Human Effect on Ecosystems

Easter Island

The story of Easter Island k k k k

Ecosystems… Supply food, fuel, natural resources, and water. Supply food, fuel, natural resources, and water. Cycle nutrients and decompose wastes. Cycle nutrients and decompose wastes. Regulate climate. Regulate climate. Have animals that help pollinate crops and disperse seeds. Have animals that help pollinate crops and disperse seeds. Provide us with cultural and recreational opportunities Provide us with cultural and recreational opportunities

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

Human activity has caused… Habitat change Habitat change Overexploitation Overexploitation Pollution Pollution Invasive Species Invasive Species Climate change Climate change

Habitat Change The process by which humans alter a habitat enough so that the native species can no longer live there. The process by which humans alter a habitat enough so that the native species can no longer live there. Clear land for agriculture, forestry, and urban development. Clear land for agriculture, forestry, and urban development.

Habitat Fragmentation Small areas within a large region are altered a bit at a time Small areas within a large region are altered a bit at a time This creates a patchwork of altered and original habitats This creates a patchwork of altered and original habitats Ie. Southern Ontario used to be covered in deciduous forests. Now, forests are interspersed among fames, suburbs, and cities. Ie. Southern Ontario used to be covered in deciduous forests. Now, forests are interspersed among fames, suburbs, and cities.

Marine Habitat Change Habitat change can happen in the oceans too. Habitat change can happen in the oceans too. A fishing method called trawling drags nets along the bottom of the oceans to catch shrimp and bottom-dwelling fish A fishing method called trawling drags nets along the bottom of the oceans to catch shrimp and bottom-dwelling fish This disrupts the ecosystem by removing many producers from the food web as well as harming coral formations This disrupts the ecosystem by removing many producers from the food web as well as harming coral formations

Overexploitation Using a resource faster than it can be replaced Using a resource faster than it can be replaced ie. overfishing in Atlantic Canada ie. overfishing in Atlantic Canada Since the 1950’s, humans have removed an estimated 90% of large fish from the sea Since the 1950’s, humans have removed an estimated 90% of large fish from the sea

Overfishing in Canada In Atlantic Canada, cod used to very abundant In Atlantic Canada, cod used to very abundant Since the 1950’s the demand for cod grew and fishing technologies allowed us to catch more cod. Since the 1950’s the demand for cod grew and fishing technologies allowed us to catch more cod. Mature cod usually swim near the surface Mature cod usually swim near the surface When those were gone, fishing fleets began fishing deeper, where the younger fish are found. When those were gone, fishing fleets began fishing deeper, where the younger fish are found. The fish on which cod fed are also located at this deeper level. The fish on which cod fed are also located at this deeper level. By fishing deeper, the industry was, in effect, collecting the next year’s cod harvest as well as the cod’s food source. By fishing deeper, the industry was, in effect, collecting the next year’s cod harvest as well as the cod’s food source. In the 1990’s, cod fishing was stopped In the 1990’s, cod fishing was stopped Populations have yet to recover Populations have yet to recover

The Jellyfish Are Coming! GuE GuE GuE GuE TM TM TM TM

The Jellyfish Problem The overfishing of their natural predators, global warming, pollution, and a lack of jellyfish fishing by humans have caused a huge population boom for jellyfish. The overfishing of their natural predators, global warming, pollution, and a lack of jellyfish fishing by humans have caused a huge population boom for jellyfish. Jellyfish are mostly prey when they are eggs or very young. As they grow older, they actually move up the food chain and prey on fish. Now, there are actually millions more predators (jellyfish) adding to the fish population problem. Jellyfish are mostly prey when they are eggs or very young. As they grow older, they actually move up the food chain and prey on fish. Now, there are actually millions more predators (jellyfish) adding to the fish population problem.

Overuse of Water Overexploitation can also happen to non- organic resources Overexploitation can also happen to non- organic resources Canada has the world’s largest supply of fresh water and can look to the Aral Sea as a warning of the consequences of mismanagement Canada has the world’s largest supply of fresh water and can look to the Aral Sea as a warning of the consequences of mismanagement

The Aral Sea Once the 4 th largest lake in the world Once the 4 th largest lake in the world Government of the then Soviet Union decided to grow cotton and rice in the region Government of the then Soviet Union decided to grow cotton and rice in the region To irrigate the crops water was diverted from the two rivers that flowed into the lake. To irrigate the crops water was diverted from the two rivers that flowed into the lake. Slowly, the lake’s water level dropped and split the lake in two, creating the North Aral Sea and the South Aral Sea. Slowly, the lake’s water level dropped and split the lake in two, creating the North Aral Sea and the South Aral Sea. The water drop affected the ecosystem in the lake, including the fish. The water drop affected the ecosystem in the lake, including the fish. Many people relied on fishing for jobs. But as the water level dropped, the fish disappeared. As a result, the lake’s commercial fishery no longer exists. Many people relied on fishing for jobs. But as the water level dropped, the fish disappeared. As a result, the lake’s commercial fishery no longer exists.

Pollution Any Substance added to the environment that produces a condition that is harmful to organisms. Any Substance added to the environment that produces a condition that is harmful to organisms. Solid waste pollution, air pollution, and water pollution Solid waste pollution, air pollution, and water pollution

Air Pollution One of the most important pollutants is human- produced carbon dioxide. One of the most important pollutants is human- produced carbon dioxide. Cars, airplanes, power plants, and factories all emit CO 2. Cars, airplanes, power plants, and factories all emit CO 2. Increased levels of CO 2 have caused global temperatures to rise, which, in turn, accelerates climate change Increased levels of CO 2 have caused global temperatures to rise, which, in turn, accelerates climate change

Water Pollution Water can become polluted very easily Water can become polluted very easily Pollution enters water sources in different ways Pollution enters water sources in different ways Point Source Pollution Point Source Pollution Non-point Source Pollution Non-point Source Pollution

Point Source Pollution Enters the body of water at a specific place from an identifiable source. Enters the body of water at a specific place from an identifiable source. Examples: Examples: Oil spills from tankers Waste water from a factory Partially treated waste water from a sewage plant

Non-point Source Pollution Enters bodies of water indirectly when water from rain and snow travels over land and picks up pollutants from many different sources before entering a stream or a lake. Enters bodies of water indirectly when water from rain and snow travels over land and picks up pollutants from many different sources before entering a stream or a lake. Examples: Examples: Fertilizer and pesticide run-off from farms Fertilizer and pesticide run-off from farms Salt run-off from roads Salt run-off from roads

Invasive Species An invasive species is a non-native species that causes harm to the ecosystem into which it has been introduced. An invasive species is a non-native species that causes harm to the ecosystem into which it has been introduced. They tend to outcompete native species, often because they have to natural predators or they reproduce faster They tend to outcompete native species, often because they have to natural predators or they reproduce faster

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Climate Change Climate is the average weather conditions in a region over a span of 30 years or more Climate is the average weather conditions in a region over a span of 30 years or more When climate change occurs, When climate change occurs, Average temperatures may rise or fall Amount of rainfall may increase or decrease General wind directions may change

Review Questions List 5 services that we rely on ecosystems to provide. List 5 services that we rely on ecosystems to provide. List 5 changes that human activity has caused to ecosystems List 5 changes that human activity has caused to ecosystems What is habitat fragmentation? What is habitat fragmentation? Name and describe two ways water can become polluted. Name and describe two ways water can become polluted. Why do invasive species often fair well in their new ecosystems? Why do invasive species often fair well in their new ecosystems?

Homework Read page Read page Answer Questions #1-4 Answer Questions #1-4