Show 23: Environmental Studies (Ecology) ­ Show Notes
August 22, 2012
Grade 10
ENVIRONMENTAL STUDIES
(ECOLOGY)
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
The Concept of an Ecosystem
Ecology: Ecology is the study of the relationship between plants and animals with each other and with the non living environment in which they live.
Ecosystem:
Is the interaction of living and non­living components in an environment.
ENVIRONMENTAL STUDIES
ENVIRONMENTAL STUDIES
Grade 10
Grade 10
Ecological Studies
Ecological Studies
The Two main components of an ecosystem are:
Abiotic Components:
1. Biotic Components:
Living organisms form the biotic component of the three spheres on the Earth.
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Definition: These are the non living chemical and physical factors that influence the living components of an ecosystem.
2. Abiotic Components:
The non living components of an ecosystem that influence the environment. This includes the soil; climate; temperature; sunlight and water.
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The growth and development of plants and animals in an ecosystem is as a direct result of the interactions with several abiotic factors.
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These factors force living organism to become adapted to live in their specific habitat.
Thus , the interaction between the biotic and abiotic factors of the biosphere form an ecosystem.
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
August 22, 2012
Grade 10
Ecological Studies
Abiotic Components:
Abiotic Components:
The 3 different types of Abiotic factors:
The 3 different types of Abiotic factors:
1. Physiographic Factors:
These are the factors that are related to the position, shape and physical geography of an area.
2. Edaphic Factors:
These are factors that are related to the soil and how they influence the organisms in an area.
3. Physical Factors:
Factors such as sunlight, temperature and water that affect the ecosystem.
ENVIRONMENTAL STUDIES
1. Physiographic Factors:
These are the factors that are related to the position, shape and physical geography of an area.
Physiographic factors include the following:
1.1 Aspect
1.2 Slope
1.3 Altitude
Grade 10
Ecological Studies
ENVIRONMENTAL STUDIES
Abiotic Components
Grade 10
1. Physiographic Factors
1.1 Aspect
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Aspect is the direction in which an area faces in relation to the direction of the sun.
In South Africa the sun shines from the north. This means that the north­facing slopes are exposed to the direct rays of the sun for longer periods than the south –facing slopes.
Ecological Studies
Abiotic Components
1. Physiographic Factors
1.2 Slope
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The slope of the land is how steep or gentle the gradient is.
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Water flows faster on the steep slopes, which means that more erosion occurs.
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The soil on steep slopes tends to be thin and infertile, and can only support smaller plants.
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Thus there is less erosion on more gradual slopes.
North­facing slopes will be hotter and drier ,while the south facing slopes will be more moist and cooler and will support the growth of more vegetation.
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
Grade 10
Ecological Studies
Ecological Studies
Abiotic Components
Abiotic Components
1. Physiographic Factors
2. Edaphic Factors
1.3 Altitude
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These are factors that are related to the soil and how they influence the area.
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Soil provides water and minerals and also holds the plant firmly in the ground.
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Edaphic factors include the following:
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Altitude is the height above sea level.
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At higher altitudes, there is decreased atmospheric pressure, oxygen content and temperature.
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Rainfall and wind speeds are greater and frost and snow occur.
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On the Drakensberg mountains, plants such
as grasses and small – leaved plants tend to GROW abundantly.
ENVIRONMENTAL STUDIES
2.1 pH of the soil
2.2 Humus content
2.3 Texture
2.4 Water retaining ability
2.5 Air content
Grade 10
Ecological Studies
ENVIRONMENTAL STUDIES
Abiotic Components
2. Edaphic Factors
Grade 10
2.1 pH of the soil
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Soil pH is measure of how alkaline or acidic the water in the soil is.
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pH is measured on a scale of 1 to 14, where pH 7 is neutral, below 7 is acidic and above 7 is alkaline.
Ecological Studies
Abiotic Components
2. Edaphic Factors
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The pH of soil determines the type of plants that will grow.
2.1 pH of the soil
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Most plants grow best in a neutral pH condition.
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0­6.9 water is acidic (more H+ ions, less OH­ions)
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(Refer to experiment)
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7 water is neutral (equal number of H+ and OH­ions)
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7.1­14 water is basic (less H+ ions, more OH­ions)
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Show 23: Environmental Studies (Ecology) ­ Show Notes
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
ENVIRONMENTAL STUDIES
Abiotic Components
2. Edaphic Factors
Grade 10
2.3 Texture
Ecological Studies
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Texture of the soil is a result of the soil particles, based on particle size, soils can be classified as SANDY, LOAMY or CLAY
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SANDY: contains large and loose particles and feels coarse even when wet.
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CLAY: contains tiny particle and soft, smooth and sticky when wet.
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LOAMY: contains mixture of sand and clay­
sized particles; particles stick together when moist; has a high humus content.
Abiotic Components
2. Edaphic Factors
2.2 Humus Content
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Humus is the organic component of soils formed by the breakdown of dead plant and animals in the soil by bacteria and fungi.
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Humus releases nutrients that can be taken up by the plants and separates the soil particles ,allowing air and water to enter.
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Soil with a high humus content is fertile and good for plant growth.
ENVIRONMENTAL STUDIES
SAND
Ecological Studies
2. Edaphic Factors
2.4 Water Retaining Ability
CLAY
ENVIRONMENTAL STUDIES
Grade 10
Abiotic Components
LOAM
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Ecological Studies
Abiotic Components
2. Edaphic Factors
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Water retention capacity of the soil refers to how much water a soil sample can hold.
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Water and dissolved minerals salts are found between the spaces in the soil particles.
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Air is found between the spaces in the soil particles.
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The water retention capacity depends on the texture of the soil.
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Air is important in soil as plant roots need oxygen for healthy growth.
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The water retaining capacity of different soil types:
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The air content varies in different soil textures.
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Sandy: large spaces between soil particles and contains a lot of air.
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Clay: have small spaces between particles, thus contains very little air.
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Loamy: contains a mixture of pore sizes and contains the right amount of air that allows plants to thrive.
Sandy: soil has large particles; water rapidly drains out of the soil, water retention is LOW.
Clay: soil has small particles that are tightly packed together, water slowly drains out of soil, water retention is HIGH
Loamy: soil is a mixture of large and small particles, humus present in soil holds moisture, water retaining capacity is MODERATE.
2.5 Air Content
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
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Ecological Studies
Ecological Studies
Abiotic Components
Abiotic Components
3. Physical Factors
3. Physical Factors
3.1 Light
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Factors such as sunlight, temperature and water affect the ecosystem.
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Sunlight is the main source of energy in an ecosystem.
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Physical factors include the following:
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The intensity of light varies in different parts and ecosystem as well as different times.
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Some plants are adapted to growing in full sun and are referred to as “sun plants” e.g. Aloes
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Some plants prefer less sunlight and grow best in shade, these are referred to as “shade plants.” e.g. ferns and indoor plants.
3.1 Light
3.2 Temperature
3.3 Atmospheric gases
3.4 Wind
3.5 Water
ENVIRONMENTAL STUDIES
Grade 10
ENVIRONMENTAL STUDIES
Ecological Studies
Abiotic Components
3. Physical Factors
Ecological Studies
3.1 Light
Abiotic Components
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Photoperiodism describes an organism s response to length of day and night.
3. Physical Factors
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Plant growth and reproduction is affected, especially in habitats where there is a big difference between the summer and winter photoperiods.
Grade 10
3.2 Temperature
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Examples: Poinsettia and thorn apples flower when nights are longer than days. Referred to as “short day plants”.
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Plants such as spinach, wheat and radish flower when nights are shorter than days. Referred to as “long day plants.”
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Photoperiodism also controls the behaviour of some animals.
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There are NOCTURNAL animals that are active at night and DIURNAL that are active during the day.
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Temperature has a huge influence on organisms.
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Organisms which cannot regulate their own body temperature are referred to as “cold blooded”. E.g. Fish, amphibians and reptiles
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Cold blooded animals are inactive when it s too hot or cold.
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"Warm blooded" animals are able to regulate their body temperature . The environment temperature does not affect their internal temperature.
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
Grade 10
Ecological Studies
Ecological Studies
Abiotic Components
Abiotic Components
3. Physical Factors
3. Physical Factors
3.2 Temperature
3.3 Atmospheric Gases
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Warm blooded animals can survive in very hot or cold conditions.
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Oxygen is produced by plants during photosynthesis. This ensure oxygen levels in atmosphere are kept at 21%
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Seasonal changes in temperature cause animals to move from one place to another. This is called MIGRATION.
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Carbon dioxide is produced by animals during respiration. Plants use Carbon dioxide during photosynthesis. The carbon dioxide level should be at 0.035 %
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Nitrogen in the atmosphere is converted into usable forms by bacteria in the nitrogen cycle and this is maintained at 78% .
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Water vapour is released into the atmosphere when plants transpire as well as during evaporation.
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Snakes and rodents HIBERNATE during winter, while snails and molluscs AESTIVATES during summer.
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Plants survive cold seasons by becoming dormant. Plants die and leaves seeds.
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Marula trees shed leaves in winter, onions and potatoes survive underground.
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
ENVIRONMENTAL STUDIES
Abiotic Components
Grade 10
Ecological Studies
3. Physical Factors
3.4 Wind
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Wind is greater at higher altitudes and this can affect the growth of trees.
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Wind also affects the distribution of plants by assisting in pollination of flowers and the dispersal of fruits and seeds.
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Plants constantly loose water from their stomata through a process known as TRANSPIRATION. Wind will increase the rate of water loss through transpiration and thus plant will need to adapt to conserve water loss.
Abiotic Components
3. Physical Factors
3.4 Wind
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Wind is moving air currents.
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Wind has an effect on rainfall.
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At the coast on a hot day, air over the land heats up and rises and draws a cool, moist breeze over the land. At night, air over the now warmer water rises and draws cooler air from the land back over the water.
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
Grade 10
Ecological Studies
Abiotic Components
ENVIRONMENTAL STUDIES
3. Physical Factors
3.4 Wind
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TRANSPIRATION. Wind will increase the rate of water loss through transpiration and thus plant will need to adapt to conserve water loss.
Grade 10
Ecological Studies
Abiotic Components
3. Physical Factors
3.5 Water
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Some plants have sunken stomata, needle like leaves and thick waxy cuticles.
ENVIRONMENTAL STUDIES
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Water is an important limiting factor in terrestrial ecosystems. A limiting factors means too much or too little will influence the organisms inhabiting that ecosystem.
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Forest have high rainfalls and a large number of plants and animals.
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Deserts have low rainfall and the plants and animals that live there must be specially adapted to dry conditions.
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
Abiotic Components
Grade 10
Ecological Studies
3. Physical Factors
3.5 Water
Abiotic Components
3. Physical Factors
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Plants have adapted to living in different areas with varying amounts of water.
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They can be thus classified in 3 groups.
3.5 Water
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Plants have adapted to living in different areas with varying amounts of water.
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E.g. Plants in wetlands and mangroves have roots that protrude above the soil(aerial roots), leaves are thick and leathery.
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Xerophytes: Grow in desert/arid habitats
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Mesophytes: Grow in areas with moderate amounts of water
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Hydrophytes: Live in water/aquatic
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
Ecological Studies
Question 1:
1.1 List FOUR climatic factors that may affect the lives of plants and animals.
(4)
Abiotic Components
ENVIRONMENTAL STUDIES
ENVIRONMENTAL STUDIES
Grade 10
Grade 10
Question 1:
Grade 10
Question 1:
1.3
Explain how plants and animals may be adapted to live in water.
(4)
1.2
State the characteristics that allow animals and plants to cope with drought. (4)
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
Grade 10
August 22, 2012
ENVIRONMENTAL STUDIES
Grade 10
Question 1:
Experiment 1:
1.4
Explain how hibernation and aestivation help animals survive.
Water retention capacity of different soil samples:
(4)
ENVIRONMENTAL STUDIES
Grade 10
ENVIRONMENTAL STUDIES
Experiment 1:
Water retention capacity of different soil samples:
Grade 10
Experiment 2:
pH of different soil samples using Universal indicator and Litmus paper.
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Show 23: Environmental Studies (Ecology) ­ Show Notes
ENVIRONMENTAL STUDIES
August 22, 2012
Grade 10
Experiment 3:
Effect of Wind on the rate of transpiration using a potometer.
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