SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 1 of 7
This guide is a general outline – you will not necessarily be required to complete all the components, and other topics and material will probably be covered and/or assigned.
Chapter 1
1. a. Read pp. 8-13.
b. Write definitions for ecosystem, food chain, producer, consumer, herbivore, carnivore, omnivore, detritus, decomposer, habitat, parasite, host, scavenger c. Why are frogs considered to be a good “indicator species”? In your answer, be sure to refer to the terms amphibious, ecosystems, habitat, thin skin.
d. Do p. 13 questions 1, 2, 3, 4 (a, c).
b. ecosystem - all the living and nonliving things in a defined area, and their relationships food chain - a step-by-step sequence linking organisms that feed on each other producer - organism that makes its own food energy; green plant consumer - organism that cannot make its own food, and must feed on a plant or other animal; animal herbivore - organism that only eats plants carnivore - organism that only eats animals omnivore - organism that eats both plants and animals detritus - waste from organisms (plants and animals), including their dead remains decomposer - tiny organisms that feed off detritus and break it up into smaller molecules (bacteria and fungi) habitat - place where an organism lives, including all the conditions parasite - an organism that permanently (or long-term) attaches to another organism to feed host - an organism that a parasite attaches to scavenger - an animal that relies on organisms that are already dead; typically do not kill their own food c. Indicator species - a plant or animal that most easily gives evidence of changes in an ecosystem.
Frogs are a good indicator species because:
• As amphibians, they live in both water and terrestrial ecosystems, meaning they encounter the conditions of 2 different ecosystems.
• Because they develop in two stages, they are affected by different food supplies – as tadpoles, they are first-order consumers, meaning they feed off plants; as adult frogs, they are 2 nd
- or 3 rd
-

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 2 of 7 order consumers, meaning they feed off animals (flies).
• Because their skin is so thin, and they breathe through it, they are easily susceptible to toxins in the air and water, and to the Sun’s u.v. radiation; e.g. acid rain, sunburn.
• d. p. 13
1.(a) Fewer frogs would mean more insects, since adult frogs eat insects.
(b) Fewer frogs would mean more algae, because tadpoles eat algae.
2. grasses —> grasshopper —> frog —> heron producer 1 st consumer 2 nd consumer 3 rd consumer heron - carnivore, since they eat the frog frog - carnivore, since they eat the grasshopper grasshopper - herbivore, since they eat grasses grasses - producer algae —> tadpole —> water boatman —> yellow perch producer primary consumer secondary consumer tertiary consumer algae - producer tadpole - herbivore, since they eat algae water boatman - carnivore, since they eat tadpoles yellow perch - carnivore, since they eat water boatman
3. As a tadpole, a frog is an herbivore (primary consumer). As an adult frog, it is a carnivore.
4. (a) In its life cycle as both tadpole and adult frog, it functions at different levels on food chains, so it is affected by more changes in other species. Its thin skin makes it very susceptible to sunlight, and toxins in the air and water.
2. a. Read pp. 14-21.
b. Do. p. 15 question 2.
c. Define mass extinction (p. 16). How long ago was the most recent mass extinction, and what species became extinct at that time?
d. In a few sentences, discuss the statement, “All species eventually become extinct.” e. In that last few thousand years, what has been the major cause of the gradual extinction of various species?
f.
What are two human activities that have caused gradual extinctions? (top p. 18) g. Define biodiversity and domino effect.
h. Do. p. 19, question 2.

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 3 of 7 c. Mass extinction is the loss of many species all at the same time, caused by a major catastrophic event.
d. The statement, “all species eventually become extinct”, is true in the long-term – maybe in a year, thousand years, million years, etc. Over the long term, all species eventually encounter conditions to which they cannot adapt, and they become extinct.
As humans, we need to try to live so that we have as little impact on other species as possible.
e. In the last few thousand years, the major cause of the gradual extinction of species has been human activity.
f. Two human activities that have caused gradual extinction are forestry, agriculture, urban spread, harvesting of marine life
(large-scale fishing).
g. Biodiversity is the degree of variation of life forms (species) within a given ecosystem.
The domino effect in ecology refers to how changes that directly affect one species then affect other species as a result of food chains and relationships – every organism in an ecosystem is connected to all the other organisms.
Classification of At-Risk Species (p. 14) extinct - species gone endangered - species almost gone (gone most areas; only few left) extirpated - species gone from one area where it used to be found threatened - species losing significant numbers and soon to be gone from an area vulnerable - species losing numbers at the fringes of its range
3. a. Read pp. 22-23.
b. Define abiotic, biotic, ecology, ecotone.
c. Do p. 23 questions 2, 3, 4, 5.
b. biotic - all the living things in an area, including anything now dead but once was living (and their waste) abiotic - all the nonliving things/factors in an area (e.g.
temperature, wind, soil, humidity) ecology - the study of the interactions among the biotic (living), among the abiotic (nonliving) factors, and among each other.

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 4 of 7 ecotone - the overlapping or transition area where two ecosystems meet c. a. water ecosystem: biotic factors = e.g. algae, species of fish, worms, bugs, osprey, abiotic factors = e.g. water temperature, air temp, depth of water, rocks, sunlight, size of lake, wind, stream-fed forest ecosystem: biotic factors = e.g. worms, bugs, owls, moose, deer, species of trees, coyotes, rabbits abiotic factors = e.g. air temp, type of soil, rocks, sunlight, wind, rainfall,
3. population - the number of a single species in an ecosystem community - all the species in an ecosystem
4. An ecosystem includes the community of species, but also all the abiotic factors.
5. The greatest number of species (biodiversity) would be found in the ecotone, since it would include organisms in the transition area of the bordering ecosystems.
4. a. Read pp. 32-33.
b. Do p. 33 questions 1, 2, 3.
1. Sunlight is important for the biosphere because it is the source of all energy on Earth.
2. To summarize illustration, 30% reflected and 70% absorbed:
Reflection:
6% = atmosphere
20% = clouds
4% = earth’s surface
30%
Absorption:
16% = atmosphere
3% = clouds
51% = earth’s surface
70%

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 5 of 7
3. albedo effect - measure of the reflection of light biosphere - the zone of life on Earth; the sum of all ecosystems. In terms of location, the area from a couple of metres below the surface of the earth (bugs, worms, roots) to the air space where birds fly, including water.
5. a. Read p. 34-39.
b. Define trophic level, autotroph/producer, heterotroph/consumer, primary consumer, secondary consumer, tertiary consumer, food web, first law of thermodynamics, second law of thermodynamics..
c. Do p. 39 questions 4, 5, 6, 7, 9.
d. Based on the statement at the bottom of p. 36, what percentage of the available energy in an organism gets transferred (used) by the next feeding level in a food chain?
e. Many food chains have only 3 trophic levels. Why are 5-level food chains not nearly as common, and why does 5 seem to be the maximum? (top p. 37) f.
Explain a pyramid of energy as shown on p. 37.
g. What two human activities have caused major shifts in the stresses on ecosystems?
(p. 38).
b. trophic level - feeding level on a food chain autotroph - green plant; producer; makes own food energy heterotroph - consumer; animal; cannot make own food primary consumer - herbivore; animal that feeds directly on plants secondary consumer - carnivore; trophic level 3; feeds on animals that ate a plant tertiary consumer - carnivore; 3 rd order consumer; trophic level 4 food web - several interconnected food chains; representation of the feeding patterns in an ecosystem first law of thermodynamics - energy can neither be created nor destroyed, but can only be changed from one form to another; the only way to get energy is from another form of energy.
second law of thermodynamics - during any energy conversion, there is always some energy lost in the form of heat; can never get
100% of the energy.
c. 4. A secondary consumer consumes meat, since a primary consumer is the trophic level that consumes plants.
5. A top carnivore is an animal that tends to be at the top of food chains because other animals typically do not rely upon them for their food source.

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 6 of 7
6. A food chain is a single, one-way connection of feeding patterns. A food web is several food chains interconnected.
7. Arctic ecosystems would be more fragile than a southern forest ecosystem because there a much lower biodiversity in the northern conditions – fewer plants and animals.
9. Only 20% of the energy available in a plant is transferred to the primary consumer because only part(s) of plants are eaten, some of what is consumed is waste (unusable), and some is lost as heat.
d. Only 10% of the energy available in an organism typically gets passed along to the next level in the food chain.
e. Five-level food chains are about the maximum, because only 10% of energy is passed along to each following level, and losing that much energy cannot support a higher level.
f. In a pyramid of energy, the size of the block at each trophic level decreases in size by a large amount, because each block should only be about 10% of the size of the one below.
g. Two human activities that have caused major shifts in the stresses on ecosystems are agriculture and industry.
6. a. Read pp. 40-44 b. Define predator, prey, scavenger, niche, exotic species c. Do p. 44 questions 2, 3, 4.
predator - an animal that hunts and kills for food prey - an animal that is hunted and killed for food scavenger - an animal that relies on organisms that are already dead; typically do not kill their own food niche - an organism’s role or function in an ecosystem (e.g. what it eats, what eats it, what it accomplishes) exotic species - a species that is not native to an area – does not grow/live there naturally invasive species - a species that spreads and takes over, usually because it does not have natural predators
7. Check with teacher for an assigned exotic species. Find out more about the species. Write a
1-page report on your findings.
Chapter 2

SCIENCE 10 ECOLOGY UNIT OUTLINE/GUIDE ANSWERS Page 7 of 7
8. a. Read pp. 50-51, 61-64.
b. On the web, find the carbon cycle, and the nitrogen cycle. Print the best material you can find, that includes illustrations and explanations.
c. Do p. 65 questions 1, 2, 3, 4, 5, 6, 8.
d. Read pp. 66-68.
e. Do p. 69 questions 1, 2, 3, 6, 8, 13.
f.
Read pp. 70-71.
e. Do p. 71 questions 1, 3, 4, 5, 6.
Chapter 3
9. a. Read pp. 97-99.
b. Draw Figure 2 p. 98.
c. Do p. 99 questions 3, 5, 6, 8.
10. a. Read pp. 106-110.
b. Do p. 110 questions 1, 2, 3, 4.
11. Case Study - check with your teacher for options and instructions.
a. Forestry (e.g. pp. 72-73; 114-115) b. Potato production (e.g. pp. 112-113)