In this activity you’ll describe what you think it might be like for humans to live in the extremes of the biosphere. Think about the challenges associated with living either underwater or in the upper atmosphere. Also, think about what humans might have to endure if the biosphere of Earth becomes inhospitable.

Humans live in a “comfort zone” close to the surface of the Earth, but there are many species that live outside of this comfort zone. What makes these regions different from the comfort zone we live in? What challenges would humans face if they chose—or were forced—to live in the extremes of the biosphere?

Study the image of the biosphere, and then make a list of 10 challenges that humans would face if they lived in the extremes of the biosphere.

Be prepared to share your ideas with the class.

In this activity, you will be assigned a mystery vocab word, and your job is to go around the room and ask enough questions of your classmates to try to figure out what the word is. You’ll have to use your questioning and deduction skills to figure out the word. In many ways, you are being asked to take context clues to help you figure out your word. This is a great way to determine if you really understand the words from the unit, or if you need more practice.

You are going to play the vocab game, “What’s My Word?” And, it’s exactly as it sounds—you’re going to be assigned a vocab word, but you won’t know what it is. Your job is to ask your classmates questions about your word until you correctly guess what it is.

Your teacher will explain how the game works. Once everyone is ready, your teacher will place a vocab word, written on an index card, face down on your desk. DO NOT LOOK AT THE WORD. Instead, when your teacher says “go,” hold up the card to your forehead, with the word facing out, and then go around the room asking questions until you’ve figured out your word.

Once your whole class has figured out their words, think about and discuss the following questions with your class:

1. What kinds of questions did you ask?
2. What types of questions most easily led you to figure out your word?
3. How might these types of questions help you figure out unfamiliar words that you encounter in the course?

Now that you’ve learned more about the emergence of life and how it evolved over time, you should revise your thinking about the Unit 5 driving question. Make sure you use the new information that you’ve learned to support your answers.

Unit 5 Driving Question: How does extinction drive evolution?

Use the DQ Notebook Worksheet – Unit 5 that you started in Lesson 5.0 to write about how we are still evolving.

The study of the biosphere, like the study of Big History, requires an interdisciplinary approach. Scientists study the biosphere from a variety of perspectives in order to monitor the conditions within it.

This article will introduce you to the biosphere and the reasons why this concept is important to life on Earth. The study of the biosphere is an interdisciplinary one that brings together a variety of scholars to understand its meaning and importance.

Skimming for Gist

The biosphere is the focus of important scientific research today. The study of the biosphere involves many different types of scientists focusing on a wide variety of topics. Some study the animals, plants, or cellular life found in the biosphere; some scientists use satellites to observe the surface of the Earth from a very broad perspective; still others study the very small scale, focusing on how various chemical elements impact the biosphere.

Understanding Content

As you read the article more carefully a second time through, think about the following questions.

1. What does the word biosphere mean and when was it first used?
2. Why was the word invented?
3. How is an ecosystem different from the biosphere?

Thinking Conceptually

What types of natural phenomena (astronomical, geological, and biological) can affect life in the biosphere?

Asteroid impacts, volcanic eruptions, and disease outbreaks can have dramatic consequences for living species in the biosphere. With this understanding of the variety of these impacts, you’re set to focus on one specific event later in the lesson: the extinction of the dinosaurs.

You’ve already learned that the biosphere is a relatively fragile area of the Earth, but this video will provide more detail about the factors that can affect the animals and organisms living here. In fact, there are some threats to life in the biosphere that you might be shocked to learn, including information about how the “wobble” of the Earth in its orbit can affect human existence.

Preview

The biosphere is a unique place. Under normal circumstances, conditions in the biosphere allow an incredible diversity of species to live and thrive, including humans. But astronomical, geological, and biological forces can change conditions in the biosphere, and scientists have recorded many examples of these changes over the Earth’s history. In some cases, these changes can be traumatic, devastating a large number of species and turning the biosphere from a very friendly to a very unfriendly place.

Key Ideas – Factual

Think about the following questions as you watch the video:

1. What makes the biosphere vulnerable to sudden changes?
2. How do the Earth’s orbit, axis, speed, and size impact the planet’s surface temperature?
3. How can the configuration of the continents impact the biosphere?
4. What were the conditions that led to “snowball Earth”?
5. What is the impact on the biosphere of the burying of carbon in the shells of dead sea animals?

It’s important to understand that even though life on Earth is closely connected, there are some important factors that distinguish species from one another.

You’re going to examine, in depth, a species of animal that’s familiar to you. Your teacher will provide a list of animals from which you can choose.

Once you’ve chosen your species, you’ll provide details on that species’ habitat, migration patterns, food sources, reproductive process, and challenges it might face from environmental and human factors over the course of one year.

Once you’ve completed the worksheet, your teacher may choose you to present to the class. If someone in the class presents on the same species you researched, and your answers are different from theirs, be sure to speak up! You should figure out if your findings conflict, or if you have a different level of detail, or something else entirely. Either way, it’s important to resolve those differences.

After everyone is done presenting, think about any common patterns that you saw across species. What are some big things that either distinguish them or make them seem similar?

The story of how scientists accumulated different types of evidence to prove the claim that the extinction of the dinosaurs resulted from an asteroid impact is a fascinating one. Extinctions like this one have happened throughout the Earth’s history, and have been the result of a variety of astronomical, geological, and biological forces. Many scholars believe that the Earth is currently in the midst of a sixth extinction event. This is a topic you’ll revisit in Unit 10.

Watch this video to learn about the evidence gathered by a team of geologists who proved how an asteroid was responsible for wiping out the dinosaurs. Your guide will be one of the lead geologists who made this discovery! If the asteroid had been less than an hour earlier or later, humans might never have existed.

Preview

Five major extinction events have been identified in the history of the Earth. The asteroid impact that led to the extinction of the dinosaurs was not the greatest of these disasters, but it is probably the best known. The claim that an asteroid made the dinosaurs extinct is a fascinating idea, but how do scientists prove a claim like this? In this video, Walter Alvarez, one of the key figures in the development of this evidence, tells how pieces of evidence were accumulated over the years to support this claim.

Key Ideas – Factual

Think about the following questions as you watch the video:

1. When Alvarez explored the clay between the Cretaceous and Tertiary rocks, what clue did the clay provide, and why were members of his team surprised by what they found?
2. What did Alvarez think about the energy of the asteroid impact and the effect it might have had on the biosphere?
3. Why was the claim that the dinosaurs became extinct because of an asteroid impact initially met with skepticism by some?
4. What was the second set of clues discovered by scientists to support the claim that an asteroid impact destroyed the dinosaurs?
5. What was the third clue found to support the claim that an asteroid impact destroyed the dinosaurs?
6. How is the development of the story of the asteroid impact that killed the dinosaurs an example of the scientific method at work?

Thinking Conceptually

How likely do you think it is that another astronomical event might impact life on Earth?