Chapter 6: Ecosystems

Chapter 6: Ecosystems

Lesson 6.1

Ecosystems

• is all the living and nonliving things in an area & their interactions
• The organisms in an ecosystem live in a habitat.
• Ecosystems contain biotic (living) and abiotic (nonliving) factors.

Types of Ecosystems

• There are many types of ecosystems
• Abiotic factors often determine what kinds of organisms live there
• Organisms living in an ecosystem have similar traits/characteristics
• Population is a group of organisms of one species that live in an area at the same time
• Different populations in an area make up a community.

Coral Reef

• Organisms living here have traits that help them live in warm, clear, shallow water
• A reef is made up mostly of skeletons of dead coral animals
• Some algae carry on photosynthesis, growing in shallow water where sunlight hits
• The coral reef can support the algae, which produce food for consumers
• examples: clown fish, anemones, sponges

Tropical Rain Forest

• Traits of organisms that live here help them survive in warm, rainy climate
• The shape of the leaves of some plants cause rain drops to fall off plants quickly
• The high amount of moisture in the air allows other plants, like orchids...
• ...to grow on trees, not in soil.

Desert

• Have little rain
• Most have hot days and cool nights
• Some deserts have sand dunes, others covered in salt
• Organisms living here have traits that survive hot, dry conditions
• Plants like cactuses, store water in their stems when it rains

Tundra

• Traits of organisms here survive cold weather with little rain
• Thick fur coats cover many of the animals that live here
• Most tundras are found in the most northern areas of Earth
• Rodents, rabbits, and caribou feed on small plants and grasses
• Weasels, polar bears, and foxes also live here.

Taiga

• Trees like fir, spruce, & hemlock live here
• Taiga has harsh, long, cold winters
• Most land has soil low in nutrients
• Squirrels, birds, insects eat berries & seeds
• Elk & moose eat tree bark & young plants

Mixed Forest

• Home to many types of trees & animals
• Oak, maple, & beech trees lose leaves in winter
• As leaves decompose, they return nutrients to soil
• Shrubs & small plants grow in the mixed forest
• Songbirds, deer, bears, & raccoons

Coastal Wetland

• In a wetland, water partly covers land during/part of the year
• Mangroves and some grasses can grow in salty water of wetlands
• Birds, snakes, and insects live here
• Coastal wetlands are found along the coast of the U.S.
• Characteristics of wetlands depend on geological location

Prairie

• Found throughout the Midwest & Great Plains
• Don't receive enough rain to support many large trees
• Have nutrient-rich soil, excellent for farming
• Produces tons of wheat, corn, soybeans
• Bison, coyotes, prairie dogs, and grasshoppers live here

Balance in Ecosystems

• Every organism in ecosystem has a niche & habitat
• Niche is the role an organism has in the ecosystem
• The niche of northern pygmy owl in mixed forest is hunter
• Habitat is a place where an organism lives
• It is made up of soil, air, water, and plants in an area

Lesson 6.2

Interactions in Ecosystems

• Ecosystems are made up of living and nonliving things.
• Living things in ecosystems interact w/ each other in many ways.
• Some organisms help one another meet their needs.
• Some may eat other organisms and get energy/nutrients from them.
• Some compete with one another for space or food.

Interactions in Ecosystems

• An animal that hunts and eats another animal is called a predator.
• Any animal that is hunted by others for food is called prey.
• The predator gets energy from the prey when the predator eats it.

Energy Roles in Ecosystems

Producers

• Producers make their own food for energy.
• Most producers use energy from the sun to make food.
• Some producers use chemicals from environment for energy.
• Producers either use energy to grow or store it for later.
• Plants and some other organisms are producers.

Consumers

• are organisms that cannot make their own food
• get their energy from producers or other consumers
• all animals and some microorganisms are consumers
• Several kinds of consumers, classified by what they eat

Consumers

• Herbivores eat plants only (ex. moose)
• Carnivores eat only other animals (ex. lion)
• Omnivores eat both plants & animals (ex. black bears)
• Scavengers are carnivores that feed on dead animals
• (ex. vultures & hyenas)

Decomposers

• are organisms that get their energy by breaking
• down wastes and dead organisms
• decomposers return materials to an ecosystem
• other organisms reuse these materials
• most decomposers can be seen w/ a microscope

Food Chains

• is a series of steps where energy moves from one living thing to another
• The shortest food chain involves only a plant and a decomposer.
• Other food chains involve a carnivore or an omnivore too.
• Arrows on a food chain show the path in which energy moves.
• Energy passes through an ecosystem when food is eaten.

Food Webs

• Is a diagram that combines many food chains
• There are many food chains in an ecosystem.
• Like a food chain, it uses arrows to show energy rel'ships
• Relationships among organisms can be complicated.
• Refer to page 221 of your book

Roles in Ecosystems

• Every organism has a niche in an ecosystem.
• A niche includes the type of food an organism takes in...
• ...how it gets its food, which other species use it as food.
• An organism may compete for the things it needs.
• (ex. soil, water, territory, mates)

Symbiosis

• is a long-term rel'ship bet. 2 organisms
• One organism is always helped.
• The other organism might be harmed, helped, or not affected.
• Parasite is an organism that lives on or inside of another organism.
• They take away nutrients where they live, which harms organisms.

Lesson 6.3

Environmental Changes

• An environment is all of the conditions surrounding an organism
• Environments may be hot or cold and on land or in water
• It changes naturally as resources change
• Populations change environments

Slow Changes

• Sometimes environments change very slowly.
• Ex. climate in a region may become drier over thousands of years
• This has happened in the Sahara, w/c has both wet & dry periods
• Seasons change slowly every year.
• Giving animals to grow winter fur & plants, new leaves.

Fast Changes

• Hurricanes, floods, fires, volcanic eruptions, earthquakes
• ...are natural events that can change the environment.
• A hurricane's strong winds can rip up trees, flatten plants.
• Lightning can strike a tree & start a forest fire.
• These rapid changes force species to leave the area.

Changes Caused by Organisms

• Organisms may alter the environment as they feed, grow, build homes.
• Ex. Locusts are insects that travel in large groups called swarms.
• They can quickly eat all the plants in large fields & destroy crops.
• Plants also cause changes. They affect the air quality for the entire planet.
• They absorb carbon dioxide from the air, & release oxygen back into atmosphere.

Changes Caused by Humans

• Humans are the most important cause of environmental change
• We change the land to plant crops, build dams to get energy,
• fish to get food, clear forests to get construction materials.
• We change the environment when we build buildings & roads.
• We must reduce the impact of our activity on the environment.

Adapting to Changes

• Changes that are harmful to some may be beneficial for others.
• Forest fire destroys trees & bushes w/c protect soil from being washed away
• It also adds smoke & carbon dioxide to the atmosphere, destroy habitats
• BUT it may also help organisms in a forest. It clears away dead and dying
• plant matter, making room for new plants to grow. Returns nutrients to soil.

Competition

• In any environment, resources are limited.
• The struggle of organisms for the same limited resources...
• ...is called competition.
• Organisms are more likely to survive if they are adapted to compete...
• ...for resources.

Survival

• In any species of plant or animal there are differences.
• Even a small advantage can help a plant or animal survive.
• Only the individuals that survive will be able to reproduce
• ...and pass along their beneficial characteristics to offspring.

Lesson 6.4

Pollution

• any substance that damages the environment
• It can affect air, water, and land.
• Cars & factories put harmful gases into the air.
• Chemicals may end up in rivers & oceans.
• People make trash.

Nonnative Species

• People may bring new plants & animals into ecosystems
• They often harm some populations in ecosystems.
• A nonnative species is a plant/animal that didn't naturally grow there
• Zebra mussels were accidentally brought to the U.S. in 1988
• They came attached to a ship from Russia.

Nonnative Species

• Once here, they spread in the lakes and rivers.
• They ate food and took the space that other species needed.
• These events changed some ecosystems permanently.

Regulation and Conservation

• Too much hunting or fishing can harm the environment
• Regulation puts limits on how many animals a person
• ...can hunt or fish.
• Conservation is an attempt to preserve or protect
• ...an environment from harmful changes.