Ecology
 The study of interactions between organisms and living and nonliving environments.
Biotic vs. Abiotic
 Biotic – living factors
 Abiotic – non-living factors
Biomes vs. Ecosystems
 Biome – distinct communities of plants and animals living together under the same
environmental conditions.
◦ Terrestrial
▪ Tundra
▪ Taiga
▪ Temperate Deciduous Forest
▪ Temperate Grassland
▪ Desert
▪ Savanna
▪ Tropical Rainforest
◦ Aquatic
▪ Freshwater
 Ponds & Lakes
 Streams & Rivers
 Wetlands
▪ Marine
 Ocean – Photatic & Aphotatic
 Coral Reefs
 Estuaries
 Ecosystem
◦ All of the organisms and the non-living environment found in a particular place at a
particular time.
Weather vs. Climate
 Weather
◦ Constantly changing
◦ Refers to the state of the atmosphere at any given time and place
 Climate
◦ based on observations of weather over time
◦ helps describe a place or region
Air
◦ mixture of gases and particles
 Variable Components
◦ Water vapor
▪ source of all clouds and precipitation
▪ Absorbs heat
 given off by the Earth
 Solar energy (some)
◦ Ozone
▪ 3 oxygen atoms (O3)
▪ Filters UV radiation
 W/out it, our planet would be uninhabitable for many organisms
Height and Structure of the Atmosphere
◦ The atmosphere rapidly thins as you travel away from Earth.
 Thermal Change
◦ Troposphere –
Alt ↑ => Temp ↓
◦ Stratosphere –
Temp stays same until 20 km. Gradual ↑ until stratopause
◦ Mesosphere –
Alt ↑ => Temp ↓
◦ Thermosphere – Alt ↑ => Temp ↑
 Heat & Temp
◦ Heat
▪ Transfer of energy
 3 mechanisms
◦ Conduction
▪ Matter toughing matter
◦ Convection
▪ Mass Movement
◦ Radiation (see more in Radiation below)
▪ Needs no medium needed to travel through
◦ Temperature (see more in Variations in Temperature)
 Measure of the averaging kinetic energy of atoms or molecules in a substance.
Radiation
 Solar Radiation
◦ When solar radiation strikes Earth & atmosphere
▪ Absorbs some energy
 50% of solar energy that passes through the atmosphere reaches the surface and is
absorbed.
 Greenhouse effect
▪ Transmits some of the energy
 through water and air
▪ Bounces off
 Reflects
◦ The same intensity as incident radiation
 Scatters
◦ A larger number of weaker rays that travels in different directions
Variations in Temperature
 Latitude
 Heating of land & water
◦ Land heats and cools more rapidly than water
◦ Land reaches temperatures higher and lower than water
 Altitude
 Geographic position
◦ Lake effect, mountains, oceans, ect.
 Cloud cover
◦ Albedo
▪ Fraction of total radiation that is reflected by any surface
 Ocean currents
Isotherms
 Lines on a weather maps that indicate where the temperature is the same
◦ Trends
▪ East & West
▪ Decrease in temperature as latitude increases
Air Masses and Weather
 Air mass – an immense body of air that is characterized by similar temperatures and amounts of
moisture at any given altitude.
 Movement of Air Masses
◦ Influence a change in characteristics of an air mass
◦ Causes the weather in the area over which the air mass moves to change.
 Types of air masses – CP, MP, CT, MT
◦ Humidity
▪ Continental (C) – Dry air mass
▪ Maritime (M) – Wet air mass
◦ Temperature
▪ Polar (P) – Cold air mass
▪ Tropical (T) – Warm air mass
◦ Two air masses in our region: CP & MT
What Happens When Air Masses Meet?
 Fronts – boundary that separates two air masses
Types of Fronts
 Warm Front
◦ Warm moist air rises over
a cool and moist air mass
Symbol: Red half circles pointing in
◦ Stable (see Stability)
the direction the front is moving.
◦ Symbol: see pic. & last page
 Cold Front
◦ Cold dense air meets warm moist air
◦ Severe weather is typical b/c of the
forceful uplifting of warm air
Symbol: Blue triangles point in the
◦ Symbol: see pic. & last page
dir. the front is moving
Stability
 Air that resists vertical changes is considered stable (doesn't rise or sink)
 Measuring stability
◦ Environmental lapse rate
▪ Change of air temperature with height
▪ Stable air: temp ↓ as height ↑
▪ Most stable air : temperature inversion
 height ↓ as temp ↑
▪ Unstable air
 Warmer near surface w/ a great diff. in the air temp. above
Movement of Fronts
 Stationary fronts
◦ surface position of the front does not move
Occluded Front
 An active cold front wedges a warm front upward
Processes that Lift Air
 Orographic Lifting
◦ Caused by mountains act as barriers to flow of air
◦ Air is forced up
 Frontal Wedging
◦ Caused by two air masses having contrasting characteristics coming into contact
 Convergence
◦ Air flows together and rises
 Localized Convective Lifting
◦ Unequal surface heating causes pockets of air to rise because of their buoyancy
Middle Latitude Cyclones
 Large centers of low pressure that generally travel from west to east and cause stormy weather
 Most often fueled air high up in the atmosphere
Air Pressure Defined
 Pressure exerted by the weight of air
 Exerted in all dir.
 Air pressure pushing down and air pressure pushing up
Measuring Air Pressure
 Barometers
◦ A device used for measuring air pressure
◦ As air pressure ↑, mercury in the tube rise. As air pressure ↓, mercury in the tube falls.
Factors Affecting Wind
 Wind
◦ Result of horizontal difference in air pressure
▪ caused by unequal heating of the Earth's surface by solar radiation
◦ Air flows from areas, high pressure to areas w/ low P (pressure)
 3 factors combined control wind
◦ Pressure Differences
▪ Δ (change) in pressure occurring over a given distance
▪ Isobars
 Lines on a map that connect places of equal air pressure
 lines close together => steep pressure gradient (change)
◦ High-winds
 lines widely spaced => weak pressure gradient
◦ Light-winds
◦ The Coriolis Effect
▪ Describes how the Earth rotation affects moving objects
 Includes all free-moving objects or fluids including wind
 Northern Hem. – deflect to the right (clockwise)
 Southern Hem. – deflects to the left (counter-clockwise)
◦ Friction
▪ Slow air movement, which changes wind direction
 Jet-stream
◦ Fast moving rivers of air that travels b/w 120 and 240 km/h in a west to east dir.
High and Lows
 Cyclones are centers of low pressure
◦ the pressure decreases from the outer isobars towards the center
 Anticyclones are centers of high pressure
◦ the pressure increases from the outer isobars toward the center
 Cyclonic and Anticyclonic Winds
◦ When the pressure gradient and the Coriolis Effect are applied to pressure centers in the N
Hem. , winds blow: H →
L
High to low, clockwise from high to counter
clockwise to low.
◦ In either Hem., friction causes a net flow of air inward around a cyclone and a net flow of
air outward around an anticyclone.
Weather and Air Pressure
 Rising air is associated w/ cloud formation and precipitation
 Sinking air produces clear skies
 Weather Forecasting
◦ Weather reports emphasize the locations and possible path of cyclones and anticyclones
◦ Low pressure centers can produce bad weather in any season
Global Winds
 The atmosphere balances differences by acting as a giant heat-transfer system.
◦ Moves warm air toward high latitude and cool air toward the equator.
 Non-rotating Earth Model: hypothetical non-rotating planet
◦ a smooth surface of either all land or all water
◦ 2 large thermally produced cells would form.
 Rotating Earth Model
◦ w/ rotation the 2-cell convection system breaks down into smaller cells.
▪ Trade winds – two belts of wind that blow almost constantly from easterly directions.
Located 30° N and S b/w subtropical highs and the equator. Produced by the Coriolis
effect.
▪ Westerlies – west to east direction. Located in the middle latitudes b/w 60° and 30° N
and S. Deflected by the Coriolis Effect.
▪ Polar Easterlies – Polar high to sub polar low, not constant. > 60° N and S. Causes
polar fronts.
▪ Polar Fronts – stormy belt caused by polar easterlies.
▪ Monsoon – seasonal reversal of wind dir. associated with large continents.
H20 + C02 → H2CO3 … Carbonic Acid
 Acid rain
◦ Any precipitation w/ less than 5.6 pH
◦ Other forms of acid rain
▪ Sulphuric Acid + Nitric Acid
 Stronger acid
Illustration 1: Warm Front
Illustration 2: Cold Front