Symbioses
Question of the Day
Question: Give examples of exponential and
logistic growth.
(Hint: Use your notes!)
Answer: … … …
Biosphere Observations
Frequently Missed Questions
The rates that affected the yeast population in our lab
were (mark all that apply):
a. Emigration
b. Immigration
c. Natality
d. Mortality
3. Natality- measure of the # of
births in a population; birth rate
4. Mortality- measure of the # of
deaths in a population; death rate
Frequently Missed Questions
What was the doubling time from 1980 – 1990 for the
human population?
a. 14 years
b. 37 years
c. 70 years
d. 140 years
= 1.96
= 36
Frequently Missed Questions
Suppose you have to do two dilutions of your yeast
culture before you are able to count the yeast cells. If
you count 48 cells in the diluted sample, how many
yeast cells were in the same area of the undiluted
sample?
a.
b.
c.
d.
e.
4.8
48
480
4800
48000
48 * 10 * 10 = 4800
(1st dilution)
(2nd dilution)
Unit 2 Vocabulary
30. Pyramid of numbers- shows the relative number of individual organisms at
each trophic level in an ecosystem
Unit 2 Vocabulary
31. Pyramid of mass (pyramid of biomass)- shows the relative amount of matter
contained within each trophic level
Unit 2 Vocabulary
32. Pyramid of energy- shows
the relative amount of energy
contained within each trophic
level
33. 10% rule- only 10% of energy
is transferred from one trophic
level to another; the rest is lost,
especially as heat
Unit 2 Vocabulary
39. Mutualism- a relationship in
which both organisms benefit
+/+
A bee drinks nectar and
pollinates a flower:
38. Commensalism- a relationship in
which one organism benefits and the
other is neither helped nor harmed
+/0
Birds eat insects that are
disturbed as water buffalo travel:
Unit 2 Vocabulary
42. parasitism- relationship in which
one organism lives inside or on
another and harms it
+/-
Leech on skin:
43. host- the organism that provides
a parasite with nutrition
Humans are hosts of tapeworms:
Unit 2 Vocabulary
23. niche- the range of physical and biological conditions in which a species
lives and the way the species obtains what it needs to survive and
reproduce
3 species with their own
niches in one tree:
Videos
p. 148 # 17, 20, 21, 24
17. What would happen to a population of predators if there was a sudden
increase in food for the prey? Explain.
17. If there is a sudden increase in food for a population of prey, the prey
population will increase. This means there will be more food for the
predators, which will then also increase.
20. How is the relationship between parasites and their hosts similar to a
predator-prey relationship?
20. The relationship between parasites and their hosts is similar to a
predator-prey relationship because in both cases the two species involved
limit one another’s population growth.
p. 148 # 17, 20, 21, 24
21. How would a drop in the water level of a river affect a fish population
living in that river?
21. A drop in the water level of a river would affect a fish population in that
river because the fish population’s density increases. This makes the fish
population more susceptible to density-dependent limiting factors.
24. How can you account for the fact that the human population has grown
more rapidly during the past 500 years than it has at any other time in
history?
24. The human population began growing more rapidly 500 years ago due to
conditions that made survival more likely, thereby decreasing the death rate.
Reliable food supply, improved sanitation, and better medical care are three
factors that caused this change.
p. 102, Analyzing Data #1, 2, 3
1.
Suppose a bacterial infection kills off
most of the prey at point B on the
graph. How would this affect the
predator and prey growth curves at
point C? At point D?
1. If most of the prey were killed off at
point B, the predator population would
decline between points B and C, allowing
the prey population to increase again by
point C.
2.
Suppose a sudden extended cold spell destroys almost the entire predator
population at point F on the graph. How would the next cycle of the prey
population appear on the graph?
2. The prey population would increase in the next cycle, reaching a peak that
is potentially even higher than the previous peaks.
p. 102, Analyzing Data #1, 2, 3
3.
Suppose a viral infection kills all the prey
at point D on the graph. What effect
would this have on the predator and
prey growth curves at point E? What
will happen in future years to the
predator population? How could
ecologists ensure the continued survival
of the predators in this ecosystem?
3. If a viral infection kills all the prey at point D, at point E, the prey population will
be zero and the predator population would be decreased, possibly to zero. In future
years, if the predators find another food resource, the population may recover. The
predator population would not recover in future years without any prey to feed on.
To ensure continued survival of the predators in this ecosystem, ecologists could
control the viral infection in the prey so that not all of them are killed by the virus,
or they could introduce new prey animals to the ecosystem.
p. 150, Analyzing Data # 34, 35
34. In which of the following years was
the rabbit population density in
South Australia most dense?
34. b. 1952
35. European rabbit fleas were
introduced in the late 1960s to help
spread the ffects of the rabbit
disease myxomatosis. Based on the
graph, what can you infer about the
rabbit population after the fleas
were introduced?
35. b. The rabbit death rate increased.
Unit 2 Vocabulary
36. Primary productivity- a measure of the synthesis of compounds like sugar;
usually happens through photosynthesis
a. Gross primary productivity- how much chemical energy producers create in a given amount
of time
Unit 2 Vocabulary
36. Primary productivity- a measure of the synthesis of compounds like sugar;
usually happens through photosynthesis
a. Gross primary productivity- how much chemical energy producers create in a given amount
of time
b. Net primary productivity- how much chemical energy producers create after subtracting
what chemical energy the producers use themselves