Unit 1 - Sustaining Earth's Ecosystems
Chapter 1: Biomes and ecosystems are divisions of the biosphere
PLO's - explain the interaction of abiotic and biotic factors within an ecosystem
Section 1.1 - Biomes
Section 1.2 - Ecosystems
The biosphere is a thin layer of life on the surface of the earth. The biosphere surrounds the earth, includes part of the atmosphere where life exits and any area underground where life exits.
Biomes
The biosphere is organized into 8 different biomes. These are areas of the world that have similar temperatures and percipitation levels throughout the year. Biomes will also have similar types of plant and animal life.
The 8 biomes are:
Which biome do you live in?
Every biome has living parts (biotic) and non-living parts (abiotic)
The biotic factors in a biome include the animals and plants that live there.
The abiotic factors of a biome include the amount of rainfall, elevation, sunlight and temperature.
The biosphere is organized into 8 different biomes. These are areas of the world that have similar temperatures and percipitation levels throughout the year. Biomes will also have similar types of plant and animal life.
The 8 biomes are:
- Boreal Forest
- Desert - to read more check out this link
- Grassland
- Permanent Ice
- Temperate Deciduous Forest
- Temperate Rainforest
- Tropical Rainforest
- Tundra
Which biome do you live in?
Every biome has living parts (biotic) and non-living parts (abiotic)
The biotic factors in a biome include the animals and plants that live there.
The abiotic factors of a biome include the amount of rainfall, elevation, sunlight and temperature.
Biomes are areas on earth that have similar characteristics. Desert biomes are located in various parts of the earth, but they all have something in common: low precipitation.
In this section we are going to look at the different reasons why biomes are the way they are.
FACTORS AFFECTING BIOME DISTRIBUTION
1. Temperature and Precipitation.
These are abiotic factors that affect biome distribution. Plants and animals that live in the different biomes need to be adapted to the amount of rainfall and temperature range of their biomes. A slug survives in the cool. wet rainforest, but would die in the hot, dry desert.
In this section we are going to look at the different reasons why biomes are the way they are.
FACTORS AFFECTING BIOME DISTRIBUTION
1. Temperature and Precipitation.
These are abiotic factors that affect biome distribution. Plants and animals that live in the different biomes need to be adapted to the amount of rainfall and temperature range of their biomes. A slug survives in the cool. wet rainforest, but would die in the hot, dry desert.
Using the graph above, which biome would have an average annual temperature of 25oC and an average annual precipitation of about 250 cm?
Complete the practice problems on page 13 using this graph.
2. Latitude
The next factor that affects biome distribution is latitude. Latitude describes how far north of south an area is from the equator.
Complete the practice problems on page 13 using this graph.
2. Latitude
The next factor that affects biome distribution is latitude. Latitude describes how far north of south an area is from the equator.
The equator is at 0o of latitude. This is where the sun's rays hit the earth most directly and therefore the regions around the equator are hot.
To the north of the equator is the Tropic of Cancer. To the south of the equator is the Tropic of Capricorn. The tropical zone lies in between. This is where you will find the tropical rainforest biome and some of the desert biomes.
The most important thing to remember about latitude is this : Generally rainfall and temperatures are highest at the equator and decrease as you move north or south away from the equator.
3. Elevation
To the north of the equator is the Tropic of Cancer. To the south of the equator is the Tropic of Capricorn. The tropical zone lies in between. This is where you will find the tropical rainforest biome and some of the desert biomes.
The most important thing to remember about latitude is this : Generally rainfall and temperatures are highest at the equator and decrease as you move north or south away from the equator.
3. Elevation
The most important thing to remember about elevation is this: Both temperature and precipitation decrease as elevation increases.
In the diagram above, demonstrates how high mountains can be covered with snow year round. The air at high elevations is thin and cannot hold much water or heat. The heaviest, warmest and wettest blanket of air occurs at sea level.
4. Ocean Currents
The last factor to affect biome distribution is ocean currents. Ocean currents refer to masses of ocean water that flow around certain land areas. The reason why Vancouver Island does not get much snow in the winter is because we have this large mass of relatively warm water surrounding us. It is like sleeping with a hot water bottle in your bed. It keeps you warm. New Zealand and Canada both have temperate rainforest biomes because of the warm ocean bodies near them.
Complete the reading Check Questions on page 15.(1-5)
In the diagram above, demonstrates how high mountains can be covered with snow year round. The air at high elevations is thin and cannot hold much water or heat. The heaviest, warmest and wettest blanket of air occurs at sea level.
4. Ocean Currents
The last factor to affect biome distribution is ocean currents. Ocean currents refer to masses of ocean water that flow around certain land areas. The reason why Vancouver Island does not get much snow in the winter is because we have this large mass of relatively warm water surrounding us. It is like sleeping with a hot water bottle in your bed. It keeps you warm. New Zealand and Canada both have temperate rainforest biomes because of the warm ocean bodies near them.
Complete the reading Check Questions on page 15.(1-5)
Climatographs
Temperature and precipitation are to important factors in biome distribution. They also are useful in describing an areas CLIMATE. Climate is the average pattern of weather that occurs in a region over a period of years.
A climatograph is a graph that shows both the temperature and precipitation averages in a region every month over a period of years.
Every biome will have a different looking climatograph because their climates are different.
Look at the climatograph below. The red line is measuring the average temperatures every month, while the bar graphs below it are measuring the average rainfall amounts.
Temperature and precipitation are to important factors in biome distribution. They also are useful in describing an areas CLIMATE. Climate is the average pattern of weather that occurs in a region over a period of years.
A climatograph is a graph that shows both the temperature and precipitation averages in a region every month over a period of years.
Every biome will have a different looking climatograph because their climates are different.
Look at the climatograph below. The red line is measuring the average temperatures every month, while the bar graphs below it are measuring the average rainfall amounts.
Lets look at another climatograph and see what information we can gather about its biome.
1. What is the temperature range for this area?
2. How does that temperature range compare to the boreal forest biome graph above?
3. Estimate the yearly rainfall amount by adding up a rough estimate for each month.
4. How does that total compare with the boreal forest graph above?
5. Based on the information you have gathered, which biome do you think Yuma, Arizona is located in?
2. How does that temperature range compare to the boreal forest biome graph above?
3. Estimate the yearly rainfall amount by adding up a rough estimate for each month.
4. How does that total compare with the boreal forest graph above?
5. Based on the information you have gathered, which biome do you think Yuma, Arizona is located in?
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Adaptations
Could a alligator survive in the arctic? Not likely. The alligator does not have the right tools to survive in a cold environment.
Organisms are specifically designed to survive in the biome in which they live.
Three different types of adaptations are possible.
1. Structural Adaptations: these are parts of an organisms body that help it to survive in its environment
Could a alligator survive in the arctic? Not likely. The alligator does not have the right tools to survive in a cold environment.
Organisms are specifically designed to survive in the biome in which they live.
Three different types of adaptations are possible.
1. Structural Adaptations: these are parts of an organisms body that help it to survive in its environment
The arctic fox has fur that changes colour with the season to camouflage it and help it capture prey.
Seals have a layer of blubber underneath their fur to keep internal organs warm in the permanent ice biome.
2. Behavioral Adaptations: these are things that an organism does to help it survive in its environment
Musk oxen huddle together to keep warm in the cold winter of the tundra.
3. Physiological Adaptations: these are things that happen inside an organisms body to help it survive its environment.
Camels store water in their humps to survive the dry desert biome
Cacti can store water inside their bodies as well. They also use less water than other plants during photosynthesis.
Ecosystems
An ecosystem refers to an area where the abiotic parts and the biotic parts of multiple communities interact with each other.
An ecosystem refers to an area where the abiotic parts and the biotic parts of multiple communities interact with each other.
Every plant, every animal and every abiotic part such as precipitation level or temperature range, plays a role in how an ecosystem functions.
Ecosystems can be very large, like the roaming range of prairie buffalo. Or ecosystems can be very small, like the size of a tide pool. The animals and plants in the tide pool do not interact with animals and plants outside of he tide pool, so the boundaries of the ecosystem are set
Biomes contain many different ecosystems, which contain many different communities, which contain many different populations of many individuals.
Ecosystems can be very large, like the roaming range of prairie buffalo. Or ecosystems can be very small, like the size of a tide pool. The animals and plants in the tide pool do not interact with animals and plants outside of he tide pool, so the boundaries of the ecosystem are set
Biomes contain many different ecosystems, which contain many different communities, which contain many different populations of many individuals.
Abiotic Interactions Within Ecosystems
The abiotic parts of an ecosystem include water, light, oxygen, temperature and soil. The interactions between the biotic components and the abiotic are very important.
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Biotic Interactions In Ecosystems
Plants and animals within an ecosystem can interact with each other in many different ways.
Many different types of relationships between organisms are possible.
Symbiotic relationships are ones between different species that live together in close proximity. Three different symbiotic relationships are possible:
1. Commensalism:
Plants and animals within an ecosystem can interact with each other in many different ways.
Many different types of relationships between organisms are possible.
Symbiotic relationships are ones between different species that live together in close proximity. Three different symbiotic relationships are possible:
1. Commensalism:
2. Mutualism:
3. Parasitism:
Other Biotic Interactions
Niches: This term describes an organisms role in an ecosystem. An animals niche is how the animal contributes to the ecosystem and how it survives in the ecosystem.
Niches: This term describes an organisms role in an ecosystem. An animals niche is how the animal contributes to the ecosystem and how it survives in the ecosystem.
Lets consider the bald eagle. It makes its home in the tall branches of Douglas Fir or cedar trees. It catches fish from nearby water sources. It also catches small land animals like mice, rats, otters, snakes. The eagle has a large food source to choose from.
All if this information describes the eagles niche.
Competition
This is a harmful interaction when two organisms use the same resource in the same location and at the same time.
Competition can be seen in trees as the tallest of the trees are the ones that out complete the rest for light
Predators compete with each other for game to hunt and kill. The fastest, strongest hunters are the ones that out compete the rest and have more energy for reproduction.
Predation
This describes the interaction where one organism (predator) eats all or some of another organism (prey).
Predators have adaptations that help them to become better hunters
Prey animals have adaptations that help them to escape predators better.
Complete the Reading Check questions on page 47
All if this information describes the eagles niche.
Competition
This is a harmful interaction when two organisms use the same resource in the same location and at the same time.
Competition can be seen in trees as the tallest of the trees are the ones that out complete the rest for light
Predators compete with each other for game to hunt and kill. The fastest, strongest hunters are the ones that out compete the rest and have more energy for reproduction.
Predation
This describes the interaction where one organism (predator) eats all or some of another organism (prey).
Predators have adaptations that help them to become better hunters
Prey animals have adaptations that help them to escape predators better.
Complete the Reading Check questions on page 47
Chapter 1 Review
We have completed the study of the first chapter in our science 10 course.
The major concepts we looked at are:
Biomes: factors influencing distribution
patterns of distribution as you move north or south of the equator
biotic and abiotic characteristics
climatographs
adaptations for survival (structural, behavioral, physiological).
Ecosystems: biotic interactions (commensalism, mutualism, parasitism, competition, predation)
To review the major concepts we looked at, please complete questions 1, 3, 6, 8 and 10 on page 51.
We have completed the study of the first chapter in our science 10 course.
The major concepts we looked at are:
Biomes: factors influencing distribution
patterns of distribution as you move north or south of the equator
biotic and abiotic characteristics
climatographs
adaptations for survival (structural, behavioral, physiological).
Ecosystems: biotic interactions (commensalism, mutualism, parasitism, competition, predation)
To review the major concepts we looked at, please complete questions 1, 3, 6, 8 and 10 on page 51.
QUIZ
Chapter 2: Energy flow and nutrient cycles support life in ecosystems
PLO's - assess the potential impacts of bioaccumulation
Section 2.1 - Energy Flow in Ecosystems
Section 2.2 - Nutrient Cycles in Ecosystems
Section 2.3 - Effects of Bioaccumulation on Ecosystems
Energy Flow in Ecosystems
Most of the energy that we enjoy in our daily lives (electricity, gasoline, light, heat etc), in one way or another, comes originally from the sun that shines on us everyday.
We are not able to use the energy that comes from the sun directly, we need something to catch it for us and change it from light, into a form that we can use.
Plants are able to trap the energy from the sun using the process of photosynthesis to produce sugar. Because the plant kingdom is able to use the suns energy directly, they are able to produce more biomass than any other organism alive today.
Biomass is the mass or weight of all the living or decaying members of a group of organisms. For example, if we asked how much biomass human beings have, we would have to weigh all the living and decaying people on earth to find their mass. Yuck!
Every ecosystem has the same direction of energy flow. Energy in ecosystems flows through trophic levels.
A trophic level describes where an organism obtains its energy from.
Organisms in the first trophic level are the producers. Plants are producers because they produce their own food using energy from the sun.
We are not able to use the energy that comes from the sun directly, we need something to catch it for us and change it from light, into a form that we can use.
Plants are able to trap the energy from the sun using the process of photosynthesis to produce sugar. Because the plant kingdom is able to use the suns energy directly, they are able to produce more biomass than any other organism alive today.
Biomass is the mass or weight of all the living or decaying members of a group of organisms. For example, if we asked how much biomass human beings have, we would have to weigh all the living and decaying people on earth to find their mass. Yuck!
Every ecosystem has the same direction of energy flow. Energy in ecosystems flows through trophic levels.
A trophic level describes where an organism obtains its energy from.
Organisms in the first trophic level are the producers. Plants are producers because they produce their own food using energy from the sun.
Organisms in the second trophic level are called primary consumers. They consume the producers. Insects, rabbits, deer or any organisms that eats plants is a primary consumer.
Secondary consumers are those animals that eat the primary consumers. Frogs, robins, dragonflies etc. are examples of secondary consumers
Tertiary consumers are the top of the food chain. These organisms feed on the secondary consumers. The organisms are the top predators in the food chain usually. Cougars, hawks, eagles, sharks etc. are examples of tertiary consumers.
Secondary consumers are those animals that eat the primary consumers. Frogs, robins, dragonflies etc. are examples of secondary consumers
Tertiary consumers are the top of the food chain. These organisms feed on the secondary consumers. The organisms are the top predators in the food chain usually. Cougars, hawks, eagles, sharks etc. are examples of tertiary consumers.
Food Chains and Food Webs
Food Chains
Food chains show the feeding relationship between trophic levels in an ecosystem. Energy is passes from one trophic level to another when organisms feed on each other. The term biomass refers to the amount of matter present in each trophic level.
Food Chains
Food chains show the feeding relationship between trophic levels in an ecosystem. Energy is passes from one trophic level to another when organisms feed on each other. The term biomass refers to the amount of matter present in each trophic level.
The diagram above shows a terrestrial (land-based) food chain and an aquatic (water-based) food chain.
Primary producers trap energy from the sun in the process of photosynthesis. They are consumed and their energy is passed on to the primary consumers. These animals are also known as herbivores because they only eat plant matter. The primary consumers pass their energy on to the secondary consumers. Secondary consumers are also known as carnivoresbecause they only eat animal matter. Secondary consumers pass their energy on to tertiary consumers. These animals are carnivores as well.
Primary producers trap energy from the sun in the process of photosynthesis. They are consumed and their energy is passed on to the primary consumers. These animals are also known as herbivores because they only eat plant matter. The primary consumers pass their energy on to the secondary consumers. Secondary consumers are also known as carnivoresbecause they only eat animal matter. Secondary consumers pass their energy on to tertiary consumers. These animals are carnivores as well.
The detrivores are a group of animals that feed on dead and decaying plant and animals material. Putting these organisms into a food chain would look like the above. Detrivores feed on all trophic levels after those animals die. Decomposers change dead organic matter into usable nutrients for the ecosystem. They help the process of decomposition which is the breaking down of organic wastes and dead organic matter. The action of living organisms in this breakdown is called biodegradation.
Omnivores are a group of animals that feed on both plant and animal matter. A grizzly or a black bear are good examples of an omnivore. Can you think of any others?
Omnivores are a group of animals that feed on both plant and animal matter. A grizzly or a black bear are good examples of an omnivore. Can you think of any others?
Food Webs
Food Webs
Food webs show a number of food chains and how these interact with each other. Organisms often have more than one food source, so a food web is a more accurate description of the feeding niches that are present in an ecosystem.
Food Webs
Food webs show a number of food chains and how these interact with each other. Organisms often have more than one food source, so a food web is a more accurate description of the feeding niches that are present in an ecosystem.
The arrows in the diagram show the direction of energy transfer. The grasses transfer their energy to the marmot because the marmot eats them.
Food webs also show that some animals belong to more than one trophic level. For example, the grouse is a primary consumer when it eats berries and flowers, but it can also be a secondary consumer when it eats the butterfly or other insects.
Food webs also show that some animals belong to more than one trophic level. For example, the grouse is a primary consumer when it eats berries and flowers, but it can also be a secondary consumer when it eats the butterfly or other insects.
Food Pyramids
Food pyramids are another way to show how energy transfers in a food chain from trophic level to trophic level.
Organisms are constantly losing energy, that is why they need to keep consuming other organisms. Energy is lost as heat, waste and maintaining body functions.
Food pyramids are another way to show how energy transfers in a food chain from trophic level to trophic level.
Organisms are constantly losing energy, that is why they need to keep consuming other organisms. Energy is lost as heat, waste and maintaining body functions.
When a predator catches and consumes its prey, the predator is only able to take in 10% of the energy its prey once had. 90% of the energy available in each trophic level is lost. A food pyramid shows the amount of available energy as you travel from trophic level to trophic level.
The producers trap energy directly from the source, the sun. They are able to store the greatest amount of energy. They also have the greatest amount of biomass compared to the other trophic levels.
This means that if you took all the plants in an ecosystem and weighed them, their weight would be much greater than the weight of the primary consumers who feed on them.
Only 10% of the available energy in the producer trophic level is passed on to the primary consumer trophic level.
10% of the energy available in the primary consumer trophic level is passed on to the secondary consumer, 10% of that available energy is passed on to the tertiary consumers.
Which trophic level has the least amount of biomass? Why is this so?
Complete the Reading Check questions on page 64
This means that if you took all the plants in an ecosystem and weighed them, their weight would be much greater than the weight of the primary consumers who feed on them.
Only 10% of the available energy in the producer trophic level is passed on to the primary consumer trophic level.
10% of the energy available in the primary consumer trophic level is passed on to the secondary consumer, 10% of that available energy is passed on to the tertiary consumers.
Which trophic level has the least amount of biomass? Why is this so?
Complete the Reading Check questions on page 64
Nutrient Cycles in Ecosystems
Nutrients are chemicals that are required for plant and animal growth and other life processes.
The nutrients that we are going to look at are :
A) Carbon B) Nitrogen C) Phosphorus
Nutrients are chemicals that are required for plant and animal growth and other life processes.
The nutrients that we are going to look at are :
A) Carbon B) Nitrogen C) Phosphorus
Each of these three nutrients has an important impact on ecosystems, places where it is stored (long term and short term), processes that move it from one store to the next and human activities that affect its cycle from store to store.
As you go through these cycles with your instructor, make sure to fill in the Nutrient Cycle Worksheet with the appropriate information.
As you go through these cycles with your instructor, make sure to fill in the Nutrient Cycle Worksheet with the appropriate information.
The Carbon Cycle
Why is carbon important?
- It forms the back bone of all molecules making up life on this earth.
- The chemical reactions that make life possible on earth, like photosynthesis and cellular respiration, use carbon as an essential component.
How is Carbon Stored?
Short Term Storage: Since all life is made of carbon, living organisms are a large, short term, storage site for carbon. The atmosphere is another short term storage site for carbon. It exists as carbon dioxide gas in the atmosphere
Long Term Storage: After millions of years of carbon-based life dying and their remains decomposing on the ground, or settling on the ocean floor, carbon rich deposits of coal, oil and natural gas are created. Marine animals who have a shell (oysters, mussels, clams, etc.) use carbonate to make their shells. When they die, those shells settle on the ocean floor. After a long period of time, that carbonate changes to limestone, or sedimentary rock.
How is Carbon Exchanged?
Photosynthesis: This is the process that plants use to create sugars from sunlight. The plant takes carbon out of the atmosphere in the form of carbon dioxide and transforms it into a sugar molecule that uses carbon as its backbone. Oxygen is created as a by-product of this reaction and is released into the atmosphere.
Cellular respiration: This process is the opposite of photosynthesis. Plant and animal cells use the sugars created by photosynthesis for their own energy purposes. When they do this, carbon dioxide is released into the atmosphere. Oxygen is used in this process.
Decomposition: This is the process of taking dead organic matter and breaking it down into a form that other organisms can use. For example, bacteria and fungi convert cellulose (dead plant matter) into carbon dioxide, which living plants then use in photosynthesis.
Human Effects on the Carbon Cycle
The most impactful activity that humans have had on the carbon cycle is taking the long term carbon stores and putting them into the atmosphere. Humans dig up the coal, oil and natural gas stores ta took millions of years to create, and burn them. This creates carbon dioxide, which is in the smoke or exhaust that ends up in the air.
Humans also cut down trees for lumber and farmland. This deforestation adds to the carbon that is in the atmosphere because the plants that were cut down would have removed carbon dioxide from the atmosphere had they been left.
Why is carbon important?
- It forms the back bone of all molecules making up life on this earth.
- The chemical reactions that make life possible on earth, like photosynthesis and cellular respiration, use carbon as an essential component.
How is Carbon Stored?
Short Term Storage: Since all life is made of carbon, living organisms are a large, short term, storage site for carbon. The atmosphere is another short term storage site for carbon. It exists as carbon dioxide gas in the atmosphere
Long Term Storage: After millions of years of carbon-based life dying and their remains decomposing on the ground, or settling on the ocean floor, carbon rich deposits of coal, oil and natural gas are created. Marine animals who have a shell (oysters, mussels, clams, etc.) use carbonate to make their shells. When they die, those shells settle on the ocean floor. After a long period of time, that carbonate changes to limestone, or sedimentary rock.
How is Carbon Exchanged?
Photosynthesis: This is the process that plants use to create sugars from sunlight. The plant takes carbon out of the atmosphere in the form of carbon dioxide and transforms it into a sugar molecule that uses carbon as its backbone. Oxygen is created as a by-product of this reaction and is released into the atmosphere.
Cellular respiration: This process is the opposite of photosynthesis. Plant and animal cells use the sugars created by photosynthesis for their own energy purposes. When they do this, carbon dioxide is released into the atmosphere. Oxygen is used in this process.
Decomposition: This is the process of taking dead organic matter and breaking it down into a form that other organisms can use. For example, bacteria and fungi convert cellulose (dead plant matter) into carbon dioxide, which living plants then use in photosynthesis.
Human Effects on the Carbon Cycle
The most impactful activity that humans have had on the carbon cycle is taking the long term carbon stores and putting them into the atmosphere. Humans dig up the coal, oil and natural gas stores ta took millions of years to create, and burn them. This creates carbon dioxide, which is in the smoke or exhaust that ends up in the air.
Humans also cut down trees for lumber and farmland. This deforestation adds to the carbon that is in the atmosphere because the plants that were cut down would have removed carbon dioxide from the atmosphere had they been left.
Complete the Reading Check questions on page 78
QUIZ
The Nitrogen Cycle
Why is nitrogen important?
Nitrogen is a major part of the DNA molecule. Every living thing passes on its genetic information to its offspring using DNA. Nitrogen is also a major part of muscle tissue. Animals use muscle tissue to move, capture prey or escape from prey. For plants, nitrogen is important for growth.
How is nitrogen stored?
The largest, long term store for nitrogen is the atmosphere. It is stored here as nitrogen gas (N2). This is a very stable molecule that does not like to react with others. So it is hard for plants and animals to get it.
Organic matter in the soil and the oceans are other major, short term sources of nitrogen.
How is nitrogen exchanged?
Most of the earth's nitrogen is in the atmosphere as N2. Organisms cannot use N2. It needs to be changed into a usable form.
Nitrogen Fixation: there are 2 ways nitrogen can be fixed so that organisms can use it. 1) lightning in the atmosphere fixes N2 into nitrate (NO3-). Rain causes the nitrate to fall out of the atmosphere and down to earth. Plants are then able to use this form of nitrogen to grow. 2) bacteria in the soil or in the ocean fix N2 into ammonium (NH4-). Plants also use this form of nitrogen to grow.
Nitrification: This process involves bacteria that take the NH4- and change it to NO3- in the soil. Plants can take up this nitrate using their roots and use it to grow
Human Effects on the Nitrogen Cycle
Fossil Fuel Burning: Nitrogen molecules that are present in coal, oil and natural gas are released into the atmosphere when these fuels are burned. Nitrogen molecules fall back to earth as nitric acid (acid rain)
Chemical Fertilizers: To produce better crops, farmers spray nitrogen chemicals on to their fields. The plants take up some of the fertilizer and the rest is washed by rain into the soil, then into ground water and other water sources. Algae blooms can result in ponds where excess nitrogen is present. This can kill a pond by robbing all other plant life of light and nutrients.
Why is nitrogen important?
Nitrogen is a major part of the DNA molecule. Every living thing passes on its genetic information to its offspring using DNA. Nitrogen is also a major part of muscle tissue. Animals use muscle tissue to move, capture prey or escape from prey. For plants, nitrogen is important for growth.
How is nitrogen stored?
The largest, long term store for nitrogen is the atmosphere. It is stored here as nitrogen gas (N2). This is a very stable molecule that does not like to react with others. So it is hard for plants and animals to get it.
Organic matter in the soil and the oceans are other major, short term sources of nitrogen.
How is nitrogen exchanged?
Most of the earth's nitrogen is in the atmosphere as N2. Organisms cannot use N2. It needs to be changed into a usable form.
Nitrogen Fixation: there are 2 ways nitrogen can be fixed so that organisms can use it. 1) lightning in the atmosphere fixes N2 into nitrate (NO3-). Rain causes the nitrate to fall out of the atmosphere and down to earth. Plants are then able to use this form of nitrogen to grow. 2) bacteria in the soil or in the ocean fix N2 into ammonium (NH4-). Plants also use this form of nitrogen to grow.
Nitrification: This process involves bacteria that take the NH4- and change it to NO3- in the soil. Plants can take up this nitrate using their roots and use it to grow
Human Effects on the Nitrogen Cycle
Fossil Fuel Burning: Nitrogen molecules that are present in coal, oil and natural gas are released into the atmosphere when these fuels are burned. Nitrogen molecules fall back to earth as nitric acid (acid rain)
Chemical Fertilizers: To produce better crops, farmers spray nitrogen chemicals on to their fields. The plants take up some of the fertilizer and the rest is washed by rain into the soil, then into ground water and other water sources. Algae blooms can result in ponds where excess nitrogen is present. This can kill a pond by robbing all other plant life of light and nutrients.
Complete the Reading Check questions on page 80 and 83
The Phosphorus Cycle
Why is Phosphorus Important?
Phosphorus is one of the main atoms in the molecule that provides energy to the cells of plants and animals. Phosphorus contributes to root development, stem strength and seed production in plants. Humans also need phosphorus to develop strong bones.
How is Phosphorus Stored?
Phosphorus is stored in rock. Phosphate rock and sedimentary rock on the ocean floor. Small amounts are found in the tissues of living organisms.
How is Phosphorus Exchanged?
Weathering of rocks can release the trapped phosphate. There are 2 types of weathering processes.
1) Chemical Weathering: chemical reactions dissolve the phosphate trapped in rocks into the soil where it can be taken up by plants. Lichen are a group of organisms that can dissolve rock through chemical means and use the phosphate that is released. Acidic rain also dissolves phosphate rock and chemically releases it into the soil.
2) Physical Weathering: wind, rain and freezing work to break exposed rock into small pieces that can eventually be used by plants as the phosphate makes its way into the soil.
Human Effects on the Phosphorus Cycle.
Phosphate is used in fertilizers and in dishwasher detergents. So humans mine the rock that contains phosphate. This releases excess phosphate into ecosystems. Excess phosphate can harm some organisms such as fish. If a great deal of phosphate is washed into a lake or pond, it can cause fish death. This is a large scale fish die off event localized to a certain region.
Why is Phosphorus Important?
Phosphorus is one of the main atoms in the molecule that provides energy to the cells of plants and animals. Phosphorus contributes to root development, stem strength and seed production in plants. Humans also need phosphorus to develop strong bones.
How is Phosphorus Stored?
Phosphorus is stored in rock. Phosphate rock and sedimentary rock on the ocean floor. Small amounts are found in the tissues of living organisms.
How is Phosphorus Exchanged?
Weathering of rocks can release the trapped phosphate. There are 2 types of weathering processes.
1) Chemical Weathering: chemical reactions dissolve the phosphate trapped in rocks into the soil where it can be taken up by plants. Lichen are a group of organisms that can dissolve rock through chemical means and use the phosphate that is released. Acidic rain also dissolves phosphate rock and chemically releases it into the soil.
2) Physical Weathering: wind, rain and freezing work to break exposed rock into small pieces that can eventually be used by plants as the phosphate makes its way into the soil.
Human Effects on the Phosphorus Cycle.
Phosphate is used in fertilizers and in dishwasher detergents. So humans mine the rock that contains phosphate. This releases excess phosphate into ecosystems. Excess phosphate can harm some organisms such as fish. If a great deal of phosphate is washed into a lake or pond, it can cause fish death. This is a large scale fish die off event localized to a certain region.
Complete Reading Check questions on page 86
NUTRIENT CYCLES SUMMARY:
Bioaccumulation
The word "accumulate" means to build up, or retain. "Bio" refers to life and living organisms. So the term bioaccumulation is the building up or retaining of chemicals in living organisms.
When these chemicals are pollutants, such as lead, pesticides, mercury, cadmium or PCB's, living organisms can be harmed.
These chemicals are not broken down by decomposers and build up in the air, the soil or the water.
Organisms take theses pollutants into their bodies through their food, skin contact or breathing. These pollutants are stored in the fat tissue of an animal.
Harmful effects can happen to an organisms nervous system, reproductive system and immune system. Birth defects or a complete failure to reproduce can happen as well.
Keystone Species are species that are most important to an ecosystem because so many other species depend on them for their survival. The salmon of the west coast of British Columbia are an example of a keystone species. Bears, eagles, wolves, crows, gulls and otters all depend on the salmon as a food source. When the salmon die and decompose, the nutrients released from their bodies supplies the trees and other plant life with nourishment.
Biomagnification: occurs when chemicals accumulate and become more concentrated at each trophic level. The producers in an ecosystem are usually the first organisms to take in the chemicals.
Each producer takes in a little of the chemical. The primary consumers spend their lives feeding on those producers, taking in a little of the chemical each time. This causes a large amount of the chemical to accumulate in the primary consumers.
The secondary consumers spend their lives feeding on the primary consumers, taking in large amounts of the chemical each time they feed. This causes even greater concentration of the chemical in this trophic level.
Finally its the tertiary consumers turn to feed and they are ingesting the largest amount of chemical out of all of the trophic levels. Concentrations of pollutants can reach fatal levels at the tertiary consume trophic level. The diagram below shows a visual representation of this.
The word "accumulate" means to build up, or retain. "Bio" refers to life and living organisms. So the term bioaccumulation is the building up or retaining of chemicals in living organisms.
When these chemicals are pollutants, such as lead, pesticides, mercury, cadmium or PCB's, living organisms can be harmed.
These chemicals are not broken down by decomposers and build up in the air, the soil or the water.
Organisms take theses pollutants into their bodies through their food, skin contact or breathing. These pollutants are stored in the fat tissue of an animal.
Harmful effects can happen to an organisms nervous system, reproductive system and immune system. Birth defects or a complete failure to reproduce can happen as well.
Keystone Species are species that are most important to an ecosystem because so many other species depend on them for their survival. The salmon of the west coast of British Columbia are an example of a keystone species. Bears, eagles, wolves, crows, gulls and otters all depend on the salmon as a food source. When the salmon die and decompose, the nutrients released from their bodies supplies the trees and other plant life with nourishment.
Biomagnification: occurs when chemicals accumulate and become more concentrated at each trophic level. The producers in an ecosystem are usually the first organisms to take in the chemicals.
Each producer takes in a little of the chemical. The primary consumers spend their lives feeding on those producers, taking in a little of the chemical each time. This causes a large amount of the chemical to accumulate in the primary consumers.
The secondary consumers spend their lives feeding on the primary consumers, taking in large amounts of the chemical each time they feed. This causes even greater concentration of the chemical in this trophic level.
Finally its the tertiary consumers turn to feed and they are ingesting the largest amount of chemical out of all of the trophic levels. Concentrations of pollutants can reach fatal levels at the tertiary consume trophic level. The diagram below shows a visual representation of this.
The types of chemicals that cause harm in ecosystems fall into one category:
Persistent Organic Pollutants
These are chemicals that remain in soil and water for many years. They do not break down.
PCB's: polychlorinated biphenyls were widely used from 1930 to 1970 when they were banned due to the understanding of the effects theses chemicals were having on ecosystems. They were used in paints, plastics and as lubricants and coolants.
DDT: used as an insecticide starting in 1941, it was banned after discovering that it bioaccumulates in organisms.
Heavy Metals: lead, mercury and cadmium are the major metals of concern in ecosystems. Human products such as electronics and batteries that are not properly disposed of can cause heavy metals to enter the ecosystem.
Please complete the "Reading Check" questions on page 96
Persistent Organic Pollutants
These are chemicals that remain in soil and water for many years. They do not break down.
PCB's: polychlorinated biphenyls were widely used from 1930 to 1970 when they were banned due to the understanding of the effects theses chemicals were having on ecosystems. They were used in paints, plastics and as lubricants and coolants.
DDT: used as an insecticide starting in 1941, it was banned after discovering that it bioaccumulates in organisms.
Heavy Metals: lead, mercury and cadmium are the major metals of concern in ecosystems. Human products such as electronics and batteries that are not properly disposed of can cause heavy metals to enter the ecosystem.
Please complete the "Reading Check" questions on page 96
QUIZ
Chapter 3: Ecosystems continually change over time
PLO's - explain various ways in which natural populations are altered or kept in equilibrium
Section 3.1 - How Changes Occur Naturally in Ecosystems
Section 3.2 - How Humans Influence Ecosystems
Section 3.3 - How Introduced Species Affect Ecosystems
PLO's - explain various ways in which natural populations are altered or kept in equilibrium
Section 3.1 - How Changes Occur Naturally in Ecosystems
Section 3.2 - How Humans Influence Ecosystems
Section 3.3 - How Introduced Species Affect Ecosystems
Change in Ecosystems
The ecosystem that you are currently enjoying has not always been as you see it today.
The earth has gone through massive changes in climate that have caused the different biomes and ecosystems around the world to change as well.
Can you think of some examples of massive changes to the earth's climate? Most people would come up with the term "ice age". These were periods in the earths history where most of the land surface was covered with glaciers.
The ecosystem that you are currently enjoying has not always been as you see it today.
The earth has gone through massive changes in climate that have caused the different biomes and ecosystems around the world to change as well.
Can you think of some examples of massive changes to the earth's climate? Most people would come up with the term "ice age". These were periods in the earths history where most of the land surface was covered with glaciers.
This effectively created a gigantic permanent ice biome that existed for thousands of years.
As the earth warmed, the glaciers retreated and new biomes were formed. The plant and animal species that existed during these changing ages needed to adapt to their new environment, move to a new environment or perish.
This section will talk about how the organisms were able to change and how the ecosystems changed as well.
This section will talk about how the organisms were able to change and how the ecosystems changed as well.
Organisms Adapting to Change
When the environment around an organisms changes, the organism needs to change as well in order to survive. Natural selection is the process which allows organisms to change to meet the needs of their environment.
Natural selection happens when certain organisms who are better suited to survive, are able to reproduce more often and pass these traits on to their offspring. Those organisms that are not able to survive as well, do not reproduce as often and eventually die off. So over the course of a few generations, organisms can become adapted to their new environment.
When the environment around an organisms changes, the organism needs to change as well in order to survive. Natural selection is the process which allows organisms to change to meet the needs of their environment.
Natural selection happens when certain organisms who are better suited to survive, are able to reproduce more often and pass these traits on to their offspring. Those organisms that are not able to survive as well, do not reproduce as often and eventually die off. So over the course of a few generations, organisms can become adapted to their new environment.
If a number of new species develop from a single ancestor, scientists call this adaptive radiation. Adaptive radiation is the development of a number of new species from a common ancestor, and the radiating out of these species to occupy new habitats and niches.
A famous example of this are the finches of the Galapagos Islands. The Galapagos Islands are a group of islands that are close together off the coast of South America.
A famous example of this are the finches of the Galapagos Islands. The Galapagos Islands are a group of islands that are close together off the coast of South America.
Thousands of years ago, one species of finch made it to the islands from the continent of South America. Once there, the species of finch spread its population to the other islands of the Galapagos. Now that the population was separated by a body of water, they no longer bred with finches on the other islands. Different finches started to feed on different food sources. Some were insect eaters, some were seed eaters, others leaves. The finch started to adapt to better feed itself. The nut and seed eaters, like the large ground finch, developed powerful, thick beaks to better crack the shells of its food source.
Ecological Succession
Ecosystems are in a state of constant change. Imagine a pristine lawn that is no longer cared for. The grass gets longer and goes to seed, other plants like dandelions, small shrubs and eventually even trees could take over.
Ecological Succession is the term given to describe the change that takes place in ecosystems over time. There are two types of ecological succession: primary succession and secondary succession.
Primary Succession begins where there is no soil present, usually there is only bare rock. Retreating glaciers can scrape away the soil, exposing bare rock, or volcanic eruptions can create new bare rock. This process can take hundreds of years.
Wind, rain or bird droppings can carry the spores of organisms such as lichen to these bare rock areas. Lichens are one of the only organisms that can grow on bare rock because the are able to dissolve the rock and extract nutrients from it. After years of life and death, the dead lichens and the weathering of the bare rock begins to form soil.
Once there is a small amount of soil present, small plants such as mosses are able to take root and grow. There spores are also dropped here.
Lichen and Mosses are known as pioneer species because they are the first to colonize bare rock. These organisms live, die, decompose and their matter begins to form the first, thin layer of soil.
Insects and micro-organisms begin to move in further contributing to the organic matter in the soil.
Small shrubs are now able to root in the thin soil layer that has been created and birds follow the insects into the area.
Once the soil layer thickens enough through many years, small trees are able to root and grow. These trees create shade and cause a change in the plant life on the forest floor. Only shade tolerant plants will survive now. Usually deciduous trees are the first to grow. Coniferous trees are able to germinate in shady areas and are next to take over.
At this point the ecosystem will have complex food webs as large herbivores and the predators that feed on them have now appeared in the ecosystem. A mature community has developed.
Ecosystems are in a state of constant change. Imagine a pristine lawn that is no longer cared for. The grass gets longer and goes to seed, other plants like dandelions, small shrubs and eventually even trees could take over.
Ecological Succession is the term given to describe the change that takes place in ecosystems over time. There are two types of ecological succession: primary succession and secondary succession.
Primary Succession begins where there is no soil present, usually there is only bare rock. Retreating glaciers can scrape away the soil, exposing bare rock, or volcanic eruptions can create new bare rock. This process can take hundreds of years.
Wind, rain or bird droppings can carry the spores of organisms such as lichen to these bare rock areas. Lichens are one of the only organisms that can grow on bare rock because the are able to dissolve the rock and extract nutrients from it. After years of life and death, the dead lichens and the weathering of the bare rock begins to form soil.
Once there is a small amount of soil present, small plants such as mosses are able to take root and grow. There spores are also dropped here.
Lichen and Mosses are known as pioneer species because they are the first to colonize bare rock. These organisms live, die, decompose and their matter begins to form the first, thin layer of soil.
Insects and micro-organisms begin to move in further contributing to the organic matter in the soil.
Small shrubs are now able to root in the thin soil layer that has been created and birds follow the insects into the area.
Once the soil layer thickens enough through many years, small trees are able to root and grow. These trees create shade and cause a change in the plant life on the forest floor. Only shade tolerant plants will survive now. Usually deciduous trees are the first to grow. Coniferous trees are able to germinate in shady areas and are next to take over.
At this point the ecosystem will have complex food webs as large herbivores and the predators that feed on them have now appeared in the ecosystem. A mature community has developed.
Secondary Succession is the development of a mature community as well, but the starting material is different. In secondary succession, soil is already present. After a forest fire, all that is left is the remains of dead trees and the exposed soil underneath.
Due to the presence of soil, seeds germinate much more quickly and a mature community will develop in a matter of decades.
Complete the reading check questions 1-4 on page 115
Complete the reading check questions 1-4 on page 115