Download BLM 1-1, You and Food Chains/ Science Inquiry BLM 1

CHAPTER 1
ANSWER KEY
BLM 1-1, You and Food Chains/
Science Inquiry
producers
Goal: Students record their information for Starting
Point Activity: You and Food Chains.
Answers:
1. to 3. Answers will vary.
4. A food chain is a linear sequence of organisms that
shows their feeding relationships. It starts with a
producer and includes one or more consumers. It
may include one or more decomposers.
wheat
grains
moss
corn
grass
rice
A
B
deer eating
grass
mould on a
rotting
apple
birds
insects
people
deer
consumers
fox
fish
snake
bees
frogs
flowers
animals
maggots
on a dead
carcass
C
decomposers
bacteria
worms
flies
fungi
beetles
BLM 1-2, Flowchart of Connecting
Links/Reinforcement
Goal: Students become familiar with terms related to
ecosystems.
Answers:
1. it captures energy from the Sun and, with water
and carbon dioxide, converts the energy into sugar
through photosynthesis
2. to capture the energy from producers by eating
them and, when no longer living, to provide
energy for decomposers
3. it helps to break down dead organisms and recycle
nutrients in ecosystems
4. create the environmental characteristics and
provide the biotic (living) factors with the
necessities of life
BLM 1-4, Getting to the Top/
Reinforcement
Goal: Students become familiar with relationships
among organisms in food chains and food webs.
Answers:
1. a food web
2. algae, wheat, and grass
3. minnow or paramecium
4. field mouse or rabbit
5. wolf
6. minnow, paramecium, mouse, or rabbit
5. a sea gull
7. herbivore
6. an ecosystem on land
8. fourth trophic level
7. a grassland and a forest
9. A top carnivore is a meat eater that is not food for
other consumers.
8. crabs, earthworms, and wood beetles
BLM 1-3, A Tribute to Trophic
Levels/Skill Builder
Goal: Students examine the concept of trophic levels.
Answers:
1.–3. Answers will vary but may include the following:
10. An omnivore is a meat and plant eater. It consumes
both animals and plants.
11. minnow
BLM 1-5, Matching Feeder Terms/
Assessment
Goal: Students assess their knowledge of terms that
describe feeding relationships.
Answers: The answers can be peer- or self-assessed.
There is no match for (m) or (n).
34
Copyright © McGraw-Hill Ryerson Limited.
ANSWER KEY
CHAPTER 1
1. (e)
5. (b)
9. (h)
2. (d)
6. (g)
10. (l)
3. (a)
7. (c)
11. (i)
4. (k)
8. (j)
12. (f)
BLM 1-6, Analyzing Food Chains/
Reinforcement
Goal: Students practise using terms that describe
organisms’ feeding patterns.
Answers:
1. and 2. Answers will vary.
3. (a) producer
(b) Producers have the ability to capture energy
from the Sun.
4. at the first trophic level, which is occupied by
producers
5. Less and less energy is passed along the food
chain.
BLM 1-7, What Eats What?/Science
Inquiry
Goal: Students record their observations for Science
Inquiry Activity: What Eats What?
Answers:
1.
4. All the food chains consist of at least one producer
and one consumer. They are in the same sequence,
going from a primary trophic level to higher
trophic levels.
BLM 1-8, Ecology Terms/
Vocabulary Check
Goal: Students review terms related to ecology and
animal feeding patterns.
Answers:
7. top carnivore
1. producer
2. food web
8. producer
3. decomposers
9. herbivore
4. consumer
10. carnivore
5. pyramid of energy flow
11. pyramid of numbers
6. food chain
12. pyramid of biomass
BLM 1-9, Going with the Flow/
Science Inquiry
Goal: Students recognize the flow of energy in a food
web.
Answers:
1. (a) The grass population may decrease if it cannot
regrow fast enough.
(b) The wolf population could increase with this
increased food supply.
Organism
Trophic level
Producer/
consumer
2. Answers will vary. Here are some examples of
possible food chains:
grass
red fox
bacteria/fungi
grasshopper
cottontail rabbit
red squirrel
common raven
willow
ruffed grouse
bunch berries
red-tailed hawk
maple seeds
first
third or higher
third or higher
second
second
second
third or higher
first
second
first
third or higher
first
producer
consumer
neither
consumer
consumer
consumer
neither
producer
consumer
producer
consumer
producer
Food chain 1: grass → mouse → snake → wolf
Food chain 2: grass → deer → wolf
Food chain 3: shrubs → rabbit → hawk
Food chain 4: shrubs → insect → frog
3.
Organism
Energy
available
grass
deer
wolf
5000 kJ
500 kJ
50 kJ
Energy used
in metabolism
4500 kJ
450 kJ
45 kJ
Energy
stored
500 kJ
50 kJ
5 kJ
2. Answers will vary.
3. raven and hawk
Copyright © McGraw-Hill Ryerson Limited.
35
CHAPTER 1
ANSWER KEY
BLM 1-10, Chains and Webs/
Reinforcement
Goal: Students increase their understanding of
relationships in food chains and food webs.
Answers:
1. (a) grass → grasshopper → frog → hawk → bacteria
Organism
grass
grasshopper
frog
hawk
bacteria
Producer/composer/decomposer
producer
consumer
consumer
consumer
decomposer
Trophic level
first
second
third
fourth
fifth
Herbivore/(top) carnivore/
detritivore/
n/a
herbivore
carnivore
top carnivore
detritivore
(b) roots → rabbit → snake → hawk → bacteria
Organism
roots
rabbit
snake
hawk
bacteria
Producer/composer/decomposer
producer
consumer
consumer
consumer
decomposer
Trophic level
first
second
third
fourth
fifth
Herbivore/(top) carnivore/
detritivore
n/a
herbivore
carnivore
top carnivore
detritivore
(c) tree → seeds → grasshopper → snake → hawk → bacteria
Organism
tree
seeds
grasshopper snake
hawk
Producer/composer/decomposer
producer
producer
consumer
consumer
consumer decomposer
Trophic level
first
first
second
third
fourth
fifth
Herbivore/(top) carnivore/
detritivore
n/a
n/a
herbivore
carnivore
top
carnivore
detritivore
2. Answers will vary.
Here is one example:
roots
tree
rabbit
snake
grass
hawk
seeds
grasshopper
bacteria
The food web here shows bacteria at the lowest
trophic level. Detritivores can be placed either at
the top or the bottom. Accept either answer in the
food web or students’ charts.
36
bacteria
Copyright © McGraw-Hill Ryerson Limited.
frog
ANSWER KEY
CHAPTER 1
BLM 1-11/Interaction Pyramids/
Reinforcement
BLM 1-13, Animal Crackers/
Science Inquiry
Goal: Students increase their understanding of
feeding relationships in pyramids.
Answers:
1. Pyramid of numbers:
3. Pyramid of energy:
Goal: Students become more familiar with concepts
related to ecosystems and interactions.
Hints & Helps: You may want to give students
some guidance for Part 1, step 2. You could suggest that students identify relationships from the
placement of the crackers or from their knowledge
of the living animals.
Answers:
Part 1
Because the “animals” are not living, and students
cannot observe actual relationships, the relationships
are difficult to determine. Some relationships can be
inferred from the way two crackers land. For example,
if the crackers land face to face, the animals could be in
competition. Accept any reasonable answers.
7
hawks
75
snakes
67 kJ
wolf
750
sparrows
670 kJ
snakes
7500
beetles
6700 kJ
rabbits
75 000
grass
67 000 kJ
grass
2. Pyramid of biomass:
5 kg
hawk
500 kg
snake
5000 kg
mouse
50 000 kg
roots
Part 2
1. injured or dead animals
2. Students should not count animals that land
outside the perimeter of the sample square or on
the tape.
BLM 1-12, Feeding Relationships
Quiz/Assessment
Goal: Students assess their knowledge of terms that
describe relationships in food chains and food
webs.
Answers:
1. first trophic level
2. grasshopper
3. snake
4. wolf
5. grass
3. (a) Answers will vary.
(b) Students may mention a variety of factors, such
as food availability, temperature, and human
activities and intervention.
(c) Answers will vary.
BLM 1-14, Beef or Corn?/Skill
Builder
Goal: Students compare different kinds of food
production.
Answers: Answers will vary.
6. consumer or carnivore
7. niche
8. terrestrial
9. food chain
10. omnivore
BLM 1-15, Growing Bacteria/Skill
Builder
Goal: Students become familiar with graphic data for
population growth patterns in a given time.
Copyright © McGraw-Hill Ryerson Limited.
37
ANSWER KEY
CHAPTER 1
3. population density
Number of bacteria
Answers:
600
1.
4. competition
570
540
510
480
450
420
390
360
330
300
270
240
210
180
150
120
90
60
30
0
5. interspecific competition
6. density-dependent factors
7. density-independent factors
8. (a) Answers will vary. An example of interspecific
competition is a mouse and a rabbit consuming
parts of the same grass population.
(b) Answers will vary. An example of intraspecific
competition is two dogs fighting for the same
piece of meat.
9.
5
10
Time (in days)
15
20
2. availability of space (increased population density),
toxicity from excess wastes, lack of sufficient food,
and too high temperature from the increased
population
BLM 1-16, Predator-Prey Patterns/
Skill Builder
Goal: Students practise collecting and interpreting
predator-prey population growth patterns.
Answers:
1. the perimeter of the sample area being studied
2. The cards, being bigger than the paper clips, represent the lynx as the predator of the smaller prey,
the rabbits. The rabbits are therefore represented
by the paper clips.
3. (a) At first, the rabbit population increases very
rapidly.
(b) Answers will vary depending on students’
graphs.
BLM 1-17, Population Terms/
Vocabulary Check
Goal: Students become familiar with terms related to
populations.
Answers:
1. intraspecific competition
2. carrying capacity
38
space
food available
soil
water
temperature
climate
densitydependent
factors
densityindependent
factors
BLM 1-18, Desertification/Science
Inquiry
Goal: Students identify factors related to human
interaction with an ecosystem.
Answers: Answers will vary.
BLM 1-19, Geometric Population
Growth/Skill Builder
Goal: Students increase their understanding of
geometric population growth.
Answers:
1. (a) 16 cells
(b) 32 cells
(c) The population is doubling with every
generation.
2. (a) There are eight divisions.
1 → 2 → 4 → 8 → 16 → 32 → 64 → 128 → 256
(b) space availability (space for population growth)
(c) 8 divisions 2 h = 16 h
Copyright © McGraw-Hill Ryerson Limited.
CHAPTER 1
ANSWER KEY
3. Factors that might limit a population’s growth
include food and water availability and increased
waste production.
Answers:
1. (a) cricket
(b) grass
(c) food chain
BLM 1-20, Population Growth
Curves/Overhead Master
Answers: not applicable
BLM 1-21, Biological Magnification
in Nature/Information Handout
Goal: Use this handout to become more aware of
biological magnification in nature.
Answers: not applicable
(d) hawk
(e) If the grass captured 10 000 kJ of energy, the
frog would have 100 kJ.
1 kJ
hawk
10 kJ
snake
100 kJ
frog
1000 kJ
cricket
10 000 kJ
grass
2. Pyramid of energy:
BLM 1-22, Unscrambling Ecology
Terms/Vocabulary Check
Goal: Students review terms related to ecology.
Answers: Sentences for terms will vary.
1. carrying capacity
2. competition
9 kJ
hawk
99 kJ
snakes
990 kJ
frogs
9900 kJ
crickets
99 000 kJ
grass
3. population density
3. (a) A producer can take energy from the Sun and
use it to produce nutrients. A consumer cannot
produce its own food. It must obtain nutrients
by consuming producers or other consumers.
4. pyramid of energy flow
5. biomass
6. detritivores
(b) A herbivore eats only plants. A carnivore eats
only meat.
7. decomposers
8. trophic levels
(c) A pyramid of biomass shows biomass decreasing among organisms in subsequently higher
trophic levels. A pyramid of energy shows
decreasing energy available for organisms to
use at subsequently higher trophic levels.
9. ecosystem
10. producers
BLM 1-23, Chapter 1 Test/
Assessment
Goal: Students assess their understanding of the
concepts they studied in Chapter 1.
Hints & Helps: You may not want students to
complete every set of questions in this test. A
computerized test bank of alternative questions is
available.
(d) Competition is the rivalry among consumers
for food for survival. Intraspecific competition
occurs when different organisms are consuming
the same food source. Interspecific competition
occurs when two organisms of the same species
are consuming the same food source.
4. A detritivore is a scavenger or decomposer. It can
break down and recycle nutrients from waste
organic material, such as dead producers and
consumers.
Copyright © McGraw-Hill Ryerson Limited.
39
CHAPTER 1
ANSWER KEY
5. As energy passes up through the trophic levels of
an ecosystem, it decreases. Therefore less energy is
available to organisms at higher levels. The
amount of water and other nutrients remains constant as these nutrients flow through an ecosystem.
6. In photosynthesis, carbon dioxide is combined
with energy captured from the Sun, and water, to
produce food. In respiration, carbon dioxide is
expelled as a waste product.
7. A top carnivore is a consumer in the highest
trophic level of a food chain or food web. It is an
organism that feeds on other organisms but is not
itself hunted for food.
8. The biotic elements of an ecosystem are the living
organisms that rely on the abiotic elements (such
as the Sun, water, heat, light, and soil) for survival.
9. Carrying capacity is the limit of food, space, and
other factors that support a population living in a
given area.
10. (a) minnow and water flea
(b) water snake or sea gull
one of the water snakes’ food sources has
decreased. On the other hand, the water
snakes’ other food source, the water flea population, might increase because there are fewer
competitors for the algae that is the water fleas’
food source. Minnows are also food for the sea
gulls. If there were no minnows, the sea gulls
would compete with the water snakes for the
only available food source common to both of
them, algae. Since it would take a lot of algae to
feed the sea gulls, it is likely that the sea gull
population would decrease.
11. DDT might be sprayed on the grain to kill insects
that might damage the grain before it can be harvested. When the sprayed grain is eaten by an
insect, some DDT is stored in the insect’s tissues.
A bird that eats the insect takes the DDT into its
tissues. There the DDT accumulates to become
greater than the original amount that was consumed by the insect. In this way, the effect of the
insecticide is magnified as it passes from organism
to organism through higher trophic levels in an
ecosystem.
(c) If the minnow population became extinct, the
water snake population might decrease, since
40
Copyright © McGraw-Hill Ryerson Limited.