Lecture 5: Evolution and coadaptation of flowers Flashcards
What are the 6 major variations in flower structure
- ) carpel organisation
- ) shape of receoptacle
- ) insertion of flower parts
- ) free or fused flower parts
- ) flower symmetry
- ) flowers may lack specific parts
What does it mean by carpel organisation
- one or many carpels
- fused or free carpels
- fused carpels divided into locules that show different patterns of placentation
- fused carpels are also called the pistil
give an example of parietal
melon
give an example of axile
orange, kiwifruit
give an example of free placentation
primula dianthus
what does it mean by shape receptacle
- elongated and floral parts spirally arranged (considered to be the more primitive type)
- compressed and disk shaped
What does it mean by insertion of flower parts
hypogynous
perigynous
epigynous
What does hypogynous mean?
flat receptacle and superior ovary
What does perigynous mean?
cup-shaped receptacle not fused to ovary
What does epigynous mean?
cup-shaped receptacle fused to ovary which is inferior
Where are the flower parts likely to be fused to
- either with each other (petal with petal to form a tube)
- or with different floral parts (petals with anther filaments)
What are the types of flower symmetry
radial symmetry (buttercup); odd bilateral (puriri); even
When is a flower deemed imperfect
- if they lack either stamens or carpel
What do you call a plant with both male and female flowers on the same plant
monoecious
What does dioecious mean
male and female flowers on separate plants
Why are flowers so variable
- due to adaptations to pollination
- two important points about pollination:
- need to transfer pollen from stamens to stigma, without this no seeds will be produced
- need to exclude ‘foreign’ pollen from other species
What are the two main types of pollination
biotic
abiotic
What does biotic mean?
- flower provides attractant (usually food) and in return gets pollen transfer. This is an incentive for the animal to visit the flower
- nectar production, sticky pollen, sticky stigma
- flowers may also practice deception
What are examples of animal mediated pollination (abiotic)
examples of animal mediated pollination exhibit co-evolution of flower and pollinator
What do beetles pollinate?
eucalyptus
Which flowers have adaptations to wind pollination
- usually small, inconspicuous flowers
- not brightly colored as no need to attract insects
- large anthers that produce copious, smooth, dry pollen
- large, often feathery or sticky stigmas to catch pollen
Why do flowers vary?
- 6 main ways that flowers vary
- flower variation driven by evolution to maximize population
- sometimes this involves co-evolution with pollinators
How are bees attracted to flowers?
UV light
How have moths and flowers co-evolve
tube shaped
