Plant Jobs Write these down… • Primary source of food for people and animals • Produce oxygen • Absorb carbon dioxide • Continued…
Plant Jobs • Slow wind speed • Provide homes for wildlife • Prevent erosion • Beautify surroundings • Furnish building materials and fuel
Parts of a plant • Four basic parts • LEAVES • STEMS • ROOTS • FLOWERS Draw this on your notes
LEAVES • The greenest part of the plant • Act as solar collectors • Large leaves= areas of little sunlight • Tiny leaves = bright sunlight • Needles = no water loss
LEAVES - structure • Epidermis - top and bottom tough layer • Pallisade Layer - most cells with chloroplasts are found here • Spongy Layer - gas exchange through stomata
LEAVES - 2 functions • Make Food (sugar) in the chloroplasts • Gas Exchange take in carbon dioxide and release oxygen and water vapor Stomata on the bottom of the leaves have guard cells that open and close as they fill up with water.
LEAVES - photosynthesis Plants make sugar using CO2 (from air) and H2O (from roots) as ingredients.
STEMS - two main functions • Liquid transport xylem cells carry water & minerals up phloem cells carry food down • Support
STEMS – example Dicot plants such as a bean (xylem & phloem in a ring under the bark) Cambium Phloem Xylem
STEMS – example Monocot plants such as a corn stalk (vascular bundles scattered throughout the setm) Phloem Cells Xylem tube
What Good Are Stems to humans? • FOOD-rhubarb, celery, white potato • WOOD – building and fuel • PAPER
Types of Modified Stems • Bulbs: (onion) • Tubers: (potato) • Stolons: above ground runner (strawberry) • Rhizomes: below ground runners (field bindweed or creeping jenny)
ROOTS - functions • Anchor plant • Suck up water and minerals • Store Sugar (radish, carrot, beets) • Reproduction (eyes on potatoes)
ROOTS - structure • root cap-protects tender cell division area as the root pushes through soil
ROOTS – root hairs Water and minerals move into root by osmosis / diffusion
What is Diffusion? • Diffusion is when particles move from areas of high concentration to low concentration. (Doesn’t have to be water) • Examples: Lighting a match, spraying perfume or cologne
What is Osmosis? • Osmosis is a special type of diffusion that involves water. • Water moves from areas of high concentration to areas of low concentration. • Diffusion is when particles move from areas of high concentration to low concentration.
FLOWERS, FRUITS, SEEDS • Main jobs involve reproduction • Attract pollinators • Disperse pollen • Fertilization • Disperse seeds
FLOWERS, FRUITS, SEEDS • POLLEN normally carried by insects or wind • FRUITS & SEEDS normally carried by wind, animals, water or shot away from parent plants (projectiles)