How Do Humans Affect Ecosystems?

Humans Change Ecosystems

What are some ways humans change ecosystems?• Mining• Farming• Burn fossil fuels• Pollution• Burning coal

Humans Change Ecosystems

Burning coal releases sulfur dioxide, a gas that can travel on the wind for many kilometers. It can mix with water vapor in the air to form sulfuric acid. This acid travels through the air and falls in precipitation on forests and farmlands far from the original source. The acid damages the leaves and stems of trees and other plants. It can damage tree roots, making it harder for trees to get nutrients. The trees weaken and are more likely to die. Acid in precipitation has not only damaged forests. It has also harmed water ecosystems, killing fish in some lakes.

~Burning Coal ~ The Journey~

Humans Change Ecosystems

Burning oil doesn’t release as many gases as coal does. However, many people depend on oil shipped from faraway places, and sometimes there are spills from tankers, pipelines, and offshore wells. Those spills harm ecosystems, too. Chemicals in the oil can kill aquatic life. Lumps of oil often was up on shore and spoil beaches.

~Burning Oil ~ The Journey~

Burning coal releases sulfur dioxide, a gas that can travel on the wind for many kilometers. It can mix with water vapor in the air to form sulfuric acid. This acid travels through the air and falls in precipitation on forests and farmlands far from the original source. The acid damages the leaves and stems of trees and other plants. It can damage tree roots, making it harder for trees to get nutrients. The trees weaken and are more likely to die. Acid in precipitation has not only damaged forests. It has also harmed water ecosystems, killing fish in some lakes.

Burning oil doesn’t release as many gases as coal does. However, many people depend on oil shipped from faraway places, and sometimes there are spills from tankers, pipelines, and offshore wells. Those spills harm ecosystems, too. Chemicals in the oil can kill aquatic life. Lumps of oil often was up on shore and spoil beaches.

ActivityDraw one of these Journeys as a comic strip

Humans Change Ecosystems

Introduction of exotic plants and animals

• Exotic organisms is one that is not native to the ecosystem

Can be harmful because they have no natural enemies in the new area.

Exotic animal population goes up and crowd out native species

Humans Change Ecosystems

Most exotic species arrive by accident but some are introduced on purpose.

~Plant Journey~Kudzu, plant native to Japan and China, was planted in the USA to stop soil erosion. It spread out of control in many parts of the country. Many native plants have died because of competition from kudzu.

What are examples of other exotic species introduced to the USA?Africanized Honeybee – accidently released during breeding experiment

Asian Carp - brought into the United States from Asia to manage water quality and vegetation in catfish.

Asian Longhorned Beetle - entered the United States in wood pallets holding pipe shipped from China for a sewer project in the late 1980s

Brown Tree Snake – found recently in Hawaii. Undetermined how.

European Wild Boar - First brought to North America by Spanish explorers to be used as domestic pigs.

Red Imported Fire Ant - Thought to have hitched a ride to the United States in ship ballast from South America

Zebra Mussel - Catching a lift from Eastern Europe aboard freighters

http://www.pbs.org/wnet/nature/episodes/animals-behaving-worse/americas-least-wanted/911/

Florida PythonsAccidentally or intentionally released pythons are inhabiting dry as well as wet habitats, and feeding on or competing with native species. Giant pythons are well-adapted for success in Florida, where the habitat is similar to their Asian home. Although they are non-venomous, pythons are among the largest snakes in the world, reaching up to twenty-six feet long. Their size and power makes them one of the top predators in Florida’s Everglades National Park, taking on even the alligators, and posing a threat to many of the indigenous and endangered species.

Invasive Pythons in Florida

EXTINCTION

Loss of an entire species.• Can occur naturally but

introduction of species can increase rates by 100 to 1000 times natural rate

• Most common cause of extinction is habitat loss

one with so few individuals that it could die out.• Ex. Black rhinoceros,

African elephant, and Blue whale

• Species decreasing in number but not yet endangered are called threatened.

ENDANGERED SPECIES

Humans Change Ecosystems

Ecosystems in Danger

People constantly change Earth’s surface to meet their needs. They drain wetlands and cut down forests to make room for homes, roads, and shopping centers. They turn natural grasslands into farms, and they fill in bays to add more dry land to cities. But while these changes might be useful for some people, they harm or destroy ecosystems.

~The Story~

Ecosystems in Danger

Tropical rainforests• Once covered 6 million sq miles of Earth• Destroyed for farmland, fuel, exotic wood• Scientists estimate about 50% tropical

rainforests have been destroyed.

Ecosystems in Danger

Grasslands• Most disrupted ecosystem• Plowed for farmland due to fertile soil• 99% of tallgrass prairie is gone• Species decrease in number or disappear

entirely.

Ecosystems in Danger

Wetlands• Years ago most people thought wetlands

were useless• People drained and filled them for farm

land and homes• More than half of the original wetlands of

the USA are gone• Many wetland species are now

endangered

How can we help?

• Laws prevent pollution• Ecosystems protected by National

Parks• Restoration programs• Protect baby animals from predators

and dangerous human interactions• Endangered Species Act (ESA)

• Several species have been saved from extinction