Please take out modules 15, 16, 18, and 20 for check-off! 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: 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 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)

Limiting factors can be: 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 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

Limited by carrying capacity 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 death rate Accounts for influence of limiting factors What will the graph look like? As population reaches carrying capacity, death rate increases When population is small, birth rate is higher than death rate Stretched out “S”

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