5.3 - Ways of Knowing: Life - islandschoolhistory

Lesson Purpose

Life first appeared on Earth around 3.8 billion years ago - not long after the Earth itself - and life forms have been changing and diversifying ever since. How is it possible for scientists to know about the history of life? What methods do they use to study life and how has it evolved over time? The methods scientists use to reconstruct the story of living things and how they change over time also change over time. New techniques and instruments are constantly being developed to look more deeply into the world of cells and DNA.

The outcomes of this lesson are: 1.) To use evidence to explain adaptation and evolution, including Darwin’s theory of natural selection and DNA.

Activity 1 - The Voyage of the Beagle

Activity Objectives
Charles Darwin’s work was critical to the development of evolutionary thinking, and his claims about how species change over time were fuelled by his experiences as a young man on a research ship called the HMS Beagle. In this activity, you will learn how to interpret images and maps in order to extract information about Darwin’s trip to the Galapagos Islands.

Activity Tasks

Working in pairs, examine the images on the image gallery and read their captions.
First look at the first four images (Route of HMS Beagle, Charles Darwin, Tierra del Fuego, Galapagos Islands) and answer these questions:
1. What information do these images provide about the voyage Darwin made and the kinds of ecosystems he explored?
Now look at the last two images (Ancient Animals of Argentina and Galapagos Finches) and answer these questions:
1. Why might someone in Darwin’s time be surprised to find fossils of extinct animals?
2. How did Darwin explain the fact that there were different types of finches, with different beaks, on each of the islands of the Galapagos?

Activity 2 - 'Darwin, Evolution, and Faith'

Activity Objectives
You will learn about the relationship between faith and science with particular focus on evolution and Darwin’s struggle to publish his work on natural selection.

Activity Tasks

Read the article 'Darwin, Evolution and Faith' and answer the following questions:
1. How can Darwin’s theory of natural selection frighten some belief systems while it strengthens faith in others?
2. John Haught suggests that there are three approaches to understanding the relationship between evolution and religion: conflict, contrast, and convergence. How does Haught describe each of the three approaches?
3. Can you think of other approaches to the relationship between evolution and religion besides the three that Haught identifies?
4. Discuss - Are religion and science, which take different approaches to knowledge, destined to always be in conflict?

Activity 3 - 'Crick, Watson, & Franklin'

Activity Objectives
In order to understand the characteristics of life, you must learn about the importance of DNA. This article explains how scientists built upon collective learning to discover the structure of DNA.

Activity Tasks

Read the article, 'Crick, Watson. & Franklin' and answer these questions:
1. What are the components of DNA?
2. Scientists in the 1950s were convinced that DNA held the instructions for creating new organisms but what key piece of evidence was still a mystery?
3. Rosalind Franklin, Francis Crick, and James Watson are all described as biochemists, but they relied on different methods for determining the structure of DNA. Franklin used x-ray crystallography. What is x-ray crystallography, and what clues did it provide about the structure of DNA?
4. Watson and Crick built models. What were their models like, and what clues did they provide about the structure of DNA?
5. How did the discovery of the structure of DNA provide evidence for Darwin’s theory of natural selection?
6. Discuss - How is the discovery of DNA and its structure an example of collective learning?

Activity 4 - Codes H2

Codes provide the instructions for life, chemistry, and technology thus connecting the Big History thresholds of new chemical elements, life, and the Modern Revolution.

Activity Objectives
Everything around us is equipped with a code, whether it’s used to program a computer, create a chemical formula, or provide instructions for the replication of cells in a living organism. Codes are as important to biology as they are to technology.

Activity Tasks

Watch the video and try to answer these questions:
1. 0:49 What do computer viruses and biological viruses have in common?
2. 1:30 How have codes changed warfare?
3. 2:24 How are computer codes similar to living organisms?
4. Discuss - How is DNA both incredibly simple and complex at the same time?

Activity 5 - Evolution and Life Timeline

Activity Objectives
You should have been creating timelines regularly at this point in the course, and you should be getting the hang of them and the ways in which they can be useful. Creating timelines adds another dimension to your understanding by providing yet another way to contextualize and understand content. This type of analysis is different from those used when reading, watching videos, or having class discussions.

Activity Tasks

You should have been keeping a timeline that records all the key scientists and their ideas.
Add Darwin, Watson, Crick, and Franklin to your timelines.
Now write a paragraph explaining the following question: 'How has our understanding and acceptance of scientific concepts related to life changed over time?' The following idea may help your answer:
1. What did the scientists that came after Darwin add to our understanding of life?
2. Does it seem like our acceptance of scientific concepts related to life and evolution has changed over time?
3. How does adding these people (and others) to the timeline help them understand changes in scientific thinking?

Investigation 5 - How does Extinction Drive Evolution?

Investigation Objectives
In this Investigation, you will evaluate how extinction events relate to the evolutionary process. You will revisit concepts like adaptive radiation, biodiversity, and niches. What happens in the immediate aftermath of an extinction event when organisms are exterminated and their niches are left empty? How do habitats, which were once teeming with webs of life, recover, only to support new webs, unique and different from the first? What determines which organisms survive events like asteroid strikes or extreme volcanic activity? These are only a few of the very important questions that remain after a disaster in biodiversity.

Investigation Tasks
You will write a 4-5 paragraph essay on the question: 'How does Extinction drive Evolution?', using past extinction events as your case studies. Complete the following steps to finish your investigation:

Firstly, look back at your DQ Notebook for the question: 'How does extinction drive evolution?'. Gather your initial thoughts on this question by thinking about not only what causes major extinction events, but also what is left in their aftermath. How could the resulting conditions contribute to the evolutionary process?
Now download and complete this research table. Use your own knowledge and the internet links to help you. This table will help you to structure your essay.
Now analyse the ten texts in this research library, and complete these research cards for each text. These texts will help provide evidence for your essay and help you to notice the relationships between extinction and evolution.
Finally, using your research you can begin to write the essay. Remember to use Big History ideas and key words, support your thinking with logic and evidence, and don't forget a final conclusion that gives a judgement on the question.

Challenge Yourself! - Optional Activities

1. The HMS Beagle Project is modern version of the sailing ship that carried Charles Darwin on the famous sea voyage.
2. A caricature of Charles Darwin captures the "men from monkeys" controversy that followed publication of The Descent of Man.
3. In 2003, The Human Genome Project completed a massive scientific research project that sequenced all three billion chemical units that make up human DNA.
4. "Great coders are today's rockstars." -will.i.am

TAKE THE QUIZ!