1. How mountains affect rainfall. RAINSHADOW

2. Show the O2 and CO2 cycle Be as detailed as possible
One person will be picked to present

3. Nitrogen cycle

4. Dispatch
If your group needs to presentfind a group to listen and approve you
If your group is approved listen to group’s nitrogen presentation if they have all components, tell me

5. Nitrogen Cycle Animation

6. Population vs. Community

7. Population Ecology QUESTIONS: What is a population?
What affects the size a population can get?

8. Population
A population is a group of individuals of a single species that simultaneously occupy the same general area.
Two characteristics that affect populations are ________ and _______

9. Population characteristics
Density~ # of individuals per unit of area
•counts •sample size estimate
•indirect indicators
•mark-recapture
Dispersion~ pattern of spacing
•random~ unpredictable, patternless spacing (a)
•clumped~ patchy aggregation (b)
•uniform~ even spacing (c)

10. Density is the result of a dynamic interplay
Between processes that add individuals to a population and those that remove individuals from it

11. Births and immigration add individuals to a population.
PopuIation size
Emigration
Deaths
Deaths and emigration remove individuals from a population.

12. Activity:
Make a graph for a bacterial population and an elephant population

15. Dispatch—Get a textbook
Draw an exponential growth curve? What species exhibit this growth?
What about the environment would make an r species exhibit exponential growth?
Describe what a population’s carry capacity is and what it means to the population?
Compare and contrast density- dependent to density-independent factors?
Take our calendar and tell your tablemates 3 upcoming deadlines
Pick up a growth half sheet and a paper that says class set
Wilderness Park 9:30 TOMORROW

16. Population Growth Models
Exponential model (blue) • idealized population in an unlimited environment (J-curve); r-selected species (r=per capita growth rate)
Logistic model (red) •carrying capacity (K): maximum population size that a particular environment can support (S-curve); K-selected species

17. Demography: factors that affect growth & decline of populations
Birthrate (natality, fecundity)~ # of offspring produced
Death rate (mortality)
Age structure~ relative number of individuals of each age
Survivorship curve~ plot of numbers still alive at each age

18. R vs. K survivorship curves

19. Population life history “strategies”
r-selected (opportunistic)
Short maturation & lifespan
Many (small) offspring; usually 1 (early) reproduction; no parental care
High death rate
Ex:________
K-selected (equilibrial)
Long maturation & lifespan
Few (large) offspring; usually several (late) reproductions; extensive parental care
Low death rate
Ex:____________

20. Population limiting factors
Density-dependent factors
•competition
•predation
•stress/crowding
•waste accumulation
Density-independent factors •weather/climate
periodic disturbances

21. Community Ecology QUESTIONS: 1) What is a community?
2) Who are the members of this community?
3) What is a food chain?

22. Differences in Community structure
Community~ an assemblage of populations living close enough together for potential interaction. Many different ______.
Communities differ dramatically in their species richness (number of species) & relative abundance of different species

23. How can we account for the species found together as members of a community?
2 Hypotheses:
•Individualistic~ all the species just happened to live in the same area b/c they all had similar abiotic requirements. Example they all needed same temperature, rainfall, soil type which is why they live in the same habitat.
•Interactive~ all the species are locked into association by mandatory biotic interactions. Species are found together b/c they have formed relationships +, - and o.

24. Between Species
TASK: Add a column to the right and give an example of each type of interaction

25. Activity: Interaction Charades
I will give your group an interaction and you act it out