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EcologyChapters 2 and 3

What is Ecology?• The scientific study of interactions among organisms and their environment or surroundings.

• Environment: living and non-living things

Biotic Factors:

Living factors in an organism’s environment.

Abiotic Factors:

Nonliving factors in an organism’s environment

Biotic Factors

ECOSYSTEM

Abiotic Factors

Abiotic and Biotic Factors

EnvironmentBiosphere

• Part of Earth in which life exists including, land, water, air or atmosphere.

•

• 5 miles above the Earth surface.

•

• 7 miles below the surface of the oceans

Lesson Learned: Biosphere 2.

• $200 million was spent in the 1990s to create a totally self contained and reliant ecosystem in the Arizona desert. The idea was 8 scientists would live with introduced plants and animals in a closed system, meaning, no energy, nutrients or material could enter or leave the system--aside energy from the sun.

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• The project failed; most of the animals died off, except for cockroaches and ants. The atmosphere inside the Biosphere built up too much poisonous gasses, and the scientists ran out of food (they were supposed to eat the plants and animals in Biosphere). This experiment showed just how precarious the Earth's ecosystems are. It now acts as a tourist attraction.

Levels of organization• Species: a group of similar organisms.

• Population: a group of individuals that belong to the same species, living in the same area.

• Communities: a group of interacting populations that occupy the same geographic area at the same time.

• Ecosystem: a biological community and all of the abiotic factors that affect it.

Biome: a large group of ecosystems that share the same climate and have similar types of communities.

Speciespopulation

community Ecosystem

Biome

A habitat is an area where an organism lives.

A niche is the role or position that an organism has in its environment.

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Flow of Energy in an Ecosystem

Sunlight: is the main energy source for life on earth.* less than 3% is used by living things

Producers:

• Organisms that capture energy from sunlight and use that energy to produce food.

•

• Autotrophs

Consumers:

• Organisms that rely on other organisms for their energy and food supply.

Heterotrophs

Types of Heterotrophs• Herbivores – eat plants (first order consumers)

• Carnivores – eat animals (second order consumers)

• Omnivores - eat both plants and animals as their primary food source. (first and second order consumers)

• Detritivores - obtain nutrients by consuming detritus (decomposing organic matter)

• Decomposers - organisms that consume dead organisms.

• Scavengers - consumes corpses or carrion that were not killed to be eaten by the predator .

Food Chain

• Energy flows through an ecosystem in one direction.

• The sun to producers, to consumers.

• The transfer of energy by eating and being eaten.

• SUN

• Grass --> antelope --> coyote

• Grass --> mouse --> snake --> hawk --> coyote

• Algae --> zooplankton --> fish --> squid --> shark

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Food webs• Link of all food chains in an ecosystem.

• Forms a network of complex interactions.

• Each step in a food chain or food web is called a:

• Trophic level.

• Producers make up the first trophic level. Consumers make up the second, third, fourth, etc.

• Each consumer depends on the trophic level below it for ENERGY.

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Ecological Pyramids

• Energy pyramid - the amount of energy available from level to level.

• Only about 10% of the energy is available from one level to the next.

• Where does the rest of the energy go?

•

• Life process - respiration, movement, reproduction.

• Lost as heat.

Pyramid of NumbersShows the relativenumber of individualorganisms at eachtrophic level.

Biomass PyramidRepresents the amount ofliving organic matter at each trophic level. Typically, thegreatest biomass is at the base of the pyramid.

Energy PyramidShows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat.

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Ecological Pyramids

• A large mass of living things at the base is required to support a few at the top ... many herbivores are needed to support a few carnivores.

Community Interactions

• Organisms that live together in a biological community constantly interact.

•Competition

• Occurs when more than one organism uses a resource at the same time.

Predation• Where one species captures and feeds on

another.

•

• Predator- the speices that does the killing and eating.

•

• Prey - the food species

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Symbiosis• Relationship between two species.

(living together)

• Mutualism

• Both species benefit from the relationship.

• (Flowers and insects) (cows and birds) Commensalism

• One species benefits and the other is neither helped or harmed.

• (whales/barnacles) (Orchids and trees)

• Parasitism

• One species benefits and the other is harmed.

• (Tapeworm/sheep) (fleas/dog )

Mutualism

Commensalism

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Parasitism

Cycles of Matter• Unlike Energy, matter is recycled within

and between ecosystems.

• Biological systems do not use up matter, they transform it.

•

• For millions of years the same molecules have been passed around again and again, within the Biosphere.

• Three main elements that must move

through an ecosystem:

• Water

• Carbon

• Nitrogen

Water Cycle• Evaporation - water changes from a liquid

to a gas.

• Transpiration - water evaporates from the leaves of plants.

• Condensation - water changes from a gas to liquid.

• Precipitation - rain, snow, sleet, or hail.

•

• * May take a single water molecule 4000 years to complete one cycle.

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Carbon Cycle• Carbon exists in the Earth's atmosphere primarily as the gas

carbon dioxide (CO2).

• Although it is a small percentage of the atmosphere, (.03%) it plays a vital role in supporting life.

• Carbon Cycle Steps:

– Plant leaves take carbon dioxide from air

– Plants store carbon in carbohydrates and starches

• (photosynthesis)– Plants and animals release carbon dioxide back into the air

• (cellular respiration)– Decomposers release carbon back into the atmosphere

(decomposition)

Producers of Carbon

• Photosynthesis, respiration, decomposition of plants and animals.

• Release of carbon dioxide gas to the atmosphere by volcanoes.

• **Burning of Fossil fuels (coal and Petroleum)

• Human activity (mining, cutting and burning of forests)

Nitrogen CycleNeeded by all organisms

Used to make proteins & nucleic acids (DNA & RNA)

Air made up of 80% nitrogen

Only certain bacteria can use nitrogen directly from the air (nitrogen fixation)

Bacteria found in the soil & on the roots of legumes (beans, peas ...)

Bacteria take nitrogen from air(nitrogen fixation)↓

Convert Nitrogen into Ammonia↓

Νitrifying bacteria in soil change Ammonia into Nitrates↓↓↓↓

Plants can absorb & use Nitrates to make proteins↓↓↓↓

Consumers eat plants and get proteins containing nitrogen↓↓↓↓

Decomposers break down dead organisms & return Nitrogen to the air↓↓↓↓

Anaerobic bacteria in the soil release Nitrogen from nitrates into the air

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Ecosystems and CommunitiesChapter 3

The role of Climate

• Average, year after yearconditions of temperatureand precipitation in a particular region.

What is Weather?

• The day to day conditions at a particular time and place.

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Temperature of Utah• Average temp. 52

• Average high 77

• Average low 27

• **Record high 118 (St. Georges)

• **Record low -69 (Peters sink)

• Phoenix 72

• Las Vegas 67

• Fairbanks 26

• Key west 77

Precipitation

• Utah average 16"

• Salt lake city average 15.7"

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• Phoenix 7" (Arizona 7.11")

• Las Vegas 4" (Nevada 7.87")

• Reno is 7.48 Inches

• Sacramento is 44.15 Inches

What factors create climate

• Trapping of the heat by the atmosphere.

• (Greenhouse effect)

• Latitude and the angle of heating.

• Transport of heat by winds and ocean currents

• The shape and elevation of land masses.

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44.15” 7.48”

Three main climate zones.

• Polar Zone: Cold area, sun’s rays strike Earth at a very low angle.

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• Temperate Zone: Hot to cold, changing angle of the sun over the course of a year.

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• Tropical Zone: Hot area, Receives direct or nearly direct sunlight year round.

Succession

• Ecosystems are constantly changing. • They change in response to:

• Natural disturbances.

• Fires, Earthquakes, Floods, Landslides, Volcanic eruptions

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• Human disturbances.

• Clearing land, Farming, Mining, Urban development

•

• **Very slow process, or a very quick process.

Two types of Ecological succession

• Primary succession

• Occurs on newly exposed surfaces.

• Pioneer species - first species to populate an area.

• Climax community - mature, stable community.

•

• Secondary succession

• Change in an existing community

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Pond Succession

• If left alone, succession will eventually cause a pond to disappear. Nature uses plants to help fill in the pond.

It often takes hundreds of years for a pond to be transformed from a body of clear water into soil.

Biome

• Geographically defined areas with similar climatic conditions, communities of plants, animals, and soil organisms.

• ***Are often referred

• to as Ecosystems.

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Tropical rain forest

Tropical dry forest

Tropical savanna Temperate woodlandand shrubland

Desert

Temperate grassland

Boreal forest

(Taiga)

Northwestern

coniferous forest

Temperate forest

Mountains and

ice caps

Tundra

-17 The World's Major Land Biomes

Compare/Contrast Table

Ten Major Biomes

mediumabsentlowpoorsummer mild, winter cold

lowTundra

sparsedensemoderatepoor, acidicsummer mild, winter cool

moderateBoreal Forest

sparsedenselowrocky, acidicsummer mild, winter cold

highNorthwestern Coniferous Forest

sparsedensehighrichsummer moderate, winter cold

moderateTemperate Forest

mediummediumlowpoorsummer hotsummer low, winter moderate

Temperate woodland and Shrubland

denseabsentmoderaterichsummer hotmoderateTemperate Grassland

sparsesparsemoderatepoorvariablelowDesert

dense

medium

sparse

Grasses

sparse

medium

dense

Trees

moderateclaymildvariableTropical Savanna

moderaterichmildvariableTropical Dry Forest

highpoorhothighTropical Rain Forest

DiversitySoilTemperaturePrecipitationBiome

Ten Major Biomes

mediumabsentlowpoorsummer mild, winter cold

lowTundra

sparsedensemoderatepoor, acidicsummer mild, winter cool

moderateBoreal Forest

sparsedenselowrocky, acidicsummer mild, winter cold

highNorthwestern Coniferous Forest

sparsedensehighrichsummer moderate, winter cold

moderateTemperate Forest

mediummediumlowpoorsummer hotsummer low, winter moderate

Temperate woodland and Shrubland

denseabsentmoderaterichsummer hotmoderateTemperate Grassland

sparsesparsemoderatepoorvariablelowDesert

dense

medium

sparse

Grasses

sparse

medium

dense

Trees

moderateclaymildvariableTropical Savanna

moderaterichmildvariableTropical Dry Forest

highpoorhothighTropical Rain Forest

DiversitySoilTemperaturePrecipitationBiome

Desert Biome

• Dry - less than 13 inches of precipitation.

• Extreme temperature changes during the course of the day. (Alternating between hot and cold)

• Soils rich in minerals, low in organic material.

• Cacti, sagebrush and other plants with short growing period.

• Mountain lions, coyotes, mule deer, antelope, owls, hawks, tortoises, rattlesnakes, lizards, bats.

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