What is a Plant?
Multicellular Eukaryotic Photosynthetic Has cell walls
containing cellulose
Lacks mobility
What did they evolve from?
Green Algae
Similarities contain
chlorophyll have cell walls
made of cellulose
store energy as starch
Original Habitat
The simplest plants live surrounded by water because water satisfies many of their needs: prevents cells from drying out gives structural support provides nutrients helps with spore dispersal and meeting of
sex cells
With time, plants adapted to live on land
Adaptations for Land
Adaptation Definition Advantage(s)
1. Cuticle waxy coating on the outer surface of plant cells
prevents the cell from drying out & acts as a barrier to pathogens
2. Stomata openings in the outer layer of leaves and some stems that allows the exchange of gases
enables exchange of gases for photosynthesis
Adaptations for Land
Adaptation Definition Advantage(s)
3. Vascular Tissues
transport tissues that move nutrients and water throughout the plant
faster transport than with osmosis or diffusion & provide structure and support for the plant
4. Reproductive Strategies
adaptations that allow sperm to meet egg without water (e.g. spores that have waterproof coverings, seeds)
enable plants to reproduce without being surrounded by water
Plant Life Cycle
The lives of plants consist of two alternating stages, or generations: a gametophyte generation and a sporophyte generation.
The stage that produces gametes (sperm and eggs) is the gametophyte generation. It is haploid.
The stage that produces spores is the sporophyte generation. It is diploid.
Plant Life Cycle
One generation is dominant over the other. This means that it is larger and lasts longer.
In most plants, the diploid sporophyte generation is dominant. In mosses, the gametophyte dominates.
Non-Vascular Plants
Include mosses, liverworts, & hornworts
1. Do not have true roots, stems and leaves - absorb water through cell walls; water moves via osmosis.
2. No vascular tissue - no xylem and phloem to transport water and nutrients
Non-Vascular Plants
3. Small size- no support from vascular tissues
4. Depend on water for reproduction- water is needed for the sperm to swim to the egg
Vascular Plants
1. Have true roots, stems and leaves
2. Contain vascular tissue- xylem transports water - phloem transports food and nutrients- run continuously through the roots, stems and the leaves
Vascular Plants
3. Larger size- vascular tissues provide support against gravity
4. Cuticle- reduces water evaporation from leaves and some stems
Seedless Plants
Most plants have vascular tissue but may or may not produce seeds.
Ferns, horsetails, and club mosses are seedless vascular plants that reproduce by spores.
Gymnosperms
Plants that reproduce by seeds are divided into 2 groups: gymnosperms and angiosperms.
Gymnosperms have "naked" seeds usually protected by cones. They include the evergreens.
Angiosperms
Angiosperms are flowering plants whose seeds are produced and protected within fruit.
Further divided into monocots and dicots.