Plants

Characteristics Eukaryotic. Multicellular. Photosynthetic. Cell walls contain cellulose. Develop from embryos protected by parental tissue.

Earliest Ancestor The earliest land plants may have evolved from algal-like organisms.

Generalized Life Cycle Alternation of generations. –Gametophyte generation (n). –Sporophyte generation (2n).

Plant Types Non-Vascular (bryophytes) Vascular (tracheophytes) –Spore-producing –Seed-producing

Non-Vascular Plants Includes mosses, liverworts and hornworts. Lack true roots, stems, leaves and vascular tissue. Grow in moist environments. Only several centimeters in height. Sexual (spores) or asexual (vegetative propagation).

Vascular Plants Conducting tissue. –Xylem & phloem. Allowed greater heights in plants.

Spore-Producing Vascular Plants Includes club mosses and horsetails. –Primarily grow in marshes and along edges of streams. Includes ferns. – Primarily grow in shady, wet environments.

Reproduction in Non-Vascular & Spore-Producing Vascular Plants Both require water for the sperm to swim from antheridium to archegonium to fertilize egg. Fern sperm

Seed-Producing Vascular Plants Most successful plants on Earth. –Due to specialized leaves, stems and roots. Sexual reproduction occurs via pollination. –Does not require water. –Seeds withstand desiccation. Includes: –Gymnosperms. –Angiosperms.

Gymnosperms Reproductive structures. –Pollen cones (male). –Seed cones (female). Pollen dispersed by wind. Pollen produces sperm when contact is made with seed cone. Sperm fertilizes ovules. Zygotes grow into seeds.

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Gymnosperms Conifers are the most numerous.

Conifers Referred to as “softwood”. Accounts for 50% of Ontario’s forests. Canada supplies 20% of world’s softwood.

Angiosperms Known as the flowering plants. Most successful plants on Earth. –Well-protected seeds. –Variety of seed dispersal mechanisms. Wind, water or animals.

Angiosperms Reproduction: –Ovum fertilized by sperm (from pollen). –Zygote develops into an embryo contained in a seed. –Seeds are enclosed in a fruit. –Seeds must be released from fruit in order to germinate.

Angiosperms Self-pollination

Angiosperms Cross-pollination Watch This!!! And This!!!