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RG: Ecology and Communities Ch: 18 & 20
Chapter 18.1: Introduction to Ecology
1. What is interdependence? Give an example.
2. Why is interdependence important? What are its effects?
Define these terms:
3. Biosphere:
4. Ecosystem:
5. Community:
6. Population
18.2 Ecology of Organisms:
7. The place where an organism lives is called its _____________________.
8. What is the difference between biotic and abiotic factors? Give a few examples of
each.
(skip Organisms in a Changing Environment)
9. Species don’t occupy all parts of their habitat at once. They have a specific role
called a _________________________.What is included in this?
10.
What is the difference between a generalist and a specialist? Give an example
of each and explain why they fit the description.
18.3 Energy Transfer
11.
Something that makes its own food is called a __________________________, or
autotroph. There are two ways to do this. Name them and give an example of
something that uses that method to make its own food.
12.
13.
Something that gets their energy by eating food are called ____________________,
or heterotrophs. Define and give an example of each of these:
Herbivore
14.
Carnivore
15.
Omnivore
16.
Detritivore (decomposer)
17.
Describe the differences between a food chain and a food web. Draw one of
each.
18.
What is a trophic level?
19.
On the average ___________ % of the total energy consumed in one trophic level
goes on to the next level. Explain why.
20.
Why are organisms at a lower trophic level much more abundant than at a
higher one?
18.4 Ecosystem recycling
Make your own drawing and describe in words, each of the following cycles in nature:
21.
the water cycle
22.
the carbon cycle
23.
Name some ways that humans impact the carbon cycle.
24.
the nitrogen cycle
25.
Why is phosphorus important to us and how do we obtain it?
20.1: Species Interactions
Define the following:
26. Predator:
27.
Prey:
What are some adaptations that…
28. Predators have that make them successful? (name several)
29.
animal prey have that make them successful? (name several)
30.
plant prey have that make them successful? (name several)
Define and give examples of the following:
31. Competition:
32.
Competitive exclusion:
33.
Symbiosis: (no need for examples)
34.
Parasitism:
35.
Mutualism:
36.
Commensalisms:
20.2: Patterns in Communities
Define:
37. species richness
38. species evenness
39. How are species richness and species evenness both important pieces of
information for a community?
Describe and give an example of how species richness is affected by…
40. latitude
41. habitat size
42. species interactions
43. Describe and give an example of a disturbance.
44. How does stability relate to species richness?
45. Define ecological succession.
46. What is the difference between primary and secondary succession?
47. The first species to develop in an area is called the _____________________________.
What traits/characteristics make them good at this?
48. DESCRIBE an example of primary succession.
49. DESCRIBE an example of secondary succession.
50. Succession may end when the ecosystem reaches a stable end point called the
_____________________________________________________.
Answer Key__
Name: __
Period: _____ Date: _____________________
RG: Ecology and Communities Ch: 18 & 20
Chapter 18.1: Introduction to Ecology
1. What is interdependence? Give an example.
All organisms interact/depend on their
surroundings, both living and nonliving things
2. Why is interdependence important? What are its effects?
b/c changes in environment can affect
creatures far away from that environment
e.g. # acorns and Lyme disease (incr. #
acorns = incr # mice and deer = incr # ticks
= incr Lyme
disease)
Define these terms:
3. Biosphere:
All the areas of the Earth and atmosphere
where living things can be found…~ 13 miles
thick, from 5-6 miles above surface to depths of
ocean
4. Ecosystem:
All the living
and nonliving
things in an
area
5. Community:
All the
interacting
living organisms
in an area
6. Population
All the members of a single species in an
area
18.2 Ecology of Organisms:
habitat
7. The place where an organism lives is called its _
_.
8. What is the difference between biotic and abiotic factors? Give a few examples of
each.
Biotic: alive…plants, animals, bacteria, fungi
Abiotic: not alive…temperature, humidity, pH,
salinity, oxygen, nitrogen, sunlight,
precipitation
(skip Organisms in a Changing Environment)
9. Species don’t occupy all parts of their habitat at once. They have a specific role
niche__.What is included in this?
called a _




Conditions they tolerate
Resources used (food, water, shelter)
Methods for getting resources
#/timing for having offspring
10. What is the difference between a generalist and a specialist? Give an example
of each and explain why they fit the description.
Generalists have a broad niche, i.e. they
tolerate lots of conditions and use a variety
of resources. e.g opossum, people
Specialists have a narrow niche, i.e. they like
very specific conditions/resources and have
trouble surviving when those are
unavailable. e.g. koala, panda
18.3 Energy Transfer
producer
11. Something that makes its own food is called a _
_, or
autotroph. There are two ways to do this. Name them and give an example of
something that uses that method to make its own food.
Photosynthesis…use light to make
food…plants, algae, cyanobacteria, protists
Chemosynthesis…use chemicals to make food
… some bacteria, Archaea
consumers_,
12. Something that gets their energy by eating food are called _
or heterotrophs. Define and give an example of each of these:
13. Herbivore:
eats only plants/producers. e.g.
antelope, cow
eats only meat/other consumers
e.g. lion, cobras, praying mantis
14. Carnivore:
eats both plants and meat, e.g. grizzly
bear, people
15. Omnivore:
feeds on dead things,
e.g. bacteria, fungi, vultures
16. Detritivore (decomposer):
17. Describe the differences between a food chain and a food web. Draw one of each.
Chain….single pathway for energy
Web…many pathways. A food web
is made of many overlapping
food chains
18. What is a trophic level?
Position in flow of
energy in an
ecosystem (e.g.
1st, 2nd, etc.)
producers are 1st trophic level
herbivores (primary consumers) are 2nd trophic
level
usually are only 3 or 4 trophic levels in a land
based ecosystem
10
19. On the average __
_ % of the total energy consumed in one trophic level
goes on to the next level. Explain why.
 Not all on lower level get eaten
 Not all that’s eaten is used for
energy…bones, fur not digested
 Not all that’s eaten is stored as
energy…some gets used for movement, etc.
20. Why are organisms at a lower trophic level much more abundant than at a
higher one?
Higher ones need more energy, so there are
fewer of them
e.g. too many hawks = not enough food = some
die off until there aren’t too many
18.4 Ecosystem recycling
Make your own drawing and
describe in words, each of the
following cycles in nature:
21. the water cycle
 Precipitation
 Percolation
 Runoff
 Evaporation
 Transpiration
22. the carbon cycle
 respiration
 decomposition
 fossil fuels
 photosynthesis
 carbon sinks
(ocean)*
23. Name some ways that humans impact the carbon cycle.
 Deforestation takes away plants that take
CO2 out of the air
 Burning fossil fuels puts CO2 into the air
24. the nitrogen cycle
 bacteria in soil
 bacteria in
roots (nitrogen
fixing)
 decomposition
 lightning
 bacteria in soil (denitrifying)
25. Why is phosphorus important to us and how do we obtain it?
 Part of the backbone of DNA, in bones and
teeth
 Slow…not really a cycle, not in atmosphere
 Plants absorb from soil, we eat plants.
20.1: Species Interactions
Define the following:
eats all or part of another species …
hunter
26. Predator:
27. Prey:
eaten by another species … hunted
What are some adaptations that…
28. Predators have that make them successful? (name several)




Acute senses (sight, hearing, smell)
Speed and large size
Camouflage
Teeth
29. animal prey have that make them successful? (name several)
 Appear like something else … mimicry
 Chemical defenses (skunks, frogs)
 Speed, small size
30. plant prey have that make them successful? (name several)
 Thorns, spikes, tough bark/leaves
 Chemicals … taste bad or reaction (poison
ivy)
Define and give examples of the following:
two or more species use same
resource (e.g. food, water, space, light)
e.g. lions and hyenas both eat zebras;
shrubs and trees in a forest both need sunlight
31. Competition:
leads to competitive exclusion…one
species eliminated.
e.g. barnacles: the yellow can live
on whole rock, but is pushed out by
the red/bigger one. The red/bigger
one can’t live above the tide line.
So there’s competition below the
line, but not above, and the yellow
one has above all to itself.
32. competitive exclusion:
One species is eliminated form an
ecosystem because another uses all the
resources
e.g. barnacles above…yellow ones grow
above tide mark, because orange one “won’t
let” them grow below
close, long term
relationship between organisms. i.e. live
together.
33. Symbiosis: (no need for examples)
+ - one is harmed (host), one is helped
(parasite). e.g. tapeworms and mammals
34. Parasitism:
+ + both are helped. e.g. plants and
insects pollination. The plant’s pollen gets
spread, and the insect gets food
35. Mutualism:
+ 0 one is helped, the other is not
affected. e.g. buffalo and birds (egrets). Buffalo
scare out small creatures the egret eats.
35. Commensalism:
20.2: Patterns in Communities
Define:
37. species richness
Number of different species in an area…just
how many
e.g. grass and robins and deer
38. species evenness
Includes the number of each species…how
many different species and the number of each
e.g. 10 grass plants, 400 robins and 3 deer
39. How are species richness and species evenness both important pieces of
information for a community?
Tells about the diversity of life supported by
an area…what kinds of living things are there
and how many
Describe and give an example of how species richness is affected by…
40. latitude
Distance from equator
Farther from equator = less species
richness
e.g. more species in tropics than at the
poles
41. habitat size
Larger the area, more species richness
e.g. small islands tend to have less diversity
42. species interactions
If there’s a predator in the area, it may
eat a lot of the other species and decrease the
richness.
43. Describe and give an example of a disturbance.
Events that change communities; destroy
habitat or organisms or resources (food, water,
shelter)
e.g. hurricane, earthquake, forest fire,
pollutution
44. How does stability relate to species richness?
Stability is how well a community resists
changes (disturbances). The more species there
are, the better the community can withstand a
disturbance.
e.g. if there’s only one kind of tree in a
forest, and a disease comes through, it’ll kill
destroy the whole forest. But if there are many
different species of tree, maybe only 1 will die
(emerald ash borer)
45. Define ecological succession.
Changes in the plants and animals in an
ecosystem over time
46. What is the difference between primary and secondary succession?
Primary is when there was no soil/nothing
living there before. e.g. after glaciers, or a
volcano erupts. Takes a long time (thousands of
years).
Secondary is when a natural disaster
happened, the living things are gone, but soil
remains. Takes less time (hundreds of years).
pioneer species_.
47. The first species to develop in an area is called the _
What traits/characteristics make them good at this?
Tend to be small and grow/reproduce
quickly, e.g. moss, lichen, grass
48. DESCRIBE an example of primary succession.
After glaciers, bare rock
first lichens…died and started to make soil
grass grew in the thin soil, making it thicker
then moss and larger grasses
eventually shrubs and trees
49. DESCRIBE an example of secondary succession.
Weeds (e.g. dandelions, annul grasses (live
only 1 year)
Then perennial grasses (live more than 1
year)
Then shrubs
Then trees
For a pond:
Gets more
and more filled
in, more and
more plants
Deep lake
to shallow
pond to swamp
to meadow to
forest
50. Succession may end when the ecosystem reaches a stable end point called the
climax community__.
_