Exam 3 lecture 10

UIC BioS 101 Nyberg

1

Global Change
& Extinctions

Many organisms have an effect on the world (eventually a difference could be detected by a sensitive observer if the organism went extinct), but humans have had a growing effect at least since they got fire.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

2

Readings

• p1238 – 1243 Human impacts on Ecosystems

• Resources are renewed by processes

  • Rain keeps falling from water that evaporates

• A resource is described as non-renewable if the rate of consumption greatly exceeds the rate of renewal.

Speaker Notes:

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Note 3rd Edition p1142 -1146; p1230-1241.

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Exam 3 lecture 10

UIC BioS 101 Nyberg

3

How have humans changed the world?

• Acquisition of fire (Homo erectus, 1 mya)

• Weapons that can kill at a distance

• Communication systems at a distance

• Transportation around world (boats, airplane)

• Industrial manufacturing (poisons, fixed nitrogen)

• Money as a measure of value

• Political and economic systems that allow accumulation/concentration of resources

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

4

FIRE

• Grasslands evolved before humans (silica in stems wore down the teeth of herbivores)

• But, many grasses burn readily while dormant and get benefit from fire top-killing of woody plants.

• Grasses and grasslands have expanded because of humans use (and abuse of fire).

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

5

Weapons

• Weapons have had a dramatic effect on other species. Weapons allow humans to kill large animals, in many cases they changed humans from prey to predator.

• Bows and guns extended the distance through which the weapons were effective.

• Extinction of the Passenger Pigeon was result of weapons and economics.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

6

Extinctions

• Since 1500, over 140 species of birds have become extinct.

  • Passenger pigeon

  • Carolina parakeet

• Around 60 species of mammals have become extinct.

• Human activity was associated with most recent extinctions.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

7

Communication Systems

• Speech

• Written words (permanence)

• Telegraph

• Telephone

• Satellites (world wide communication)

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

8

Transportation

• Water –over ocean and in rivers

• Land – the wheel, roads, railroads

• Air –Airplane, helicopter

• Colonization by people has brought microbes, animals and plants to new places and changed conditions to those that favor particular species.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

9

Industrial Processes

• Creation of tools that have altered the world. Tractor, plow, chain saw, etc.

• Creation of compounds that are new to natural world. DDT, PCB, nylon, etc.

• Electrical generation and distribution.

• Fixation of atmospheric nitrogen.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

10

Money and Politics

• Money is a system of value that individuals substitute for biological value.

• Money and collective control allow the concentration of resources on projects involving many people.

• Research and culture advance through this concentration of resources.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

11

Where it makes sense to live

• 1870 homesteading

  • Water

• 1900 urban environment

  • Rail transportation, can heat but not cool

• 1970

  • Roads, energy to both heat and cool

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

12

Energy Production & Consumption

• World oil use = 83 million barrels a day

  • Oil is hydrocarbon probably of biological origin.

• World coal use = 4,686 million tonnes yr-1

• Burning of fossil fuels puts 6.3 gigatons of carbon into atmosphere as CO2

• What is the impact of burning carbon for energy?

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

13

Greenhouse Effect

• Energy from the sun = 1500 Watts per m2

• Some of that energy is absorbed by the atmosphere but much reaches surface of earth.

• Energy absorbed by molecules is often reradiated as heat (Infrared).

• Certain gases effectively absorb infrared radiation.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

14

Glass models the greenhouse effect

• Visible light (and associated energy) goes thru glass quite well.

• Infrared light (longer wave lengths than red) does not go thru glass.

• Greenhouses are warm because energy of visible light is absorbed and reradiated as infrared which can not escape thru glass.

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

15

Greenhouse gases

• Gases that absorb part of the radiation reradiated from the earth surface are known as green house gases.

• Carbon dioxide (now 380 ppm)

• Nitrous oxide (2) now 320 ppb (parts per billion)

• Methane (CH4) now 1770 ppb

• Chlorofluorocarbon (Freon) 800 ppt (trillion)

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

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Trends in greenhouse gases

• Carbon dioxide is going up, 1.7 ppm yr-1

  • Burning of fossil fuel for energy

• Nitrous oxide is going up, 0.7 ppt yr-1

  • Catalytic converter on automobiles

  • Generation of electric power

  • Agricultural nitrogen

• Methane is stable

• Chlorofluorocarbon is declining, -2 ppt yr-1

Speaker Notes:

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Exam 3 lecture 10

UIC BioS 101 Nyberg

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Major effect of changes in atmosphere is warming of earth

• Warming changes not just temperature, but also precipitation.

• Changes will not be the same everywhere, but will be spatially structured.

• Much water is tied up as ice in glaciers, increased warming is melting glaciers and causing a rise in sea level.

Speaker Notes:

17

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Exam 3 lecture 10

UIC BioS 101 Nyberg

18

Vocabulary

• Atmosphere

• Fire

• Gigaton

• Greenhouse gas

• Non-native species

• Radiation

• ppm

• ppb

• ppt

Speaker Notes:

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