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WorksheetsUnit 5 Review: Ecosystem Dynamics
Total questions: 27
Worksheet time: 42mins
What is an ecosystem?
Populations of organisms in their environment
All the organisms of the same or closely-related species
Two or more populations of organisms
Animals that hunt and kill others for food are ____?
Consumers
Predators
Producers
In an ecosystem, there are always:
the same number of predators as prey.
more prey than predators.
more predators than prey
SONORAN PRONGHORN: The Sonoran pronghorn, an endangered species in the Arizona desert, is the fastest land mammal in North America and feeds on desert plants. Increasing droughts in the region threaten their survival, especially affecting vulnerable fawns.
What factor is threatening the survival of the Sonoran pronghorn, especially affecting vulnerable fawns?
Increasing droughts
Predation by mountain lions
Habitat loss due to urbanization
Competition with other herbivores
Graybirds and whitebirds both live on North Island. Both types of birds eat the berries of the berry bush. The seeds of the berry bush grow best after the berries are eaten by birds and dropped elsewhere around the island.
Whitebirds are also found on nearby South Island. The whitebirds on South Island eat berries and the nuts of the nut tree.
Rats are found on both islands. The rats eat berries and bird eggs.
MATCHING: Identify an example of each type of ecosystem relationship.
competition
whitebird and greybird
predator-prey
rat and birds (eggs)
mutualism
whitebird and berry bush
Berry bushes need lots of rainfall. Which graph best predicts
what would happen to the populations on the North Island during a 10-year period of decreasing rain.
The graph shows that the (a) population decreases by half. This is because
there aren’t as many (b) for them to eat and the (c) eat more bird eggs because there are fewer
berries available. The bird population doesn’t drop as much as the berry population, though, because they are also able to eat (d) . This causes the population of nut trees to decrease as well.
Since the rats need to eat berries or bird eggs, their population goes (e) as the berries drop and
the ones left will eat more bird eggs.
If the Robins begin to disappear from this forest ecosystem, which other population would be likely to decrease?
caterpillars
hawks
bass
bears
What would likely happen to other populations in this food web if the algae began disappearing? Check all that apply.
The population of minnows would decrease.
The population of bass would increase.
The population of bears would decrease.
The population of robins would increase.
The population of caterpillars would decrease.
SCENARIO 1 - Freshwater Lake Fish: Rainbow smelt are a freshwater fish that can survive in a wide range of lake environments. When rainbow smelt were introduced to Crystal Lake in northern Wisconsin, they quickly changed ecological interactions in the lake. For example, they ate up much of the food preferred by other fish. They have nearly eliminated the yellow perch, another type of fish.
Which graph best shows this scenario?
GRAPH A
Graph B
GRAPH C
Graph D
Graph E
SCENARIO 2 - Marine Worms and Ocean Temperatures: A kind of scaleworm lives on sea stars in shallow ocean waters of the Pacific northwestern U.S. The population of the worms increases when water temperatures drop in winter, and then the population decreases as water temperatures rise through the summer.
Which graph best shows this scenario?
GRAPH A
Graph B
GRAPH C
Graph D
Graph E
SCENARIO 3 - Phosphorus and Algae Growth: Phosphorus is an abiotic substance needed by plants and algae to grow. When phosphorus levels in water rise due to sewage waste, the population of algae increases.
Which graph best shows this scenario?
GRAPH A
Graph B
GRAPH C
Graph D
Graph E
SCENARIO 4 - Canadian Lynx and Snowshoe Hare: The Canada lynx is a member of the cat family, not much larger than a house cat. In northern Canada, the lynx prefers to eat snowshoe hare. When the snowshoe hare population decreases, the lynx kittens are often unable to survive.
Which graph best shows this scenario?
GRAPH A
Graph B
GRAPH C
Graph D
Graph E
SCENARIO 5 - Oxygen and Fish Populations: Investigations of a fish population in a lake showed that it was able to survive some decrease in oxygen. But as oxygen levels continued to drop, the fish population decreased rapidly.
Which graph best shows this scenario?
GRAPH A
Graph B
GRAPH C
Graph D
Graph E
The graph shows the populations of 5 different species over a year. What effect did the loss of species B have on species A?
Species A's population decreased.
Species A's population increased.
Species A's population remained the same.
Species A went extinct.
Which species was not affected by the loss of Species B?
A
C
D
E
The Sumatran rhinoceros is a critically endangered animal that lives in the rainforests of Sumatra, Borneo, and the Malay Peninsula. It is estimated that there are fewer than 100 left. Which of the following are the most likely reasons that they are in danger of extinction?
Habitat loss and poaching
Climate change and pollution
Overpopulation and disease
Lack of food and water
The table shows the population size of 6 different species in four areas. Area (a) has the GREATEST biodiversity and Area (b) has the LOWEST.
D
Based on the graph, more snow causes the deer population to (a) .
What can you claim about wolves and moose based on the graph?
Wolves and moose have no impact on each other.
As the wolf population increases, so does the moose population.
A decrease in the wolf population causes an increase in the moose population.
Coyotes
In 1970, the moose population was (a) than the wolf population, so the wolves had (b) This caused their population to increase drastically. By 1980, the wolf population got so high that there (c) , so their population (d) . This caused the moose population to (e) .
Henry observed birds, bees, and cherry trees each spring for five years and created the model showing how they interact. Which claim is supported by his model?
The bees and birds are competing with each other.
The bees are a parasite to the cherry trees.
The birds prey on the bees.
The bees, birds, and cherry trees interact in a mutually beneficial way.
Julia learned in school that coral reefs have animals called corals and small plant-like organisms called algae that live there. Algae live inside corals and make them look colorful. She also learned that rising ocean temperatures are harming some corals in coral reefs. Julia visited coral reefs the following summer. When she dove under the water, she saw a pattern where in one area, the corals looked colorful and healthy while in another area, the corals were white and dead.
Julia created a model using what she knew about interactions between ocean temperatures, corals, and algae. She wants to use her model to try and understand the pattern she observed when she visited coral reefs in the summer.
The interaction between coral and algae is an example of ___.
competition
predation
parasitism
mutualism
What claim can you make based on Julia's model?
A rise in ocean temperature harms algae which therefore harms the coral.
A rise in ocean temperature helps algae which therefore harms the coral.
A rise in ocean temperature harms algae but has no impact on the coral.
A rise in ocean temperature harms coral but doesn't impact the algae.
Farmer Nelson is planting sunflowers on his farm. He wants to know how closely he can plant the sunflower plants to grow the most sunflower plants without affecting their growth. He knows that height and weight are used together to measure the growth of plants. Farmer Nelson has data on how the number of sunflower plants in the same area affects growth.
Based on the data, what is the maximum number of sunflower plants Farmer Nelson should plant per 10 square meters to get the most growth?
2 sunflower plants
3 sunflower plants
4 sunflower plants
5 sunflower plants
James observed different birds around his home, such as Eastern bluebirds, tree swallows, and starlings, living in trees. He decided to study their different interactions. James remembered in class that Eastern bluebirds and tree swallows compete for places to live (called nesting sites). In competing for these nesting sites, the tree swallows often win. The starlings do not compete for these nesting sites because starlings cannot fit inside the nesting sites of bluebirds and swallows.
Every day for 5 months, Peter observed and counted the Eastern bluebirds, tree swallows, and starlings in nesting sites around his house. Using this data he created a graph.
On the graph, which bird is which population?
Species A
Eastern Bluebirds
Species B
Tree Swallows
Species C
Starlings
Why do starlings not compete for the nesting sites of bluebirds and swallows?
They are just very generous birds.
They are too big to fit in the nesting sites of the other birds.
They don't find bluebird nests comfy enough so don't even bother.
They migrate to other areas instead.
A group of farmers heard that crop-eating insects called locusts are moving toward their farms. Sometimes millions of locusts travel together. The farmers are wondering how the locusts will affect their crops. The farmers have found a graph that shows what happened to the number of crops when millions of locusts arrived in nearby farms.
Using the graph, predict what will happen to the number of cotton crops if millions of locusts arrive in the farms.
The farmers' crops will eaten by the locusts and dramatically decrease.
Seed from the farmers' crops will be dispersed causing them to increase.
The farmers crops will not be impacted by the locusts at all.
Cassidy heard a news story about a new fish called Asian silver carp that has come into Lake Erie. In the news story, Cassidy learned that Asian silver carp eat small plants and animals. Even though Asian silver carp do not eat other fish, they are still causing the populations of some fish to change in the lake. She found a data table on the change in populations of three different fish after the Asian silver carp came into Lake Erie.
CLAIM: Shad and shiner fish have been (a) by the introduction of the Asian Silver Carp to Lake Erie, but Smallmouth Bass have (b) .
EVIDENCE: What evidence supports the claim?
Asian silver carp do not eat other fish.
Shiner have decreased by 35%.
Smallmouth bass have increased by 16%.
Shad have decreased by 20%.
Asian silver carp are a non-native species.
REASONING: The Asian silver carp is a species that has (a) Lake Erie. This has caused a (b) in the population of two other fish populations, Shad and Shiner. This is most likely because the Asian silver carp are (c) , small plants and animals. Shad, Shiner, and Asian Silver Carp are in (d) . The Smallmouth bass population has increased since the Asian silver carp arrived. This is because the bass can eat the Asian silver carp. Since the bass now has more food available to it, its population has increased. This is a (e) relationship.
Amelia noticed an increase in fire ants (insects) in her garden. She used a chemical to decrease the number of fire ants. She is wondering if the decrease in the fire ant population will affect the population of other insects in her garden, such as ladybugs and aphids (small insects). To figure this out, Amelia collected data on what the three insects eat and how their populations changed after she used the chemical to decrease fire ants.
CLAIM: Which claim is supported by the data Amelia collected?
A decrease in the fire ant population helps both aphids and ladybugs.
A decrease in the fire ant population helps aphids, but harms ladybugs.
A decrease in the fire ant population harms aphids, but helps ladybugs.
A decrease in the fire ant population has no impact on aphids or ladybugs..
EVIDENCE: What evidence supports the claim?
The ladybug population increased by 70%
The ladybug population decreased by 70%
The aphid population increased by 60%
The aphid population decreased by 60%
REASONING: Fire ants eat ladybugs, so when the fire ant population decreased by 90%, the ladybug population increased by 70%. This is a (a) relationship. The (b) , on the other hand, decreased by 60% when the fire ant population decreased. This means that the aphids must somehow benefit from the fire ants and are (c) when the fire ants disappear. Fire ants benefit from (d) made by the aphids, and although it doesn’t say exactly how the aphids benefit, they must be getting something in return. This is an example of (e) .
Cassowaries are in danger of extinction due to _______ ____.
(a)
What is the primary role of cassowaries in the rainforest ecosystem?
Seed disperser
Predator
Pollinator
Scavenger
What do you predict will happen if the cassowary goes extinct?
The population of poisonous fruits such as Cassowary Plum will increase since they aren't being eaten.
The population of poisonous fruits such as Cassowary Plum will decrease since they won't have anyone to disperse their seeds.
The population of fruits such as Cassowary Plum will stay the same since they are poisonous and can not be eaten.
