The Physical Environment

1. FIELD BIOLOGY & METHODOLOGYFall 2013 Althoff Lecture 02 The Physical Environment pH Heat exchange/thermal environment

2. Key Points – Physical Environment (PE) • PE _____ “isolated” from biotic entities • PE strongly “____________” living organisms • In PE, energy __________________ follow paths of least resistance

3. Key Distinction Living organisms have ability to act against physical forces AND Living organisms have _________________existence

4. The Physical Environment • Soil (?) • Water • Temperature • Acidity (pH) • O2, CO2, etc. • Light (spectrum from ultravioletvisible infrared) • Radiation • Nutrients (Ca, N, P, K, etc.) • Etc.

5. Water • ______ energy required to “evaporate” (500 X vs. 10C) • ______ energy to “freeze” (80X) • Becomes _____ dense at lower temps…_______ upon freezing • Immense capacity to _________

6. Water…con’t • “Availability” in soil influenced by physical _________: clay vs. silt vs. sand….the more surface area, more soil can “hold” water.

7. Temperature • Most life occurs > 00C and < 450C • Influences freezing point of water, other substances • glycerol/glycoproteins in organisms impacts “survival” in harsh conditions • Impact on chemical reactions

8. Temperature influences ____________ of enzyme’s ability to facilitate chemical reactions Rate of Reaction (product per unit of time Temperature 0C

9. pH • Concentration of H+ in the environment or organism critical • pH scale 0 to < 7 = acidic 7 = neutral >7 - 14 = basic (alkaline) • Most life: _____ pH environment

10. Most life: pH 6-9

11. C, O, & Biological Energy Transformations • _____________ & ______________ = “big time” energy transformation processes • Plants ______________ carbon…more than they oxidize it in respiration…so they can grow • Plants need to deal with low O2 levels in certain situations… ex. Cypress – roots in “saturated conditions”

12. ______________ Nutrients • 8 major nutrients required by organisms: __________________________ • See key functions summarized in Ricklefs (Table 2.1, p 27) handout • Ex: N abundant in air but not “accessible” to most plants

13. Limiting Factors All factors discussed so far, and ones to come…and many others…often serve to “______” the distribution of living organisms.

14. Osmotic Potential • Ability or tendency of a solution to attract water • Mechanisms: semi-permeable membranes & ion transport • Hyperosomotic vs. hyposomotic (ex: freshwater vs. saltwater fishes) thus, salt concentration in aquatic ecosystems “_______” organism’s presence/absence

15. Light • _____________ is “the” primary source of energy FOR the biosphere…KEY INPUT • _______ properties of sunlight: and key absorption abilities of plants….why are plants green or red???? (see next 2 slides)

16. Different ___________ absorb different wavelengths of light

17. Different ________ vary in rates of photosynthesis due to pigments present and wavelengths of light received

18. Thermal Environment • Radiation • Conduction • Convection • Evaporation

19. ______________—electromagnetic energy ________________--transfer of kinetic energy between substances in contact

20. ________________--transfer of energy (heat) via movements of liquids or gases (wind) over a surface ______________--liquid to gas

21. Plant “_____________” with thermal environment (i.e., thermal environment subset of physical environment)

22. Animal “____________” with thermal environment (i.e., thermal environment subset of physical environment)

23. Organisms use physical stimuli to “_____” the environment. For example… • …pick up electromagnetic radiation • …soundwaves (sense of hearing) • …molecules (sense of smell) • …tactile contact (sense of touch) Leaf-nosed bat Star-nosed mole

24. In summary… • Physical environment is important • Can talk about physical environment (i.e. non-living/abiotic components) separately but it does not exist in isolation from living world (i.e., living/biotic components) • Life depends on the physical environment • The physical environment is influenced by life • The form and function of all plants and animals have _______________in response to conditions existing of the physical environment