[Science] Chapter 10: Ecosystems

Explain how the amount of energy transferred from one trophic level to another is not complete.

Most of the energy is lost through biological processes like movement or growth.

(Wkbk pg. 167): What element is not usually found in biomass?: Trees, rabbits, rocks, fish, and lady bugs.

Rocks. Biomass is anything that is living.

What is the toxicity threshold?

The level of concentration above which a contaminant causes one or more harmful effects in an organism. In other words, the minimal concentration of the contaminant that nonetheless produces a harmful effect on an organism.

What role do consumers play in biomass?

They move biomass from one trophic level to another.

How do consumers get their nourishment?

They must feed off of another organism

Using your knowledge of biocontamination, explain why a pregnant woman should not consume any contaminants.

Because it would affect the growth of the fetus and cause complications in its development.

What is another word for a decomposer?

A detrivore

What is a producer?

A producer is any organism that can produce its own food. (Photosynthesis) They also change inorganic matter from the environment into organic matter.

What is a food chain?

A simplified version of a food web.

What does material flow and chemical recycling entail? When does the exchange of matter occur?

All the living things in an ecosystem exchange matter and energy either amongst themselves or with their environment. The exchange of matter occurs during feeding or decomposition.

The diagram to the right (see EST review) shows the trophic relationship between humans and several types of aquatic species. It is recommended that women do not consume too much salmon and tuna during pregnancy. Use your knowledge of bioaccumulation to explain this recommendation.

As the trophic level increases, so do the amount of contaminants that accumulate in the organs and fatty tissues of the organisms in the higher trophic levels. Since salmon and tuna are near the top of the food chain, they would have a greater concentration of contaminants in their tissues. When a woman who is pregnant consumes this type of fish, the contaminants are fed to the fetus. While the contaminants may not harm the woman, the much smaller fetus would be more greatly affected.

What are examples of decomposers?

Bacteria, worms and mushrooms.

Which of the following organisms is a producer in the food web? A) Zooplankton B) Phytoplankton C) Osprey D) Grass shrimp

B. Phytoplankton have photosynthesis capacities. A) Zooplankton do not have photosynthesis capacities. C and D are consumers.

Which is an example of a human disturbance? a) Tornado b) Hydroelectric dam c) Flooding d) Drought

B. A, C and D are all natural disturbances. (see the illustrations on the ST review that correspond to this question)

What are trophic (feeding) relationships?

The feeding connections among the living organisms in an ecosystem.

(Txtbk pg. 342): A carnivore cannot be a primary consumer in a food chain. Why?

Because then they wouldn't be a carnivore anymore, they would either be an omnivore or a herbivore (since they consume plants).

the process by which a contaminant from the environment or food supply accumulates in an organism" What does this define?

Bioaccumulation

What is biomagnification?

Bioaccumulation in food chains (same thing)

"a special case of bioaccumulation by which an organismaccumulates a contaminant through direct contact with a substance as "the minimum concentration of a substance that produces a significant harmful effect in an organism (mg/kg of the organism's mass)" What does this define?

Bioconcentration

What is detritus?

Dead organic matter. Decomposers eat this dead organic matter. A decomposer's waste is inorganic matter.

(Txtbk pg. 342): Which trophic level do detritivores belong to? Explain your answer.

Decomposers

Which of the following is false? A) Phytoplankton convert inorganic matter into organic matter B) Phytoplankton perform photosynthesis. C) Phytoplankton get their energy by eating other organisms. D) Phytoplankton introduce energy into the food web.

C and D: A) Yes. That is the role of producers and phytoplankton is a producer. B) True. Producers perform photosynthesis and phytoplankton is a producer. C) No. That is what consumers do and phytoplankton is not a consumer. D) False. The sun introduces energy into the food web, not the producers. Producers simply convert energy from the sun.

Put the various possible steps in an ecological succession following a forest fire in order: A. Hares are attracted by the plants and the young tree shoots. B. In the underbush, species of trees that tolerate shade, such as the balsam fir start to appear. C. Herbaceous plants that like intense light and adapt to disturbances grow and provide humus on the ground when they die. D. Species of trees that like a lot of light take root.

C. Give away = "grow" "adapt" "like intense light" A. Give away = "young tree shoots" D. Give away = "like a lot of light" "take root" "trees" B. Give away = "underbush" "shade" (thus indicating that plants have grown already as they know provide shade) "appear"

Which of the following events is NOT a disturbance to a community?" A) Flood B) Mud slide C) A high tide D) A termite infestation

C. Has no effect on the community whatsoever. A) is a natural disturbance. B) also a natural disturbance D) also a natural disturbance

(Txtbk pg. 342): Which level of ecological organization does the following example illustrate?: Wolves hunting a caribou herd.

Community because we deal with predation, which is a term associated with communities.

Saturated

Containing the highest amount of substance or something

The feeding relationships between individuals in an ecosystem can be represented in what way?

In a food chain

(Wkbk pg. 168): See #7

Ok

Where do producers get their energy from?

The sun (photosynthesis)

What is the difference between trophic networks and trophic relationships?

Trophic networks represent all the trophic relationships in an ecosystem. They are represented by a FOOD WEB. Trophic relationships are the feeding connections among the living organisms in an ecosystem. They are represented by a FOOD CHAIN. The position of each organism in a chain corresponds to its TROPHIC LEVEL.

(Txtbk pg. 342): What is the name of the feeding relationships between the living organisms of an ecosystem?

Trophic relationships

(Wkbk pg. 164): True or false? A squirrel that eats nuts is a first-order consumer.

True

(Wkbk pg. 167): True or false? In an ecosystem, a part of the energy is lost in the form of heat.

True.

(Wkbk pg. 167): True or false? Matter is always circulating in the ecosystem, nothing is lost.

True.

(Wkbk pg. 167): True or false? No ecosystem is immune to disturbances.

True.

What are zooplankton?

Zooplankton is another type of organism without photosynthesis capacities. Marine organisms eat zooplankton. Zooplankton eat phytoplankton, which are organisms with photosynthesis capacities.

All food chains start with __________.

plants

Primary productivity

(of an ecosystem) is the amount of new biomass generated by its PRODUCERS.

(Wkbk pg. 164): Using the following organisms, build a food chain. Specify the trophic level of each of the organisms: owl, fungus and mouse.

*ALWAYS PUT ARROWS WHEN BUILDING A FOOD CHAIN AND INDICATE THEIR TROPHIC LEVEL* Owl (primary or first-order consumer) --> Mouse (secondary or second-order consumer) --> Fungus (decomposer) You would also draw the arrow from the owl AND the mouse to the decomposer, because technically the decomposer decomposes both organisms. You would draw it like a triangle.

(Wkbk pg. 164): Using the following organisms, build a food chain. Specify the trophic level of each of the organisms: grasshopper, raccoon, bull frog, plant.

*ALWAYS PUT ARROWS WHEN BUILDING A FOOD CHAIN AND INDICATE THEIR TROPHIC LEVEL* Plant (producer) --> Grasshopper (primary consumer OR first-order consumer) --> Bull frog (secondary OR second-order consumer) --> Raccoon (tertiary OR third-order consumer)

What is material flow?

*Remember* the law of conservation of mass; nothing is lost, and nothing is created; matter is *transformed*. The law is valid not only in the laboratory; it also applies to the matter in an ecosystem. Producers are continually changing inorganic matter from the environment into organic matter. At this constant rate, all the inorganic matter might be expected to disappear with time, transformed into organic matter. Producers would no longer be able to find food and would die, putting the entire ecosystem at risk. Matter passes from one state to another, but it remains in circulation in the ecoystem. For example, when a hare grazes on clover, the substances contained in the clover are transferred to the hare. Then, if a lynx eats the hare, the predator gains access to the matter now in the hare, and so on. In the end, the matter in the detritus left by the living organisms becomes available to decomposers, which break it down into inorganic matter and return it to the ecosystem, where it can be used once again by the clover.

How does bioconcentration work in a food chain?

- An organism at a higher trophic level feeds on organisms from lower trophic levels. - An organism will absorb the contaminants that have accumulated in the organisms from lower trophic levels. - Consequently, the higher up the food chain an organism lies, the greater its concentration of such contaminants. This phenomenon is called bioconcentration (or bioamplification)

(Txtbk pg. 342): Approximately 10 percent of the energy absorbed by one consumer is available to the next consumer in a food chain. What happens to the energy that is lost at each level of a food chain? Give two explanations.

- At each level, organisms release some energy in the form of waste. - They also use a considerable amount of energy to perform various activities, such as moving, growing, or reproducing. Part of the energy loss take the form of heat. For example, when we run for a certain length of time, we use a lot of energy and give off heat.

Explain how bioaccumulation works.

- Human activities: discharge pollutants/contaminants - Pollutants/contaminants mix with inorganic matter such as water in an environment - Living organisms can absorb the pollutants/contaminants when they eat or drink - Once inside an organism, certain contaminants (ex: heavy metals, chemicals called PSBs, and DDT, an insecticide), cannot be eliminated. - Over time, they accumulate in the tissues of affected organisms. This phenomenon is called bioaccumulation.

(Txtbk pg. 342): What is the difference between a community and an ecosystem?

A community is a set of populations of different species sharing the same habitat. An ecosystem is a community of living organisms interacting with one another and with the nonliving components of the environment they inhabit. Here are some more differences; • Ecosystem is a collection of communities, but community is a collection of populations. • Ecosystems could be either manmade or natural, but communities are always natural; or at least, communities are mended naturally inside a manmade ecosystem. • Ecosystem is larger in all parameters than the community is. • Community is not defined with particular characteristics, whereas a particular ecosystem is defined for its characteristics based on environmental and biological parameters. • Communities are subjected to change with the affecting conditions, but a particular ecosystem does not change with those factors as it becomes another ecosystem with varying conditions. • Ecosystem is always a saturated system but not the community. In short, an ecosystem is a collection of communities, and a community is a collection of populations. Additionally, an ecosystem is larger than a community is.

A primary consumer is a herbivore, carnivore, or omnivore?

A herbivore or an omnivore (they eat plants or plants and other animals).

What is a food web?

A more accurate representation of the trophic relationships in an ecosystem.

What is chemical recycling?

A natural phenomenon by which decomposers make inorganic matter available in an ecosystem by breaking down organic matter.

Define bioconcentration/bioamplification.

A phenomenon by which the concentration of a contaminant in the tissues of living organisms tends to increase with each trophic level.

(Txtbk pg. 342): Which level of ecological organization does the following example illustrate?: a pack of wolves

A population because we're talking only about one species: wolves.

Depending on its location in a food chain, what can a consumer be?

A primary, secondary, tertiary, etc. consumer. Alternatively, you could say a first order consumer, second order consumer, or a third order consumer, respectively.

What is an ecosystem?

An ecosystem is the relationship between the living and the non-living components of a habitat.

What is an ecological footprint?

An estimate of the total area used to acquire all our needs and the disposal of our waste. It is EVERYTHING. Like where you get your food, clothes, recycling (gets reused), driving. See that page in workbook for an example.

Disturbance

An event that damages an ecosystem. It can lead to the elimination of organisms and alter the availability of resources.

(Txtbk pg. 342): Which level of ecological organization does the following example illustrate?: A lone wolf

An individual, as there is only one organism

Heterotroph

An organism that cannot make its own food (AKA consumer)

[EST]: What is a disturbance to ecosystems?

Any event, whether natural or human, that damages an ecosystem.

Define contaminant.

Any type of substance or radiation that is likely to cause harm to one or more ecosystems.

Explain the increase/decrease of the predator/prey relationship.

As the prey population increases, so does the predator population and as the prey population goes down, so does the predator population. It does not work if we reverse predator and prey. For instance, if the predator population increases, then the prey population would DECREASE. AND, if the predator population decreases, the prey population would INCREASE.

Where are autotrophs found in the food chain?

At the beginning

What are producers called?

Autotrophs

Which of the following statements is FALSE? A) Drought is a natural disturbance. B) An oil spill is a natural disturbance. C) Flooding from heavy rain is a natural disturbance. D) Overfishing is a human disturbance

B. It is a human disturbance.

Explain how the construction of a hydroelectric dam is a disturbance to a community.

Communities are often affected by the construction of dams because the need to flood the land to control the flow, level, etc of water. In this process of flooding many habitats are destroyed and contaminants dissolved in the water may be toxic. In addition, to build a hydroelectric dam, forests must be cleared for the construction of the power plant. This in turn destroys more habitats.

(Txtbk pg. 342): Explain the role of decomposers in the material flow of an ecosystem.

Decomposers break down the organic matter in the detritus (waste or debris of any kind) they feed on, producing the inorganic matter that plants need, such as nitrogen, potassium and phosphorus.

What is chemical recycling? Explain.

Decomposers break down the organic matter in the detritus they feed on, producing the organic matter that plants need, such as nitrogen, potassium and phosphorus. This is the process involved in composting. Producers thus have continual access to inorganic matter and so can create organic matter. This phenomenon of ecosystems is called *chemical recycling*. Chemical recycling is a natural phenomenon by which decomposers make inorganic matter available in an ecosystem by breaking down organic matter.

(Wkbk pg. 167): What would happen if there were no more decomposers?

Decomposers take the organic matter and turn it into inorganic matter. So, without decomposers, the cycle would stop.

Going back to chapters 6, 7, and 8, what are some more examples of human disturbances?

Deforestation (logging, cattle ranches), flooding (building of dams), water pollution (fertilizers and detergents, oil spills, thermal pollution).

What are some examples of human disturbances and what are the effects of them?

Deforestation, flooding of land or water pollution can also lead to the elimination of species or availability of resources.

Why does a tropical rainforest have a high primary productivity?

Due to the amount of light, water, and general temperature of its environment.

Which of the following is related to ecological footprint? a) Using less fuel b) Buying local produce c) Using electricity d) Using roadways and other types of transportation infrastructures e) All of the above

E, because: a) Decreases ecological footprint b) Decreases " " c) Increases " " d) Increases " " e) All of them have to do with ecological footprint

If we study our ________________, we can better understand the impact that our way-of-life has on ecosystems.

Ecological Footprint

What is this series of changes, occurring after a disturbance, called?

Ecological succession.

(Txtbk pg. 342): Which level of ecological organization does the following example illustrate?: A pack of wolves drinking from a lake

Ecosystem. Why? Well, when life (wolves) and the nonliving (water) are both taken into consideration in an environment, then its study has reached a fourth ecological level: the ecosystem.

What is NOT transferred and conserved within the ecosystem? Explain.

Energy. There is a heat (energy) loss from one trophic level to the next. The sun energy gets used up. Basically, the producer (plant) consumes a certain amount of energy from the sun. The primary consumer will not consume that same amount of energy, will ingest a lesser amount. A secondary consumer will consume a lesser amount of energy from the primary consumer as well. Why is there less and less energy from one trophic level to the next? Because it gets lost in the form of heat.

Ecological footprints

Estimates of the surface area individual humans or populations require to obtain the resources for satisfying all their needs and to ensure the disposal of their waste. Ecological footprint of a population = Land and water occupied by the population + Land and water used to produce goods and services for the population + Land and water used to dispose of the population's waste

What is composting? Explain.

Explanation from the textbook: (pg. 323): Two main reasons explain the growing popularity of composting organic waste. First, the process reduces the volume of our household waste. Second, it produces a natural and inexpensive fertilizer rich in the elements that our lawns, gardens and house plants need to grow.

(Txtbk pg. 343): True or false? Explain your answers: Transforming forests into farmland constitutes a natural disturbance.

False, this transformation is done by *humans*, thus it is a *human disturbance*.

(Wkbk pg. 167): True or false? A natural disturbance is always less serious than a human disturbance.

False.

(Wkbk pg. 164): True or false? A heterotrophic organism can produce its own food.

False. A heterotroph is a consumer.

(Txtbk pg. 343): True or false? Explain your answers: Ecological succession occurs only after a natural disturbance.

False. It can *also* occur after a human disturbance.

(Txtbk pg. 343): True or false? Explain your answers: All types of natural disturbance can occur in Quebec.

False. It is highly unlikely for a volcanic eruption or an earthquake to occur in Quebec.

(Wkbk pg. 164): True or false? Fungi are producers.

False. They are decomposers.

(Wkbk pg. 167): True or false? The energy in an ecosystem is recycled.

False. Unlike matter, the energy in an ecosystem is never recycled. Ecosystems must receive a continual supply of new energy from the sun. Energy is LOST in the form of heat, thus why it doesn't get reused.

(Wkbk pg. 164): True or false? A trophic network is the representation of a single food chain in an ecosystem.

False; a trophic network is a food web, a more accurate representation of the trophic relationships in an ecosystem (than a food chain)

(Wkbk pg. 167): True or false? The new biomass includes the matter produced by producers and consumers.

False; not consumers. Consumers don't PRODUCE new biomass. Plants (producers) do. New organic matter is generated by producers. This matter is the new biomass of the ecosystem. Measuring the amount of new biomass reveals the primary productivity of the ecosystem.

What does a decomposer (detrivore) do?

Feeds off of the waste left by other organisms and transforms the organic matter (like plants) back into inorganic matter (like minerals).

(Txtbk pg. 344): Explain why it is dangerous to eat a cabbage that has been grown in soil containing a substantial amount of heavy metals.

Heavy metals, which are contaminants, cannot be eliminated once inside an organism. Over time, they accumulate in the tissues of affected organisms. This phenomenon is called *bioaccumulation*.

(Wkbk pg. 168): Indicate if the following statement is a natural disturbance or a human disturbance: Land flooded by the construction of dams.

Human disturbance (humans built it)

(Wkbk pg. 168): Indicate if the following statement is a natural disturbance or a human disturbance: The ocean level rises as a result of global warming.

Human disturbance. (Humans contribute to global warming).

Is ecotoxicology referring to natural or human occurrences? Explain.

Human. Human activities affect ecosystems by polluting them with substances that do not occur there naturally or by significantly increasing concentrations of substances already present. Example: discharge from a pulp and paper mill.

Why are human disturbances a major source of environmental damage?

Humans are a major source of environmental disturbances. Humans have a damaging effect on ecosystems, whether small or large scale, more frequently (a daily occurrence compared to a more random occurrence of natural disturbances).

(Txtbk pg. 343): If you tried to establish the feeding relationships between all the organisms of the lake ecosystem, would you be drawing a food chain or a trophic network? Explain your answer.

I would be drawing a trophic network because a food web is a more accurate representation of the trophic relationships in an ecosystem.

What are main classes of contaminants?

Inorganic (ex: lead), organic (ex: pesticides), microbial (ex: harmful bacteria), radioactive (ex: uranium).

Is the amount of food a biotic or abiotic factor? Explain your answer.

It is a biotic factor because it is involving life (bio = life). How? Well, the amount of food is determined by the amount of producers, consumers, and decomposers.

What do the arrows mean in a food web?

It shows where the energy goes to.

What does the toxicity of each contaminant depend on?

Its concentration, the type of organism it comes in contact with (certain contaminants are toxic to some organisms but not to others), and the length of exposure (the longer a contaminant is in contact with an organism, the greater the risk of toxicity. ex: the more you are exposed to smoke, the higher you have a risk of contracting lung cancer).

What happens to the energy as it is passed from one trophic level to the next?

Less energy is available because the energy transfer is not completely efficient. Reason: Only about 10% of the food energy taken in by a herbivore is passed on to carnivores. The rest is used during cellular respiration and excretion. NOT: 2. More energy is available to higher levels because it is concentrated in the organisms' tissues. Reason: Only about 10% of the food energy taken in by a herbivore is passed on to carnivores. The rest is used during cellular respiration and excretion. 3. Less energy is available because there are fewer organisms at higher levels. Reason: Only about 10% of the food energy taken in by a herbivore is passed on to carnivores. The rest is used during cellular respiration and excretion. 4. Energy cannot be created or destroyed, so the energy is the same for each level. Reason: Energy cannot be created or destroyed, so it is released back into the environment (usually as heat).

What are the four levels of ecological organization?

Level 1: Individual Level 2: Population Level 3: Community Level 4: Ecosystem

Marcie moved to a new neighborhood since she wanted to reduce her commute time to work. She now shops at the nearby farmer's market and purchases local produce. She has also decided to cancel her newspaper subscription and relies on online content to keep her informed. How have Marcie's decisions affected her ecological footprint?

Marcie's decisions have decreased her ecological footprint. By reducing her commute time, she not only makes use of a smaller living area (radius) but she also consumes less fuel. By shopping at her local farmer's market she relies less on imported food items. This also reduces the amount of fuel need to transport her foods as well as making less use of roadways and other types of transportation infrastructures. By cancelling her newspaper subscription she consumes less paper products. (My addition: being online uses up electricity, so she is increasing her ecological footprint as well).

What gets recycled in an ecosystem?

Matter

What is transferred and conserved within the ecosystem? Explain.

Matter (when organisms consume, they create their own mass (body stores it). Becomes part of waste so stays within the cycle.

(Txtbk pg. 342): What is transferred from one organism to another within each ecosystem?

Matter and energy

What do producers feed off of?

NOT decomposers, but the result of what the decomposers do. So decomposers turn organic matter into inorganic matter. The plants feed off of that inorganic matter that results from what the decomposers did.

(Txtbk pg. 342): All the living organisms in an ecosystem need organic matter to survive. Which organisms are responsible for producing new organic matter (biomass)?

New organic matter is generated by *producers*.

Look at the booklet you did on ecosystems (with the illustration of the ecosystem, look at that particular question)

Ok

Please see the ST review on trophic relationships, as I cannot ask them here (requires a picture)

Ok

Take a look at the diagram about energy flow in notes, and the food web.

Ok

Consumers can be what? (three types of consumers)

Omnivore, herbivore or a carnivore.

(Txtbk pg. 345): Why is it correct to identify phytoplankton as producers?

Phytoplankton are microorganisms which can perform *photosynthesis*. It also transforms *inorganic matter into organic matter*.

Producers are typically what?

Plants

(Txtbk pg. 345): For the following food chain, name the trophic level of the human: Grain --> Human

Primary consumer.

Explain the role of producers in the material flow of an ecosystem.

Producers are continually changing inorganic matter from the environment into organic matter. At this constant rate, all the inorganic matter might be expected to disappear with time, transformed into organic matter.

What would happen to producers if there were no more inorganic matter?

Producers would no longer be able to find food and would die, putting the entire ecosystem at risk. (Producers feed on inorganic matter). And when there's no more producers, the food chain stops there. Primary consumers would have nothing to consume, thus dying. And so would the secondary, tertiary, decomposers, etc would die. So in a food chain, organisms depend on each other.

What are the three main types of trophic levels?

Producers, consumers, and decomposers.

(Txtbk pg. 345): For the following food chain, name the trophic level of the human: Phytoplankton --> Zooplankton --> Herring --> Tuna --> Human

Quaternary consumer.

(Txtbk pg. 345): For the following food chain, name the trophic level of the human: Grain --> Cow --> Human

Secondary consumer.

(Txtbk pg. 344): Certain factories in Quebec sometimes discharge low concentrations of contaminants into the environment. Explain why even small amounts of contaminants can nonetheless be hazardous to humans or other organisms at the top of food chains.

Since humans or other organisms occupy the highest trophic levels in food chains, we/they can be faced with high concentrations of contaminants in our/their bodies. In a food chain, an organism at higher trophic levels feeds on organisms from lower trophic levels. In the event of *bioaccumulation*, an organism will absorb the contaminants that have accumulated in the organisms from lower trophic levels. Consequently, the higher up the food chain an organism lies, the greater its concentration of such contaminants. This phenomenon is called *bioconcentration* (AKA *bioamplification*) In short, due to the phenomenon of *bioconcentration*, the higher an organism's trophic level in a food chain, the greater its concentration of contaminants.

Why are humans particularly affected by contaminants? Explain this using the phenomenon of bioconcentration.

Since we occupy the highest trophic levels in food chains, we can be faced with high concentrations of contaminants in our bodies. Due to the phenomenon of bioconcentration, the higher an organism's trophic level in a food chain, the greater its concentration of contaminants.

What are some examples of natural disturbances and what are the effects of them?

Storms, volcanic eruptions and earthquakes can damage ecosystems (they are not directly affected by humans).

(Txtbk pg. 342): Build a food chain based on: seal, sunflower, fly, and fish and specify the trophic level for each of the living organisms in your food chain.

Sunflower --> Fly --> Fish --> Seal Producer --> Primary Consumer --> Secondary Consumer --> Tertiary Consumer

(Txtbk pg. 342): What is the main source of energy in an ecosystem?

Sunlight is usually the primary source of energy in an ecosystem (to allow photosynthesis in plants)

What will happen to the size of the owl population if there is a decrease in the number of shrews? Explain.

TIP: Look at the relationships between the animals the question asks about. ANSWER: The owl population will decrease. The shrew is consumed by weasels and hawks who are also a source of food for the owl. There will be competition amongst the three to get to the shrews (though there's less). When there is a decrease in the number of prey, the predator population also decreases.

What is the primary productivity of an ecosystem determined by?

The amount of producers (plants) in the ecosystem.

What happens after suffering through a disturbance? Explain with an example.

The ecosystem will undergo a series of changes until it regains its balance. For example: the series of changes it takes to go from a baby tree to a mature tree.

What is material and energy flow?

The exchange of matter and energy between the living organisms in an ecosystem and between those organisms and their environment.

How is it that the mass of a consumer is a factor that affects the toxicity of a substance to humans?

The human body is mostly water, so the bigger the body, the more water there is to dilute the substance, and the less effect it will have on body tissues. 1 gram of a substance in the body of a small child will be much more concentrated than 1 gram of the same substance in an adult. That is why toxicity is usually given in mg/kg, milligrams of a substance per kg of body mass. Doing this also allows us to do toxicity testing on small animals like rats and then extrapolate the results up to humans, although that is not always a valid assumption of course because of the differences in biochemistry and physiology.

(Txtbk pg. 345): Suppose that a contaminant is introduced into the environments of the three food chains: a) Grain --> Human b) Grain --> Cow --> Human c) Zooplankton --> Herring --> Tuna --> Human This contaminant can accumulate in grain and in phytoplankton. In which food chain the human health hazard the greatest? Explain your answer.

The human health hazard is the greatest in chain C, since there's more trophic levels. This can be explained by the phenomenon of *bioaccumulation*, which is when an organism absorbs the contaminants that have accumulated in the organisms from lower trophic levels. Consequently, the higher up the food chain an organism lies, the greater its concentration of such contaminants. This phenomenon is called *bioconcentration* OR bioamplification.

What do we mean by 'law of conservation of mass/matter' within an ecosystem?

The mass stays the same in an ecosystem. It does not increase as you go from trophic level to trophic level. Why? Well, for example, as you consume a plant, yes you acquire an increased mass, you get bigger, BUT, the mass of the plant goes down and therefore is no more, but YOU have the mass. So that's how the mass stays the same WITHIN an ECOSYSTEM.

(Wkbk pg. 167): What is the link between the primary productivity of an ecosystem and the number of animals in that ecosystem?

The more new organic matter is created in an environment, the greater the capacity of the ecosystem to supply energy to many constituent organisms.

Pesticides are applied in fields. Explain how this affects humans.

The pesticides (contaminants) are carried by rainwater into rivers, where they are ingested day after day by phytoplankton. The phytoplankton are eaten by mayflies, which, in turn, are consumed by trout, which may be part of a human diet. Our bodies thus absorb a certain amount of contaminants.

Which of the following factors does NOT affect primary productivity in an ecosystem?

The population distribution Reason: Correct answer. The amount of light, amount of available water, access to essential nutrients, and the temperature all affect primary productivity.

(Txtbk pg. 342): All the living organisms in an ecosystem need organic matter to survive. What indicator is obtained by measuring the amount of new biomass produced by these organisms over a certain length of time?

The primary productivity of an ecosystem.

(Txtbk pg. 342): All the living organisms in an ecosystem need organic matter to survive. Name four factors that can affect the production of new biomass.

The production of new biomass AKA the primary productivity. Four factors; - The amount of light because the radiation energy of the sun is necessary for photosynthesis - The amount of water available because water, too, is necessary for photosynthesis - Access to essential nutrients for producers, especially carbon, nitrogen, phosphorus and potassium - The temperature because some weather conditions promote the growth of producers

What does a food chain show?

The relationship between producers, consumers and decomposers.

(Wkbk pg. 168): Considering the ecological footprint, name an advantage linked to recyling and composting.

The resources would be reused, thus reducing the ecological footprint. Recycling uses less energy and produces less pollution than making things from scratch. Compost restores organic content in soil and rebuilds the soil food web.

Ecological succession

The series of changes that occur in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored.

Define ecotoxicology.

The study of the ecological consequences of polluting the environment with various substances and radiation, released by human activity.

What is bioaccumulation?

The tendency among certain contaminants to accumulate over time in the tissues of living organisms.

What is biomass?

The total amount (mass) of organic matter in a community is its biomass.

Biomass

The total mass of organic matter in an ecosystem at any given time. The TOTAL mass of ALL organic matter (plant AND animal) in an ecosystem is called the biomass.

What does energy flow entail?

There is a flow of energy that occurs from one trophic level to another and to and from the environment. IN DEPTH EXPLANATION FROM TEXTBOOK; Matter is not the only thing that circulates in an ecosystem. The energy stored in plants is also in flux (flux = the action or process of flowing or flowing out). Sunlight is usually the primary source of energy in an ecosystem. Through the action of autotrophic organisms, part of the radiation energy that enters the ecosystem is transformed into chemical energy and then passed on to consumers. At every trophic level, organisms obtain energy from their food and store it in their tissues. A large part of this energy is always lost, however, as it passes from one trophic level to the next. At each level, organisms release some energy in the form of waste. They also use a considerable amount of energy to perform various activities, such as moving, growing, or reproducing. Part of the energy loss take the form of heat. For example, when we run for a certain length of time, we use a lot of energy and give off heat. Unlike matter, the energy in an ecosystem is never recycled. Ecosystems must receive a continual supply of new energy from the sun.

What are terms associated with ecosystems?

Trophic relationships (food chain, trophic levels) Producers (AKA autrotrophs) Consumers (AKA heterotrophs. Primary/first order, secondary/second order, tertiary/third order, quaternary/fourth order. Omnivores, carnivores, herbivores) Decomposers (AKA detritivores) Trophic network (food web) Ecosystem dynamics (material and energy flow) Material flow Chemical recycling Energy flow Primary productivity (affected by amount of light, water, and temperature) Biomass Disturbance (natural, human) Ecological succession Ecological footprints Ecotoxicology Contaminant (Types; inorganic, organic, microbial, radioactive. Factors; concentration, type of organism it comes in contact with, length of exposure) Toxicity threshold (lethal doses) Bioaccumulation Bioconcentration

(Wkbk pg. 167): True or false? The flooding of land by a beaver dam is a natural disturbance.

True.

(Txtbk pg. 343): True or false? Explain your answers: Excessing hunting and fishing are human disturbances of ecosystems.

True. Humans are a principal source of disturbance in this case, since humans hunt and fish.

(Txtbk pg. 343): True or false? Explain your answers: The freezing of a lake can be considered a natural disturbance.

True. The freezing of a lake is an event triggered by freezing temperature of water of the lake.

(Wkbk pg. 164): True or false? A carnivore cannot be a first-order consumer.

True. They must either be a herbivore or an omnivore.

(Txtbk pg. 343): True or false? Explain your answers: A flood following heavy rain is a natural disturbance.

True. This is an event triggered by environmental phenomena. Humans are not involved here.

What can a disturbance vary in?

Type, frequency, and degree of seriousness (how are area it affected).

(Wkbk pg. 174): What is an inorganic matter that is necessary to all?

Water and oxygen.

Looking at a graph, and knowing that the Earth's ecological carrying capacity is 1.6 hectares per person, do the ecological footprints of North Americans exceed the Earth's carrying capacity? You also know that the USA's and Canada's ecological footprints per person are 9.6 hectares and 7.6 hectares, respectively.

Yes! By a lot, too! 9.6 + 7.6 = a cumulative of 17.2 hectares per person in North America... which exceeds Earth's carrying capacity of 1.6 hectares per person by A LOT!

an agent that causes changes in the physical, chemical or biological properties of an environment or an organism What do these two definitions define?

a contaminant

(Txtbk pg. 345): Suppose that 10 percent of the available energy is converted into biomass at each change of trophic level. For each of the three food chains, calculate the percentage of the energy from the producers that the humans eventually convert into biomass: a) Grain --> Human b) Grain --> Cow --> Human c) Zooplankton --> Herring --> Tuna --> Human

a) 100% x 0.1 (AKA 10%) = 10% of the energy available to humans that the humans eventually convert into biomass b) 10% x 0.1 = 1% of the energy available to humans that the humans eventually convert into biomass c) 0.01% of the energy available to humans that the humans eventually convert into biomass. Why? Well, let's break it up: 100 x 0.1 (AKA 10%) = 10% of the energy available from phytoplankton to zooplankton. Then, 10 x 0.1 = 1% of the energy available to the herring. Then, 1 x 0.1 = 0.1% of the energy available to the tuna. Then, 0.1 x 0.1 = 0.01% of the energy available to the *human*.

(Txtbk pg. 344): Which of the following statements about ecological footprints is correct according to the 2003 study for the World Wildlife Fund? a) The ecological footprint of North Americans does not exceed the Earth's carrying capacity. b) If all the people in the world had the same rate of consumption as the Japanese, we would need about 2.5 planets the size of the Earth to satisfy our needs. c) On average, the global human ecological footprint does not exceed the Earth's carrying capacity.

a) Incorrect. It does; By a lot, too! 9.6 + 7.6 = a cumulative of 17.2 hectares per person in North America... which exceeds Earth's carrying capacity of 1.6 hectares per person by A LOT! b) Correct. To find that out you would do 4.4 (the ecological footprint in hectares of the Japanese) divided by 1.6 (Earth's ecological carrying capacity) = 2.5 planets. c) Incorrect. To calculate the average, add all the values as seen on the graph (ecological footprint in hectares relative to the countries shown) = 33.1 divided by the # of countries, 7 = 4.5 hectares. This exceeds Earth's ecological carrying capacity of 1.6 hectares.

Chemical recycling refers to the process in which:

decomposers break down organic matter to make inorganic matter. Reason: Correct answer. The process described is chemical recycling. NOT: radiation energy is transferred from one trophic level to the next. Reason: Incorrect answer. The process described is called energy flow. an ecosystem's balance is restored. Reason: Incorrect answer. The process described is called ecological succession. a population periodically rises and falls over time. Reason: Incorrect answer. The process described is called biological cycle.

Energy must be continually supplied from the ________.

sun