Plants for Food and Fibre

Unit 2 Science 7

Unit 2 Topics 1 and 2

1. People and Plants2. Structure and Adaptations

Topic 1: People and Plants

Think about it: What do we use

plants for? Plants

People and Plants › Food – fruits and

vegetables› Medicine –

natural/herbal remedies and narcotics

› Clothing – cotton, linen, hemp

› Paper – pulp, rice paper› Building materials –

wood, linoleum, textiles, insulation

› Fuels and oils› Dyes and pigments

Plants in the Environment 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

Plants for Food 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

Plants for Food 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 powderis mixed withmilk to make chocolate.

Plants for Food Some seaweeds are

nutrient rich

Seaweed is often part of pasta sauces, sushi, soups, ice cream, chocolate milk, pies, jellies and candies

Plants for Food Edible oils mostly come from plants Most vegetable oils are from canola

› Corn› Olive› Peanut› Soybean› Rice› Palm› Sunflower

Plants for Food

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 for Fibre

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

used › Living Bridge

Plants for Fibre: Cotton 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

Plants for Fibre: Hemp 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

Plants for Fibre: Flax 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.

Plants for Fibre: Medicine Over 7000 medicines: heart drugs,

cancer meds, antibiotics, and pain meds come from plants.

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

Plants for Fibre: Medicine

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

Plants for Fibre: Medicine

Quinine from the Cinchona is used to prevent malaria.

Until Quinine came along malaria killed 2 000 000 people a year.

[Video]

Plants for Fibre: Transport Rubber is a very

important plant product

It’s from the Brazilian Rubber Tree

Shoes, tires, playgrounds, erasers, tubing, and many more uses

Plants for Fibre: Fuel & Oil

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, cosmeticsand other industrial uses are met by plants

Plants for Fibre: Fuel & Oil

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] Bio Fuels [Video- 9.50]

End of Topic 1- REVIEW

Topic 2Structure and Adaptations

Introduction

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

Brainstorm 3 ways a plant may need to be adapted

Roots 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› Absorb water and minerals from the soil.› Support and anchor the plant.› Store food in times of scarcity.

Roots: Types of Roots

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.

Roots: Types of Roots

1. Tap Roots2. Fibrous Roots

› Shallow system of similar sized roots that can quickly suck up moisture.

What adaptations might these plants have?

Adapted: Moss Campion

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.

Adapted: Duckweed Found near ponds in spring

and summer. Have tiny roots that grow of

the underside of the leaf and are surrounded entirely by water

Roots: Crops

Many vegetables we eat are roots › Carrots, turnips, beets, radishes, parsnips

all come from roots.

› Roots

Roots: the Cell Membrane

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

Roots: Diffusion 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

Roots: Osmosis 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

Roots: Osmosis

Question:

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

Answer:

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

Stems

After water and nutrients are absorbed by plant cells by diffusion and osmosis they move up through the plant through the stem.

Transport happens inthe xylem & phloem

Stems also support the plant and help get the leaves closerto the sun

Stems: Parts of a Trunk

xylem

Stems: Food Storage 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

Stems

Runners

Rhizome

Tuber

Leaves: Photosynthesis 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 Rap

Leaves: Photosynthesis 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: Transpiration During the day CO2 is taken in for

photosynthesis, oxygen is given off At night respiration occurs and oxygen is

taken in and CO2 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

Waxy Layer

Spongy Layer

Stomata & Guard Cells

Veins

Leaves: Parts