Human Dependence on Earth

Human Dependence on Natural Resources

Middle School

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Learning Objectives

• Describe how the availability of resources affects populations of organisms.

• Explain how natural hazards and climate change can impact human society.

• Describe how technology influences the relationship between humans and the environment.

Key Vocabulary

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Photosynthesis

The process plants use to convert sunlight, water, and carbon dioxide into their food energy.

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Renewable Resource

A natural resource that can be replaced naturally and can be used over and over again.

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Nonrenewable Resource

A natural resource that cannot be re-grown or used on a scale that sustains its consumption.

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Sustainability

The ability of an environment to meet a population's needs now and into the future.

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Topsoil

The uppermost layer of soil, which is rich in organic matter and crucial for plant growth.

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Fossil Fuels

Natural fuels like coal or gas, formed from the remains of long-dead organisms over time.

Key Vocabulary

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Water Scarcity

The lack of sufficient available freshwater resources to meet the demands of a specific region.

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Strip Contour Cropping

A farming method where different crops are planted in alternating rows along the contours of the land.

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Our Fundamental Dependence on Earth

• All humans depend on the Earth to meet their most basic needs.

• ​These needs include food, water, clean air, fuel, and shelter.

• Photosynthesis provides the foundation for nearly all of the food we eat.

• This has shaped civilization, from nomadic tribes to the first farms.

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Multiple Choice

What is the most fundamental way that the Earth supports human life?

• By providing for basic survival needs.

• By offering locations for cities and roads.

• By creating interesting landscapes to explore.

• By supplying materials for modern technology.

Multiple Choice

What is the relationship between photosynthesis and the ability of humans to survive?

• Photosynthesis is the primary source for the food that humans need.

• Photosynthesis provides the fuel humans use for transportation.

• Photosynthesis creates all the clean air that humans breathe.

• Photosynthesis is the process that purifies all drinking water.

Multiple Choice

How did the human need for a reliable food source, like that from photosynthesis, most likely impact the development of early societies?

• It led to the development of farming and more settled communities.

• It caused all humans to remain in nomadic tribes.

• It reduced the importance of clean water and air.

• It stopped the development of new forms of shelter.

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Renewable vs. Nonrenewable Resources

• Renewable resources can be replaced naturally and used over and over again.

• ​Examples include solar energy, wind, geothermal heat, and trees for lumber.

• Nonrenewable resources form over millions of years and cannot be easily replaced.

• These include fossil fuels like coal, petroleum, natural gas, and various minerals.

Multiple Choice

What is the main difference between renewable and nonrenewable resources?

• The time it takes for them to be replaced.

• The amount of energy they can produce.

• Whether they are found underground or on the surface.

• Whether they come from plants or animals.

Multiple Choice

What is the importance of knowing that nonrenewable resources form over millions of years?

• It explains why some resources are limited and cannot be easily replaced.

• It shows that all underground resources are nonrenewable.

• It proves that fossil fuels are the only type of nonrenewable resource.

• It describes how to use renewable resources like solar and wind power.

Multiple Choice

Imagine a new type of wood is discovered from a tree that takes 500 years to grow to maturity. How would this resource be classified based on the definitions provided?

• It would be considered nonrenewable because it cannot be replaced quickly.

• It would be considered renewable because it is a natural material.

• It would be considered nonrenewable only if it is a fossil fuel.

• It would be considered renewable because it is not a mineral like iron or zinc.

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Sustainability and Resource Misuse

Sustainable Environment

• Sustainability is when an environment can meet the needs of its people now and in the future.

• This requires using natural resources like water, soil, and forests in a responsible and balanced way.

• A sustainable ecosystem remains healthy and productive for current and future generations to enjoy and use.

Resource Misuse

• Overusing resources can damage an ecosystem, making it unable to support its population long-term.

• The Maya civilization declined after clearing rainforests, which led to drought and loss of animals.

• People on Easter Island faced destruction after cutting down all their forests for homes and farmland.

Multiple Choice

What is the primary goal of sustainability?

• To ensure an environment can meet the needs of its people now and in the future.

• To use up natural resources as quickly as possible.

• To clear all forests for building homes and farms.

• To focus only on the needs of the current population.

Multiple Choice

What is the most likely long-term effect of overusing natural resources in an ecosystem?

• The ecosystem becomes healthier and more productive.

• The ecosystem may become unable to support its population.

• The number of natural resources available will increase.

• The needs of future generations will be more easily met.

Multiple Choice

Based on the patterns seen with the Maya and Easter Island civilizations, what can be predicted about a modern community that clears a large rainforest for farmland?

• The community will find new and better resources automatically.

• The loss of the forest ecosystem will likely lead to negative consequences for the community.

• The community will become more sustainable in the long term.

• The soil and water quality in the area will improve.

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Critical Resources: Water and Soil

Water Scarcity

• ​Although water covers most of Earth, only about 1% of it is available freshwater for our use.

• ​​Early civilizations, like those in Mesopotamia, were built near major rivers to ensure access to water.

• ​Today, water scarcity is a global issue that affects about one-fifth of the world's entire population.

Topsoil Depletion

• ​Topsoil is the most fertile soil layer and is considered a nonrenewable resource because it forms very slowly.

• ​​Poor farming practices can lead to the erosion of topsoil, as seen in the American Dust Bowl.

• ​Methods like strip contour cropping were developed to help protect valuable topsoil from being lost to erosion.

Multiple Choice

Why is topsoil considered a nonrenewable resource?

• Because it forms very slowly over time.

• Because it is the most fertile layer of soil.

• Because it is easily moved by wind and water.

• Because it is only found in certain parts of the world.

Multiple Choice

What is the relationship between human activities and topsoil loss?

• Poor farming practices can increase the rate of topsoil erosion.

• All types of farming help to create new, fertile topsoil.

• Farming practices only affect the layers of soil below the topsoil.

• Methods like strip contour cropping increase water scarcity.

Multiple Choice

What is the most likely challenge a society would face if it experienced both a shortage of fresh water and the depletion of its topsoil?

• It would struggle to produce enough food for its people.

• The amount of available freshwater would naturally increase.

• It would be easier to build new civilizations near rivers.

• The topsoil would quickly become fertile again on its own.

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Natural Hazards and Climate Change

Natural Hazards

• ​Natural events that change Earth's systems and can have a large impact on humans.

• ​​Some examples include earthquakes, hurricanes, and floods, which can sometimes be predicted by scientists.

• ​These events can destroy habitats and farms, and may even force human populations to migrate.

Climate Change

• ​This refers to the long-term change in the usual weather pattern of a region.

• ​​A small warming is causing significant impacts, such as melting ice caps and rising oceans.

• ​It is also causing changes in crop growth and the distribution of animal populations.

Multiple Choice

What is the definition of a natural hazard?

• A natural event that can significantly impact Earth's systems and human populations.

• A long-term change in the usual weather pattern of a region.

• An event that is caused exclusively by human activities.

• A process that only affects the migration of animal populations.

Multiple Choice

How does climate change impact Earth's systems?

• It causes long-term changes in weather patterns, leading to effects like rising oceans.

• It is a sudden event, like an earthquake, that scientists can sometimes predict.

• It only has a minor impact on the environment that is easily reversed.

• It is a type of natural hazard that only destroys habitats and farms.

Multiple Choice

What conclusion is supported by the information about both natural hazards and climate change?

• Both phenomena can damage food sources, affecting farms and crop growth.

• Climate change makes the prediction of all natural hazards easier for scientists.

• Only natural hazards can force human populations to migrate to new areas.

• The melting of ice caps is the primary cause of all major earthquakes and floods.

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The Role of Technology

Accessing Resources

• Technology helps people access essential resources to support growing populations and meet their daily needs.

• Ancient Romans built aqueducts to transport water over long distances for their cities and farms.

• Modern tools help us locate and extract important energy sources like oil and natural gas.

Mitigating Hazards

• Technology provides tools to help us prepare for and reduce the dangers of natural hazards.

• An early example is the Chinese seismoscope, an ancient tool used to detect distant earthquakes.

• Today, satellites help predict hurricanes, giving communities time to prepare and stay safe.

Multiple Choice

What is a primary purpose of technology for human societies?

• To help people access resources and reduce the dangers of natural hazards

• To create new types of energy sources and predict the weather

• To replace ancient tools like seismoscopes and aqueducts

• To allow populations to grow and to locate oil reserves

Multiple Choice

What do Roman aqueducts and modern tools for extracting natural gas have in common?

• Both are used to help people access essential resources.

• Both are ancient technologies for managing water.

• Both are modern tools for finding energy sources.

• Both are used to help communities prepare for natural disasters.

Multiple Choice

A coastal town is threatened by storms but also relies on the ocean for food. How could technology best be used to address this situation?

• By developing systems to predict storms and using tools to get food from the sea

• By relying only on ancient tools like the seismoscope to detect danger

• By using technology only to find a new source of water inland

• By building aqueducts to move ocean water to a safer location

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Common Misconceptions

Misconception	Correction
All the water on Earth is available for humans to use.	Only 1% of Earth's water is freshwater that is available for our use.
Soil is a renewable resource because it forms naturally.	Topsoil is nonrenewable because it takes thousands of years to form.
Climate and weather are the same thing.	Weather is the day-to-day change; climate is a long-term pattern.
Technology only helps humans use up resources.	Technology is also crucial for conservation and predicting natural hazards.

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Summary

• Humans depend on Earth's renewable and nonrenewable resources for survival.

• Sustainability is vital for managing limited resources like freshwater and topsoil.

• Natural hazards and long-term climate change significantly impact human populations.

• Technology helps humans access resources and protect them from natural disasters.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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• 2

• 3

• 4