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7 Grade 15 week DCA Study Guide
Test is: Wednesday, February 6th
1. How much energy is transferred from one organism to the next in a food chain? 10 percent
2. What do the arrows indicate in a food web or food chain? The arrows show the flow of energy in an
ecosystem (food chains, food web) (points to the consumer)
3. Indicate how the following organisms obtain their food.
Carnivores By eating (consuming) other animals = meat eater = secondary/tertiary consumers
Herbivore By eating (consuming) plants = primary consumers
Omnivores By eating (consuming) plants and animals = primary/secondary consumers
Decomposers By breaking down dead organisms (plants and animals)
Scavengers By eating (consuming) dead animals
Producers By absorbing the sun’s energy and carrying out photosynthesis to produce glucose
Primary consumer By eating (consuming) producers______
Secondary Consumers By eating (consuming) primary consumers
Tertiary Consumer A consumer that has no natural predators in the food web
4. What are the reactants in photosynthesis? Water, CARBON DIOXIDE, sun light
5. What are the products of photosynthesis? OXYGEN and glucose
6. Where does all energy on earth originate from? The sun
7. Which of the following if removed would cause the collapse of an ecosystem? Producers
Decomposers Producers Carnivores Herbivores Omnivores
8. How is oxygen returned to the environment? Through the process of photosynthesis
9. Create a food chain using the following organisms.
Cricket Plant Snake Bird Frog
Plant > Cricket > Frog > Snake > Bird
10. Why do animals need plants? Plants provide animals with food and the oxygen they need
11. Why do plants need animals? Animals provide plants with carbon dioxide they need and when they
die and decompose nutrients are released into the soil that plants take in through their roots
12. What happens during decomposition? During decomposition bacteria, fungi, and other decomposers
breakdown dead organisms releasing nutrients back into the environment
13. How does photosynthesis and respiration work together? They work together to cycle oxygen and
carbon dioxide through the environment. Photosynthesis uses carbon dioxide released during the
process of respiration. Oxygen is produced and released by the process of photosynthesis and then
used to carry out respiration
14. Why do we need decomposers? They return nutrients back into the environment to be reused
by other organisms.
15. List the following organisms in orders of the most efficient users of solar energy to the least efficient.
Decomposers Producers Carnivores Omnivores Herbivores
Producers Herbivores Omnivores Carnivores Decomposers
16. List all of the Producers.
Grass
List all of the primary consumers
Rabbit, Grasshopper,
List all of the secondary consumers
Toad, Spider, Mouse, Preying Mantis, Sparrow, Garter snake, Hognose snake
Name the tertiary consumer
Hawk
Use the following food web to answer the questions
17. What would happen to the spider population if the insectivorous bird population increased?
The spider population will decrease (More birds eating them)
18. What would happen to the predaceous insect population if the toad population decreased?
The predaceous insect population would increase (fewer toads eating them)
19. If the producers died out, what would happen to the food web?
Without producers there would not be energy to fuel the rest of the ecosystem and it would collapse
20. What is the difference between autotrophs and heterotrophs?
Autotrophs can make their own food (Photosynthesis) and a Heterotroph can not make their own food and must rely on other organisms for energy.
21. What type of materials does it take to create a compost bin?
Brown stuff (Carbon) dead leaves, pine needles, sawdust etc…
Green Stuff (Nitrogen) Grass clippings, vegetable and fruit scraps, etc…
Water, oxygen, Decomposers
22. What happens to the height and the temperature of compost as it decomposes?
The height of the compost decreases as it breaks down and the temperature increases because of chemical reactions transforming chemical energy into thermal energy.
23. What are some examples of decomposers?
Bacteria, Fungi, Worms, Microscopic organisms
24. What is a microhabitat? List at least 3 examples.
A small area that can support a variety of organisms. Rotting log, small pond, garden, ant hill,
25. What is biodiversity? All the living organisms in an area – includes all the different species, genetic variety within the species, variety of ecosystems, and the different ways energy can flow through the system
26. Why is biodiversity important? biodiversity is important because it gives the organisms in an ecosystem a better chance to survive, gives humans useful materials (building, medicines etc.)
27. What is meant by the term sustainability? The ability to maintain and continue forever, a system is able to go on generation after generation
28. How are biodiversity and sustainability connected? Increased biodiversity = Increased sustainability
This is just a basic study guide, you need to reread and study your notes, check out your teacher’s website for power points used in class. Ask your teacher about tutoring if you need additional help, would like help studying, or just want to review.
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