Unit 2 Science 7

1. People and Plants 2. Structure and Adaptations

 Think about it:  What do we use plants for?  Plants Plants

› Food – fruits and vegetables › Medicine – natural/herbal remedies and narcotics › Clothing – cotton, linen, hemp › Paper – pulp, rice paper › Building materials – wood, linoleum, textiles, insulationinsulation › Fuels and oils › Dyes and pigments

 Plants are needed in all ecosystems › They use the sun to produce energy for all food chains › They produce oxygen for animals to breathe › Plants use carbon dioxide (a greenhouse gas) which cleans polluted air.  A single tree can produce enough oxygen for 2 humans

 Humans eat vegetables and fruit.  75% of the worlds food supply is based on 7 major crops › Wheat › Rice › Maize (corn) › Potatoes › Barley › Cassava › Sorghum

 Chocolate comes from the cacao tree in tropical areas (Theobroma Cacao Latin name for cacao tree)  Beans are spread to dry in the sun  They are roasted, shelled, and crushed in a factory  Cocoa butter and powder are separated.  Cocoa powder is mixed with milk to make chocolate.

 Some seaweeds are nutrient rich  Seaweed is often part of pasta sauces, sushi, soups, ice cream, chocolate milk, pies, jellies and candies

 Edible oils mostly come from plants  Most vegetable oils are from canola › Corn › Olive › Peanut › Soybean › Rice › Palm › Sunflower

 ½ of the worlds sugar comes from sugar beets  Grown in the north (Canada & Russia)  The sugar is in the roots  The beet is shredded, heated in water and the clear liquid that is left evaporates into sugar.

 Plants provide fibre for a variety of needs. › Clothing › Paper › Shelter › Transportation › Saps and byproducts are used › Living Bridge Living Bridge

 The most commonly used natural fiber.  Absorbs moisture and allows it to evaporate.  The fibers of cotton are strong, flexible, and have a gradual spiral that allows it to be spun into thread.  Fuzzy fibers too – cotton batting

 Clothing in the 1800s was often made from hemp  Hemp: › produces a lot of fiber › grows very quickly › Paper can be recycled many more times than pulp and is very strong › Is a hardy plant – no need for insecticide › Cannabis Economics Cannabis Economics

 Grown in northern cooler climates  Fibers are 2-3 times stronger than cotton.  Naturally smooth and straight  Used for making clothes, linens, and paper  Grown for linseed oil: dry oil in paints, use in linoleum, printing inks.

 Over 7000 medicines: heart drugs, cancer meds, antibiotics, and pain meds come from plants.medicines  Ginger roots can sooth an upset stomach.  Natives used the bark of white willow to kill pain which was turned into aspirin  Echinacea, aloe and other natural remedies are from plants  Herbal teas soak remedies out of the leaves of plants

 Opium poppies are used to produce morphine a powerful painkiller used in hospitals.  Codeine a cough suppressant from poppies.  Morphine given to soldiers during the war

 Quinine from the Cinchona is used to prevent malaria.  Until Quinine came along malaria killed people a year.  [Video]

 Rubber is a very important plant product  It’s from the Brazilian Rubber Tree  Shoes, tires, playgrounds, erasers, tubing, and many more uses

 Wood is still used by over a billion people to heat their homes, and cook their food.  Coal was once living plants compressed by pressure into a fossil fuel.  Linseed oil, Tung oil, castor oil (paints), lubricants, cosmetics and other industrial uses are met by plants

 Biofuel is fuel made from plant based products  It is an alternative to fossil fuels  Sugar in plants can be distilled into ethanol – corn especially  Ethanol Fuel [Video- 3.20] Ethanol Fuel  Bio Fuels [Video- 9.50]  End of Topic 1- REVIEW

 Plants are found in almost all habitats on earth. › Each habitat has different: temperatures, light, water and soil conditions.  Plants need to be adapted to survive in their environments  Plant Adaptations Plant Adaptations

 There is much of the plant that grows below the surface.  1/3 of a plant can be found under the ground as roots  Roots Roots › Absorb water and minerals from the soil. › Support and anchor the plant. › Store food in times of scarcity.

1. Tap Roots › Single prominent root with small roots coming out of it. › Smaller roots covered in root hairs. › Root hairs increase surface area to absorb water and nutrients.  Most trees  Large desert plants.

1. Tap Roots 2. Fibrous Roots › Shallow system of similar sized roots that can quickly suck up moisture.

 Grows low to the ground › Traps heat › Prevents wind damage › Reduces water loss  Grows high in the mountains; cold and dry.  First 5 years it grows mostly roots up to 2m deep.  Can take up 25 years to bloom.

 Found near ponds in spring and summer.  Have tiny roots that grow of the underside of the leaf and are surrounded entirely by water

 Many vegetables we eat are roots › Carrots, turnips, beets, radishes, parsnips all come from roots. › Roots Roots

 Protective outer layer of a cell that controls what goes in and out

 The process of particles spreading until they are spaced evenly  Substances move from high concentration to low concentration  Substances in the soil will move into a root through Diffusion Diffusion

 A special type of diffusion  The diffusion of water and nutrients across a semi-permeable membrane  A cell membrane is selectively [semi-] permeable because it will let some substances in while keeping other substances out

 What would happen if the concentration of water were higher inside the root cell than outside?

 Water would diffuse out of the cell and the plant would wilt.

 After water and nutrients are absorbed by plant cells by diffusion and osmosis they move up through the plant through the stem.  Transport happens in the xylem & phloem  Stems also support the plant and help get the leaves closer to the sun

xylem

 Stems Stems  Some stems store food › Potatoes are swollen underground stems called tubers › They store food as starches which the potato will use to grow.  Some plants store food as sugars like the sugar cane

Runners Rhizome Tuber

 Water + carbon dioxide + energy are used by the plant  Produces oxygen and sugar  The oxygen is released and the sugar is used for energy  Photosynthesis Photosynthesis  Photosynthesis Rap Photosynthesis Rap

 Chlorophyll makes some leaves green and traps energy from sunlight for photosynthesis  Stomata in the leaves open and close to allow carbon dioxide in and out of the leaf.  Guard cells surround the stomata to control the size of the opening  Leaves Leaves

 During the day CO 2 is taken in for photosynthesis, oxygen is given off  At night respiration occurs and oxygen is taken in and CO 2 is given off  When guard cells open the stomata, plants release water through transpiration  Water moves up to the leaves by osmosis, through long straw like cells called Xylem.  Transpiration Transpiration

Waxy Layer Spongy Layer Stomata & Guard Cells Veins