11:216:352 Lecture Notes - Lecture 2: Countercurrent Exchange, Photic Zone, Sulfur
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Published on 27 Feb 2018
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Thursday, January 22, 2015 - Ch
Principles of Ecology
● Concept 1.1: events in the natural world are interconnected
● Concept 1.2: ecology: scientific study of interactions between organisms and their
environment; how organisms affect and are affected by other organisms and their
surroundings
● Concept 1.3: ecologists evaluate competing hypotheses about natural systems with
observations, experiments, and models
molecules > organelles > cells > tissue > organs > organ systems > organisms > populations >
community > ecosystem > biosphere
● humans have a huge impact on the planet
● important to understand how natural systems work
● examples of human domination of the environment
○ agriculture and urbanization
○ climate change
○ invasive species, extinction
○ acidification, nutrient enrichment, deoxygenation of water
● anthropocene: term for the proposed epoch that began when human activities had a
significant global impact on the Earth's ecosystems
● amphibian deformities due to pesticides
○ immune malfunction
○ limb deformities
● out of 35 ponds, 13 had healthy tree frogs, but 4 had deformed tree frogs AND snails
○ the snail was found to be the host of a parasite (flatworm) that brought on
deformity
find more resources at oneclass.com
find more resources at oneclass.com
Monday, January 26, 2015 - Ch 2
The Physical Environment
Nitrogen, Oxygen, and Phosphorus enriched water à algae blossoms (algal blooms) and
creates a hypoxic zone in the water. Events in man’s world penetrate into the natural world.
Hypoxic zone - Dead zone - low oxygen
The Mississippi Drainage - Carries millions of nitrogen based water to the Gulf of Mexico
● It is then distributed by gulf currents
- Organisms interact with each other, directly and indirectly
- Amphibian deformities à Pacific Tree frogs deformed by a trematode flatworm Ribeiroria
ondatrae. Further studies show that an aquatic snail was also present in the ponds where the
deformed frogs resided. The snail was the intermediate host for the parasite
o Factorial anova to determine the effect of pesticides and parasites on the deformities of the
frogs. Higher percentage of deformities when pesticides AND parasites were present.
o So what effect do pesticides have on frogs? Weakens immune systems of the frog
§ Test pestIcide with a control on solvent
Replicated Factorial Design: 9 replicated of each 4 treatments
36 cages in total: 6 cages of each 6 ponds
Six ponds
6 cages in each pond
3 no pesticide; 3 pesticide
3 no parasite
9 cages; 9 cages 0 deformed; 0
deformed
3 parasite
9 cages; 9 cages 4% deformed; 29%
deformed
● Experimental results suggested weakening immune system
● Frogs also indicated cysts under the forearms
● This experimentation was firmly grounded in natural history
Use the case studies to understand the process of observing changes in the environment,
creating a hypothesis and testing it to find a casual relationship and how it may affect other
aspects of the environment.
Nitrogen fixation
Haber- Bosch Process
1918 Nobel Prize awarded to Haber for synthesis of NH3
N2(g) + 3H2(g) = 2NH3(G)
find more resources at oneclass.com
find more resources at oneclass.com
Chapter 2- Six Major Concepts
1. Climate: most fundamental component of the physical environment
2. Atmospheric and oceanic circulation: from differential solar radiation
3. Global Climatic Patterns: result of circulation patterns
4. Regional Climate: result from influences of oceans, continents, mountains, vegetation
5. Climatic Variation over time: Earth’s position relative to the sun
6. Chemical Environment: salinity, acidity, oxygen and more.
Weather vs. Climate
weather
climate
current, short terffm
● temperature
● precipitation
● humidity
● cloud cover
time average of weather
● predicted from long-term patterns
● controls where and how organisms
live
Sun is the main source of energy
- Solar radiation is either:
o Reflected by clouds, aerosol, atmospheric gases – 23%
o Reflected by surface (Albedo) – 9%
o Absorbed by atmosphere – 19%
o Absorbed by surface- 49%
albedo: solar radiation reflected by earth’s surface
Methane and CO2 à threatening greenhouse gases
- Without greenhouse gases, Earth’s climate would be 33 degree Celsius cooler
● too much GHG is bad, but a balance is essential
● GHGs regulate earth’s temperature
● methane is an “effective” GHG (effective in destruction, bad for climate change), but
lasts only ~10 years in atmosphere
○ CO2 lasts >100 years
● human activity leads to increased GHGs, alters energy balance, causes change to the
global climate system
Winds and ocean currents result from differences in solar radiation across Earth’s surface
- Solar radiation/winds is more concentrated in Equatorial regions than the poles
- Tropical regions receive the most solar radiation and most precipitation -30N to – 30S
o Hadley Cell- regions of high pressure and low rain fall (major deserts of the world)
find more resources at oneclass.com
find more resources at oneclass.com