Chapter 5 reading guide
1. Define: Community Effect
- The size of a population decreases by an animal that indirectly destroys a habitat.
2. Explain WHY the Sea Otter is considered the Keystone Species in this ecosystem.
- Because Sea Otter eat sea urchins and sea urchins eat kelp (many different marine organisms home)
3. Why were Sea Otters endangered and how dis their numbers rebound?
- They were brought almost to extinction by commercial hunting for their fur during the 18th and 19th century.
Several small populations survived and have increased since then so today sea otters numbers are in the hundreds of thousands.
5-1 The Ecosystem: Sustaining Life on Earth
1. Define Ecosystem Structure
- An ecosystem has 2 major parts: nonliving and living. The nonliving part is the physical - chemical environment. The living part, called the ecological community, is the set of species interacting within the ecosystem.
2. What two main processes must occur to maintain an ecosystem?
- A flow of energy and a cycling of chemical elements
5-2 Ecological Communities and Food Chains
1. What is the difference between a food chain and a food web?
- A food chain is a single line of organisms, where each is preceded by something that it consumes and is followed by something that consumes it. A food web branches out in all directions with arrows pointing from organisms to any number of organisms that consume it.
2. Define Trophic Level
- Nourishing level consists of all organisms in a food web that are the same number of feeding levels away from the original energy source.
3. Define Autotrophs, Heterotrophs, Carnivores, Decomposers.
- Autotrophs - "auto" (self) and "trephein" (to nourish), are grouped into the first trophic level.
- Heterotrophs - organisms deriving its nutritional requirements from complex organic substances.
- Carnivores - meat-eaters, that feed directly on herbivores make up the third trophic level.
- Herbivores - organisms that feed on plants, algae, or photosynthetic bacteria - are members of the second trophic level.
- Decomposers - organism that feed on dead organic material, are classified in the highest trophic level in an ecosystem.
4. Explain the food web of Yellowstone Hot Springs. Explain each trophic level.
- Typical pelagic (open-ocean) ecosystem microscopic single-cell planktonic algae and planktonic photosynthetic bacteria are in first trophic level. Small invertebrates called zooplankton and some fish feed on the algae and photosynthetic bacteria, forming second trophic level. Other fish and invertebrates feed on these herbivores and form the third trophic level.
A Closer Look - Land and Marine Food Webs
1. Look at the terrestrial food web. Should we include people within this ecosystem's food web? That would place us within nature. OR should we place people outside of the ecosystem. Thus separate from nature?
- We shouldn't because any change could alter the food web and create a complete disaster. We should place people outside of the ecosystem because of this fear of creating a problem instead of a solution.
5-3 Ecosystem as Systems
1. Why are ecosystems considered to be OPEN systems?
- Because energy and matter flow into and out of them.
2. Explain: Ecosystem Energy Flow - what two ways does energy enter an ecosystem?
- Ecosystem energy flow is the movement of energy through an ecosystem from the external environment through s series of
organisms and back to the external environment. Energy enters an ecosystem by two pathways: energy fixed by organisms and moving through food webs within an ecosystem; and heat energy that is transferred by air or water currents or by
convection through soils and sediments and warm living things.
The Laws of Thermodynamics and the Ultimate Limit on the Abundance of Life
1. The First Law of Thermodynamics is also known as what? Define it.
- The First Law of Thermodynamics, known as the law of conversation of energy states that in any physical or chemical change, energy is neither created nor destroyed but merely changed from one to another.
2. What is the Second Law of Thermodynamics say?
- The 2nd law of thermodynamics, "no use of energy in the real (not theoretical) world can ever be 100% efficient whenever useful work is done, some energy is inevitably converted to heat.
3. Define Entropy
- The measure of the decrease in order (the disorganization of energy).
4. What is an intermediate system?
- The ecosystem is said to be an intermediate system between the energy source and the energy sink.
5-5 Biological Production and Biomass
1. What is biomass?
- The total amount of organic matter in any ecosystem .
2. Define the following:
- Biological Production - the capture of usable energy from the environment to produce organic matter. (or organic compounds)
- Gross Production - the increase in stored energy before any is used.
- Net Production - the amount of newly acquired, energy stored after some energy has been used.
3. What are the 3 measures that are used for biomass and biological production?
- 3 measures are used for biomass and biological production: the quantity of organic material (biomass), energy stored, and
carbon stored.
4. What is primary production - who carries this out?
- The production carried out by autotrophs is called primary production.
5. What is second production - who carries this out?
- The production carried out by autotrophs is called second production.
6. Who are chemoautotrophs?
Explain - where are they usually found?
- Some autotrophic bacteria live in deep-ocean vents, where they provide the basis for a strange ecological community. Chemoautotrophs are also found in muds of marshes, where there is no free oxygen.
5-6 Energy Efficiency and Transfer Efficiency
1. What is energy efficiency?
- The ratio of output to input, and it is usually further defined as the amount of useful work obtained from some amount of available energy.
2. How would energy efficiency look with a wolf and moose population? Explain.
- The wolf needs energy to travel long distances and hunt. And the best moose would be one that used little of the energy it took in, storing most of it as muscle and fat, which the wolf can eat.
3. What is food-chain or trophic level efficiency?
- A common ecological measure of energy efficiency is called food-chain or trophic level efficiency.
4. Generally. How much energy is lost to heat when being transferred between trophic levels?
- The organisms in one trophic level tend to take in much less energy than the potential maximum a!ailable
to them and they use more energy than they store for the next trophic level.
5-7 Ecological Stability and Succession
1. What is ecological succession?
- The observed process of change in the species structure of an ecological community over time
2. Compare and contrast primary and secondary succession- give an example of each
- primary succession is the establishment and development of an ecosystem where one did not exist previously.
ex: Coral reefs that form on lava emitted from a volcano and cooled in shallow ocean waters.
- secondary succession is reestablishment of an ecosystem after disturbances.
ex: a coral reef has been killed by poor fishing practices, pollution, climate change , or predation, and then recovers.
3. Explain how succession would look in a Dune
- Sand dunes are continually being formed along sandy shores and then breached and destroyed by storms. Dune grass puts out runners with sharp ends, just under the surface. It rapidly form a complex network of underground runners, crisscrossing almost like a coarsely woven mat. Above the ground, the green stems carry out photosynthesis, and the grasses grow. Once the dune grass is established, its runners stabilize the sand, and seeds of other plants have a better change of germinating.
4. Explain how succession would look in a Bog.
- They form a complex, mat like network similar to that formed by dune grass. The stems of the sedge grow on the runners and carry out photosynthesis. The floating mat becomes thicker as small shrubs and trees, adapted to wet environments, grow.
5. Explain how succession would look in a Old-field.
- As small plants become established, other, larger plants enter. Eventually, larger tree grow, such as sugar maple, beech, white pine, and yellow birch, forming a dense forest.
6. Explain how succession would be look in a coral reef.
- The coral reefs settle on a solid surface and produce a hard polyp of calcium carbonate (limestone). As old individuals die, this hard material becomes the surface on which new individuals establish themselves. Eventually, a large and complex structure results involving many other species, including autotrophs and heterotrophs.
5-9 How Species Change Succession
1. Explain facilitation in succession and where is it most common?
- In facilitation, an earlier-successional species changes the local environment in ways that make it suitable for another species that is characteristic of a later successional stage. Role of facilitation can be useful in the restoration of damaged areas. Facilitation is common in tropical rain forests, and also in coral reefs, mangrove swamps along ocean shores, kelp beds along cold ocean shores.
2. Explain interference in succession and what it can lead to.
- Interference refers to situations where an earlier-successional species changes the local environment so it is unsuitable to another species characteristic of a later-successional stage. It can create a problem for those species that depend on that area.
3. What is chronic patchiness? When does this occur?
- Chronic patchiness is characteristic of highly disturbed environments and highly stressful ones in terms of temperature, precipitation, or chemical availability, such as deserts. It occurs when no species interact through succession.
Critical Thinking Issue: Should People Eat Lower on the Food Chain?
1. Why does the energy content decrease at each higher level of a food chain? What happens to the energy lost at each level?
- According the Second Law of Thermodynamics says that every time is transferred some is lost. In food chain this happens because organism use some of the energy they got from the previous energy source.
2. Why it is appropriate to use to represent energy content?
- Because it shows how much of something is needed to supply energy to higher up in the food chain.
3. Using the average of 21 kilojoules of energy to equal 1g of completely dried vegetation and assuming that wheat is 80% water, what is the energy content of the 333,000kg of wheat shown in the pyramid?
- 333,000 / 21 = 15,857 kJ
4. Make a list of environment arguments for and against vegetarian diet for people. What might be the consequences for the US agriculture if everyone in the country began to eat lower on the food chain?
** For
1. Saving natural resources.
2. Eating healthier instead of eating processed meat.
3. Eating lower on food chain.
** Against
1. Meat is a great source of protein
2. It's natural way of living
3. Eating meat is just as healthy as eating salad, you get your share of nutrients
---> The meat production would lose money so they wouldn't want to spend more money on making sure things are in good conditions so maybe the meat that will be bought will be old or just prepared unsanitary.
5. How low do you eat on the food chain? Would you be willing to eat lower? Explain
- I would eat as low as vegetables that is what I eat the most of. Personally, I could easily survive on just vegetables. You are getting a load of protein from meat but you are not getting all the natural nutrients supplied from plants.
Study Questions:
1. Farming has been described as managing land to keep it in an early stage of succession. What does this mean, and how is it achieved?
- It means that if a piece of land was left alone for many years it would evolve through natural selection starting from grasses to shrubs to trees.
2. Keep track on the food you eat during one day and make a food chain linking yourself with the sources of those foods.
Determine the biomass (grams) and energy (kilocalories) you have eaten. Using an average of 5Kcall/g, then using the information on food packaging or assuming that your net production is 10% efficient in terms of energy intake, how much additional energy might you have stored during the day? (What is your weight gain from the food you have eaten?)
*** Breakfast = 2 slices of sandwich + nutella => more or less 375
*** Lunch = rice + egg = more or less 300
*** Dinner = fruit = more or less 200
==> Total calorie intake : 675
- The size of a population decreases by an animal that indirectly destroys a habitat.
2. Explain WHY the Sea Otter is considered the Keystone Species in this ecosystem.
- Because Sea Otter eat sea urchins and sea urchins eat kelp (many different marine organisms home)
3. Why were Sea Otters endangered and how dis their numbers rebound?
- They were brought almost to extinction by commercial hunting for their fur during the 18th and 19th century.
Several small populations survived and have increased since then so today sea otters numbers are in the hundreds of thousands.
5-1 The Ecosystem: Sustaining Life on Earth
1. Define Ecosystem Structure
- An ecosystem has 2 major parts: nonliving and living. The nonliving part is the physical - chemical environment. The living part, called the ecological community, is the set of species interacting within the ecosystem.
2. What two main processes must occur to maintain an ecosystem?
- A flow of energy and a cycling of chemical elements
5-2 Ecological Communities and Food Chains
1. What is the difference between a food chain and a food web?
- A food chain is a single line of organisms, where each is preceded by something that it consumes and is followed by something that consumes it. A food web branches out in all directions with arrows pointing from organisms to any number of organisms that consume it.
2. Define Trophic Level
- Nourishing level consists of all organisms in a food web that are the same number of feeding levels away from the original energy source.
3. Define Autotrophs, Heterotrophs, Carnivores, Decomposers.
- Autotrophs - "auto" (self) and "trephein" (to nourish), are grouped into the first trophic level.
- Heterotrophs - organisms deriving its nutritional requirements from complex organic substances.
- Carnivores - meat-eaters, that feed directly on herbivores make up the third trophic level.
- Herbivores - organisms that feed on plants, algae, or photosynthetic bacteria - are members of the second trophic level.
- Decomposers - organism that feed on dead organic material, are classified in the highest trophic level in an ecosystem.
4. Explain the food web of Yellowstone Hot Springs. Explain each trophic level.
- Typical pelagic (open-ocean) ecosystem microscopic single-cell planktonic algae and planktonic photosynthetic bacteria are in first trophic level. Small invertebrates called zooplankton and some fish feed on the algae and photosynthetic bacteria, forming second trophic level. Other fish and invertebrates feed on these herbivores and form the third trophic level.
A Closer Look - Land and Marine Food Webs
1. Look at the terrestrial food web. Should we include people within this ecosystem's food web? That would place us within nature. OR should we place people outside of the ecosystem. Thus separate from nature?
- We shouldn't because any change could alter the food web and create a complete disaster. We should place people outside of the ecosystem because of this fear of creating a problem instead of a solution.
5-3 Ecosystem as Systems
1. Why are ecosystems considered to be OPEN systems?
- Because energy and matter flow into and out of them.
2. Explain: Ecosystem Energy Flow - what two ways does energy enter an ecosystem?
- Ecosystem energy flow is the movement of energy through an ecosystem from the external environment through s series of
organisms and back to the external environment. Energy enters an ecosystem by two pathways: energy fixed by organisms and moving through food webs within an ecosystem; and heat energy that is transferred by air or water currents or by
convection through soils and sediments and warm living things.
The Laws of Thermodynamics and the Ultimate Limit on the Abundance of Life
1. The First Law of Thermodynamics is also known as what? Define it.
- The First Law of Thermodynamics, known as the law of conversation of energy states that in any physical or chemical change, energy is neither created nor destroyed but merely changed from one to another.
2. What is the Second Law of Thermodynamics say?
- The 2nd law of thermodynamics, "no use of energy in the real (not theoretical) world can ever be 100% efficient whenever useful work is done, some energy is inevitably converted to heat.
3. Define Entropy
- The measure of the decrease in order (the disorganization of energy).
4. What is an intermediate system?
- The ecosystem is said to be an intermediate system between the energy source and the energy sink.
5-5 Biological Production and Biomass
1. What is biomass?
- The total amount of organic matter in any ecosystem .
2. Define the following:
- Biological Production - the capture of usable energy from the environment to produce organic matter. (or organic compounds)
- Gross Production - the increase in stored energy before any is used.
- Net Production - the amount of newly acquired, energy stored after some energy has been used.
3. What are the 3 measures that are used for biomass and biological production?
- 3 measures are used for biomass and biological production: the quantity of organic material (biomass), energy stored, and
carbon stored.
4. What is primary production - who carries this out?
- The production carried out by autotrophs is called primary production.
5. What is second production - who carries this out?
- The production carried out by autotrophs is called second production.
6. Who are chemoautotrophs?
Explain - where are they usually found?
- Some autotrophic bacteria live in deep-ocean vents, where they provide the basis for a strange ecological community. Chemoautotrophs are also found in muds of marshes, where there is no free oxygen.
5-6 Energy Efficiency and Transfer Efficiency
1. What is energy efficiency?
- The ratio of output to input, and it is usually further defined as the amount of useful work obtained from some amount of available energy.
2. How would energy efficiency look with a wolf and moose population? Explain.
- The wolf needs energy to travel long distances and hunt. And the best moose would be one that used little of the energy it took in, storing most of it as muscle and fat, which the wolf can eat.
3. What is food-chain or trophic level efficiency?
- A common ecological measure of energy efficiency is called food-chain or trophic level efficiency.
4. Generally. How much energy is lost to heat when being transferred between trophic levels?
- The organisms in one trophic level tend to take in much less energy than the potential maximum a!ailable
to them and they use more energy than they store for the next trophic level.
5-7 Ecological Stability and Succession
1. What is ecological succession?
- The observed process of change in the species structure of an ecological community over time
2. Compare and contrast primary and secondary succession- give an example of each
- primary succession is the establishment and development of an ecosystem where one did not exist previously.
ex: Coral reefs that form on lava emitted from a volcano and cooled in shallow ocean waters.
- secondary succession is reestablishment of an ecosystem after disturbances.
ex: a coral reef has been killed by poor fishing practices, pollution, climate change , or predation, and then recovers.
3. Explain how succession would look in a Dune
- Sand dunes are continually being formed along sandy shores and then breached and destroyed by storms. Dune grass puts out runners with sharp ends, just under the surface. It rapidly form a complex network of underground runners, crisscrossing almost like a coarsely woven mat. Above the ground, the green stems carry out photosynthesis, and the grasses grow. Once the dune grass is established, its runners stabilize the sand, and seeds of other plants have a better change of germinating.
4. Explain how succession would look in a Bog.
- They form a complex, mat like network similar to that formed by dune grass. The stems of the sedge grow on the runners and carry out photosynthesis. The floating mat becomes thicker as small shrubs and trees, adapted to wet environments, grow.
5. Explain how succession would look in a Old-field.
- As small plants become established, other, larger plants enter. Eventually, larger tree grow, such as sugar maple, beech, white pine, and yellow birch, forming a dense forest.
6. Explain how succession would be look in a coral reef.
- The coral reefs settle on a solid surface and produce a hard polyp of calcium carbonate (limestone). As old individuals die, this hard material becomes the surface on which new individuals establish themselves. Eventually, a large and complex structure results involving many other species, including autotrophs and heterotrophs.
5-9 How Species Change Succession
1. Explain facilitation in succession and where is it most common?
- In facilitation, an earlier-successional species changes the local environment in ways that make it suitable for another species that is characteristic of a later successional stage. Role of facilitation can be useful in the restoration of damaged areas. Facilitation is common in tropical rain forests, and also in coral reefs, mangrove swamps along ocean shores, kelp beds along cold ocean shores.
2. Explain interference in succession and what it can lead to.
- Interference refers to situations where an earlier-successional species changes the local environment so it is unsuitable to another species characteristic of a later-successional stage. It can create a problem for those species that depend on that area.
3. What is chronic patchiness? When does this occur?
- Chronic patchiness is characteristic of highly disturbed environments and highly stressful ones in terms of temperature, precipitation, or chemical availability, such as deserts. It occurs when no species interact through succession.
Critical Thinking Issue: Should People Eat Lower on the Food Chain?
1. Why does the energy content decrease at each higher level of a food chain? What happens to the energy lost at each level?
- According the Second Law of Thermodynamics says that every time is transferred some is lost. In food chain this happens because organism use some of the energy they got from the previous energy source.
2. Why it is appropriate to use to represent energy content?
- Because it shows how much of something is needed to supply energy to higher up in the food chain.
3. Using the average of 21 kilojoules of energy to equal 1g of completely dried vegetation and assuming that wheat is 80% water, what is the energy content of the 333,000kg of wheat shown in the pyramid?
- 333,000 / 21 = 15,857 kJ
4. Make a list of environment arguments for and against vegetarian diet for people. What might be the consequences for the US agriculture if everyone in the country began to eat lower on the food chain?
** For
1. Saving natural resources.
2. Eating healthier instead of eating processed meat.
3. Eating lower on food chain.
** Against
1. Meat is a great source of protein
2. It's natural way of living
3. Eating meat is just as healthy as eating salad, you get your share of nutrients
---> The meat production would lose money so they wouldn't want to spend more money on making sure things are in good conditions so maybe the meat that will be bought will be old or just prepared unsanitary.
5. How low do you eat on the food chain? Would you be willing to eat lower? Explain
- I would eat as low as vegetables that is what I eat the most of. Personally, I could easily survive on just vegetables. You are getting a load of protein from meat but you are not getting all the natural nutrients supplied from plants.
Study Questions:
1. Farming has been described as managing land to keep it in an early stage of succession. What does this mean, and how is it achieved?
- It means that if a piece of land was left alone for many years it would evolve through natural selection starting from grasses to shrubs to trees.
2. Keep track on the food you eat during one day and make a food chain linking yourself with the sources of those foods.
Determine the biomass (grams) and energy (kilocalories) you have eaten. Using an average of 5Kcall/g, then using the information on food packaging or assuming that your net production is 10% efficient in terms of energy intake, how much additional energy might you have stored during the day? (What is your weight gain from the food you have eaten?)
*** Breakfast = 2 slices of sandwich + nutella => more or less 375
*** Lunch = rice + egg = more or less 300
*** Dinner = fruit = more or less 200
==> Total calorie intake : 675