darren mcdonald @ stkh 2017-18 email: darrenmcdonald@nlesd...
TRANSCRIPT
World Geography 3202 Unit Three Ecosystems: Notes and Activities Name: _______________________
henever you see words in italics in this handout; it will be a description of some sort of learning activity for 6you to completeW
Ecosystem: A community of plants and animals within a physical environment. It ranges from a pond (small scale) to a rain112forest (large-scale).
Differentiate the terms food web & food chain. P. 94Food chain = linear sequence representing the nutrition of various species from the simplest plant to the top carnivore.Food web = a series of interconnecting food chains in an ecosystem.
Natural Vegetation Zones in Canada (Refer to p.102, Text)
There is a very strong relationship between climate and the location of an ecosystem: precipitation and temperatures.
In Canada, ecosystems are greatly influenced by temperatures and precipitation, which in turn are affected by latitude.
Generally, Canada is classified as a Nordic (northern) climate - cold climate. While summers are generally warm and at times hot, they are all too short. Winters on the other hand can be long and cold. These conditions are also directly related to wet and dry conditions which can affect soil fertility -
hence inability to produce vegetation.
On the map below; use green to map Boreal forest, brown to map tundra, yellow to map grasslands and red to map deciduous forests
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The Web Of Life p. 92 Food Relationships p. Be able to answer questions #3-9 in the bookDefine Ecosystem: the network of relationships among plants, animals and the non-living constituents in an environment.Differentiate the terms producers, consumer, decomposers. P. 93
Producer = a plant which can synthesize carbohydrates using carbon dioxide and the sun’s energy. Make their own food(sugars) in photosynthesis
Decomposers = Simple organisms that obtain their food from dead organisms and wastes. Consumers = All those organisms in trophic levels other than producers. Consumers eat their food. In a food chain the arrow points to the organism doing the eating
In the space below draw a food chain which includes LOCAL examples of producer, primary consumer, secondary consumer and tertiary consumer
View figure 6.3 on page 94 of your text and you can see that there are a lot of living things (plants & animals) and non-living things (soil, water, sun, temperature etc.) that affect each other. It is the system of relationships between the organisms and between the organisms and the non-living environment that makes up the ecosystem
Consumers, producers & decomposersSimilarities: All three are terms referring to the way organisms obtain food & energyDifferences: The way they obtain food > producers make it, Consumers eat it, decomposer feed on wastes & dead material.
Organisms in an Ecosystem· Producer: a plant which can synthesize carbohydrates using carbon dioxide and the sun’s energy. Eg grass trees, shrubs
for example in figure 6.3 on page 94 all the plants, like Duck weed, Willow, cat tails etc. are producers and convert the sun's energy into carbohydrates (food energy) for all other organisms in the ecosystem.
Producers are so named because they actually produce the food for the ecosystem.
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Consumers: All those organisms in trophic levels other than producers. Consumers eat their food. For example in figure 6.3 on page 94 all the animals, Raccoon, bass, duck etc. are consumers. Consumers are so named because they have to eat or consume their food.
1st-order or primary consumers eat producers. Animals that feed directly on plants (also called herbivores)
2nd-order or secondary consumers eat primary consumers. Animals that feed on other animals (also called carnivores)
3rd-order or tertiary consumers eat secondary consumers. Third order or tertiary consumers eat Second Order (Secondary) consumers
Decomposers: Simple organisms that obtain their food from dead organisms and wastes. Decomposers: Organism that feeds on dead plants and animals. Simple organisms that obtain their
food from dead organisms and wastes. For example in Figure 6.3 on page 94 of your text the colony of bacteria, protozoa, and flatworms are all decomposers. Decomposers are so named because they are actually responsible for decomposing dead organisms. They release nutrients back into the soil. Ex. Bacteria, Fungi
In the space provided draw an example of a food web containing humans (see p 94)
Use the diagram on the top of page 94 in your textbook to identify examples of producers & consumers record them in the table provided:
Producers Consumers
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Following are some local examples of species in a food chainBacteria, Seal, Phytoplankton, Shark, Krill, Caplin, CodDraw the food chain in the space provided
Add the following species to the food chain to create a food web:Puffin, seagull, beluga whale, dogfish, man, squid, mackerelDraw the food web in the space provided
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Outcome 3.3 Outline the Energy Flow in an Ecosystem
Tree → insect → insect eating bird → hawkProducer Primary consumer 2nd order consumer 3rd order
consumer
Note: The arrows indicate the flow of energy & nutrients
Using figure 6.5 on page 95 you can summarize the main energy flows in an ecosystem: the Sun is the source of all ecosystem energy; producers make food via photosynthesis; consumers eat plants and other consumers to get energy; each time energy moves from one organism to another, energy leaves the system in the form of heat; decomposers return nutrients to the soil but energy is not recycled.
Food Pyramids p. 95-100 Define Food Pyramid: a diagram showing each trophic level as a horizontal bar; producers are located on bottom & higher trophic levels are placed on top of each other; each bar is drawn in proportion to the mass of organisms, giving the triangle shape.
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Pyramid of Numbers: Why are there fewer organisms at each trophic level? P. 97 Less energy available at each level Fewer organisms can obtain energy to live Therefore fewer organisms at increasing levels Only a fraction of the energy available at one trophic level is transferred to the next trophic level. The
rule of thumb is 10%, this is very approximate. Typically the numbers and biomass of organisms decrease as one ascends the food chain.
Pyramid of Energy:There is a high degree of energy loss at each trophic level. The producers only store 1% of the sun's energy as food energy. Each consumer level loses energy for several reasons:
much of the energy is lost as heat; most of the energy is used to carry out life functions—ie. we burn many calories of energy each day,
so do all organisms; if an organism dies without being eaten the energy goes to the decomposers and not up the trophic
levels; consequently only about 10-15% of the energy is stored as usable food energy at each level..
If we look at this in terms of units of energy and we start with 1000 units of energy at the producer level then: the primary consumers would only have 100-150 units of food energy stored for the next level; the secondary consumers would only have 10-15 units of food energy stored for the next trophic level; the tertiary consumers would only have 1-1.5 units of food energy stored as food energy—it is easy to
see why we do not often see a quaternary trophic level
Match the lettered term (see next page) with the numbered definition Definition Term1. The network of relationships among plants, animals and the non-living constituents
in an environment.2. A diagram showing each trophic level as a horizontal bar3. A plant which can synthesize carbohydrates using carbon dioxide and the sun’s
energy.4. Linear sequence representing the flow of energy & nutrients from the simplest
plant to the top carnivore5. Simple organisms that obtain their food from dead organisms and wastes.6. All those organisms in trophic levels other than producers. Consumers eat their
food. 7. Animals that feed directly on plants8. A series of interconnecting food chains in an ecosystem.9. The term used to describe the fact that higher trophic level receive a higher dose
of food chain toxins.10.The source of all ecosystem energy11.Eat second order consumers12.The natural vegetation in the last possible stage of vegetation development.13.A particularly dangerous toxin because it is fat soluble and stays in an animal's fat.14.Animals that feed on other animals
A. Tertiary consumers B. Sun C. Food web D. Food PyramidE. Climax Vegetation F. Biological Amplification G. Ecosystem H. DDT
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I. Producer J. Decomposers K. First order consumers L. Consumers M. Food chain N. Carnivores
Use local examples to complete the table below, the complete pages 9 -13
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Producers Consumers
Herbivores Carnivores
Food Chain WorksheetRead the passage then answer the questions below.
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Food Chain Quiz - Multiple choice comprehension questionsColor the circle by each correct answer.
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Match each Food Chain Word to its Definition.
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Why are there fewer organisms at each trophic level? P. 97
Less energy available at each level Fewer organisms can obtain energy to live Therefore fewer organisms at increasing levels Only a fraction of the energy available at one trophic level is
transferred to the next trophic level. The rule of thumb is 10%, this is very approximate.
Typically the numbers and biomass of organisms decrease as one ascends the food chain.
Farmer question about energy efficiency P. 97a. Wheat would be far more efficient than cattle.b. Wheat is a producer and producers contain more energy than
primary consumers (like cows) as is seen in the food pyramid. The energy flow diagram shows that each trophic level loses energy as heat.
c. Farmers would have many other real concerns. Price, growing conditions, markets etc.
Ecosystems are in a very delicate balance. Changing one thing in the ecosystem will have a domino effect through the system because of the relationships that exist.
The introduction of Large mouth bass would cause: Sun fish move to reeds to escape predation by the large mouth bass The Plankton population might decrease because the bluegill sunfish would be feeding on them more
now that they can not stay in the open and eat the larva The Sun fish might decrease in size and abundance because the plankton is not as full of energy. The Larvae population might increase due to less feeding by the sun fish.
How do food pyramids help explain DDT Bioamplification? Outcome 3.4: Define the term biological Amplification (Magnification of Toxin Levels)Biological Amplification is the term used to describe the fact that higher trophic level receive a higher dose of food chain toxins.
This problem has occurred in our environment. The most common case was that of DDT which was used to control insect populations
DDT was a particularly dangerous toxin because it is fat soluble and stays in an animal's fat. (Some poisons are water soluble and can be excreted from the system.)
Lower order organisms ingest some poison which may or may not affect them. Higher order organisms eat large numbers of lower order organisms
Bioaccumulation Some pesticides were fat soluble which lead to a problem known as bioaccumulation. As each organism feeds on one lower in the food chain, the fat soluble pesticide began to be
concentrated in ever higher amounts as you move toward the top of the food pyramid.
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Biomagnifcation results from bioaccumulation Lower order organisms ingest some poison which may or may not affect them. Higher order organisms eat large numbers of lower order organisms. A small amount of toxin in a frog becomes a large amount in a hawk that eats 100 frogs. Since every organism eats far more than its own body mass in food, the tiny amounts found in each
organism consumed began to build up in greater concentrations in the consuming species This is illustrated by the damage done to predatory birds as a result of bioaccumulation of DDT. As a result DDT has been banned from use in North America.
In the spce below draw a food chain that illustrates how Biomagnifcation results from bioaccumulation. Start with DDT dispersed in fresh water and end with a tope presdator
Ecosystems are in a very delicate balance. Changing one thing in the ecosystem will have a domino effect through the system because of the relationships that exist.
Effect on ecosystem with the introduction of new species In 1997, a pack of 5 coyotes walked across the Strait of Bell Isle. People wanted to shoot them, however, fish and wildlife did not allow this. What impact did this have on the Newfoundland ecosystem?
Climax Vegetation
Climax Vegetation is the natural vegetation in the last possible stage of vegetation development. Climax vegetation is stable and in balance with the climatic conditions. It should change very little if left undisturbed.
Ecosystems are largely defined by the climax vegetation that grows in it. The type of vegetation is largely determined by the climate.The vegetation that would exist in an area if growth had proceeded undisturbed for an extended period. This would be the "final" collection of plant types that presumably would remain forever, or until the stable conditions were somehow disturbed.
Ecosystems of the world pp 101 109 (NOTE: for each heading there is map work on p 20 of the text)
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1. Coniferous (Boreal) Forests Shade some Coniferous Forests regions with green colour on map #1
The climax vegetation in coniferous forest is Evergreen trees (conifers)
. It is found only in the northern hemisphere and is located in a broad band across Northern North America and Northern Eurasia.Coniferous trees are well adapted to lack of water in winter (it is all frozen):
needle leaves reduce surface area for transpiration; drooping branches and conical shape allow heavy snow to fall off relieving the pressure; thick bark reduces water loss. The climate in the boreal forest is temperate cold winter. Warm summers Moderate precipitation It is found only in the northern hemisphere and is located in a broad band across Northern North
America and Northern Eurasia. Look at figure 6.8 on page 102 and locate the boreal forest; then turn to page 75 and locate the
temperate cold winter (subarctic) climate region. The two match very closely.
2. Tundra Shade some Tundra regions with brown colour on map # 1 Climate: ·Polar – sub arctic climate
Short summers Avg. monthly temp. always below 10oC Very cold long winter Light precipitation
The location of the Tundra can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found only in the northern hemisphere and is located north of the Boreal forest across Northern North America and Northern Eurasia.
The “climax vegetation” in the Tundra is: grasses, shrubs and low plants
The shrubs and bushes are well adapted to the extreme climate of the north where winter is long and summer is very short:
shallow roots are needed because 1-3 meters below the surface the soil is completely frozen (Permafrost);
the fast flowering and reproduction cycle is needed because the growing season is very short, lasting only 1-2 months.
Animals have a variety of adaptations to the harsh Tundra climate. hibernation from the cold winter; migration in for the summer season and out for the winter season is a common strategy for Birds and
even larger animals like caribou; the development of insulating features like thick fur & fat insulation is common among polar bears and
other mammals; white fur/feathers to help with camouflage is another common adaptation.
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· The climate in the Tundra is so definitive of the tundra that it is called Tundra climate. Look at figure 6.8 on page 102 and locate the Tundra; then turn to page 75 and locate the Polar (Tundra) climate region. the two match very closely.
3. Polar Ice Caps Draw an arrow towards the ice caps on map # 1The climax vegetation in the Polar Ice Cap is Phytoplankton beneath the ice.The location of the Polar Ice Caps can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found only in both hemispheres and is located only in the extremely high latitudes. The adaptation of producers to this ecosystem is extreme. There is no land for the producers to grow in so there are only small phytoplankton to form the base of the food chain. Animals have a variety of adaptations to the harsh Polar ice cap climate.
migration in for the summer season and out for the winter season is a common strategy for Birds and even larger animals like caribou;
the development of insulating features like thick fur & fat insulation is common among polar bears and other mammals;
white fur/feathers to help with camouflage is another common adaptation.
The climate in the Polar ice cap is so definitive of the Polar ice cap that it is called Polar (ice cap) climate. Look at figure 6.8 on page 102 and locate the Polar ice cap; then turn to page 75 and locate the Polar (Ice cap) climate region. The two match very closely.
4. Temperate Grasslands Shade some Grassland regions with brown colour on map # 1· The “climax vegetation” in Temperate Grasslands is grass with:
shallow roots; a small water requirement. Grasses are well adapted to lack of water: the small size of the plant means that it requires less water.
The climate in the temperate grassland is semi-arid in most locations but in some regions it is temperate cold winter.
Semi-arid climate or temperate cold winter Light precipitation, most of it occurs in summer Warm to hot summer Cold winters
The location of the temperate grassland can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found in North America, South America, Australia and Eurasia.Look at figure 6.8 and locate the temperate grassland; then turn to page 75 and locate the semiarid climate region. The two match very closely.
5. Temperate Deciduous Forests Shade some Deciduous Forest regions with red colour on map # 1
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The “climax vegetation” in Temperate forests is deciduous trees like oak, birch and maple which lose leaves in winter Deciduous trees are well adapted to lack of water in winter. Losing their leaves in winter helps them reduce water loss. Most water loss occurs through the leaves.
The climate in the Temperate Forest is temperate mild winter. Warm – hot summers Moderate - heavy precipitation
The location of the Temperate Forests can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. It is found predominantly in North America and South America but is present in Australia and Europe and Asia. ; then turn to page 75 and locate the temperate mild winter climate region. The two match very closely.
6. Tropical Rain Forests Shade some Tropical Rain Forest regions with blue colour on map #2
· The “climax vegetation” is tall Evergreen Broadleaf trees, these are well adapted to the thin soil with buttress roots (figure 6.15 on p 108) to help support their height. . Some plants are epiphytes which are well adapted to the rain forest. They reach the sun by lying in the canopy while they get water through roots that hang in the air and absorb moisture. Some animals are adapted to spend their entire life in the canopy.
Some animals are adapted to spend their entire life in the canopy.
Tropical Wet climate: High temperatures and precipitation year round
· The location of the Tropical Rainforest can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. These Rain Forests are mostly concentrated in two bands around the earth 10-30 North and South of the equator It is found in South America, Africa, Australia and South east Asia. and is contained within the tropics. then turn to page 75 and locate the tropical wet climate region The two match very closely.
7. Savannah Grasslands Shade some Savannah regions with green colour on map #2
· The climax vegetation in the savannah is grass with: shallow roots; small water requirement.
Grasses are well adapted to lack of water: the small size of the plant means that it requires less water. The climate in the Savannah is tropical wet & dry in most locations but in some regions it is semi-arid . Look at figure 6.8 on page 102 and locate the Savannas; then turn to page 75 and locate the Tropical Wet and dry climate to semi-arid climate. The two match very closely. It is found in South America, Australia, Africa and Southeast Asia. High temperatures most of the year Light to Moderate precipitation usually all in one season
8. Deserts Shade some desert regions with brown colour on map #2
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The climax vegetation in the Desert is cacti and fleshy plants well adapted to lack of water.
Cacti are well adapted to lack of water. They are often referred to as Xerophytes: long roots help them obtain water deep in the water table; water storage capability gives them the ability to endure long periods without rain; leaves modified as needles reduces the surface area for transpiration and helps reduce grazing which
would severely increase water loss.
Many animals have unique adaptations to the desert: deer mice can get all the water they need from the food they eat; toads have the behavioural adaptation of hibernating thorough the driest seasons; some Reptiles reduce water loss by excreting solid uric acid crystals instead of water containing urine; some mammals have the behavioural adaptation of nocturnal behaviour, which keeps them out of the
day time heat. The climate in the Desert is Arid. High temperatures year round and little precipitation
The location of the Desert can be seen by analyzing the world ecosystem map (figure 6.8) on page 102. ; then turn to page 75 and locate the arid climate region. The two match very closely. It is found in North America, South America, Australia, Africa and Asia. Deserts are mostly concentrated in two bands around the earth 10-30 North and South of the equator.
9. Mountain Ecosystems Use these symbols to indicate areas with mountains on map #2: ^^^^^^^
Mountains ecosystems are not exclusively low latitude, on the contrary they occur in most latitudes and as you will see in figure 6.10 on page 104 mountains can contain all types of ecosystems from all latitudes. The figure well-illustrates the fact that latitudinal succession closely parallels altitudinal succession. · The changes we see in ecosystems as we move north from the equatorare generally, tropical rain forest, Temperate forest, Coniferous forest, shrubby tundra and then polar ice cap. The same changes in ecosystem can be seen as you move up a tropical mountain.
Mountain ecosystems vary with altitude and temperature. Different climates at different elevations High elevations often like tundra
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Map #1
Map # 2
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Analyze world ecosystem map Boreal Forest & tundra are wide spread in high latitudes Tropical Rain Forests occur in low latitudes Tropical Rain forest is most predominant in South America. South America, Africa, Australia and Antarctica do not have tundra. Boreal forest is our ecosystem
Relationship between Ecosystems and Latitude The further north you travel the colder and drier it gets thus less vegetation. Winters are longer (colder) and summers are shorter (less heat). Mountains are the exception because elevation/altitude determines the type of vegetation. The higher you rise on the land the colder and drier it will be thus vegetation will change. Climate controls biome distribution by an altitudinal gradient and a latitudinal gradient. With increases of either altitude or latitude, cooler and drier conditions occur. Cooler conditions can cause aridity since cooler air can hold less water vapor than can warmer air.
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ADAPTATION: A specific or unique feature that enables an organism to become better suited to its habitat/environment.The change in an organism that allows it to live successfully/survive in its environment
Describe the adaptations shown
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Matching Exercise TWO
Match the lettered term with the numbered definitionDefinition Term1. Adaptations to the harsh Polar ice cap climate2. Climate in the Temperate Forest3. Climax vegetation in coniferous forest4. Below the surface the soil is completely frozen5. Are well adapted to lack of water6. Roots of broadleaf trees in the rainforest7. Reduce surface area for transpiration (coniferous trees)8. Climax vegetation in the Polar Ice Cap9. Lose their leaves in winter10. Climax vegetation in the Tundra11. Small size of the plant means that it requires less water12. Adaptations to the harsh Tundra climate13. Have the behavioural adaptation of hibernating thorough the driest seasons14. Reduces water loss.15.Occur in most latitudes16.Needed because the growing season is very short, lasting only 1-2 months.17.Trees of tropical rain forestA. Coniferous B. Grasses, shrubs and low plantsC. HibernationD. Deciduous treesE. CactiF. Phytoplankton G. Thick fur & fat insulationH. PermafrostI. Temperate mild winter.J. Broadleaf K. ToadsL. Mountains ecosystemM. Fast flowering and reproduction cyclesN. ButtressO. Needle leavesP. Thick bark Q. Grasses
Identify the ecosystems where the threat of desertification is greatest and describe the underlying causes
Deforestation contributes to the removal of nutrients from the soil and exposes more land to erosion. These directly contribute to desertification and as such, it can be considered an indicator of possible risks of desertification.
The following map shows the areas experiencing deforestation as well as land degradation in drylands Areas in Asia are experiencing both net loss of forests as well as land degradation. In many of these areas, the two drylands and forests are located fairly close to each other which allows
for desertification to spread more quickly. The areas shown on this map that are experiencing deforestation are all more likely to be subjected to
desertification at a faster rate than they would be without the removal of the forests.
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Desertification-is the process by which land becomes desert. Drought and overpopulation are main causesSigns
Lowering of water table Marked reduction of water supply Progressive destruction of native vegetation Accelerated soil erosion
Case Study: The Sahel The Sahel is becoming more like desert with thin, dry, sandy soils Soil erosion has created bare rock Vegetation is sparse
Climate
Drought: low rainfall since 1968. Soils become dry and there is no water left in wells. Trees die, grass withers and is replaced by poor desert scrub. Crops fail and cattle feed on poor pasture. Less roots to protect the topsoil, less humus; soils become more sandy and dry. Wind erosion removes the soil, causing dust storms, leaving bare rock.
Human activity Population is high and increasing fast. To increase food supplies more crops are grown and more cattle kept leading to over-cultivation and
over-grazing. Yields decline and cattle are undernourished and die. Demand increases for water as population grows. Trees are cut down for fuel supplies. Less vegetation; more dry, bare soil; more wind erosion.
Animals/insects Locusts destroy the crops. Overgrazing means all vegetation is eaten. Animals trample the ground reducing it to dust. Animals die and can’t breed.
Starvation Food and water shortages lead to malnutrition, famine, disease and high death rates.
Aid Programmes Large numbers of people become dependent on food aid programmes.
Migration From rural to urban areas causing over-population in towns. To refugee camps.
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Solutions In the short-term, provide food aid and water supplies to prevent suffering. Improve water supplies by building large reservoirs and drilling deeper wells. Conserve water in local small-scale schemes Encourage sustainable farming practices (using locally-made tools, not tractors). Provide drought-resistant seed such as millet (northern Nigeria). GM crops. Tree planting schemes to reduce soil erosion (Mauritania). International action to reduce the causes of global warming.
Outcome 3.11 Describe the factors that affect soil fertility.
Soil CharacteristicsThere are several characteristics of soil that affect its value for farming and growing vegetation.
Organic Content: a soil's fertility is determined as a ratio of the organic content to the content of ground bed rock.
Mineral content: varies with precipitation because heavy rains tend to leech soils removing minerals from the root region of soil.
Soil Texture: this will be discussed in the next lesson but refers to the mixture of fine particles (sand), very fine particles (silt) and extra fine particles (clay). The best texture for agriculture is an even mixture of each.
Soil ProfileTo understand about different soils you must understand that there are fairlydistinct layers within soil.
Top Layer: Dark color & Rich in Humus 2nd Layer: Mineral layer deposited from above 3rd Layer: weathered bed rock 4th Layer: Bed rock
As you can imagine the thickness and quality of the top humus layer is very important for plant life.
Label the soil horizon diagram at the right ==>Three Types of Soil Podzol: soils which predominate the boreal forest and tend to be somewhat acidic Chernozem: soils which tend to be the best for agriculture. They are found in grasslands which are semi-
arid resulting in less leeching and a mineral rich soil. Latosol: soils which are very infertile due to the high amount of leeching. They are found in tropical rain
forests with high amounts of rain which result in leeched mineral-poor soil.
Environmental Factors Affecting Soil Temperature: affects the development of humus. Too cold and the decay of organic matter is
slowed considerably.
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Precipitation: affects the mineral content of soil. Too much rain and minerals are leeched beyond the reach of plant roots. Too much rain also results in eluviation which moves small particles down through the soil.
Soil texture refers to the size of particles in the soil. While you don't have to memorize the exact sizes given on p.138 you should realize that:
o stones are approximately baseball-sized;o gravel is small stones;o sand is fine particles;o silt is very fine particles;o clay is extremely fine particles.
In the diagram to the left label the particles as either gravel clay, silt or sand
Soil is predominantly composed of sand, silt and clay. Its texture is determined by the mixture of these three. The best agricultural soils are an even mixture of all three and are referred to as Loam. While the earth's surface is covered in soil the amount of fertile soil valuable for agriculture is limited and is dwindling yearly. Poor soil management can lead to loss of fertile soil.Grasslands are semi-arid regions with extremely fertile soil. However, if proper soil management is not practiced these are among the most fragile places. Globally desertification of grasslands adjacent to deserts has been a problem.
Agricultural land on slopes/hills or mountains are very susceptible to water erosion.
Urban expansion has also been a factor in the loss of agricultural land. People have traditionally settled in rich farmland and increasing urbanization is covering up good farmland.Overgrazing, flooding and deforestation have also lead to the degradation of arable land.
Human Factors: Land use practices
1. Crop rotation: This procedure allows nutrients/minerals to replenish because differentcrops require different amounts and different types of nutrients and minerals. By rotating
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crops throughout different fields in essence it allows soil fertility to maintain itself.
2. Fallow field and Disk ploughing: Refers to growing a close growing crop, like grasses or clover in a section of the farm that will not be harvested during harvest season. Instead, the close growing crop is ploughed back into the ground to maintain and increase soilfertility.
3. Avoiding Chemical Fertilizers: Farmers use chemical fertilizers to increase farm production.Unfortunately at the same time they are killing micro-organisms and decomposers whichwork to produce top soil form dead organic matter. This is challenging because chemicalfertilizers work for the short term to increase soil fertility but over the long they are breakingdown the soil.
Natural factors: four soil forming processes
1. Humus: Refers to dead, decaying organic matter such as plants and animals.- This process assists soil fertility- Humus contains valuable nutrients and also helps to retain moisture.
2. Leaching: Rainwater percolates down through the soil and carries with it valuable soluble nutrients from the top soil to the subsoil.- This process strips the soil fertility from the topsoil.
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3. Capillary action: this process happens in warm dry areas where the sun evaporates surface water and draws water upwards from the subsoil to the topsoil.- This process results in more nutrients being brought upward to the topsoil by the water.
4. Eluvation: Like leaching, elevation results in less fertile soil.- However, unlike leaching, elevation, deals with insoluble minerals.- These mineral get carried deeper in the ground (topsoil to subsoil) by water or burrowing organisms which make a pathway for the minerals to sink
In the space provided draw a carefully labelled diagram of a typical soil profile for the boreal forest of NL -->
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Matching Exercise THREE Match the lettered term with the numbered definition
Definition Term1. Fairly distinct layers within soil2. Soils which predominate the boreal forest3. Extremely fine particles4. Refers to the mixture of fine particles (sand), very fine particles (silt) and extra fine
particles (clay).5. Soils which are very infertile due to the high amount of leeching6. Soils which tend to be the best for agriculture, found in grasslands7. Moves small particles down through the soil8. Lowest layer of the soil9. Best agricultural soils are an even mixture of sand, silt and clay10.Refers to dead, decaying organic matter such as plants and animals.11.Process happens in warm dry areas where the sun evaporates surface water and
draws water upwards from the subsoil to the topsoil.12.Varies with precipitation because heavy rains tend to leech soils removing
minerals from the root region of soil13.Rainwater percolates down through the soil and carries with it valuable soluble
nutrients from the top soil to the subsoil.14.Procedure allows nutrients/minerals to replenish because different
crops require different amounts and different types of nutrients and minerals15.Affects the development of humus16.Can lead to loss of fertile soil.17.Been a factor in the loss of agricultural land
. A. Clay B. Soil ProfileC. Mineral content: D. Urban expansion E. Latosol F. Bed rockG. Humus H. Crop rotationI. Poor soil management J. ChernozemK. Soil Texture L. TemperatureM. Podzol N. LeachingO. Capillary action P. LoamQ. Eluviation . R. Soil Profile
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Unit Three Completion Exercise
1. Ecosystem: the network of _______________ among plants, animals and the non-living constituents in an environment.
2. Producer: a plant which can synthesize _____________ using carbon dioxide and the sun’s energy.
3. __________________ are simple organisms that obtain their food from dead organisms and wastes.
4. Consumers are all those organisms in trophic levels other than ______________. Consumers eat their food.
5. Producers are so named because they actually produce the food for the ______________.
6. 1st-order or _________________ consumers eat producers.
7. 3rd-order or tertiary consumers eat __________________ consumers.
8. In a food chain the arrow points to the organism doing the ___________________
9. Food chain: ___________________ sequence representing the flow of energy & nutrients from the simplest plant to the top carnivore.
10. Food web: a series of ________________________ food chains in an ecosystem..
11. The Sun is the source of all ecosystem ______________________;
12. Food Pyramid: a diagram showing each trophic level as a ______________________ bar; producers are located on bottom & higher trophic levels are placed on top of each other
13. Only a fraction of the ___________________ available at one trophic level is transferred to the next trophic level. The rule of thumb is 10%, this is very approximate.
14. Each consumer level loses energy for several reasons: for one much of the energy is lost as ____________________.
15. Biological Amplification is the term used to describe the fact that higher trophic level receive a higher dose of food chain ____________________________.
16. ____________ was a particularly dangerous toxin because it is fat soluble and stays in an animal's fat. (Some poisons are water soluble and can be excreted from the system.)
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17. Climax Vegetation is the natural vegetation in the __________ possible stage of vegetation development.
18. Climax vegetation is stable and in balance with the _______________ conditions. It should change very little if left undisturbed.
19. Ecosystems are largely defined by the climax vegetation that grows in it. The type of vegetation is largely determined by the ___________________.
20. The climax vegetation in coniferous forest is ____________________ trees with: needle-like leaves and a thick bark
21. ________________ trees are well adapted to lack of water in winter (it is all frozen): needle leaves reduce surface area for transpiration and thick bark reduces water loss.
22. The shrubs and bushes are well adapted to the _______________ climate of the north where winter is long and summer is very short: shallow roots are needed because 1-3 meters below the surface the soil is completely frozen (Permafrost);
23. Animals have a variety of ___________________ to the harsh Tundra climate ; hibernation from the cold winter; and migration in for the summer season and out for the winter season is a common strategy for Birds and even larger animals like caribou;
24. The development of _____________________ features like thick fur & fat insulation is common among polar bears and other mammals;
25. White fur/feathers to help with ____________________ is another common adaptation.
26. The climax vegetation in the Polar Ice Cap is _________________ beneath the ice.
27. The “climax vegetation” in Temperate forests is _____________________ trees like oak, birch and maple which lose leaves in winter
28. Deciduous trees are well adapted to lack of water in winter. ______________ their leaves in winter helps them reduce water loss. Most water loss occurs through the leaves.
29. The climax vegetation in The Tropical Rain Forest is Tall Evergreen Broadleaf Trees with _______________________ roots.
30. Some rainforest animals are adapted to spend their entire life in the _________________.
31. The climax vegetation in the ________________ is grass with shallow roots and small water requirement.
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32. Cacti are well adapted to lack of water. They are often referred to as _________________:
33. Cacti have long roots help them obtain water deep in the water _________________;
34. Cactus leaves are modified as needles reduces the surface area for _______________ and helps reduce grazing which would severely increase water loss.
35. Many animals have unique adaptations to the ____________, for example deer mice can get all the water they need from the food they eat.
36. Toads have the behavioural adaptation of ________________ thorough the driest seasons.
37. Some reptiles reduce water loss by _________________ solid uric acid crystals
instead of water containing urine;
38. Certain mammals have the behavioural adaptation of _______________ behaviour, which keeps them out of the day time heat.
39. Organic content: a soil's _________________ is determined as a ratio of the organic content to the content of ground bed rock.
40. Soil __________________ refers to the mixture of fine particles (sand), very fine particles (silt) and extra fine particles (clay).
41. To understand about different soils you must understand that there are fairly distinct layers within soil. As you can imagine the thickness and quality of the top _____________ layer is very important for plant life.
42. Podzol: soils which predominate the boreal forest and tend to be somewhat ___________
43. Chernozem: soils which tend to be the best for agriculture. They are found in grasslands which are semi-arid resulting in less leeching and a mineral rich soil.
44. Latosol: soils which are very ____________ due to the high amount of leeching. They are found in tropical rain forests with high amounts of rain which result in leeched mineral-poor soil.
45. Temperature affects the development of humus. If it is too cold the ____________ of organic matter is slowed considerably.
46. Precipitation affects the mineral content of soil. Too much rain and minerals are ________ beyond the reach of plant roots.
47. Too much rain also results in _____________ which moves small particles down through the soil.
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48. The best agricultural soils are an even mixture of sand, silt and clay and are referred to as _______________.
49. While the earth's surface is covered in soil the amount of fertile soil valuable for agriculture is ____________________ and is dwindling yearly. Poor soil management can lead to loss of fertile soil.
50. ____________________ are semi-arid regions with extremely fertile soil. However, if proper soil management is not practiced these are among the most fragile places.
51. Globally ____________________ of grasslands adjacent to deserts has been a problem.
52. Agricultural land on slopes/hills or mountains are very susceptible to water ____________.
53. Urban _____________________ has also been a factor in the loss of agricultural land. People have traditionally settled in rich farmland and increasing urbanization is covering up good farmland.
54. Overgrazing, flooding and deforestation have also lead to the ___________ of arable land.
55. Crop rotation: This procedure allows nutrients and minerals to _______________ because different crops require different amounts and different types of nutrients and minerals.
56. By __________________ crops throughout different fields in essence it allows soil fertility to maintain itself.
57. ___________ field and disk ploughing refers to growing a close growing crop, like grasses or clover in a section of the farm that will not be harvested during harvest season.
58. Farmers use _____________________ fertilizers to increase farm production.
59. Chemical fertilizers work for the short term to increase soil ________________ but over the long they are breaking down the soil.
60. Humus contains valuable nutrients and also helps to retain ___________________.
61. Leaching rainwater ____________________ down through the soil and carries with it valuable soluble nutrients from the top soil to the subsoil.
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62. Capillary action: this process happens in warm dry areas where the sun _______________ surface water and draws water upwards from the subsoil to the topsoil.
63. Like leaching, ____________________ results in less fertile soil. However, unlike leaching, elevation, deals with insoluble minerals.
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