Click for the student learning guide that accompanies this module.

1. Introduction

In the last two tutorials, which focused on the carbon cycle and the nitrogen cycle, we saw how carbon and nitrogen atoms move through ecosystems in various pathways in a never-ending cycle. Now, let’s look in more detail at some of the organisms that make up these pathways.

2. Getting Matter and Energy

Ecologically, plants are producers and autotrophs

Almost every ecosystem on our planet is powered by light energy from the sun. Through photosynthesis, plants convert light energy into chemical energy, primarily in the form of carbohydrates. The ability of plants to produce chemical energy makes them ecological producers. Producers are also called autotrophs. Autotroph means “self-feeder,” which is exactly what plants do: they feed themselves by making their own food through photosynthesis. Here’s the equation for photosynthesis:

6CO2 + 6H2O + light energy ? C6H12O6 + 6O2

An ecosystem could consist entirely and solely of plants and decomposers (the bacteria and fungi that break down dead organisms and return make their atoms available for recycling in biogeochemical cycles). But commonly there’s a level of animals who eat the plants. Several terms are used to refer to these plant-eaters. These animals are primary consumers (because they’re the first in a chain of animals that consume the matter and energy that’s been produced by plants). They’re also referred to as herbivores (“herb” is Latin for plant; “vore” is the same root that’s in the word “devour”). Finally, any organism that doesn’t make its own food is called a heterotroph. All consumers/heterotrophs get their energy from the carbohydrates produced by plants, and release that energy through cellular respiration: C6H12O6 + 6O2 ?  energy(ATP) + 6CO2 + 6H2O

Four primary consumers, or herbivores. Clockwise from top left: cow, grasshopper, garden snail, earthworm

Carnivores, or secondary consumers eat the primary consumers. The term “predator” is mostly synonymous with carnivore.

The cheetah: a carnivore or secondary consumer
The cheetah: a carnivore or secondary consumer

And the chain can go higher still: A third level (tertiary) consumer, would eat a secondary consumer. But as we’ll see, while there are some carnivores which, as the opportunity arises, might eat another carnivore, there are few organisms that eat primarily at this tertiary level. These ways of getting matter and energy (producer, primary consumer, secondary consumer)  make up an ecosystem’s trophic levels. Trophic levels are feeding levels. Organisms at the same trophic level are positioned in a similar place in terms of the way that energy flows through an ecosystem. This becomes clearer when we look at the concept of food chains and food webs.

3. Food Chains

Two food chains. Source: wikimedia commons

You can follow this flow of matter and energy in a food chain, as shown below.

A food chain shows who eats whom in an ecosystem. It’s a pathway of matter and energy through a series of organisms, as you can see in the diagram below. In the food chain on the left, a flowering plant (a producer) is eaten by grasshoppers and bees (the primary consumers), which are eaten by other insects (secondary consumers), which are eaten by frogs (a third-level consumer in this food chain) and so on.

[qwiz style = “border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Food Chains, CFU (Ecosystems)”]

[h] Checking Understanding: Food Chains

[i] Just to make sure you’ve mastered all of the terms above, take this short quiz. It’s three questions, all based on the diagram above.

If you haven’t taken a sciencemusicvideos quiz before, here’s how it works: Each question is multiple choice, but the entire quiz is like a series of flashcards. If you get the question right, it comes off the deck. If you get the question wrong, it goes to the bottom of the deck.

Click “start” to begin.

[!] question 1[/!]

[q] In the diagram, which number refers to a primary consumer?

[c] 1

[c*] 2

[c] 3

[c] 4

[f] No. The organisms on the bottom of a food chain are always producers.

[f] Nice job: the organisms shown at “2” are eating the producers, which makes them primary consumers

[f] No. The organisms shown at “3” are secondary consumers, or carnivores. [f] No. The organisms shown at “4” are third level, or tertiary consumers.

[!] question 2[/!]

[q] In the diagram, which number refers to producers?

[c*] 1

[c] 2

[c] 3

[c] 4

[f] Excellent. Level 1 consists of producers.

[f] No. Producers are always at the bottom of a food chain. Level 2 consists of primary consumers.

[f] No. Producers are always at the bottom of a food chain. Level 3 consists of secondary consumers.

[f] No. Producers are always at the bottom of a food chain. Level 4 consists of third level, or tertiary consumers.

[!] question 3[/!]

[q] Which is the only level which performs photosynthesis?

[c*] 1

[c] 2

[c] 3

[c] 4

[f] Excellent. Level 1 consists of producers. Only producers perform photosynthesis.

[f] No. Level 2 consists of primary consumers.Only producers perform photosynthesis.

[f] No. Level 3 consists of secondary consumers. Only producers perform photosynthesis.

[f] No. Level 4 consists of third-level consumers. Only producers perform photosynthesis.

[x] If you want to take this quiz again, click the button below. Otherwise, continue reading.

[restart]

[/qwiz]

4. Food Webs

A food web shows all the interconnected food chains in an ecosystem. In the food web below, you can start from the phytoplankton (floating-organisms that do photosynthesis), and follow the pathway of matter and energy to the bivalves, to sea ducks, to the bald eagle. That is only one of several food chains that you could follow in this food web. See if you can find two or three others.

A food web

5. Other Ways of Getting Food: Omnivores, Scavengers, Decomposers, and Parasites

Many animals can’t be neatly classified as either primary or secondary consumers: the way they make a living (also known as their ecological niche) involves eating at multiple levels. A grizzly bear, for example, is an omnivore. It eats plants such as berries, but it will also hunt for rodents, rabbits, and salmon. Humans, of course, are also omnivores.

Grizzly bears are omnivores

Scavengers eat recently killed animals. Vultures are scavengers. So are bald eagles. Hyenas are both carnivores and scavengers.

Vultures are scavengers. Here you see them feeding on a carcass.

Many organisms participate in consuming and breaking down dead organic matter, which is a process that occurs in many stages. Decomposers, primarily fungi and bacteria, play the final role in this process, breaking down dead material into simple molecules that can re-enter biogeochemical cycles like the carbon cycle.

Decomposers, such as the fungi shown on the far right, complete the breakdown of dead material into simpler forms

Finally, parasites live inside and consume living prey. Some parasites can be as large as the pork tapeworm, which infects the muscle tissue of pigs and the intestines of humans. In humans, tapeworms can grow up be up to twenty feet long. However, many more parasites are microscopic, like the the parasitic bacteria that cause diseases like diphtheria and cholera, or viruses, which parasitize cells.

The pork tapeworm has two hosts: pigs and humans

6. Flashcards: Food chains, Food Webs, Trophic Levels

At this point, you should be able to describe how food chains and food webs work, and the basic roles that organisms play within food chains and webs. This includes understanding the following terms:

  1. food chain
  2. food web
  3. producer
  4. primary consumer
  5. herbivore
  6. autotroph
  7. heterotroph
  8. secondary consumer
  9. carnivore
  10. predator
  11. trophic level
  12. omnivore
  13. decomposer
  14. scavenger
  15. parasite

To help you master these terms, spend as much time as you need working through these flashcards:

[qdeck style=”border: 2px solid black;” random = “true” qrecord_id=”sciencemusicvideosMeister1961-Food Webs, Trophic Levels FC (Ecosystems)”]

[h] Flashcards: Food Chains and Food Webs [i] Welcome to this set of flashcards about food chains and food webs. Here’s how it works.

  • Click ‘Flip’ to see the answer to each card.
  • Type in the answer
  • If you know it, click ‘Got it.”
  • If you don’t know it as well as you’d like, click ‘Need more practice,’ and that card will go to the bottom of the deck so you can practice it again.
  • ‘Shuffle’ lets you shuffle the deck.

[start]

[!] Card 1+++++++++++++++++++++++[/!]

[q] A _____ _____ is one pathway showing the flow of energy and matter through an ecosystem.

[textentry]

[a] A food chain is one pathway showing the flow of energy and matter through an ecosystem.

[!] Card 2+++++++++++++++++++++++[/!]

[q] All of the food chains in an ecosystem make up a ______ ______.

[textentry]

[a] All of the food chains in an ecosystem make up a food web.

[!] Card 2b+++++++++++++++++++++++[/!]

[q] All of the food chains in an ________ make up a food web.

[textentry]

[a] All of the food chains in an ecosystem make up a food web.

[!] Card 3+++++++++++++++++++++++[/!]

[q] A organism in an ecosystem, typically a plant, that creates food through photosynthesis is known as a ________.

[textentry]

[a] A organism in an ecosystem, typically a plant, that creates food through photosynthesis is known as a producer.

[!] Card 3b+++++++++++++++++++++++[/!]

[q] A organism in an ecosystem, typically a plant, that creates food through ________ is known as a producer.

[textentry]

[a] A organism in an ecosystem, typically a plant, that creates food through photosynthesis is known as a producer.

[!] Card 4+++++++++++++++++++++++[/!]

[q] _______ consumers are organisms that eat producers.

[textentry]

[a] Primary consumers are organisms that eat producers.

[!] Card 5+++++++++++++++++++++++[/!]

[q] _______ are also known as primary consumers.

[textentry]

[a]  Herbivores are also known as primary consumers.

[!] Card 5b+++++++++++++++++++++++[/!]

[q]  Herbivores are also known as _______ consumers.

[textentry]

[a]  Herbivores are also known as primary consumers.

[!] Card 6+++++++++++++++++++++++[/!]

[q] ________ are organisms that can feed themselves by making their own food.

[textentry]

[a] Autotrophs are organisms that can feed themselves by making their own food.

[!] Card 7+++++++++++++++++++++++[/!]

[q] All organisms that eat other organisms (as opposed to making their own food) are __________.

[textentry]

[a] All organisms that eat other organisms (as opposed to making their own food) are heterotrophs.

[!] Card 8+++++++++++++++++++++++[/!]

[q] A _______ _______ is an organism that eats eats a primary consumer.

[textentry]

[a] A secondary consumer is an organism that eats eats a primary consumer.

[!] Card 8b+++++++++++++++++++++++[/!]

[q] ________, like wolves, are also known as secondary consumers.

[textentry]

[a] Carnivores, like wolves, are also known as secondary consumers.

[!] Card 10+++++++++++++++++++++++[/!]

[q] A ________ is an animal that preys on other animals. In terms of trophic levels, these organisms are secondary or tertiary (third-level) consumers

[textentry]

[a] A predator is an animal that preys on other animals. In terms of trophic levels, these organisms are secondary or tertiary (third-level) consumers. (note that “carnivore” is a perfectly good response here).

[!] Card 11+++++++++++++++++++++++[/!]

[q] An _________ is an animal that eats both as an herbivore (or primary consumer) and as a carnivore (or secondary consumer).

[textentry]

[a] An omnivore is an animal that eats both as an herbivore (or primary consumer) and as a carnivore (or secondary consumer).

[!] Card 12+++++++++++++++++++++++[/!]

[q] Producer, primary consumer, secondary consumer: all of these are examples of ________ levels.

[textentry]

[a] Producer, primary consumer, secondary consumer: all of these are examples of trophic levels.

[!] Card 13+++++++++++++++++++++++[/!]

[q] A _________ is an organism that gets energy by breaking down dead material into simple molecules that can re-enter biogeochemical cycles.

[textentry]

[a] A decomposer is an organism that gets energy by breaking down dead material into simple molecules that can re-enter biogeochemical cycles.

[!] Card 13a+++++++++++++++++++++++[/!]

[q] A decomposer is an organism that gets energy by breaking down _______ material into simple molecules that can re-enter biogeochemical cycles.

[textentry]

[a] A decomposer is an organism that gets energy by breaking down dead material into simple molecules that can re-enter biogeochemical cycles.

[!] Card 13b+++++++++++++++++++++++[/!]

[q] A decomposer is an organism that gets energy by breaking down dead material into simple molecules that can re-enter __________ cycles.

[textentry]

[a] A decomposer is an organism that gets energy by breaking down dead material into simple molecules that can re-enter biogeochemical cycles.

[!] Card 14+++++++++++++++++++++++[/!]

[q] Whereas carnivores kill animals and eat them, ________ eat the remains of animals that other organisms have killed.

[textentry]

[a] Whereas carnivores kill animals and eat them, scavengers eat the remains of animals that other organisms have killed.

[!] Card 14a+++++++++++++++++++++++[/!]

[q] Whereas ________ kill animals and eat them, scavengers eat the remains of animals that other organisms have killed.

[textentry]

[a] Whereas carnivores kill animals and eat them, scavengers eat the remains of animals that other organisms have killed.

[!] Card 15+++++++++++++++++++++++[/!]

[q] A _________ is an organism that lives inside of (or on) a living host, consuming that host while it’s still alive.

[textentry]

[a] A parasite is an organism that lives inside of (or on) a living host, consuming that host while it’s still alive.

[x] If you want more practice, please press the restart button below. Otherwise, continue to the final quiz.

[restart]

[/qdeck]

7. Quiz: Food Chains, Food Webs, Trophic Levels, etc.

[qwiz style = “border: 3px solid black;”random = “true” qrecord_id=”sciencemusicvideosMeister1961-Food Chains, Food Webs Quiz (Ecosystems)”]

[h] QUIZ: Food Chains and Food Webs

[i] This quiz covers key concepts and terms related to food chains and food webs

  • The quiz consists of a series of multiple choice questions, but it behaves like a stack of flashcards.
  • If you get a question right, you move on to the next question.
  • If you get a question wrong, you’ll get an explanation, and then that question goes to the bottom of the stack.
  • To exit the quiz, you have to answer each question correctly. The program will keep track of how many times you tried and how you did in each area that the quiz covers.
  • At the end of the quiz, the program will report back to you about how you did, and, if necessary, offer some suggestions for review.

[!] question 1+++++++++++++++++++++++[/!]

[q] What is the source of energy in almost all ecosystems?

[c] ATP

[c*] sunlight

[c] water

[c] glucose

[f] No. ATP is the energy source within cells. But cells power their ATP production through cellular respiration, using glucose as a fuel. Glucose is created by photosynthesis. What powers photosynthesis?

[f] Yes. Light from the sun is the energy source for almost all ecosystems.

[f] No. Water makes up most of the mass of most living things, but it’s not an energy source. The chemical energy for life comes from carbohydrates, which are made by photosynthesis. What powers photosynthesis?

[f] No. Glucose is a key form of chemical energy, but glucose itself is made by photosynthesis. What powers photosynthesis?

 

[!] question 2+++++++++++++++++++++++[/!]

[q] The organisms that create the food that supports ecosystems are known as

[c] herbivores

[c*] producers

[c] consumers

[c] decomposers 

[f] No. Herbivores eat plants. Ecologically, what are plants?

[f] Yes. The plants the create the food that supports an ecosystem are known as producers.

[f] No. Consumers consume plants. Plants are also known as…

[f] No. Decomposers are essential for breaking down organic matter into a form that can be reused by other organisms. But what’s the name for the organisms who make the food.

 

[!] question 3+++++++++++++++++++++++[/!]

[q] One of these things is not like the other ones. Which one doesn’t fit?

[c] Plant

[c] Producer

[c*] Heterotroph

[c] autotroph

[f] No. The unifying concept here is being able to produce your own food. Plants feed themselves through photosynthesis Which term refers to organisms that can’t?

[f] No. The unifying concept here is being able to produce your own food. ‘Producers’ produce food. Which term refers to organisms that can’t?

[f] Yes. Heterotrophs need acquire energy from other organism. ‘Heterotroph’ means ‘other-feeder.’ All the other terms are for organisms that make their own food.

[f] No. The unifying concept here is being able to produce your own food. ‘Autotroph’ means ‘self-feeder.’ Which term refers to organisms that can’t feed themselves?

 

[!] question 4+++++++++++++++++++++++[/!]

[q] One of these things is not like the other ones. Which one doesn’t fit?

[c*] Plant

[c] Consumer

[c] Heterotroph

[c] Animal

[f] Yes. All the other terms are unified by needing to acquire energy from another organism. Plants, which can perform photosynthesis, feed themselves.

[f] No. The unifying concept here is needing to acquire energy from another organism. Consumers need to consume plants (or animals) to stay alive. Which of the listed categories does not need to consume other organisms?

[f] No. The unifying concept here is needing to acquire energy from another organism. ‘Heterotroph’ means ‘other feeder.’ Heterotrophs need to consume plants (or animals) in order to stay alive. Which of the listed categories does not need to consume other organisms?

[f] No. The unifying concept here is needing to acquire energy from another organism. Animals need to consumer plants (or other animals) in order to stay alive. Which of the listed categories does not need to consume other organisms?

[!] question 5+++++++++++++++++++++++[/!]

[q] The correct chemical equation for photosynthesis is

[c] C6H12O6 + 6 CO2 + energy (ATP) -> 6CO2 + 6O2

[c] C6H12O6 + 6O2 -> energy(ATP) + 6CO2 + 6H2O

[c*] 6CO2 + 6H2O + Energy(light) -> C6H12O6 + 6O2

[c] 6H2O + 6O2 -> 6CO2 + 6H2O

[f] No. The reaction above shows glucose being combined with carbon dioxide. In photosynthesis, carbon dioxide is combined with water to create glucose, with oxygen released as a byproduct.

[f] No. In photosynthesis, carbon dioxide is combined with water to create glucose, with oxygen released as a byproduct.

[f] Yes. In photosynthesis, carbon dioxide is combined with water to create glucose, with oxygen released as a byproduct.

[f] No. Find a reaction that begins with carbon dioxide and water, and combines those inputs to create glucose, with oxygen released as a byproduct.

 

[!] question 6+++++++++++++++++++++++[/!]

[q] The term that best describes the kind of organism that directly consumes plants is

[c] secondary consumer

[c*] primary consumer

[c] animal

[c] heterotroph

[f] No. Secondary consumers consume primary consumers. What kind of organism eats plants?

[f] Yes. Primary consumers are herbivores, and eat plants.

[f] No. ‘Animal’ is a bit too broad. Animals can be herbivores or carnivores. What’s a synonym for herbivore?

[f] No. Heterotroph is too broad. To be a heterotroph means needing to acquire food from another organism, as opposed to making it yourself (like a plant can). Heterotrophs can be herbivores, carnivores, even decomposers. You need to find the ecological equivalent for ‘herbivore.’

[!] question 7 +++++++++++++++++++++++[/!]

[q] The correct chemical reaction for cellular respiration is

[c] C6H12O6 + 6CO2 + energy(ATP) -> 6CO2 + 6O2

[c*] C6H12O6 + 6O2 -> energy(ATP) + 6CO2 + 6H2O

[c] 6CO2 + 6H2O + Energy(light) ->C6H12O6 + 6O2

[c] 6H2O + 6O2 -> 6CO2 + 6H2O

[f] No. Find a reaction that begins with glucose, combines it with oxygen, and releases energy, carbon dioxide, and water.

[f] Excellent. Cellular respiration begins with glucose, combines it with oxygen, and releases energy, carbon dioxide, and water.

[f] No. Find a reaction that begins with glucose, combines it with oxygen, and releases energy, carbon dioxide, and water. This equation, by the way, is the correct equation for photosynthesis. If you reverse the reaction, you’ll have the reaction for cellular respiration.

[f] No. Find a reaction that begins with glucose, combines it with oxygen, and releases energy, carbon dioxide, and water.

 

[!] question 8+++++++++++++++++++++++[/!]

[q] ‘Herbivore’ means the same as

[c] secondary consumer

[c*] primary consumer

[c] animal

[c] heterotroph

[f] No. Secondary consumers consume primary consumers. What kind of organism eats plants?

[f] Yes. Primary consumers are herbivores, and eat plants.

[f] No. ‘Animal’ is a bit too broad. Animals can be herbivores or carnivores. What’s a synonym for herbivore?

[f] No. Heterotroph is too broad. To be a heterotroph means needing to acquire food from another organism, as opposed to making it yourself (like a plant can). Heterotrophs can be herbivores, carnivores, even decomposers. You need to find the ecological equivalent for ‘herbivore.’ 

 

[!] question 9+++++++++++++++++++++++[/!]

[q] If you need to acquire your food from another organism (as opposed to making it yourself), you’re a(n)

[c] plant

[c] autotroph

[c] producer

[c*] heterotroph

[f] No. Plants can make their own food. What kind of organism can’t make its own food?

[f] No. ‘Autotroph’ means ‘self feeder.’ What kind of organism can’t make its own food?

[f] No. Producers are plants (or some other photosynthetic organism) that produce food for themselves and other organisms. What kind of organisms can’t produce their own food?

[f] Yes. To be a heterotroph means needing to acquire food from another organism, as opposed to making it yourself (like a plant can). Heterotrophs can be herbivores, carnivores, and even decomposers.

[!] question 10+++++++++++++++++++++++[/!]

[q] A pathway of matter and energy that flows from one organism to another is known as a

[c] food web

[c*] food chain

[c] biogeochemical cycle

[f] No, but you’re very close. A food web is all of the food chains in an ecosystem. Next time, choose just a single pathway.

[f] Yes. A food chain is a pathway of matter and energy from one organism to the next in an ecosystem.

[f] No. A biogeochemical cycle shows the cycling of matter between abiotic and biotic components in an ecosystem. To answer this question just focus on the pathway of matter and energy between organisms.

[!] question 11+++++++++++++++++++++++[/!]

[q] An organism that primarily gets food by by eating herbivores is a(n)

[c] Producer

[c] Primary consumer

[c*] Secondary consumer

[f] No. In most ecosystems, producers are the plants that produce the food for themselves and other organisms. Who eats the herbivores?

[f] No. A primary consumer eats plants. Who eats the primary consumers?

[f] Yes. Secondary consumers are carnivores that eat primary consumers. 

[!] question 12+++++++++++++++++++++++[/!]

[q] One of these things is not like the other ones. Which one doesn’t fit?

[c] carnivore

[c] predator

[c] Secondary consumer

[c*] herbivore

[f] No. The unifying concept for this and two of the other choices is ‘meat eater.’ Which one does NOT mean meat eater?

[f] No. The unifying concept for this and two of the other choices is ‘meat eater.’ Which one does NOT mean meat eater?

[f] No. The unifying concept for this and two of the other choices is ‘meat eater.’ Which one does NOT mean meat eater?

[f] Yes. Herbivores eat plants. All the other terms refer to meat eaters.

 

[!] question 13+++++++++++++++++++++++[/!]

[q] The diagram at right depicts

[c*] two food chains

[c] a food web

[c] ecosystem

[c] biogeochemical cycle

[f] Yes. The pathway of food from one organism to the next is a food chain.

[f] No. A food web shows all the food chains in an ecosystem. This image is showing two pathways of food energy. What’s the best term for that?

[f] No. A diagram of an ecosystem would include both the living community in an area, and the non-living parts of the environment that support that community. What kind of image shows a single pathway of food through an ecosystem?

[f] No. A biogeochemical cycle diagram would show the flow of matter from living to non-living components of an ecosystem. This image is showing two pathways of food energy. What’s the best description of that? 

 

[!] question 14+++++++++++++++++++++++[/!]

[q] This diagram depicts a  [c] food chain

[c*] a food web

[c] ecosystem

[c] biogeochemical cycle

[f] No. A food chain is the pathway of food from one organism to the next. This diagram shows multiple food chains.

[f] Yes. A food web shows all the food chains in an ecosystem.

[f] No. A diagram of an ecosystem would include both the living community in an area, and the non-living parts of the environment that support that community. What kind of diagram would show all the food chains in an ecosystem?

[f] No. A biogeochemical cycle diagram would show the flow of matter from living to non-living components of an ecosystem. What kind of diagram would show all the food chains in an ecosystem?

[!] question 15+++++++++++++++++++++++[/!]

[q] The organisms at number four in this diagram are

[c] producers

[c] primary consumers

[c] secondary consumers

[c*] tertiary (3rd-level) consumers 

[f] No. Producers are always at the bottom of a food chain.

[f] No. Primary consumers are shown at number 2. They eat producers. [f] No. Secondary consumers are shown at number 3. They eat the primary consumers.

[f] Yes. A tertiary (3rd-level) consumer would be at number 4 in this diagram. Tertiary consumers eat secondary consumers (carnivores). 

[!] question 16+++++++++++++++++++++++[/!]

[q] The organisms at number one in this diagram are

[c*] producers

[c] primary consumers

[c] secondary consumers

[c] tertiary (3rd-level) consumers

[f] Yes. Producers are always at the bottom of a food chain.

[f] No. Primary consumers are shown at number 2. They eat producers.

[f] No. Secondary consumers are shown at number 3. They eat the primary consumers.

[f] No. A tertiary (3rd-level) consumer would be at number 4 in this diagram. Tertiary consumers eat secondary consumers (carnivores).

 

[!] question 17+++++++++++++++++++++++[/!]

[q] The organisms at number three in this diagram are

[c] producers

[c] primary consumers

[c*] secondary consumers

[c] tertiary (3rd-level) consumers

[f] No. Producers are always at the bottom of a food chain. They’re shown at number 1.

[f] No. Primary consumers are shown at number 2. They eat producers.

[f] Yes. Secondary consumers are shown at number 3. They eat the primary consumers.

[f] No. A tertiary (3rd-level) consumer would be at number 4 in this diagram. Tertiary consumers eat secondary consumers (carnivores).

[!] question 18+++++++++++++++++++++++[/!]

[q] The organisms at number two in this diagram are

[c] producers

[c*] primary consumers

[c] secondary consumers

[c] tertiary (3rd-level) consumers

[f] No. Producers are always at the bottom of a food chain. They’re shown at number 1.

[f] Yes. Primary consumers are shown at number 2. They eat producers.

[f] No. Secondary consumers are shown at number 3. They eat the primary consumers.

[f] No. A tertiary (3rd-level) consumer would be at number 4 in this diagram. Tertiary consumers eat secondary consumers (carnivores).

[!] question 19+++++++++++++++++++++++[/!]

[q] An animal like a grizzly bear that eats plants and preys on other animals is a(n)

[c] herbivore

[c] primary consumer

[c] secondary consumer

[c*] omnivore

[f] No. Herbivores eat plants.

[f] No. Primary consumer is equivalent to ‘herbivore.’ These animals solely eat plants.

[f] No. Secondary consumers are solely carnivores. Find the name of a type of organism that eats both plants and animals.

[f] Yes. Bears (like people) are omnivores, eating both plants and animals.

[!] question 20+++++++++++++++++++++++[/!]

[q] An animal like an elk that eats almost exclusively plants is a(n)

[c*] herbivore

[c] producer

[c] secondary consumer

[c] omnivore

[f] Yes. Elk are herbivores, or plant eaters.

[f] No. Producers are plants. What type of organism eats plants?

[f] No. Secondary consumers are carnivores. Find the name of a type of organism that eats only plants.

[f] No. Omnivores eat both plants and animals. Find the name of a type of organism that eats only plants.

[!] question 21+++++++++++++++++++++++[/!]

[q] An animal like a vulture that eats the remains of dead animals is a(n)

[c] herbivore

[c] parasite

[c] secondary consumer

[c] omnivore

[c*] scavenger

[f] No Herbivores are plant-eaters

[f] No. Parasites feed on a living host.

[f] No. Secondary consumers are carnivores. They kill their prey.

[f] No Omnivores eat both plants and animals. What kind of organism eats the remains of dead animals.

[f] Yes. A vulture feeds on the remains of dead animals, making it a scavenger.

 

[!] question 22+++++++++++++++++++++++[/!]

[q] An organism like a tapeworm that feeds off a living host is a(n)

[c] herbivore

[c*] parasite

[c] secondary consumer

[c] omnivore

[c] scavenger

[f] No Herbivores are plant-eaters. What kind of animal preys on a living host?

[f] Yes. Parasites, like the tapeworm, feed off of a living host.

[f] No. Secondary consumers are carnivores. They kill their prey. What kind of animal preys on a living host?

[f] No Omnivores eat both plants and animals. What kind of animal preys on a living host?

[f] No. A scavenger feeds on the remains of dead animals. What kind of animal preys on a living host?

 

[!] question 23+++++++++++++++++++++++[/!]

[q] Organisms like this fungus that get their nutrients from dead and decaying organic matter, breaking it down into simple forms that can re-enter biogeochemical cycles, are

[c*] decomposers.

[c] producers.

[c] parasites.

[c] predator

[f] Yes. Decomposers, which include organisms like fungi and bacteria, get their nutrients from the breakdown of dead and decaying organic matter.

[f] No. Producers are organisms like plants that can produce food.

[f] No. Parasites are organisms that prey on a living host.

[f] No. Predators kill other animals for food.

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[/qwiz]

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