Astrobiology in the Classroom

NASA – CERES Project –http://btc.montana.edu/ceres

Montana State University

Preliminary Edition

“Designer Genes for a Designer World”

In this series of guided inquiry activities, students explore how organisms adapt to their environments through changes in their genetic codes. In the first activity, students create make-believe creatures and environments that have specific characteristics that are determined by the students. Students then rate the success of each creature in a randomly assigned environment by examining which of the creature's characteristics help, hinder, or have no effect on the creature's success in each environment. In the second activity, students write the genetic code for their creatures from a list of fictitious genetic codes. Finally, students apply their knowledge of genetic codes and environments to engineer new creatures that could survive in various environments within our solar system.

Designer Genes for a Designer World

Part I

Activity #1

In this activity you will construct imaginary creatures and environments from the lists of characteristics below. Be creative since these creatures and environments do not have to behave like anything here on Earth.

A. As a group, you will need to decide which characteristics you want your imaginary creature to have. To do this first obtain a creature card from your teacher, then make a single choice from each of the 6 creature characteristics. Once you all have made your choices, fill out your creature card (including a name for your creature) and put it in the class creature box. Repeat this process two more times to construct two more creatures. Make sure you create significantly different creatures each time.

B. Obtain three environment cards from your teacher then follow the steps in part A using the environment characteristics to create an interesting environment. (Note: The environments you create in no way need to match the creatures you have already created.) Record your choices on your environment card and then put it in the environment box. Repeat part B two additional times, making sure that each environment you create is different.

Creature Characteristics

# 1: Respiration

a. uses oxygen (much like humans/animals) d. does not respire

b. uses methane gas e. uses carbon dioxide (much like plants)

c. uses sulfur dioxide

# 2: Temperature

a. lives in very cold environments ( like Antarctica )

b. lives in very hot environments (like desert, volcanoes, or hot springs)

c. lives in a temperate environment

# 3: Surroundings

a. lives mainly in water c. lives in a liquid other than water

b. lives mainly on land d. lives in an acidic/basic environment

# 4: Light Requirements

a. needs little or no sunlight to live

b. relies on sunlight to live

# 5: Food Source

a. eats other organisms as its food source

b. can make its own food from the sun

c. can make its own food from other sources, like minerals in the soil

# 6: Other

a. has the ability to dig c. can change colors

b. can run very fast like the roadrunner d. has a keen sense of smell and sight

Environment Characteristics

# 1: Atmosphere

a. none d. sulfur dioxide gas

b. methane gas e. oxygen

c. carbon dioxide

# 2: Temperature

a. very hot (like in a desert or volcano) c. very cold (like in Antarctica)

b. temperate (moderate temperatures year round)

# 3: Surroundings

a. primarily water (like an ocean) c. mainly land (no lakes/oceans/etc.)

b. very acidic/basic d. consists of methane lakes/molten lava

# 4: Light

a. little to no sunlight b. abundant sunlight

# 5: Food Source

a. mineral/nutrient rich soil d. no plant life/organisms

b. barren soil (no nutrients) e. plant life/organisms present

c. sunlight f. no sunlight

# 6: Other

a. fast predators c. multi-colored terrain

b. soft ground d. dimly lit, hard to find your prey

C. Once every group has finished filling out their creature and environment cards and put them in the appropriate box, pass the boxes around the room. Now it is time for your group to draw a single creature card and a single environment card from each box. This will be your first creature/environment pair to study. Once each group has drawn their first pair, each group will draw a second creature/environment pair. Repeat this process again so that each group has a third creature/environment pair.

D. Your group should now have three creature/environment pairs to study. In this portion of the activity, we want to determine the success of each creature in the environment with which it was paired. To do this we will compare each creature characteristic and environment characteristic one pairing at a time. Obtain a scoring worksheet from your teacher.

To score your creatures, use the following set of rules.

i. Award one point if the creature characteristic helps your creature survive in that environment. For example, if the creature characteristic chosen from group #1 is “uses methane gas” and the corresponding environment characteristic from group #1 is “methane gas”, then your creature would have earned one point.

ii. Award zero points if the creature characteristic and environment characteristic has no effect on your creature’s success. For example, if the creature characteristic chosen from group #6 is “has the ability to dig” and the corresponding environment characteristic chosen from group #6 is “multi-colored terrain”, then your creature would have earned zero points.

iii. Subtract one point if the environment characteristic restricts your creature’s ability to survive. For example, if the creature characteristic chosen from group #1 is “uses oxygen” and the corresponding environment characteristic from group #1 is “carbon dioxide gas”, then your creature would have lost one point.

E. Score each pair of creature and environment characteristics. Once you are done, record the total score on the provided scoring worksheet.

F. Would you rate the creature with the greatest score as having been very successful, moderately successful, not successful in its environments? Describe the success or failure of the interaction between the creature and its environment for each set of characteristics.

G. Give an example of an organism found on Earth that has a unique characteristic which makes it specifically suited to live in a particular habitat.

H. Sometimes the characteristic that an organism has that makes it successful in its natural environment becomes useless when the organism is placed in another environment. Describe a real creature and environment found on Earth that would be an example of this situation.

I. What one change would you make to your creature to make it more successful in the environment with which it was paired? Explain why you chose to make this change. If you feel no changes are needed for this creature, choose one of your less successful creatures to answer this question.

Part II

In the real world, we know that the physical characteristics we are born with are due to the genes we inherit from our parents. Human cells contain 46 chromosomes, 23 from each parent. Each chromosome contains several genes, which dictate how our bodies will look and behave. What truly distinguishes each of us from everyone else is our genes. For example, Susie has longer arms than her sister Sally. Chances are Susie has a different gene than Sally that has “programmed” her to have longer arms. Since humans have thousands of different genes, it is sometimes difficult to know which genes control particular features or functions of our bodies. That is why scientists started the Human Genome Project. The goal of this project is for scientists to work together to discover all the different genes in humans and to know their function.

Activity #2

A. We might imagine that each characteristic of your creatures is caused by a different gene. Using the chart below, write out the genetic code for the original creatures you created in Activity #1.

Creature #1:

Creature #2:

Creature #3:

Characteristic	Genetic Code
Uses oxygen	AAAA
Uses methane gas	CCCC
Uses sulfur dioxide	GGGG
Does not respire	TTTT
Uses carbon dioxide	ACAA
Lives in very hot environments	ACGA
Lives in very cold environments	AGCA
Lives in a temperate environment	CAGG
Lives mainly in water	CATT
Lives mainly on land	CACC
Lives in a liquid other than water	CAAA
Lives in an acidic/basic environment	CGAA
Needs little or no sunlight to live	GACT
Relies on sunlight to live	GACA
Eats other organisms as its food source	TACT
Can make its own food from the sun	TACG
Can make its own food from other sources, like minerals in the soil	TACA
Has the ability to dig	GGCG
Can run very fast like the roadrunner	TCAG
Can change colors	TGAC
Has a keen sense of smell and sight	GAGT

B. In question “I” of activity #1 you were asked which one change you would have made to your creature to make it more successful in its environment. Write out the genetic code of your creature as if it possessed these new characteristics.

C. Have one member of your group change one aspect of the environment used in the previous question. Describe how the creature would have to change in order to adapt to this environmental change. Write a new genetic code for the creature to reflect how it might change to adapt to its new environment.

D. As an environment changes over time we note that an organism evolves to adapt to those changes. On the cellular level, what is it specifically about an organism that must also change with time if the organism is to survive?

Part III

When an environment presents characteristics that make life difficult for a life form we often use the word extreme to label the environment. Obtain a set of planet and moon environment cards from your teacher. These cards list the characteristics of different extreme environments found in our solar system.

Activity #3

A. As a group, design a creature that could live in each of the planet/moon environments described on your cards. Fill out a creature card for each new creature and set it next to the corresponding planet or moon. Using the table of genetic codes write out the genetic make-up for each of your new creatures.

B. What characteristics of your creatures are similar to creatures found on Earth?

C. Are there characteristics that your creatures possess which are not found with creatures on Earth?

D. Which of these planets/moons do you think is most likely to already have living organisms on it? Explain your reasoning.

E. On which of the planets/moons do you think Earth-like life forms could survive? Explain why you think this.

F. If you were going to start a colony somewhere in the solar system, which planet/moon would be the most successful colonization site in your opinion? Explain your reasoning.

Scoring Worksheet

Names of group members: __________________________________________

Creature/Environment Pair #1: Names__________________________________

Creature Characteristics	Environment Characteristics		Score
Group #1	Group #1
Group #2	Group #2
Group #3	Group #3
Group #4	Group #4
Group #5	Group #5
Group #6	Group #6
		Total Score ®

Creature/Environment Pair #2: Names__________________________________

Creature Characteristics	Environment Characteristics		Score
Group #1	Group #1
Group #2	Group #2
Group #3	Group #3
Group #4	Group #4
Group #5	Group #5
Group #6	Group #6
		Total Score ®

Creature/Environment Pair #3: Names__________________________________

Creature Characteristics	Environment Characteristics		Score
Group #1	Group #1		1
Group #2	Group #2		1
Group #3	Group #3		1
Group #4	Group #4		1
Group #5	Group #5		1
Group #6	Group #6		1
		Total Score ®