MonthDayTopic Nov.8Individuals to populations 10Holiday! 13Populations to communities 15Community patterns 17Ecosystems 20Film-1 st showing 22Film-2 nd showing 24Holiday! 27Ecosystem services

Why do communities vary in space?

Communities vary in space Time Relief/aspect Parent material Climate Organisms

Terrestrial biome

A major community type that differs from other types in the structure of its dominant vegetation.

Terrestrial biome A major community type that differs from other types in the structure of its dominant vegetation. Primarily controlled by climate. –Relationship between rainfall and temperature

The vegetation of a biome has a similar appearance wherever on Earth that biome is found. In many cases, this is due to convergent evolution. Biomes

EuphorbiaceaeCactaceae

Tundra

-severe winters -short growing season, cool summer -arctic or alpine Tundra

Temperate Forest Temperate forest

-distinct winter season, frost a defining feature -summer season usually moist Temperate Forest

Desert

-hot or cold deserts exist -low precipitation

Desert

-found near the equator -temperature varies little from approximately 23°C -Over 2 m of rainfall Tropical Rain Forest

-canopy trees up to 55 m tall -largest biome, on an area basis -soils are generally unfertile -nutrients and carbon stored in plant biomass, not soils

Picture of sun

Solar energy drives global climates

Global atmospheric circulation

The amount of heat that an ecosystem receives is determined by: 1.The angle of the sun (latitude)

The amount of heat that an ecosystem receives is determined by: 1.The angle of the sun (latitude) 2.Altitude

The amount of heat that an ecosystem receives is determined by: 1.The angle of the sun (latitude) 2.Altitude 3.Wind

Local climate

Maui cloud Local climate

Land-shore system

The amount of heat that an ecosystem receives is determined by: 1.The angle of the sun (latitude) 2.Altitude 3.Wind 4.Ocean currents

Global oceanic circulation

Energy flow through ecosystems Only 5% of the solar energy that arrives on earth is captured by photosynthesis.

Energy flow through ecosystems Only 5% of the solar energy that arrives on earth is captured by photosynthesis. The energy captured powers life.

The 2 nd law of thermodynamics

When energy is converted from one form to another, some of it becomes unavailable to do work...

The 2 nd law of thermodynamics When energy is converted from one form to another, some of it becomes unavailable to do work... Key to understanding energy flow through ecosystems.

Gross primary productivity (GPP) The amount of energy that plants assimilate through photosynthesis.

Gross primary productivity (GPP) The amount of energy that plants assimilate through photosynthesis. CO 2 + H 2 O + light = energy compounds.

Gross primary productivity (GPP) The amount of energy that plants assimilate through photosynthesis. CO 2 + H 2 O + light = energy compounds. Fixed carbon = energy

Net primary productivity (NPP) GPP – plant respiration = NPP NPP is: –Food –Fiber –Fuel –Shelter

Climate drives NPP

NPP provides energy to heterotrophic organisms

Trophic levels Number of steps through which energy passes before an organisms uses it.

Trophic levels LevelSource of energy Primary producersSolar energy

Trophic levels LevelSource of energy Primary producersSolar energy HerbivoresPrimary producers

Trophic levels LevelSource of energy Primary producersSolar energy HerbivoresPrimary producers Primary carnivoresHerbivores Secondary carnivoresPrimary carnivores

Trophic levels LevelSource of energy Primary producersSolar energy HerbivoresPrimary producers Primary carnivoresHerbivores Secondary carnivoresPrimary carnivores OmnivoresEverything!

Trophic levels LevelSource of energy Primary producersSolar energy HerbivoresPrimary producers Primary carnivoresHerbivores Secondary carnivoresPrimary carnivores OmnivoresEverything! DecomposersDead things

Energy is lost between trophic levels Energy decreases as it moves from lower to higher trophic levels The “trophic pyramid”

The efficiency of energy transfer is determined by:

How much of the energy at one trophic level gets eaten by another trophic level

The efficiency of energy transfer is determined by: How much of the energy at one trophic level gets eaten by another trophic level How those organisms divide the ingested energy between production and respiration.

A food web

Food webs in real ecosystems are complex

Some ecosystems are not powered by direct sunlight

Deep sea vent ecosystems

Humans manipulate energy flow Forestry Agriculture Fisheries management Game management Land use change Burning fossil fuels...

Assume that energy transfer efficiency between trophic levels is 10%. a)How much grain would be required to produce 70 Kg of human biomass if that grain is first eaten by cows, and the cows are then eaten by humans? b)How much grain would be required to produce 70 Kg of human biomass if the humans ate the grain?