Download POPULATIONS JIGSAW ACTIVITY

APES 11.10 and 11.12
Please take out modules 15, 16, 18,
and 20 for check-off!
Learning Targets


I can understand the threat posed by invasive
species to biodiversity.
I can differentiate between different
reproductive strategies of organisms.
Multiple Choice Answers
Module 15:
1. B 2. D 3. C
 Module 16:
1. D 2. A 3. B
 Module 18:
1. C 2. A 3. C
 Module 20:
1. B 2. D 3. B

4. D 5. B 6. C 7. A
4. C
4. D 5. A
4. D 5. A
Ecocolumns- Water Quality
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Find the document on the labs page of my
website about freshwater quality indicators
Record on your data table the optimal levels
for the abiotic factors we’ve been measuring
Record if your column was healthy or
unhealthy this week for each indicator
Invasive Species
Remember, Invasive Species are one of the 6
threats to biodiversity:
Habitat Destruction/Fragmentation
Invasive Species
Population Growth
www.youtube.com/watc
Pollution
h?v=Q0Nk9EJpQWU
Climate Change
Overexploitation

Native vs. Alien

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Native Species = species that live in their
historical range; thrive there due to natural
selection
 Endemic species = only live in a small area; at
greatest risk (i.e. hot springs fish)
Alien Species = species living outside its
historical range
Invasive Species= alien species that spreads
rapidly across large areas
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Example: Zebra Mussels
Native to Black Sea and Caspian Sea (Europe, W. Asia)
Cargo ships carrying seawater came over to St.
Lawrence River and the Great Lakes in the 1980’s and
dumped their unneeded water
Zebra mussels colonized the Great Lakes, killing off
native mussels
Can multiply so fast (1 female = 30,000 eggs) that they
clog industrial pipes!
http://wdfw.wa.gov/ai
/
Your Turn!
Number off by 4’s
1’s: Silver carp, Kudzu
2’s: Scotchbroom, Cane
toads
3’s Brown tree snake,
Lionfish
4’s: Nile perch, Asian
longhorn beetle
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
1.
2.
3.
4.
5.
For your species:
Where they’re from
Current range
How they spread
Why they are so effective
at colonizing new areas
Negative consequences
to native ecosystems
Principles of
Population
Growth
Or when your snails
will die…
Exponential Model of Population Growth

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Population increases rapidly with no limit
What will a graph look like?
“J” shaped curve
Rare in nature. Why?
Limit on the amount of resources (food / space)
Limiting Factors on Population Growth
Populations can’t grow
exponentially forever because of
limiting factors
 Limiting factors can be:
BIOTIC– Predators, food, disease,
competition from other species
 ABIOTIC– Space, water, shelter,
salinity, soil, etc.

Density and Population Growth

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Density-dependent limiting factors:
competition, predation, parasitism,
disease
Density-independent factors: habitat
destruction, weather, natural disasters
Notice that density-dependent factors
are biotic, while density-independent
factors are abiotic
Population Growth
Limited by carrying capacity
The number of individuals the
environment can support
over a long period of time
Logistic Model of Population Growth


When at carrying capacity,
birth rate is equal to
Accounts for influence
death rate
of limiting factors
What will the graph
Aslike?
population reaches
look
carrying capacity,
death rate increases
“S”
WhenStretched
populationout
is small,
birth rate is higher
than death rate
Transitioning to Logistic
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Exponential populations don’t just “smooth out”
Usually there is an overshoot, where the
population grows beyond carrying capacity
Followed by a die-off
Can happen many times
Reproductive Strategies

R-strategists: have tons of offspring, don’t
care for them, have short lives



Limited by density-independent factors
Ex: mice, small fish, most insects
K-strategists: have few offspring, care for
young, have long lives


Limited by density-dependent factors
Ex: humans, most birds, deer
Reproductive Strategies  r vs. K
selected species
K species’ populations settle near K
Reproductive Strategies


R-strategist populations have exponential
growth with violent population changes
K-strategist populations remain at a stable
carrying capacity

Or do they?...
Making Connections
#
offspring
Rstrategists
Kstrategists
Type of
pop.
growth
Factors
Factors
limited by are biotic
or abiotic
Survivorship Curve

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Relationship
between death &
age for different
species
Type I  Death =
old age
Type II  same
mortality rate in
every age group
Type III  Death =
young age