Mon. Tues. Wed. Thurs. Fri. Week of Sept. 8 Outdoor lab – dress for weather Week of Sept. 15 Active outdoor lab – dress for weather Week of Sept. 22 Indoor lab – bring caculator Week of Sept. 29 Oct. 3 Exam 1 Wet outdoor lab – wear closed-toed shoes

Environmental variability Applied Ecological Issues Structure of course Environmental variability Organisms Ecosystems Populations Species interactions Communities Applied Ecological Issues

Outline Types of variation Variability on a global scale - climate Smaller scale variation Consequences of variation in climate

Temporal variation - changes through time Spatial variation - changes through space

Scale: the dimension in time or space over which variation is perceived. Scale of variation importance is a function of the organism

Scale of measurement affects perception of variability Too coarse Too fine

Temporal and spatial variation are often correlated

Ecological scales of variation

Outline Types of variation Variability on a global scale - causes of variation in climate - example of unpredictable variability Smaller scale variation Consequences of variation in climate

Why is it colder at the poles than in the tropics? A. over the course of a year, the tropics receive more hours of sunlight B. sunlight is more intense on average at the equator C. the poles are farther from the sun than the tropics

What is it warmer in the summer than in the winter at high latitudes? A. the summer has more hours of sunlight B. the sun rises higher in the sky C. both A and B

Why is the seasonal range in temperature greater in the northern latitudes than in the southern latitudes?

What is the main cause of winds? A. the rotation of the earth around the sun B. the rotation of the earth on its axis C. the differential heating and cooling of different geographical locations on earth

Rotation deflects Hadley cells to drive wind patterns

Polar desert

Hadley cells explain some patterns of precipitation

Winds and position of land masses drive ocean currents

Outline Types of variation Variability on a global scale - causes of variation in climate - example of unpredictable variability Smaller scale variation Consequences of variation in climate

Example of an unpredictable pattern of climate variability - El Niño Southern Oscillation (ENSO) events

ENSO index = difference between barometric pressure in Tahiti (island in Pacific Ocean) and Western Australia Measures oscillation in pressure over Pacific Ocean

Ecological effects of ENSO events Examples: 1. Australia - El Niño brings drought and increased mortality of red kangaroos 2. Islands off of Peru - La Niña brings drought and increased mortality of ground finches El Nino brings rain, more food, and more finches

3. Zimbabwe - El Niño = drought = lower corn yield

Outline Types of variation Variability on a global scale Smaller scale variation - Example: elevation Consequences of variation in climate

Suppose the earth were exactly like it is today, except that oceans covered the entire surface. Then, the average temperature at the Equator would be less than the average temperature at the north pole. b. the difference between the average temperature at the north pole and the average temperature at the Equator would be less than now. c. wind speeds throughout the world would be greater than they are now. d. temperature and wind speeds would be the same are they are now.

Outline Types of variation Variability on a global scale - climate Smaller scale variation in climate Consequences of variation in climate - the biome concept

Outline The biome concept - terrestrial - aquatic Survey of the biomes Variability in Connecticut

Biomes - categories of biological communities based on dominant plant forms - primarily used for terrestrial systems

Biomes of the world

Why are there distinct biomes?

Sugar Maple range map

Terrestrial biomes - defined by temperature and precipitation

Aquatic systems - defined by physical factors such as depth, temperature, water flow

Outline The biome concept Survey of the biomes Variability in Connecticut

Terrestrial biomes of the world

Biome : Climate: Vegetation: The dominant types Animals: A few of the charismatic ones Net Productivity: rate of plant biomass production Diversity: # of plant and animal species

Biome : Tundra Climate: Short, cool summers Long, very cold winters Permanently frozen soil (permafrost) Vegetation: No trees Very short vegetation Animals: Caribou, lemmings, artic fox Net Productivity: Low Diversity: Low