Environmental science exam #1

Environmental science

Study of how the natural world works, how the environment affects humans, and how humans affect the environment.

Scientific method: three key qualities

Testable, repeatable, and verifiable.

Experimental control

Ideally, all variables remain stable except the one variable being tested.

Laboratory study

Environmental study with relatively high experimental control.

Field study

Real-world environmental study where many variables may interact and be difficult to control.

Computer model limitation

A model depends on the quality of its inputs and how well the researcher understands the system.

Ecological footprint

Amount of land and water needed to provide the resources a population consumes and absorb its wastes.

Anthropocentric

Human-centered environmental perspective.

Biocentric

Perspective centered on living organisms.

Ecocentric

Perspective centered on the entire ecosystem, including living and nonliving components.

Cumulative impacts

Integrated effects of changes as they work throughout a system.

Four major Earth systems

Lithosphere/geosphere, atmosphere, hydrosphere, and biosphere.

Lithosphere / geosphere

Solid outer Earth and its inorganic materials.

Atmosphere

Gases surrounding Earth.

Hydrosphere

Earth's water.

Biosphere

All living organisms.

Element

Basic building block of matter.

Mineral

Naturally occurring inorganic material with a definite chemical composition and atomic structure.

Rock

Aggregate of minerals in the solid state.

Density formula

Density = mass ÷ volume.

Felsic rock

Relatively low-density rock; continental crust is largely felsic. Granite is an example.

Mafic rock

Denser than felsic rock; oceanic crust is largely mafic. Basalt is an example.

Ultramafic rock

Dense Fe- and Mg-rich rock; characteristic of the mantle. Peridotite is an example.

Continental crust composition

Primarily felsic.

Oceanic crust composition

Primarily mafic.

Mantle composition

Primarily ultramafic.

Moho

Boundary between the crust and mantle.

Outer core

Liquid iron and nickel.

Inner core

Solid iron and nickel.

Plate tectonics

Theory that the lithosphere is divided into moving plates.

Approximate plate movement

About 1–6 inches per year according to the lecture.

What drives plate movement?

Mantle convection currents, according to the lecture.

Continental + oceanic collision

Subduction; lecture example: Pacific Northwest.

Oceanic + oceanic collision

Island arcs; lecture example: Aleutian Islands.

Continental + continental collision

Active mountain building; lecture example: Himalayas.

Separating plate boundary

Seafloor spreading; lecture example: Mid-Atlantic Ridge.

Transform boundary

Plates slide past each other; lecture example: San Andreas Fault.

Igneous rock

Rock formed by cooling magma or lava.

Intrusive igneous rock

Cools below the surface; slower cooling produces larger crystals.

Extrusive igneous rock

Cools at the surface; faster cooling produces smaller crystals.

Sedimentary rock

Rock formed from reconsolidated eroded/deposited material.

Metamorphic rock

Existing rock changed by heat and/or pressure.

Shale metamorphic sequence

Shale → slate → schist → gneiss.

Limestone metamorphoses into

Marble.

Sandstone metamorphoses into

Quartzite.

Differential weathering

Different rock types weather or erode at different rates.

Normal fault

Pull-apart fault.

Reverse fault

Push-together fault.

Strike-slip fault

Fault involving sliding motion.

Role of atmosphere

Controls and filters incoming radiation and redistributes energy and matter.

Atmospheric pressure

Force or weight of air; also called barometric pressure.

Atmospheric layers, bottom to top

Troposphere → stratosphere → mesosphere → thermosphere.

Temperature pattern through atmospheric layers

Troposphere decreases; stratosphere increases; mesosphere decreases; thermosphere increases.

Conduction

Heat transfer through material without bulk movement.

Convection

Heat transfer through circulation of a fluid.

Radiation

Energy transfer by electromagnetic waves.

Earth's principal external energy source

The Sun.

Wien's Law

λ = K/T; as temperature increases, wavelength decreases.

Absorption

Radiant energy is taken in.

Scattering

Radiant energy is deflected.

Reflection

Radiant energy is sent back.

Albedo

Reflectivity.

Total incoming shortwave radiation reflected in lecture energy budget

32%.

Incoming shortwave radiation absorbed by the ground

50% in the lecture energy budget.

Shortwave radiation

Radiation arriving from the hotter Sun.

Longwave radiation

Radiation reradiated by the cooler Earth.

Greenhouse gases

Trap/absorb some outgoing longwave radiation.

Equator energy balance

Energy surplus.

Polar energy balance

Energy deficit.

Meridional transport

North-south transport along longitude; helps redistribute energy.

GCM

Atmospheric model only, as framed in the lecture.

CGCM

Coupled atmosphere-ocean model; lecture says it works better by connecting both systems.

Evaporation

Liquid → gas.

Condensation

Gas → liquid.

Melting

Solid → liquid.

Freezing

Liquid → solid.

Sublimation

Solid ↔ gas.

Heat of evaporation/condensation

600 calories in the lecture.

Heat of melting/freezing

80 calories in the lecture.

Heat of sublimation

680 calories in the lecture.

Absolute humidity

Quantity of water vapor in a particular volume of air.

Relative humidity formula

Amount of water vapor present ÷ capacity at that temperature × 100.

Warm air and moisture capacity

Warmer air can hold more moisture.

Percent of Earth's water in oceans

97.5%.

Percent of Earth's water that is fresh

2.5%.

Water budget formula

P = R + ET + G.

P in water budget

Precipitation.

R in water budget

Runoff.

ET in water budget

Evapotranspiration.

G in water budget

Groundwater.

Drainage basin / watershed

Area drained by a river or stream; fundamental surface-hydrology unit and topographically defined.

Discharge

Amount of water flowing through a river/stream over time.

Discharge formula

Q = A × V.

A in Q = A × V

Cross-sectional area.

V in Q = A × V

Velocity.

Hydrograph

Graph of discharge over time.

Hydrograph sequence

Point of rise → rising limb → peak discharge → recession limb.

Flashy hydrograph

Hydrograph with rapid rise/sharp peak; lecture says deserts tend to be flashier than tropical rainforests.

Direct runoff

Immediate runoff associated with precipitation/storm event.

Through flow

Flow reaching the stream through pathways/tributaries as described in lecture.