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EEB 2100 UConn Exam 1
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EEB 2100 UConn Exam 1
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EEB 2100 UCONN EXAM 1 QUESTIONSAND ANSWERS GRADED A+
l Main questions of course - 1. How do humans alter earth
2. how do human alterations affect the biosphere
3. What can be done to alleviate human alterations of the biosphere
Greatest ecological impacts of humans(most to least) - 1. Nitrogen fixation
2. Water use
3. Land transformation
4. CO2 concentration rise
5. Ocean acidification
6. Bird extinction
7. Plant invasion
Planetary Boundaries - Limits between which global systems must operate to prevent abrupt and
irreversible environmental change
Planetary Boundaries that have been crossed - 1. Biogeochemical flows of Nitrogen and
Phosphorous(Nitrogen fixation)
2. Genetic diversity (biodiversity loss)
Success story of planetary boundaries - Restoration of the ozone layer
Non-linear dynamics - Outcome is not proportional to input
- to revert back to a stable state, it will take more effort than getting to where you are now(It takes much
less equipment to pollute a pond than to clean it up after it has been polluted)
Tipping Points - a critical threshold when a small change can have potentially drastic effects. Mostly
linked to climate change and pollution and the increase in the emmition of greenhouse gases
Increased atmospheric CO2 - Result of increased burning of fossil fuels and land use change(getting rid of
plants by burning which uptake CO2)
-caused global warming of 0.8-1.2 degrees Celsius
Oceanic CO2 - -25% of carbon from CO2 gets taken up by oceans
, -Caused the average ocean ph to drop by 0.1 units and because ph is a log scale resulted in 26%
increased acidity causing major changes to ocean ecology
nitrogen fixation - process of converting nitrogen gas into nitrogen compounds that plants can absorb
and use
Nitrogen in Ecosystems*dont understand* - added to ecosystems through fixation by microorganisms
and limits the growth of many ecosystems
Large mammal biomass - 97% of large mammal biomass is human(30%) or domestic animals(67%)
Human water use - -35% of all of the earths usable water goes toward agricultural needs while 15% goes
to other human needs
-37% of rivers globally including 2% in the US are UNimpeded by dams which makes it hard for
microorganisms and fish to travel
Extinction rate on earth - -100-1000 times the background rate
-Yearly loss of 11-58k species
-Rates only comparable to 5 times in last 500 million years which could indicate 6th mass extinction
biotic homogenization - Certain species coexist well with humans so they are favored in many areas
throughout the world, decreasing overall biodiversity in the world
Examples of biotic homogenization - -mixing of biota(plant or animal life native to a certain region)
across oceans
-many continental regions have 20% of plant life as exotic(not native to the area)
Big picture behind planetary boundaries - All these disturbances are connected to one another so one
major change could result in an even large change somewhere else due to the many indirect
consequences
Anthropocene - a new geological period dominated by human destabilization of the earth's natural
systems
Common Geological time units - Eras: Hundreds of millions of years
periods: 50-200 million years
epoch: 5-30 million years
Formal criteria for new geological time units - 1. Must be stratigraphic evidence(evidence in rock layers)
for start date all over the world.
2. Must persist for millions of years
3. accompanied by a mass extinction
"Golden Spike" - (GSSP) Global Stratotype Section and point and refers to evidence in geological strata
that signifies the start of a new geological stage of time.
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