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 4. D 5. B 6. C 7. A Module 16:

1. D 2. A 3. B 4. C Module 18:

1. C 2. A 3. C 4. D 5. A Module 20:

1. B 2. D 3. B 4. D 5. A

Ecocolumns- Water Quality

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

Pollution

Climate Change

Overexploitation

www.youtube.com/watch?v=Q0Nk9EJpQWU

Native vs. Alien

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

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/ais/dreissena_polymorpha/

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

For your species:

1. Where they’re from

2. Current range

3. How they spread

4. Why they are so effective at colonizing new areas

5. Negative consequences to native ecosystems

Principles of Population Growth

Or when your snails will die…

Exponential Model of Population Growth Population increases rapidly with no limit

What will a graph look like? Rare in nature. Why?

“J” shaped curve

Limit on the amount of resources (food / space)

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.

Limiting Factors on Population Growth

Density and Population Growth

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

Accounts for influence of limiting factors

What will the graph look like?

Stretched out “S”When population is small,

birth rate is higher

than death rate

As population reaches

carrying capacity,

death rate increases

When at carrying capacity,

birth rate is equal to

death rate

Transitioning to Logistic 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

Type of pop. growth

Factors limited by

Factors are biotic or abiotic

R-strategists

K-strategists

Survivorship Curve 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