Ecology Ch.2 - The Physical Environment

3 Levels of interactions

• global

• regional

• local

Organism interactions with physical environment

• energy sources

  • sunlight

  • chemical

• gas exchange

• temperature

• inorganic nutrients

• water and precipitation

Weather

current conditions (temp, precip, humidity, cloud cover)

Climate

long-term weather (cycles, long-term trends)

Global climate is driven by…

energy which is driven by solar radiation

How much radiation is reflected back by clouds and aerosols?

1/3 or 33%

How much incoming radiation is absorbed by ozone, clouds, and vapor?

1/5 or 20%

How much radiation is absorbed by Earth?

49%

Outgoing Energy

• sensible heat

• latent heat

• long-wave (infared) radiation

Long-wave (infared) radiation

• emitted by surface

• re-radiated back to Earth by greenhouse gases

Energy is spread which way by winds and ocean currents?

pole-ward

Low pressure

warm, rising air

High pressure

dry, cool, falling air

Prevailing winds

consistent patterns of air movements resulting from wind flow from areas of high pressure to low pressure

Coriolis effect

winds deflected due to the rotation of the Earth

Heat capacity

unit of heat required to inc temp of substance by 1 degree

Shallow oceanic circulation

surface currents are driven by surface winds

Deep oceanic circulation

density driven (temp & salinity)

• little vertical motion, highly stratified

Ocean currents are responsible for what percentage of heat exchange between the tropics and polars?

40%

Downwelling

colder, saltier water sinks

Upwelling

water from depths rises to surface

What alters global patterns of temp & precipitation

• ocean currents

• topography

• distribution of land and water masses

Why does it get colder as you move up a mountain?

• pressure decreases with elevation

  • decreases heat capacity

• highlands exchange air more effectively with cooler air in surrounding atmosphere

Lapse rate

decrease in temp with inc height above surface

Continental climate

• climate of terrestrial areas

• greater variation in daily & seasonal temps

Maritime climate

• coastal areas

• less variation in temp due to ocean

Albedo

amount of solar radiation a surface reflects

Evapotranspiration

water loss through transpiration by plants, plus evaporation from the soil (cools the land)

How does temperature effect transfer of energy?

• smooth surfaces allow for less transfer of energy by wind than rough surface

• rough surfaces inc turbulent air flow, which inc heat exchange btwn land & atmosphere

How are seasonal changes measured in the tropics?

• precipitation

• movement of intertropical convergence zone (ITCZ)

Intertropical Convergence Zone (ITCZ)

zone of maximum solar radiation & atmospheric uplift

Stratified water

warm surface water on top of colder, denser water results in layers that do not mix

Acidity

ability of a solution to act as an acid (gives up H+)

Alkalinity

ability of a solution to act as a base (receives H+ or gives up OH-)

Hypoxic

• low oxygen conditions

• promotes formation of toxic chemicals