of an insect pollinated and a wind pollinated flower and explain how each is adapted for pollination.
Learning Objectives• Be able to identify and label the reproductive structures of a
flower, both wind and insect pollinated• Appreciate the structural adaptations that both wind and insect
pollinated flowers exhibit• Distinguish between the terms cross and self-pollination and
understand why and how flowers try to prevent self-pollination
Enhancement of learning• Show an appreciation of the potential impact that the depletion
in honey bee numbers may have on human populations
Structure and function of the flower
stigma
style
ovary
ovule
carpelfilament
stamen
petal
sepal
receptaclepeduncle
anther
Flower Structure Quiz
• What is the name of the structure labelled X in the diagram?
B. sepal
C. stamen
D. peduncle
A. carpel
X
Flower Structure Quiz
• Where is the ovule found in a flower?
A. petals
B. style
C. nectary
D. ovary
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
Flower Structure Quiz• Which parts of the flower are labelled below:
B. X = filament, Y = anther
X
YC. X = stigma, Y = style
D. X = anther, Y = filament
A. X = style, Y = stigma
Pollination
The pollen grain contains the male sex cell (gamete)
Wind-pollinated flowers are different in structure to insect pollinated flowers as they do not have to attract insects to them
but do need to be exposed to the wind.
Petals are small and green as there is no need to attract insects
Stigmas are feathery to catch pollen carried in wind
Anthers are exposed to the wind so that pollen can easily be blown away
Pollen grains are very small and light. They occur in very large numbers
No scent or nectary
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
Insect-pollinated flowers are adapted to attract insects to enable the transfer of pollen
Sticky stigma to collect pollen Brightly coloured
petals
nectar and a scent present
Pollen has barbs for hooking onto insect fur
Anthers positioned to rub pollen onto insects
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
Pollination can be self pollination or cross-pollination
This is an example of cross-pollination as the pollen travels from one flower to a different flower.
Self-pollination occurs when pollen falls from the anther ontothe stigma of the same flower
Self-pollination is not desirable as it reduces genetic variation
Pollination Quiz
• Pollination is the transfer from….?
A. stigma to anther
B. style to stamen
D. anther to stigma
C. ovule to filament
Pollination Quiz
• The two mechanisms for pollination are?
A. Wind and water
C. Insect and water
B. Insect and wind
D. Wind and birds
Pollination Quiz
• Cross-pollination…
A. Increases genetic variation
B. Decreases genetic variation
D. Is only performed by wind
C. Is only performed by insects