Do Now What do plants need in order to survive? What organism do you think plants evolved from? (Hint: think about plant-like organisms that we’ve learned about already) Write 5 facts you currently know about plants

Plant Evolution and Diversity

Review Are plants…. Alive or not alive? Able to move or stationary? Unicellular or multicellular? Prokaryotic or Eukaryotic? Autotrophic or Heterotrophic? Contain cell walls or no cell walls?

What is a plant? Plants are multicellular eukaryotes that have cell walls made of cellulose. They develop from multicellular embryos and carry out photosynthesis using green chlorophyll pigments located in their chloroplasts.

What do plants need to survive? Sunlight Water and minerals Gas exchange Movement of water and nutrients What gas specifically? What does it need this gas for? Co2  sugars Why do we need plants? Oxygen, source of energy for the rest of the food pyramid

Plant Life Cycle Plants mainly reproduce by sexual reproduction ALL plants have two alternating phases of life – one is called the sporophyte phase and the other is called the gametophyte phase. Sporophyte – spore producing plant **In plants, meiosis results in the production of spores, not gametes! Gametophyte – gamete producing cell

Alternation of generations

Where did plants evolve from? GREEN ALGAE Green algae are multicellular, photosynthetic, plantlike protists. Green algae have cell walls and have size, color, appearance of plants. Green algae is not in the plant kingdom because they don’t have true roots, stems, or leaves.

Earliest plants – Seedless Nonvascular Plants Nonvascular Plants are plants that depend on water for reproduction. They lack tissues that can move water, so they can only draw up water by osmosis a few centimeters above the ground. Mosses Liverworts Hornworts

Seedless vascular plants Vascular plants – plants that have a transport system with vascular tissue, which is specialized to conduct water throughout the plant Ferns Club mosses Horsetails Have true roots, stems, and leaves

Roots, stems, leaves Roots – absorb water and nutrients Stems – provide support and water transport Leaves – absorb sunlight, site of photosynthesis

Transport of water and nutrients in Vascular Plants 2 Types of Vascular Tissues XYLEM - carries water PHLOEM – carries sugars and nutrients Talk about plant circulatory system – xylem and phloem allow plants to grow taller Why are humans not able to be 8+ feet tall – heard can’t circulate blood all over big body Every cell in the plant needs sugars – phloem brings it

Seed plants – Gymnosperms & Angiosperms Can reproduce without water Adaptations that allow seed plants to reproduce without water include flowers or cones, the transfer of sperm by pollination, and the protection of embryos in seeds.

Seed plants - Gymnosperms Gymnosperms – Cone-bearing plants Cones are the seed-bearing structures of gymnosperms Ex: conifers

Seed plants - Angiosperms Angiosperms – Flowering plants Flowers are the seed-bearing structures of angiosperms Ex - Fruits

x x x x x x x Vascular Tissue Seeds Flowers Cones Mosses Ferns Gymnosperms Angiosperms x x x x x x x