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Ecosystems and Communities

The Role of Climate&

What shapes an ecosystem?

What is climate?

• Weather = day-to-day condition ofEarth’s atmosphere at a particular timeand place.

• Climate = average temperature andprecipitation in a particular region.

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The Greenhouse Effect

• Atmosphere = the mass of airsurrounding the earth.

• Atmospheric gases trap heat energyfrom the sun and mountain's the Earth’stemperature range.

The Greenhouse Effect

• Greenhouse effect = the retention of heat bythe atmosphere.

• Sunlight hits the Earth.• The sunlight is reflected back into the

atmosphere as heat.• Some of the heat passes through the

atmosphere and into space.• Some of the heat bounces off of the

atmosphere back to the Earth.

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The Effect of Latitude onClimate

• Solar radiation (sunlight) strikesdifferent parts of the Earth at differentangles.

• This results in different climate zones

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The Effect of Latitude onClimate

• Polar Zones– Cold zones where sunlight strikes the Earth at a

low angle.– Cold climate

• Temperate Zones– Climate ranges from hot to cold depending on the

season.• Tropical Zone

– Near the equator.– Warm climate

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Heat Transport in the Biosphere

• Air Currents (Winds)– Air that is heated near the equator rises.– Cooled air over the poles sinks to the

ground.– The upward movement of warm air and the

downward movement of cool air creates aircurrent (winds)

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Heath Transport in the Biosphere• Ocean currents

– Cold water near the poles sinks to theocean bottom and flows toward warmerregions.

– The cold water rises up to the surface atthe warmer regions.

– Surface water is moved by winds.– Surface ocean currents warm or cool the

air above them.

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Biotic and Abiotic Factors

• Biotic factors = Living components of anecosystem.– Examples: plants, animals, bacteria.

• Abiotic factors = nonliving components of anecosystem.– Examples: wind, temperature, precipitations,

sunlight, soil type….• Habitat = the combination of biotic and abiotic

factors.– The organism’s address!

The Niche

• Niche = The role of an organism in anecosystem.– The organism’s occupation– Examples

• types of food eaten.• How food is obtained.• Which species use this organism as food.• Where the organism lives.• Temperature needed to survive.• When the organism reproduces.• ………

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The Niche

The Niche• Competitive exclusion principle = No two

species can occupy the same niche in thesame habitat at the same time.

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Community Interactions -Competition

• Competition = organisms of the same ordifferent species attempt to use anecological resource in the same placeat the same time.

• Resource = a necessity of life– Examples = water, nutrients, light, food,

space.

Community Interactions -Predation

• Predation = one organism captures andfeeds on another organism.

• Predator = the organism that does thekilling.

• Prey = the food organism.

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Community Interactions -Symbiosis

• Symbiosis = any relationship in whichtwo species live together.– Mutualism– Commensalism– Parasitism

Community Interactions -Symbiosis

• Mutualism = bothspecies benefit fromthe relationship.

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Community Interactions -Symbiosis

• Commensalism =one organismbenefits and theother is neitherhelped or harmed.

Community Interactions -Symbiosis

• Parasitism = oneorganism benefitswhile the other isharmed.

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Ecological Succession

• Ecosystems and communities arealways changing in response to naturalor human disturbances.– Examples: change in temperature, amount

of rainfall, fire, flood, earthquake….• Ecological succession = changes in a

community that occur over time.

Ecological Succession -Primary Succession

• Primary succession = changes on surfaceswhere no soil exists.

• Pioneer species = the first species topopulate an area.

• Lichen = a common pioneer species whichgrows on bare rock.– Made up of fungus and an algae (an example of

mutualism)– Breaks up the rocks to form soil.

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Ecological Succession -Primary Succession

Ecological Succession -Primary Succession

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Ecological Succession -Secondary Succession

• Secondary succession = Succession ona previously established ecosystem.

• Started by an event.– Forest fire– Harvesting– Hurricane

Ecological Succession -Secondary Succession

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Ecological Succession - SecondarySuccession

Climax Community

• The development of vegetation in acommunity over time throughsuccession has reached a steady state(equilibrium).

• The plants and animals in thecommunity are best adapted to theenvironment.

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