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Identikit of an alien

Created: 2024-12-08

Author(s):
Sandro Bardelli (INAF), Elena Zucca (INAF), Angelo Adamo (INAF)

What would an alien look like? Can we learn from terrestrial animals how they adapt to their environment and imagine how an alien would do the same in an extraterrestrial world? In this activity, you will imagine an alien world and its conditions (like gravity, star luminosity and presence of intelligence) and build the identikit of the alien that could inhabit it.

Materials

Power point presentation to be projected - attachment: Alien-Identikit-presentation.ppt or Alien-Identikit-presentation.pdf
Alien parts to be printed on A3 or A4 (see instructions below) - attachment: Alien-parts.pdf

If you are doing it as a group activity, using the blackboard:

Self-supporting display totem (suggested size: 40cm X 1.80 m). NOTE: you can also use the blackboard, attaching the pieces with tape.
Printed and precut alien parts to be attached on the Totem (see attachments, to be printed on A3, AlienIdentikit-AlienPieces.pdf)
Pins, tape, velcro or other to attach alien parts on the Totem or blackboard.

If you are doing it as an individual activity, having each student create his/her own alien:

One Printed alien part for each student - attachments: AlienIdentikit-AlienPieces.pdf , to be printed on A4
Scissors, tape and an A4 piece of paper to create your alien.

Image 1: the parts of your alien to be printed out

Goals

Developing the ability to make a reasonable hypothesis and test it
Thinking about life on Earth and understanding that it adapts to the planet's conditions
Imagining possible life forms of life inhabiting other planets
Environmental awareness.

Learning Objectives

Identifying the most important physical parameters for a planet to sustain life (gravity, atmosphere, energy from its star, temperature).
Identifying the common characteristics of life forms and learning the strategies adopted by animals to adapt to the environment.

Background

Life is an adaptive process. We know the conditions of the Earth, the only planet known to host life. Our bodies are adapted to the physical condition of Earth, like gravity, atmosphere, solar luminosity… This idea comes from the Darwinian theory: life forms on Earth evolve by adapting to the environment.

To date, many extrasolar planets (planets orbiting stars) are known. Just like on Earth, physical conditions like gravity, distance from the host star and the luminosity of the star are likely to constrain the form and the structure of living beings.

In our activity, we will consider only a few parameters influencing life:

Gravity:

Gravity is the force that makes us weigh, preventing us from flying away. See your weight on planets with different gravity. Gravity also limits the height of your jumps.
To know more about gravity and how it is related to weight:

http://www.exploratorium.edu/ronh/weight/

Intelligence

Scientists find it difficult to define intelligence and relate it to physical characteristics. They think that intelligence is not related to the size of the brain, otherwise whales should be more intelligent than humans, but to the brain size with respect to the body. Intelligence seems to be related to the ability to modify the environment (in other words to work).

Luminosity and temperature
The luminosity and the temperature on the surface of a planet are determined by its star and by the atmosphere composition. If the star is very bright and near, we will have high luminosity during the day. Alien eyes should adapt to this luminosity. A lot of extrasolar planets are detected around red dwarfs that are relatively faint with a low surface temperature.

The ability to communicate

The great majority of the most intelligent beings on Earth developed some form of language, like whales, monkeys, and dolphins. For this reason, we believe that also aliens should use a communication form but this is related to the characteristics of the home planet. Should be sound if the atmosphere permits an efficient transmission, or colours, lights, smells or other chemical signals.

Full Description

Before the activity

This activity can be done as a group activity, putting together your alien on a totem or the blackboard OR as a one-by-one activity where each student will create his/her own alien on an A4 piece of paper.

For the Group activity: prepare the Totem in front of the classroom or clean the blackboard to be used as a Totem. Print the alien parts on A3 heavy paper and cut them, preparing the parts to be attached on the Totem and the material to attach them (velcro, pins, tape or other). Be ready to use the presentation throught the activity.

For the individual activity: you don't need the blackboard/totem, but will need one printed A4 copy of Alien_parts for each student.

Image 2: students working on the individual version of the activity

During the activity
The teacher will use the powerpoint presentation to introduce the different topics, asking the questions and guiding the students to the defintion of the identikit.

Slide 1 Introduction to the activity

Guiding text for the teacher: How do you imagine an alien living on a distant, alien planet?
In this activity, we will consider humanoid bodies like ours, while keeping in mind this can be incorrect because we do not know exactly how life and intelligence emerged on Earth. We have to start only from what we know and make reasonable hypotheses that we will verify the day we discover aliens. At the moment, we haven't found life outside of Earth and scientists think that the most common life we will encounter in space are single-celled bacteria but…who knows?

Slide 2 what is an identikit?

Guiding text for the teacher: Normally the police draws a person based on what a witness says. Here we will build an alien body based on scientific hypotheses. We will imagine a planet with its properties and will predict some alien characteristics.

Slide 3 Introduction of the Darwin theory of evolution.

Guiding text for the teacher: Life is adaptive, all animals adapt to environment. Look at the following animals and discuss why they have those characteristics. Evolution: in a situation where the leaves are very high the giraffes with longer necks have advantages. They can eat more, live more and have more descendants. After some generations, almost all giraffes will have long necks.
The shape of sharks is adapted to be faster in water.
When in a population appears a character due to a mutation that permits the animal to eat more, live more and therefore to have more descendants (in other words to adapt better to the environment) this new population will expand with time and substitute the old population. Make examples with specific characteristics of known animals.

Image 3: some examples of animals on Earth

Slide 4 What about aliens from Sci-fi movies?

Guiding text for the teacher: Look at the following aliens and discuss which can be their environments. Possible answers or suggestions (not unique, the goal is the discussion)

For ET:
Big eyes ==> dark environment?
Long neck ==> savanna environment? Need to see above high grass?
short legs ==> no need to run from predators
For Bob the Blob:
No skeleton ==> low gravity, live in water (as the octopus)?
For Alien:
Note the characteristics of a predator (black, teeth…).

Slide 5 Let's choose the possible characteristics of our planet. Please note that choices can be done a-priori or decided togheter with students (depending on the size of the group).
Guiding text for the teacher: From here we have to choose the planet (and alien) properties. In particular:
Gravity: high or low gravity; intelligence: do we want the alien intelligent or not?; Surface luminosity (depending on the star luminosity and distance).

Slide 6 Discuss what is gravity.

Guiding text for the teacher: What is gravity? Planets with higher gravity have more mass and are larger. What would happen to you if gravity disappeared? If we double gravity, your weight will be larger? If gravity is higher (and you weigh more), what about jumps?

Slide 7 Calculating weight on different planets

Guiding text for the teacher: Calculate your weight on different planets using: https://www.exploratorium.edu/ronh/weight/

Slide 8: How high can you jump?

Guiding text for the teacher: After having discussed the weights on different planets, try to extrapolate the height of jumps related to gravity.
Predict your jumps on Earth, Jupiter, Pluto and comet 67P using: http://cosmos-book.github.io/high-jump/index.html

Slide 9 We choose our planet.

Guiding text for the teacher: Choose a planet and a name for it.

Slide 10 We choose the body structure of your alien and attach it to the Totem.

Guiding text for the teacher: What is the gravity of your planet? Is it strong or weak? The skeleton is the part of our body that resists gravity. If gravity is stronger than on Earth, how would the skeleton look like? Think about you when you carry a heavy weight: you tend to have a collected posture and to bend the legs. Bones and the body structure have to be more resistant and larger. Let’s choose the body structure and discuss the choice.

Slide 11 Let's discuss what intelligence is and choose the upper part of the skull.

Guiding text for the teacher: Let's try to define intelligence. You will discover that it is quite difficult (also for scientists). What are the “outward” signs of intelligence? Look at the picture with two beings, one with a big head and the other with a small one. Who is expected to be more intelligent? But the size of the brain is not the whole story. More important is the ratio between the brain and the total body. Think about the whales. So, let's decide on the upper part of the skull.

Slides 12-13 Intelligent life can modify the environment and to do this they need hands. Let's choose the hands of our alien.

Guiding text for the teacher: I landed on a planet, why can I say that aliens are intelligent? Because the environment has been modified. An intelligent being can modify the environment and to do this hands are needed!! Let's discuss what you can do or can’t do with the three types of hands of slide. I have to use a screw: is it better with tentacles (without bones inside) or with hands like ours? I have to write: better with tentacles, chelae or hands? I have to play guitar: which hands? Here there is no definitive answer between octopus and hands with finger. Probably octopus fingers are more efficient in water or a moist environment, where objects can slip away. Let's decide on the hands of your alien and put them on the Totem.

Slides 14-15 Each living being needs to receive information from the environment using its senses. Here we concentrate only on sight. Let's decide on our alien's eyes.

Guiding text for the teacher: Each living being needs to receive information from the environment using its senses. Here we concentrate only on sight. What kind of eyes do you know? Look at the eyes of owls, cats to highlight adaption to dark and luminosity. Are there eye differences among animals living during the day or by night? Can you predict which are the eyes of night animals in slide 14?
If Earth was nearer to the Sun, how would be the luminosity? How bright would it be for us? There are stars more and less luminous than the Sun (see http://www.astronomynotes.com/starprop/s4.htm by Nick Strobel).
So let's decide on our alien's eyes and put them on the Totem.

Slides 16-17 Let's discuss whether our aliens are good or bad and why.

Guiding text for the teacher: First of all, choose a name for our alien. Are you expecting this alien to be good or bad? Can we communicate with him? Make a role-playing game: one student is the first astronaut from Earth on the planet and another student is an inhabitant of the planet. What should the astronaut do to communicate with the alien?
How universal is your language? Is your gesture correctly understandable? Let's analyse some examples as the “peace gesture” of showing an open hand...that can be misinterpreted as “I give you a slap”.
So, let's decide on a mouth for our alien...

Image 4: some examples of aliens

Slide 18 Many other factors can modify your alien. A final discussion...

Guiding text for the teacher: Look at your alien and raise the following questions:
It has a shape similar to a human (2 legs, 2 arms…). Is this the only possibility? It could have a shape similar to other animals...
It might have other senses other than sight: can you imagine them? (hearing, touch, smell and taste and maybe others)
Consider a planet that is nearer to the Sun than Earth: is it colder or hotter? And what if the star is brighter than our Sun? How does our alien adapt to warm or cold weather?
What does this alien eat? Is it vegetarian, carnivorous or omnivorous?
The skin is green: what color can the skin of an alien be?
The alien is naked! Shall we choose some clothes for our alien (slide 19)?

There is a number of things we did not consider....

Evaluation

After the teacher-led discussion, each student can choose a planet and make his/her own alien identikit, explaining his/her choices.

Alternatively, the teacher can assign to student groups the planet's physical parameters, and the groups should prepare and explain the identikit.

Additional Information

As a further step, students can draw their own alien pieces with the colors they choose (always motivating the choice) and cover the body with clothes.

As an extension of the activity, they can also write or play a “first contact protocol”, i.e. what to do or not to do in case of an encounter with an alien’’.