Alternation of Generations [has asexual and sexual parts]
gametophyte [1n] produces gametes [1n]
gametes fuse (fertilization) to form sporophyte [2n]
sporophyte produces spores [1n] through meiosis
spores form gametophyte plant
Vegetative Reproduction: reproduction from existing plant structures
Ferns – non seeded vascular plants
- On leaf, flagellated sperm [reprod. cells] need water to swim
to eggs [reprod. cells] @ the top of the structure.
- Gametophyte is very small [at most, 1cm!]
- Sporophyte plant is formed by sperm and egg fertilization.
Flowers – reproductive structure.
- petal: leaf-like structure, typically colorful around top of
stem; functions to attract insects/animals for pollination
- sepal: leaf-like, usually green, encircles bottom of flower
- stamen: male reproductive organ
o filament: long tube-like projection that holds anther
o anther: contains pollen [sperm]
- pistil: female reproductive organ
o ovary [contains ovules/eggs], style [long part connecting
ovary & stigma], stigma [sticky top portion @ top of style]
Why Flowers? Used to attract pollinators for fertilization [like, the
sexy-clothes of the plant]. They do this through colors [UV colors,
too], patterns, or shapes.
Fertilization – this happens MANY times to complete fertilization –
think of how many seeds are in a watermelon!
Ovule = plant egg [female gamete]; Pollen = plant sperm [male
Think about all the pollen on your car, home, etc. in the
spring/summer in Georgia!!
Steps of fertilization:
1. pollen lands on stigma [carried by wind, insect…etc]
2. pollen tube pollen tube grows down the style to the ovules for
Seeds – zygote of the plant
- after fertilization, flower parts die
- the ovary wall becomes the fruit and the ovules become seeds
Seed dispersal – burrs, maple “helicopters,” dandelion “poofs,” some
need to be eaten…
- greater dispersal = hopefully less competition where they land
- where seeds end up is due to chance
Germination: the beginning of development of the embryo into a new
- remember dormancy – many seeds can remain dormant for long
periods of time!]
- requires water, oxygen, correct temperature
o before germination can occur, some require:
saturation of salt water [coconuts]
or other conditions
- once germination begins, it cannot be halted except for death.
- Vegetative Reproduction:
o Bulbs, rhizomes, tubers – faster than sexual reproduction
o Complete flowers: contain both reproductive sex parts
o Incomplete flowers: contain only one sex or another [corn]