Environmental Change

In this lesson, students evaluate the science phenomena of how organisms are affected when the environment changes. Students carry out an experiment to analyze two possible solutions that could be used to help a population of harpy eagles recover from the impacts of deforestation over time. This is a high-level extract of this lesson.

Science Background for Teachers:

Science background gives teachers more in-depth information about the topic students explore in this unit. Below is an excerpt from the background information on environmental change.

The need for energy and nutrients closely links organisms in a biome to one another and to their environment. An ecosystem is a community of different organisms that depend on interacting with each other and their physical environment for survival. Matter is continually cycling and energy is continually flowing in all ecosystems. All of the producers, consumers, and decomposers in an ecosystem are able to survive because they each have a specific function that contributes to the health of the ecosystem.

Because of this interconnectedness, if one part of an ecosystem changes, the whole ecosystem is affected. For example, the harpy eagle—one of the largest and most powerful eagles in the world— lives in Central and South America, particularly in the Amazon rainforest. A forest is an area of land covered by trees. It has become threatened by deforestation in the rainforest.

Deforestation is the removal of trees by humans. The loss of trees negatively impacts the harpy eagle, which needs large amounts of forest to hunt. It also affects its ability to build nests, which are usually found 27 to 43 meters (90 to 140 feet) above the ground. The nests are made of sticks and branches and are large enough to fit at least one adult human.

Another threat to the harpy eagle is hunting. This giant eagle does not have any natural predators. However, humans hunt the eagles because they see them as pests or for their plumage.

Scientists study harpy eagles because their presence indicates the health of the ecosystem. If the number of harpy eagles decreases, it tells scientists that something is wrong in the ecosystem. It could be that there aren’t enough animals for the eagles to consume. Or it could mean that there is a problem with the environment, such as polluted water or air.

Scientists are working to protect the harpy eagle through conservation. Conservation is the study of how to protect organisms and their ecosystems. Conservation aims to protect the organisms we share the planet with, while at the same time ensuring the survival of our own species. For example, scientists have learned that harpy eagles can survive in some environments that people have changed as long as there is enough food to eat, there are tall trees to nest in, and people don’t harm them.

One way to protect the harpy eagle is to prevent humans from cutting down large amounts of rainforests. Scientists are also following eagles in the wild to learn more about what, how, and where they hunt.

Supports Grade 3

Science Lesson: Discovering Environmental Change

Once students understand how organisms depend on one another and their environment for energy and nutrients, they analyze how a change in the environment will impact the organisms that live there. Specifically, they model how deforestation impacts a top predator of the Amazon rainforest, which affects the entire food web.

Science Big Ideas

  • Ecosystems are communities of different organisms that depend on interacting with each other and their physical environment for survival.
  • Scientists study harpy eagles because harpy eagles can indicate whether the ecosystem is healthy or struggling. The harpy eagle is a top predator in the Amazon rainforest.
  • If one part changes, the entire ecosystem will be affected because of its interconnectedness.

Sample Unit CTA-2
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Science Essential Questions

  • Why is an ecosystem a system?
  • Why are nonliving things important in an ecosystem?
  • Why do all ecosystems need producers?
  • What role does the harpy eagle have in the Amazon ecosystem?
  • Why does the harpy eagle eat other animals? Why does the harpy eagle need tall trees?
  • Why is it beneficial for harpy eagles to work together?
  • Why do scientists want to know if the number of harpy eagles in an ecosystem decreases?
  • How are harpy eagles affected by deforestation?
  • How does conservation seek to help the harpy eagle?

Common Science Misconceptions

Misconception: Ecosystems do not change much over time.

Fact: Ecosystems change for a variety of reasons, including environmental changes and human activity.

Misconception: The organisms in an ecosystem are not part of a larger whole, but instead are just a collection of living things surviving independently of one another and their environment.

Fact: Ecosystems are systems, made up of smaller interacting parts. Both the living and nonliving parts of an ecosystem influence the overall ecosystem.

Science Vocabulary

Biome : a specific geographic area with a particular climate that supports different kinds of organisms

Consumer : an organism that eats other organisms

conservation : the study of how to protect organisms and their ecosystems

Decomposer :an organism that breaks down organic material and feeds on the nutrients

Deforestation : removal of trees by humans

Ecosystem : a community of different organisms that depend on interacting with each other and their physical environment for survival

Energy : the ability to do work (move an object, heat up an object, charge an object, etc.)

Forest : an area of land covered by trees

Photosynthesis : the process of turning sunlight, carbon dioxide, and water into glucose and oxygen

Producer : an organism that captures energy from sunlight through a process called photosynthesis

Lexile(R) Certified Non-Fiction Science Reading (Excerpt)

The Harpy Eagle

The harpy eagle is one of the largest and most powerful eagles in the world. Its claws are the same size as a grizzly bear’s claws. Its wings stretch two meters (six feet) across. It can see much more than people can see.

Harpy eagles live in Central and South America. They are often found in the Amazon rainforest. Unlike some birds, the harpy eagle does not fly above the trees. Instead, harpy eagles fly between the trees of the forest. A forest is an area of land covered by trees.

They also build nests for their young high up in the tallest trees. The nests are sometimes made of up to 300 sticks and branches. They can be large enough to fit an adult human.


Forming Groups

Harpy eagles mate for life. This means that some harpy eagle pairs stay together for 30 years. They work together to raise their young.

The female harpy eagle lays one or two eggs. She then sits on the egg until it is ready to hatch. This usually takes about 55 days. During this time, the male harpy eagle hunts. He brings back the food he catches to the nest to feed the female. Once the egg hatches, this food will also feed the baby harpy eagle.

Working together helps the harpy eagles get food. They can also help each other defend their nest from predators. A predator is an animal that eats other animals. Animals that get eaten by other animals are called prey.

Not all animals mate for life. Some kinds of animals form larger groups. For example, ants form colonies where each ant has a job. Some ants get food for the colony. Some protect the colony. Some build tunnels. Others raise the young.


A Healthy Ecosystem

Scientists study harpy eagles because they are predators at the top of the food chain. Harpy eagles are carnivores. They consume many different kinds of animals. They eat monkeys, sloths, iguanas, large rodents, and other birds.

Scientists study harpy eagles. The eagles are part of an ecosystem. An ecosystem is a community of different organisms that depend on interacting with each other and their physical environment for survival. All of the different parts of an ecosystem depend on one another. A biome can be made up of many smaller ecosystems.

In the Amazon rainforest, the ecosystem includes all of the producers, consumers, and decomposers in the food web. It also includes nonliving parts. Nonliving parts include oxygen and carbon dioxide in the atmosphere. It also includes water and energy from the sun.


Hands-on Science Activity

In this lesson, students use a model of the Amazon rainforest to analyze how deforestation affects harpy eagle survival. Students investigate how two different solutions (reforestation and nesting towers) affect the survival of the harpy eagle in its environment. They also analyze how deforestation affects the forest ecosystem (the number of forest trees, prey animals, harpy eagles, and harpy nest sites). Students collect data by simulating how populations change over time and record in separate tables. Students then create bar graphs for the number of forest trees, prey animals, and harpy eagle population over three years in each solution. Students use the data they gathered in the experiment to explain which solution would best improve the survival chances of harpy eagles over time.

Science Assessments

KnowAtom incorporates formative and summative assessments designed to make students thinking visible for deeper student-centered learning.

  • Vocabulary Check
  • Lab Checkpoints
  • Concept Check Assessment 
  • Concept Map Assessment 
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Science Standards

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Download the Alignment to NGSS

Standards citation: NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.