Unit Test: Ecosystem Dynamics

Question 1

Orangutans eat the fruit of rainforest trees and later drop the seeds in new places far from the parent tree, where the seeds can grow. This helps both the orangutans and the trees. What type of relationship is this?

Accepted Answer

Mutualism

Question 2

Which choice is the BEST example of an ecosystem service that people receive from a rainforest?

Accepted Answer

Bees from the forest pollinating nearby crops

Question 3

A class modeled an orangutan population in a forest area over several years. Use the data table below to answer the question. Which statement BEST explains the pattern in the data?

Accepted Answer

Fewer fruit trees meant less food, so fewer orangutans survived.

Question 4

A student's investigation counted bird species in three land types of equal size near a rainforest. Use the graph to answer the question. Figure: Bird Species Counted by Land Type — Bar graph showing number of bird species: rainforest 60, mixed crop farm 34, oil palm monoculture 9. — Rainforest: 60 · Mixed crop farm: 34 · Oil palm monoculture: 9 Which conclusion is BEST supported by the data?

Accepted Answer

Monoculture farms support the fewest bird species of the three.

Question 5

A community must choose a farm design for land next to a rainforest. Use the sample data from a model in the table below. The goal is to protect orangutans and biodiversity while still supporting farmers' incomes. Which design BEST meets ALL of these criteria?

Accepted Answer

Design B, because it balances income and habitat

Question 6

A monoculture farm grows one crop, such as oil palm, over a large area of land.

Accepted Answer

true

Question 7

Orangutans eat fruit and later drop the seeds in new places. This helps fruit trees spread, so orangutans and fruit trees both benefit from their relationship.

Accepted Answer

true

Question 8

A class modeled the orangutan population in a forest patch as the number of fruit trees changed. Use the table to answer. The model shows that as fruit trees decreased, the orangutan population also decreased.

Accepted Answer

true

Question 9

Figure: Species Counted on Two Farms (Sample Survey) — Bar graph comparing species counts on two farms: the mixed-crop farm has 34 bird, 21 insect, and 12 mammal species; the monoculture farm has 11 bird, 9 insect, and 3 mammal species. — Birds: Mixed-crop farm 34, Monoculture farm 11 · Insects: Mixed-crop farm 21, Monoculture farm 9 · Mammals: Mixed-crop farm 12, Monoculture farm 3 A student's sample survey counted animal species on two kinds of farmland. According to the graph, the monoculture oil palm farm supports more bird species than the mixed-crop farm.

Accepted Answer

false

Question 10

If orangutans went extinct in a rainforest, the fruit tree species whose seeds they spread could become less common over time, which could affect other animals that rely on those trees.

Accepted Answer

true

Question 11

Define the term BIODIVERSITY. Then name TWO ecosystem services that people receive from a rainforest, and explain why each one is helpful to people.

Accepted Answer

Biodiversity means the variety of different species living in an ecosystem. One ecosystem service is pollination, which helps people because insects and bats pollinate crops so farmers can grow fruit and other food. A second ecosystem service is nutrient recycling, which helps people because decomposers break down dead material and return nutrients to the soil so plants and crops can grow.

Question 12

Figure: An orangutan eats fruit in a rainforest tree while a young fruit tree seedling grows in a sunny patch some distance away. (labels: 1 the orangutan, 2 the fruit tree, 3 the young seedling) The picture shows an orangutan in a rainforest and a young fruit tree growing in an open area. Describe the relationship between orangutans and fruit trees. Explain how EACH organism benefits, and name the type of relationship.

Accepted Answer

Orangutans benefit from fruit trees because the fruit gives them food and energy. Fruit trees benefit from orangutans because the orangutans eat the fruit, travel, and drop the seeds in their waste far from the parent tree, so new seedlings like the young seedling can grow in new places without competing with the parent tree. This type of relationship is called mutualism because both organisms benefit.

Question 13

A class modeled how the number of fruit trees in a section of forest affects the number of orangutans that section can support. Sample data from the model are shown below. Describe the pattern in the data. Then explain why the orangutan population stops increasing between 40 and 50 trees per km², using the idea of resources.

Accepted Answer

As the number of fruit trees increases from 10 to 40 per km², the number of orangutans increases steadily from 0.5 to 2.0 per km², because more trees provide more food. Between 40 and 50 trees, the population stays at 2.0. The population stops increasing because food is no longer the limiting resource; another resource, such as space for each orangutan's home range or nesting sites, now limits how many orangutans can live there.

Question 14

Figure: Animal Species Found by Land Type (Model Data) — Bar graph showing 120 animal species in intact rainforest, 70 in an agroforestry farm, and 25 in an oil palm monoculture. — Intact rainforest: 120 · Agroforestry farm: 70 · Oil palm monoculture: 25 A student's model compared the number of animal species found in three types of land in the same region. Use the graph to compare the oil palm monoculture with the agroforestry farm and the rainforest. Then explain HOW replacing rainforest with an oil palm monoculture causes this change in biodiversity, and predict ONE effect on a population that depended on the lost species.

Accepted Answer

The graph shows that the oil palm monoculture has 25 species, compared with 70 in the agroforestry farm and 120 in the rainforest, so it has the lowest biodiversity. This happens because a monoculture grows only one plant, so animals lose the variety of food, shelter, and nesting sites they need, and many cannot survive or must leave. One population that could be affected is fruit trees, because if seed-dispersing animals like orangutans or birds disappear, fewer seeds get carried away and fewer new fruit trees grow.

Question 15

A community is choosing between two farm designs for land next to a rainforest. A student's model produced the sample data below. Evaluate BOTH designs. Decide which design better meets the needs of BOTH farmers and orangutans. Support your argument with at least TWO pieces of data, and describe ONE trade-off of your chosen design.

Accepted Answer

I think Design B is the better solution because it supports both people and wildlife. The data show that Design B supports 0.8 orangutans per km² while Design A supports 0, and Design B has 45 bird species compared with 15, so it protects biodiversity and ecosystem services like pollination and pest control, which is why it needs fewer pesticides. One trade-off of this design is that farmers earn $400 less per hectare per year ($1,600 compared with $2,000). However, farmers could sell fruit from the extra trees, and they would spend less on pesticides, which could help make up the difference.

Question 16

Figure: A rainforest with an orangutan eating fruit in a tree, a stream, sunlight through the canopy, and soil on the forest floor. (labels: 1 the orangutan, 2 the fruit tree, 3 the stream, 4 the sunlight, 5 the soil) The picture shows part of a rainforest ecosystem. Identify TWO living (biotic) parts and TWO nonliving (abiotic) parts of the ecosystem. Then describe ONE way a living part depends on a nonliving part.

Accepted Answer

Two living parts of this ecosystem are the orangutan and the fruit tree. Two nonliving parts are the sunlight and the stream. The fruit tree depends on sunlight because it uses light energy to make its own food through photosynthesis. It also takes in water and nutrients from the soil to grow and make fruit.

Question 17

A class modeled the number of orangutans that could live in four sample forest areas of the same size. Use the data table below. Describe the relationship between fruit trees and the orangutan population. Explain WHY resource availability causes this pattern.

Accepted Answer

As the number of fruit trees increases, the orangutan population increases. Area A has 5 fruit trees per hectare and only 2 orangutans, while Area D has 30 fruit trees and 12 orangutans. This happens because fruit is the orangutans' main food resource. When more food is available, more orangutans can get enough energy to survive and reproduce, so the area can support a larger population. With few trees, orangutans compete for limited food and fewer survive.

Question 18

Orangutans eat fruit from rainforest trees and later drop the seeds far away in their waste, where new trees can grow. Explain what type of relationship this is and how BOTH the orangutans and the fruit trees benefit. Then predict what would happen to the fruit tree population if orangutans went extinct.

Accepted Answer

The relationship between orangutans and fruit trees is called mutualism. The orangutans benefit because they get food and energy from the fruit, and the trees benefit because orangutans carry their seeds to new places where they can sprout without competing with the parent tree. If orangutans went extinct, the fruit tree population would decrease over time because fewer seeds would be spread to new areas. Fewer new trees would grow, which could also hurt other animals that depend on those trees.

Question 19

A student's model compared the number of species found on two types of farms of the same size. Figure: Species Found on Two Farm Types (Model Data) — Grouped bar graph comparing species counts: the monoculture oil palm farm has 4 bird, 6 insect, and 2 mammal species; the diverse agroforestry farm has 18 bird, 35 insect, and 9 mammal species. — Birds: Monoculture 4, Agroforestry 18 · Insects: Monoculture 6, Agroforestry 35 · Mammals: Monoculture 2, Agroforestry 9 Use the graph to compare the biodiversity of the two farms. Then explain how ONE ecosystem service (such as pollination or nutrient cycling) might differ between them and why this matters to farmers.

Accepted Answer

The agroforestry farm has greater biodiversity because it has more species of every type, including 35 insect species compared to only 6 on the monoculture farm. One ecosystem service that would differ is pollination. With many more insect species, the agroforestry farm likely has more pollinators like bees, so crops produce more fruit. This matters to farmers because better pollination means larger harvests and more income without paying extra costs.

Question 20

A community wants to grow oil palm to support farmers' incomes, but the land is next to rainforest where orangutans live. Two designs are proposed: Evaluate both designs. Argue which design better balances the needs of farmers AND orangutans. Support your argument with evidence about resources, biodiversity, and ecosystem services, and describe ONE trade-off of your chosen design.

Accepted Answer

I argue that Design 2 is the better solution because it supports both farmers and orangutans. Design 1 removes all of the forest, so orangutans would lose their food and space, and their population would decline or disappear. Monoculture also lowers biodiversity, reducing ecosystem services like pollination and nutrient cycling, so farmers may need more fertilizer and pesticides over time. Design 2 keeps 40% of the forest and adds fruit trees, giving orangutans food resources, and the corridors let them travel to find mates and food. Greater biodiversity provides pollinators and healthier soil, which keeps farmer income stable. One trade-off of this design is that farmers earn less money at first because they grow fewer oil palms on the land.

Year	Fruit Trees in Area	Orangutans in Area
1	1,200	40
2	1,150	39
3	800	31
4	500	20
5	480	18

Unit Test: Ecosystem Dynamics

Part A: Multiple Choice

Part B: True / False

Part C: Short Answer

Part D: Essay / Extended Response

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