Mosses Ferns Conifers (gymnosperms) Flowering (angiosperms) no no yes yes Water required for fertilization present absent absent absent Flowers and fruits enclosed in fruit exposed on cones absent absent Seeds present present absent absent Pollen advanced advanced present absent True leaves, stems, and roots advanced advanced present absent Conducting Tissue advanced advanced present absent Stiff support tissue Flowering Plants Conifers Ferns Mosses Plant Group
Challenges to Life on Land
1. Mechanical support against gravity
- rigid cell walls and supportive tissue
3. Avoid Drying out
- waxy cuticle
4. Movement of nutrients and water
- vascular tissues
A seed is an embryo, along with its food supply,
packaged in a protective coat.
It was formed when the
sperm fused with the ovule
(egg cell) in the ovary of
the plant and then the
zygote begin dividing
by mitosis to form an embryo
Just like animals, plants need
a covering to avoid drying out
What is fruit? Fruit is the mature ovary of a flowering plant. The purpose of fruit is to attract animals to the expendable flesh. The seed which is inside the fruit is indigestible and is passed through the animal.
Angiosperms are Flowering Plants What is the purpose of a flower? Video of a Moon Flower ( Ipomoea alba ) Plants In Motion Website Flowers are used for reproduction, not photosynthesis. A flower may contain male parts, female parts, or BOTH!
Function of a flower
Attract pollinators with colorful petals, scent, nectar and pollen
What is pollination?
Pollination : The transfer of pollen from the male anther to the female stigma
In animals: It’s easy because you have separate male and female individuals.
In flowering plants: Not so easy, because most flowers have both male and female parts in them, called perfect flowers .
So flowering plants have evolved special ways to prevent inbreeding.
*Inbreeding = less variation
Strategies to avoid self-pollination
Perfect flowers have both male and female organs, so plants have strategies to avoid self-pollination:
1. Timing – male and female structures mature at different times
2. Morphological – structure of male and female organs prevents self-pollination (imperfect flower)
3. Biochemical – chemical on surface of pollen and stigma/style that prevent pollen tube germination on the same flower (incompatible)
How do plants get pollen from one plant to another?
Because plants are rooted in the ground, they must use different strategies:
Gymnosperms and some flowering plants (grasses, trees) use wind pollination .
Not a very efficient method (too wasteful)
Many flowering plants rely on animals for
Insects – bees, wasps, flies, butterflies, moths
Birds – hummingbirds, honey creepers
Mammals – bats, mice, monkeys
Even some reptiles and amphibians!
Getting the pollinator’s attention
Plants advertise their pollen and nectar rewards with:
Colors – bees see blue , yellow , UV; while birds see red . Bats don’t see well, so flowers are white.
Nectar or honey guides – a visual guide for pollinator to locate the reward (pansy flower)
Aromas – for insects, nectar. Can also be carrion or dung smell