Photosynthesis Review Equation? –6H 2 O + 6CO 2 ----------> C 6 H 12 O 6 + 6O 2 What do plants give us? Site for gas exchange? –Stomata Light
Introduction to Plants Multicellular or unicellular? Carry out photosynthesis using the green pigments chlorophyll a and b What do plants need to survive? –Sunlight, H2O & minerals, gas exchange movement of water and nutrients
Early Plants The first plants evolved from organisms much like the green algae living today –Photosynthetic pigments –DNA sequence, close relationship –Fossils- similarities to today's mosses
Bryophytes Mosses & their relatives are generally called bryophytes, or NON- VASCULAR, plants. Depend on water for reproduction Why non-vascular? Draw water up by osmosis Mosses, liverworts, hornworts
Seedless Vascular Plants Fossil evidence shows ~420 million years ago moss-like plants were joined w/ other plants species These new plants were the 1 st to have a transport system w/ vascular tissue What is the function of vascular tissue? –Transport water & nutrients
Vascular Tissue Tracheids are the key cells in xylem, the transport system that carries water upward from roots Phloem, second vascular tissue that transports nutrients and carbohydrates produced by photosynthesis. Transpiration?
Seed Plants Over 1 million years plants with the capability to form seeds became the most dominant group of photosynthetic organisms on land.
Seed Plants Gymnosperms bear their seeds directly on the surface of cones Angiosperms, “flowering plants,” bear their seeds w/in a layer of tissue that protects the seed
Angiosperms: Flowers & Fruits Angiosperms, “enclosed seed,” develop unique reproductive organs known as flowers Flowers contain ovaries, which surround and protect the seeds Fruit- a wall of tissue surrounding the seed
Diversity of Angiosperms Incredibly diverse group…. Categories provide a way of organizing diverse angiosperms Two classes w/in angiosperms: monocotyledons (monocots) & dicotyledonae (dicots) Names for the number of seed leaves, or cotyledons in the plant embryo.
Diversity of Angiosperms Monocots have one seed leaf, and dicots have two Cotyledon is the 1 st leaf or 1 st pair of leaves produced by the embryo of a seed plant