Back to Details Unit Test - Ecosystems, Interactions, and Energy Open in Editor

Unit Test - Ecosystems, Interactions, and Energy

Grade 8 Science Unit Assessment

            📚 Science
                            🎓 Grade 8
                                        ⏱️ 45 minutes
                    

Learning Objectives

Describe how water is distributed on Earth and explain why freshwater is a limited resource
Explain the processes of the water cycle and the concept of residence time
Describe how surface and deep ocean currents form and affect climate
Explain how groundwater forms and moves, describe watersheds, and analyze human impacts on water quality
Explain photosynthesis using the equation CO2 + H2O + sunlight -> sugar + O2, model energy flow through food webs, and apply the 10% rule

1
Unit Test
                            ~45 minutes                        

Question 1

What percentage of Earth's total water is salty ocean water?

About 50% of all the water on the planet
About 71% of all the water on the planet
About 96.5% of all water on the planet
About 80% of all the water on the planet

Question 2

Where is MOST of Earth's freshwater stored?

In rivers, streams, and surface lakes
Deep underground inside aquifer systems
In ice caps and glaciers as frozen ice
As invisible water vapor in the atmosphere

Question 3

Less than 1% of Earth's total water is readily accessible freshwater for human use.

Question 4

What provides the energy that drives the water cycle?

Internal heat rising from Earth's core
The gravitational pull of the Moon
Energy from the Sun heating water
Wind generated by ocean circulation

Question 5

When water vapor condenses to form clouds, energy is:

Absorbed from the surrounding environment
Released into the surrounding environment
Neither absorbed nor released during this process
Converted from heat energy directly into matter

Question 6

Match each water cycle process with its description:

Question 7

Why is groundwater pollution considered especially dangerous compared to surface water pollution?

Groundwater flows much faster than any surface rivers or streams
Groundwater serves as the sole water source across the planet
Its long residence time means contamination lasts centuries
Groundwater sits too deep underground for any cleanup effort

Question 8

Arrange these water reservoirs from SHORTEST residence time to LONGEST:

[Unsupported question type: ordering]

Question 9

What is the PRIMARY force that drives surface ocean currents?

The gravitational pull of the Moon on the ocean
Persistent global wind patterns across the ocean
Differences in water temperature and its saltiness
The magnetic field generated by Earth's iron core

Question 10

The Coriolis effect causes moving objects in the Northern Hemisphere to:

Travel in perfectly straight lines across the globe
Curve to the left of their direction of motion
Curve to the right of their direction of motion
Sink directly downward toward the ocean floor

Question 11

What drives deep ocean currents, also called thermohaline circulation?

Strong persistent wind patterns blowing across the surface
Density differences caused by temperature and salinity
The Coriolis effect deflecting water at extreme depths
Underwater volcanic activity heating the deep ocean floor

Question 12

The Gulf Stream keeps Western Europe warmer than expected because it:

Pulls cold Arctic water far away from the European coastlines
Carries warm tropical water northward across the Atlantic
Pushes European landmasses closer to the equator than maps show
Reflects incoming sunlight energy back toward the European continent

Question 13

Upwelling brings warm surface water down to the deep ocean, making coastal fishing areas less productive.

Question 14

Put these steps of the global ocean conveyor belt in the correct order:

[Unsupported question type: ordering]

Question 15

What is the difference between porosity and permeability?

They are two different names for the exact same property
Porosity measures empty space; permeability measures flow ease
Porosity measures water quality; permeability measures quantity
Porosity applies only to rock; permeability applies to soil only

Question 16

What natural features define the boundaries of a watershed?

Roads, highways, and bridges that cross rivers
State, county, and municipal political borders
Ridges and hills forming natural drainage divides
The locations of dams, lakes, and water reservoirs

Question 17

Match each term with its correct description:

Question 18

How do impervious surfaces like pavement and buildings affect a watershed?

They help filter pollutants from rainwater naturally
They increase the amount of water soaking into soil
They increase runoff and carry pollutants to waterways
They have no measurable effect on water systems at all

Question 19

Which are functions of a HEALTHY watershed? (Select ALL that apply)

Absorbs rainfall and reduces flooding
Filters pollutants through soil and vegetation
Creates impervious surfaces to block water flow
Recharges groundwater through natural infiltration

Select all that apply.

Question 20

In a watershed, pollution released upstream has no effect on communities located downstream.

Question 21

In the photosynthesis equation, what are the REACTANTS (the substances that go IN)?

Oxygen and glucose are consumed by the plant
Carbon dioxide, water, and sunlight energy
Sugar and oxygen are combined with carbon
Glucose and carbon dioxide react inside cells

Question 22

In the photosynthesis equation, what are the PRODUCTS (the substances that come OUT)?

Carbon dioxide and water vapor are released as waste
Water and sunlight energy are stored inside the plant
Glucose (sugar) and oxygen are produced by the plant
Carbon dioxide and oxygen are both released as gases

Question 23

Which of the following are REQUIRED INPUTS for photosynthesis to occur? (Select ALL that apply)

Carbon dioxide (CO₂)
Oxygen (O₂)
Water (H₂O)
Sunlight energy

Select all that apply.

Question 24

In the photosynthesis equation (CO₂ + H₂O + sunlight → sugar + O₂), classify each substance as a REACTANT (input) or PRODUCT (output):

Question 25

In photosynthesis, producers convert ___1___ energy from the Sun into ___2___ energy stored in glucose.

Question 26

In a food web diagram, an arrow pointing from grass to a rabbit represents:

The rabbit provides energy or nutrients to the grass
Energy flows from the grass to the rabbit that eats it
The grass and rabbit compete for the same food source
The rabbit and grass share the same natural habitat

Question 27

If producers in an ecosystem contain 10,000 Joules of energy, approximately how much energy is available to secondary consumers?

About 1,000 Joules at the secondary level
About 100 Joules at the secondary level
About 10,000 Joules at the secondary level
About 10 Joules at the secondary level

Question 28

Match each ecosystem role with its function in energy flow:

Question 29

Place these organisms in the correct order of energy flow through an ecosystem:

[Unsupported question type: ordering]

Question 30

Why are there typically FEWER apex predators than herbivores in an ecosystem? (Select ALL that apply)

Only about 10% of energy passes to each higher trophic level
Less total energy is available to support life at the top
Predators voluntarily limit their own population sizes
Energy lost as heat at each level limits how many can survive

Select all that apply.

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