Chapter 5: Interactions in Ecosystems
Lesson #1: What is an ecosystem?
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Ecosystem- is all the living and nonliving things in one area.
Population- is a group of organisms of one species that live in an area at the same time.
Community- is made up of all the population in an area.
Niche- is the role that an organism has in an ecosystem.
Habitat- is the place in which it lives.
A. Water, air, soil, temperature, and sunlight are some examples of nonliving parts of an
ecosystem.
B. The ecosystem is similar to your digestive system because they are both made up of all
parts that work together to meet the needs of all parts.
C. Biome- is a large ecosystem with generally the same climate, plants, and animals.
D. Trees like maple and spruce grow well in the dry, cool climate.
E. The spotted owl has the role of hunter in the temperate rainforest. It hunts and eats
small animals.
F. If no rain falls for several years, some organisms might leave because of less food or
others might not survive, and this will keep the habitat remain balanced.
Lesson #2: What are land biomes?
A. Some animals hibernate, while the fur color of other animals change to help them adapt
to colder temperatures.
B. Tropical rainforests are home to more species than any other biome.
C. If winter lasted year round, some animals would have difficulty surviving the continuous
cold. The food and water available might not be enough to sustain them.
D. Most of the grassland in the United States has been changed to farmland.
E. Fur and feathers help animals survive the cold taiga winters.
F. Plants in the desert would most likely have a large root system, close to the surface.
G. Gray wolves eat prairie dogs. If prairie dogs decrease in numbers and farmland
increases, gray wolves have to find food and space elsewhere.
H. Four limiting factors to a biome are: amount of water, space, food, and shelter.
I. Lack of water in a desert means that there are few plants, so grazing animals would
have little to eat.
Lesson #3: What are water ecosystems?
A. Swamps- are wetlands with trees and bushes.
B. Everglades- are wetlands with saw grass.
C. A river otter’s niche would be that it lives in a hole at the river’s edge. It eats small
mammals, fish, and frogs. It has a streamlined body that helps it swim and catch food in
and out of water.
D. Differences between river and wetland ecosystems would be speed and depth of the
water.
E. Creatures that live in the deep ocean need to adapt to high pressure.
F. A coral reef benefits from other organisms because it provides homes for many plants
and animals and protects shorelines from ocean storms.
G. If a lot of nutrients were introduced into the water, coral’s enemies would grow so the
coral might be harmed.
H. Bacteria that live near deep-sea vents and green plants are similar due to that they both
produce food for other organisms.
Lesson #4: How do organisms interact?
A. If an organism cannot compete it may die or may be forced to move away.
B. Desert animals might compete for plants to eat.
C. The kudzu might die out, or its growth might be slowed down if a competing organism
shared the same ecosystem.
D. Symbiosis- happens only between members of different species.
E. Competition- happens between members of the same species or members of different
species.
F. Cattle egret and the buffalo demonstrate symbiosis because the cattle egret feeds on
insects stirred up by the buffalo and the buffalo is not harmed.
G. It the parasite’s host dies, it has nothing left to feed on and will most likely die as well.
Lesson #5: How does energy move in ecosystems?
1. Energy pyramid- is a diagram that shows the amounts of energy that flow through each
level of a food chain.
A. Producers- are organisms that make their own food for energy. Examples are: acorn
trees, grass
B. Consumers- organisms that cannot make their own food. Examples are: lions, rabbits,
owls
C. Decomposers- eat waste or dead organisms. Example: fungi
D. If an organism dies before it is eaten, the dead organisms’ energy is passed on to
decomposers.
E. Carnivores obtain energy by eating animals.
Lesson #6 What cycles occur in ecosystems?
1. Cycle- is a repeating process or a repeating flow of material through a system.
A. Carpenter ants are considered to be decomposers because they chew through wood,
making dust, which is added to fertilizer.
B. If there were no decomposers, life would cease to exist because there would be no
materials cycled back into the soil.
C. Herbivores get nitrogen by eating plants.
D. Fewer nitrogen compounds would be available to move through food chains if lightning
did not exist.
E. Plankton in the oceans is the source for much of the oxygen in the atmosphere.
F. Trucks, cars, power plants, and volcanoes are major sources of carbon dioxide.
G. Burning and the formation of rust are alike in that both processes take oxygen from the
air.