Grade 11 biology notes based off of 'McGraw-Hill Ryerson Biology 11' textbook and in-class lectures. Contact @samanthaguu on Instagram for a shared version on google drive with interactive links and document outline.
13.1 - Plants as Valuable Bioresources
Ecosystem services provided by plants
- Photosynthesis, cellulose, food production, habitat for other organisms, fibre
production for clothes and structures, reduction of soil erosion, biofuels
Photosynthesis
Occurs in: plants, bacteria and some protists
Word Equation:
- 50% of the oxygen in the atmosphere is produced by plants
- The remaining 50% comes from bacteria and protists
Cellulose
Cellulose: A large carbohydrate molecule found in cell walls of many sugars
Uses:
1. Cellulose from vegetables and cotton plants is used to make fabric
2. Cellulose from wood pulp is used to make paper and cardboard
Agriculture
- Only 150 species out of 50 000 edible plant species are used for commercial
food production because farmers choose:
1. Plants w/ the best yield to crop area ratio
2. Plants that are easy to pollinate
- Wheat, rice and corn make up 60% of the calories consumed by humans directly
from plants
Canadian Agriculture:
- Important because it creates job opportunities, contributes to 10% of the
canadian GDP and contributes to a large portion of international exportations
- Canadian grain crops: wheat, barley and oats
- Canadian food oils come from: soybeans and flaxseeds
Aboriginal Agriculture:
- ‘The 3 sisters’: corn, climbing beans and squash
- All benefit each other and grows most successfully when planted together
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Food Security
- The state where all people at all times, have access to enough safe and
nutritious food to meet their dietary needs and preferences to allow them to lead
an active and healthy life
Importance:
- Allows from economic benefits, trade opportunities, poverty reduction and
improved health
Monoculture:
- The cultivation of a single type of plant grown over a vast area
- Advantages:
1. Similar treatment = ease in caring for crops
2. Increase in crop yield
- Disadvantages:
1. Planting a single crop over the same area of soil repeatedly can deplete
the soil of valuable nutrients, therefore farmers must use more synthetic
fertilizers
2. Monocultures are vulnerable to crop-specific pests, therefore more
pesticides are used
3. Increased use of synthetic fertilizers and pesticides can be costly and
ruins the water quality nearby
Sustainable Agriculture:
- The goal is to produce enough food to feed the world while taking account the
economy, society and the environment in an integrated way
- Sustainable practices:
1. Crop rotation; keeps soil healthy w/ less synthetic fertilizer
2. Use of natural predators to reduce use of pesticides
3. Hiring more people; reduces use of machinery and allows for economic
benefits
Fibres and Building Materials
Materials made from plant fibers: paper, cardboard, rope, fabric, linen (from flax plants)
Timber:
- Trees in their natural state or wood that has been prepared for use of a building
material
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Biochemicals
- Plants use chemicals to attract pollinators or repel threats
- Human uses: medicines, perfumes and dyes
Medicinal Uses:
- 25% of prescription medicine contains plant extracts
- Deforestation causes loss of biodiversity which threatens undiscovered species
and their potential to help fight conditions
- Example of medicinal uses:
- Rosy Periwinkle: Hodgkin’s disease
- Ginseng: immune system
- Goldenseal: colds and mouthwash
Fuels & Erosion Control
Biofuel:
- A fuel that is produced from renewable biological sources
- Ex. Ethanol, biogas
Soil Erosion:
- A natural process in which wind and water remove the top layers of soil
- Consequences:
1. Topsoil is crucial to good crop growth and is not easily replaced
2. Eroded soil washes down embankments; makes roads impassable and
can redirect streams
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