Human Effect on Human Effect on EcosystemsEcosystems

Easter IslandEaster Island

The story of Easter IslandThe story of Easter Island

http://www.youtube.com/watch?v=K0v1lh2ijhttp://www.youtube.com/watch?v=K0v1lh2ijwkwk

Ecosystems…Ecosystems…

Supply food, fuel, natural resources, and Supply food, fuel, natural resources, and water.water.

Cycle nutrients and decompose wastes.Cycle nutrients and decompose wastes. Regulate climate.Regulate climate. Have animals that help pollinate crops and Have animals that help pollinate crops and

disperse seeds.disperse seeds. Provide us with cultural and recreational Provide us with cultural and recreational

opportunitiesopportunities

Sustainable UseSustainable Use

Using an Using an ecosystem’s ecosystem’s resources in a way resources in a way that meets our that meets our current needs current needs without without compromising the compromising the ability of future ability of future generations to meet generations to meet their needs.their needs.

Human activity has caused…Human activity has caused…

Habitat changeHabitat change OverexploitationOverexploitation PollutionPollution Invasive SpeciesInvasive Species Climate changeClimate change

Habitat ChangeHabitat Change

The process by which The process by which humans alter a habitat humans alter a habitat enough so that the enough so that the native species can no native species can no longer live there.longer live there.

Clear land for Clear land for agriculture, forestry, agriculture, forestry, and urban development.and urban development.

Habitat FragmentationHabitat Fragmentation

Small areas within a large Small areas within a large region are altered a bit at a region are altered a bit at a timetime

This creates a patchwork This creates a patchwork of altered and original of altered and original habitatshabitats

Ie. Southern Ontario used Ie. Southern Ontario used to be covered in deciduous to be covered in deciduous forests. Now, forests are forests. Now, forests are interspersed among fames, interspersed among fames, suburbs, and cities.suburbs, and cities.

Marine Habitat ChangeMarine Habitat Change Habitat change can Habitat change can

happen in the oceans too.happen in the oceans too. A fishing method called A fishing method called

trawling drags nets along trawling drags nets along the bottom of the oceans the bottom of the oceans to catch shrimp and to catch shrimp and bottom-dwelling fishbottom-dwelling fish

This disrupts the This disrupts the ecosystem by removing ecosystem by removing many producers from the many producers from the food web as well as food web as well as harming coral formationsharming coral formations

OverexploitationOverexploitation

Using a resource faster Using a resource faster than it can be replacedthan it can be replaced

ie. overfishing in ie. overfishing in Atlantic CanadaAtlantic Canada

Since the 1950’s, Since the 1950’s, humans have removed humans have removed

an estimated an estimated 90%90% of of large fish from the sealarge fish from the sea

Overfishing in CanadaOverfishing in Canada In Atlantic Canada, cod used to very In Atlantic Canada, cod used to very

abundantabundant Since the 1950’s the demand for cod Since the 1950’s the demand for cod

grew and fishing technologies grew and fishing technologies allowed us to catch more cod.allowed us to catch more cod.

Mature cod usually swim near the Mature cod usually swim near the surfacesurface

When those were gone, fishing fleets When those were gone, fishing fleets began fishing deeper, where the began fishing deeper, where the younger fish are found.younger fish are found.

The fish on which cod fed are also The fish on which cod fed are also located at this deeper level.located at this deeper level.

By fishing deeper, the industry was, By fishing deeper, the industry was, in effect, collecting the next year’s in effect, collecting the next year’s cod harvest as well as the cod’s food cod harvest as well as the cod’s food source.source.

In the 1990’s, cod fishing was In the 1990’s, cod fishing was stoppedstopped

Populations have yet to recoverPopulations have yet to recover

The Jellyfish Are Coming!The Jellyfish Are Coming!

http://www.youtube.com/watch?v=XnHk3I7Yhttp://www.youtube.com/watch?v=XnHk3I7YGuEGuE

http://www.youtube.com/watch?v=eyCigZ_bshttp://www.youtube.com/watch?v=eyCigZ_bsTMTM

The Jellyfish ProblemThe Jellyfish Problem

The overfishing of their natural The overfishing of their natural predators, global warming, predators, global warming, pollution, and a lack of jellyfish pollution, and a lack of jellyfish fishing by humans have caused a fishing by humans have caused a huge population boom for huge population boom for jellyfish.jellyfish.

Jellyfish are mostly prey when Jellyfish are mostly prey when they are eggs or very young. As they are eggs or very young. As they grow older, they actually they grow older, they actually move up the food chain and prey move up the food chain and prey on fish. Now, there are actually on fish. Now, there are actually millions more predators (jellyfish) millions more predators (jellyfish) adding to the fish population adding to the fish population problem.problem.

Overuse of WaterOveruse of Water

Overexploitation can Overexploitation can also happen to non-also happen to non-organic resourcesorganic resources

Canada has the world’s Canada has the world’s largest supply of fresh largest supply of fresh water and can look to water and can look to the Aral Sea as a the Aral Sea as a warning of the warning of the consequences of consequences of mismanagementmismanagement

The Aral SeaThe Aral Sea Once the 4Once the 4thth largest lake in the world largest lake in the world Government of the then Soviet Union decided Government of the then Soviet Union decided

to grow cotton and rice in the regionto grow cotton and rice in the region To irrigate the crops water was diverted from To irrigate the crops water was diverted from

the two rivers that flowed into the lake. the two rivers that flowed into the lake. Slowly, the lake’s water level dropped and Slowly, the lake’s water level dropped and

split the lake in two, creating the North Aral split the lake in two, creating the North Aral Sea and the South Aral Sea. Sea and the South Aral Sea.

The water drop affected the ecosystem in the The water drop affected the ecosystem in the lake, including the fish. lake, including the fish.

Many people relied on fishing for jobs. But as Many people relied on fishing for jobs. But as the water level dropped, the fish disappeared. the water level dropped, the fish disappeared. As a result, the lake’s commercial fishery no As a result, the lake’s commercial fishery no longer exists.longer exists.

PollutionPollution

Any Substance added to Any Substance added to the environment that the environment that produces a condition produces a condition that is harmful to that is harmful to organisms.organisms.

Solid waste pollution, Solid waste pollution, air pollution, and water air pollution, and water pollutionpollution

Air PollutionAir Pollution

One of the most important One of the most important pollutants is human-pollutants is human-produced carbon dioxide.produced carbon dioxide.

Cars, airplanes, power Cars, airplanes, power plants, and factories all plants, and factories all emit COemit CO22..

Increased levels of COIncreased levels of CO2 2

have caused global have caused global temperatures to rise, which, temperatures to rise, which, in turn, accelerates climate in turn, accelerates climate changechange

Water PollutionWater Pollution

Water can become Water can become polluted very easilypolluted very easily

Pollution enters water Pollution enters water sources in different sources in different waysways Point Source PollutionPoint Source Pollution Non-point Source Non-point Source

PollutionPollution

Point Source PollutionPoint Source Pollution

Enters the body of water Enters the body of water at a specific place from at a specific place from an identifiable source.an identifiable source.

Examples:Examples: Oil spills from tankersOil spills from tankers Waste water from a Waste water from a

factoryfactory Partially treated waste Partially treated waste

water from a sewage water from a sewage plantplant

Non-point Source PollutionNon-point Source Pollution

Enters bodies of water Enters bodies of water indirectly when water from indirectly when water from rain and snow travels over rain and snow travels over land and picks up pollutants land and picks up pollutants from many different sources from many different sources before entering a stream or a before entering a stream or a lake.lake.

Examples:Examples: Fertilizer and pesticide run-Fertilizer and pesticide run-

off from farmsoff from farms Salt run-off from roadsSalt run-off from roads

Invasive SpeciesInvasive Species

An invasive species is a An invasive species is a non-native species that non-native species that causes harm to the causes harm to the ecosystem into which it ecosystem into which it has been introduced.has been introduced.

They tend to They tend to outcompete native outcompete native species, often because species, often because they have to natural they have to natural predators or they predators or they reproduce fasterreproduce faster

Phython vs AlligatorPhython vs Alligator

http://www.youtube.com/watch?v=xfYAj1k9uhttp://www.youtube.com/watch?v=xfYAj1k9uZM&feature=results_video&playnext=1&list=ZM&feature=results_video&playnext=1&list=PLB961EB77F2635E84PLB961EB77F2635E84

Climate ChangeClimate Change

Climate is the average Climate is the average weather conditions in a weather conditions in a region over a span of 30 region over a span of 30 years or moreyears or more

When climate change When climate change occurs,occurs, Average temperatures may Average temperatures may

rise or fallrise or fall Amount of rainfall may Amount of rainfall may

increase or decreaseincrease or decrease General wind directions may General wind directions may

changechange

Review QuestionsReview Questions

List 5 services that we rely on ecosystems to List 5 services that we rely on ecosystems to provide.provide.

List 5 changes that human activity has caused List 5 changes that human activity has caused to ecosystemsto ecosystems

What is habitat fragmentation?What is habitat fragmentation? Name and describe two ways water can Name and describe two ways water can

become polluted.become polluted. Why do invasive species often fair well in Why do invasive species often fair well in

their new ecosystems?their new ecosystems?

HomeworkHomework

Read page 60-63Read page 60-63 Answer Questions #1-4Answer Questions #1-4