1. Ecology: Lecture 2

2. Biomes as related to Temperature and Moisture

3. Global distribution of terrestrial biomes

4. What causes the poles to be colder than equatorial regions?  Key reason: Curvature of the earth and resultant angle of sun’s rays [Fig. 2.7a]

5. Which other factors mediate the distribution of global temperature?  Earth’s rotation  air and ocean currents that affect the distribution of heat energy  Earth’s tilt (angle of axis)  Albedo

6. Movement of air masses  If the earth had no rotation:

7. Movement of air masses  With rotation:

8. Ocean circulation patterns and heat distribution  Example: Effect of the Gulf Stream on temperatures (E. North America; W. Europe)

9.  The angle of the earth’s axis is responsible for seasonal variations on the earth. Fig. 50.12 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

10.  Position shifts between summer and winter (why?)

11. Albedo: reflectance of solar radiation  Snow and Ice: high albedo  (Photo: K. Haberman)   Forested areas: low albedo   Photo: Natl. Park Svc.

12. Global patterns of precipitation

13.   Warm air holds more moisture than cold air   Warm air rises and cools, dropping moisture close to where it was picked up, so that moist areas tend to remain moist, and dry areas tend to remain dry   Warm, dry air picks up additional moisture…

14. Altitude and Rain shadows

15. North vs. south facing slopes

16. North vs. south facing slopes (cont.)

17. Microclimate example: Effects of vegetation on temperature

18. Nutrients  Macronutrients  Definition?  Examples: C, H, N, O, P, Ca, Mg, K, S, Na, Cl  Micronutrients  Definition?  Examples: Fe, Mn, B, Co, Cu, Mo, Zn, I, Se

19. Global distribution of productivity in the ocean

20. Upwelling

21. Focus on light  Characteristics that vary with climate/microclimate  wavelength  intensity  duration  directionality

22. Light energy as a function of latitude and time of year

23. PAR: Photosynthetically active radiation (400-740 nm)

24. Attenuation of light through water

25. Attenuation of light through vegetation  Leaf area index

26. Attenuation of light through vegetation (cont.)

27. Other key factors  Salinity  Example: Different estuarine species are tolerant to different conditions  Oxygen concentration  Example 1: Surface waters vs. sediments in an estuary  pH  Substrate (i.e. soil type, rocky vs. muddy river bottom, etc…)  Example: Distribution of macroinvertebrates in streams.