INTRODUCTION TO USERS:

Welcome to your first learning and activities in Earth and Life Science 11! Prepare yourself as we dive into our main topic, entitled "Uniqueness of the Planet Earth." I know that you are knowledgeable about your own home and its importance. But, this worksheet will help you appreciate further our planet Earth for its unique characteristics that make it possible to sustain life.

In this worksheet, you will be introduced to the different factors or reasons why the Earth can sustain life. This is followed by activities that will increase your awareness of the planet where you live and help you think of ways to take good care of it. This may not be a skill for you to apply, but this will help you understand our planet's importance to you and the next generation.

LEARNING AREA: Earth and Life Science 11 Quarter: One

MOST ESSENTIAL LEARNING COMPETENCIES:

At the end of this module, you should be able to a) recognize the uniqueness of Earth, being the only planet in the solar system with properties necessary to support life; and, b)explain that the Earth consists of four subsystems, across whose boundaries matter and energy flow.

INTRODUCTION TO THE LESSON:

Specific objectives:

At the end of this topic, you should be able to: a) identify the characteristics of the planet Earth that made it the only planet in the solar system that can sustain life; b) recognize the difference in the properties between the Earth and its neighboring planets; and, c)explain the interconnectedness of the four subsystems of the planet Earth.

Factors or Criteria that make a Planet Habitable

Read and understand carefully the following criteria for a planet to sustain life and evaluate each planet in the solar system. In this case, you can understand why the Earth is the only habitable planet discovered. While reading each criterion, which among the planets passed the requirements?

1. Orbits a star that remains stable and that could live for billions of years.

This is important for developing a planet and for a planet to have time to attain the criteria for life existence or evolution. The sun, the star of the solar system, is about 4.6 billion years old. It is stable, allowing organisms to receive a steady input of either light or chemical energy to run the chemical reactions they need to live.

2. Distance from the star

The distance of a planet from the sun should be just right to allow liquid, solid, and gas to exist and help a planet achieve a life-friendly temperature. The planet should not be too near to the sun or too far from the sun. The identified temperature range that life could handle is from -15oC to 115oC.

3. Rotation

The rotation of the planet should be stable. Its velocity should be just right to allow nearly equal, regular, and frequent day and night to prevent extreme temperature during daytime or during nighttime that is not life friendly. Also, it influences weather formation, which includes wind direction and cloud formation. Not only that, but it also has a significant role in the circulation of air, preventing extreme temperatures at different parts of a planet. Too fast planet rotation will decrease the temperature difference between the poles and the equator, lessening the air circulation or the Hadley cells and cloud formation, causing extreme temperatures. On the other hand, prolonged planet rotation will cause higher temperatures during daytime and cooler temperature during nighttime.

4. Presence of magnetic field

The magnetic field protects a planet from dangerous rays and flares from a star that would strip a planet's atmosphere, especially if it is too near.

5. Atmosphere

Aside from the Earth's magnetic field, it has a thick atmosphere with the right components to protect life from dangerous radiation and meteorites coming from outer space. Not only that, but the atmosphere is also composed of elements or compounds that are very important for life, such as nitrogen and oxygen, and carbon dioxide. It is also the place where air circulation and weather formation occur mainly.

6. An abundant amount of water

Earth consists of about 71% of water, which has a vital role in the existence of life. Water vapor is one of the greenhouse gases. It allows plate tectonics to happen. It is believed that water is a vital criterion for complicated life to exist. Also, water can store, absorb, and release large amounts of energy.

7. Greenhouse gases

The presence of greenhouse gases in a planet's atmosphere is essential in trapping enough heat on the planet's surface and maintaining a temperature that is enough to sustain life. A planet without greenhouse gas would be too cold because a star's heat will quickly dissipate to the outer space even if it reached a planet's surface. On the other hand, too much or too thick greenhouse gases would provide a very high temperature because it traps too much heat on a planet's surface.

8. Size of a planet

The greater the size of a planet, the stronger its gravitational force and the thicker its atmosphere. A planet should be huge enough to have a gravity that is enough to hold a thick atmosphere.

THE EARTH'S FOUR SUBSYSTEMS

The Earth is considered a close system because it allows energy to be converted from one form to another or allows matter to exchange energy from one another but not the exchange of matter itself. The Earth's system has four interconnected subsystems: atmosphere, lithosphere, hydrosphere, and biosphere. Based on your prior knowledge, how are these four subsystems interrelated?

1. Atmosphere

This includes the gaseous component that surrounds the Earth’s lithosphere or the Earth’s crust.

^{Layers of the Earth's Atmosphere}

Importance

• It protects the Earth from hazardous radiation or ultraviolet rays from the sun and from foreign bodies.

• It helps in maintaining the average temperature of the Earth’s surface. o It is where weather occurs. o It has a significant role in the atmospheric circulation and the continuous exchange of moisture and heat between the hydrosphere and atmosphere. This is important in maintaining a balanced temperature and humidity.

• It contains the gaseous components essential for all living things such as oxygen, carbon dioxide, and nitrogen.

2. Lithosphere

This includes the non living components of the Earth, starting from the crust to the inner core.

Importance

• It is the home of all living things.

• The convection process in the mantle allows the formation of volcanoes, mountains, and earthquakes, which are significant in developing habitable crust that has a renewable source of nutrients for plants and other living organisms.

• It is where the electromagnetic field that protects the Earth from solar flares and winds originates.

3. Biosphere

This includes all living things starting from the unicellular organisms to the complex organism, all forms of plants, and ecosystems.

Importance

• It has a great help in regulating the Earth's climate and converting Earth’s energy, making it alive and interactive.

• It helps in maintaining the ecosystem.

4. Hydrosphere

This includes all forms of Earth water.

Importance

• It sustains a wide variety of living things.

• It regulates the Earth's atmosphere.

• It efficiently distributes essential substances to a wide area, making it easy for organisms to take.
• It covers a more significant portion of living organisms. For instance, a human is 75% water.

ACTIVITY 1: VENUS, EARTH, and MARS

Below is a table comparing the characteristics of the three planets, Venus, Earth, and Mars. Compare the three planets' characteristics and evaluate each planet according to the factors or criteria that make a planet habitable by completing the table that follows.

Which among the criteria did the planet Mars, Earth, and Venus pass? Check if you think the planet passed the criteria. Otherwise, write an X mark if the planet failed to meet the criteria. This will help you understand why we are staying on Earth, not on Mars or Venus.

ACTIVITY 2: WHAT IFS

In addition to what you learned, read the table below. This will give you a clearer insight into what would happen if a planet has too much or less of the factors that make a planet habitable. After this, answer the follow-up questions.

Follow up questions:

1. What if the Earth could reach a temperature of 125oC, what would be its possible effect/s to living things?

2. What if there is no interconnectedness among the 4 subsystems of the Earth? What might happen:

a. to the temperature of the Earth’s surface?

b. will the Earth still be habitable? Why?

3. What if the Earth has a gravitational force that is half of its current gravitational force,

a. what would be the thickness of its atmosphere:

b. What criteria would it fail to meet? Give a short yet clear and direct explanation.

ACTIVITY 3:

Part I. Below are the characteristics of the three planets. Analyze each planet's qualities and, based on the criteria of a habitable planet, answer the questions below the table.

1. Can planet A sustain life? Justify your answer.

2. Can planet B sustain life? Justify your answer.

3. Can planet C sustain life? Justify your answer.

Part II. The Earth has its natural greenhouse gases. What would happen if we still produce a great amount of greenhouse gases?

ACTIVITY 4: GENERALIZATION

Since you learned that the four Earth's subsystems are interconnected, give at least 2 activities of human beings that negatively affect the other subsystem and what should you do (as students) to help lessen such activities' effect.

ACTIVITY 5: ASSESSMENT

11-15. Image analysis

Analyze the image below. It portrays the interconnectedness of the four subsystems. Your task is to explain how this ecosystem shows the interconnectedness of the four subsystems. Make your explanation direct yet concise and clear.

ACTIVITY 6: ENRICHMENT

Below is an article about two discovered planets that believed to have the ability to sustain life. Read the article and identify the characteristics of the two planets that gave the Scientists basis in saying that the planets are habitable. On the other hand, write the weaknesses of the planet that might lead to the claim's rejection. Write your answer on the table after the article.

^{Two potentially life-friendly Planets found Orbiting a Nearby Star}

^{b y N a d i a D r a k e p u b l i s h e d J u n e 1 8 , 2 0 1 9}

https://www.nationalgeographic.com/science/2019/06/two-potentially-life-friendly-planets-found-12-light-years-away-teegardens-star/

A tiny, old star just 12 light-years away might host two temperate, rocky planets, astronomers announced today. If they’re confirmed, both of the newly spotted worlds are nearly identical to Earth in mass, and both planets are in orbits that could allow liquid water to trickle and puddle on their surfaces.

Scientists estimate that the stellar host, known as Teegarden’s star, is at least eight billion years old, or nearly twice the sun’s age. That means any planets orbiting it are presumably as ancient, so life as we know it has had more than enough time to evolve. And for now, the star is remarkably quiet, with few indications of the tumultuous stellar quakes and flares that tend to erupt from such objects.

These factors, plus the system’s relative proximity, makes the system an intriguing target for astronomers seeking to train next-generation telescopes on other worlds and scan for signs of life beyond Earth.

“Both Teegarden’s planets are potentially habitable,” says Ignasi Ribas of the Institute of Space Studies of Catalonia, a team member reporting the planets today in the journal Astronomy & Astrophysics. “We will eventually see if they are actually habitable and, perhaps, even inhabited.”

Stellar runt

The two worlds orbit a star so faint that it wasn't even spotted until 2003 when NASA astrophysicist Bonnard Teegarden was mining astronomical data sets and looking for dim, nearby dwarf stars that had so far evaded detection.

Teegarden’s star is a stellar runt that’s barely 9 percent of the sun’s mass. It’s known as an ultra-cool M dwarf, and it emits most of its light in the infrared—just like the star TRAPPIST-1, which hosts seven known RDM, SSTI

rocky planets. But Teegarden's star is only a third as far from Earth as the TRAPPIST-1 system, making it ideal for further characterization.

Ribas and his colleagues are currently searching for planets orbiting 342 small stars, so they aimed the CARMENES instrument, located at Spain’s Calar Alto Observatory, at the mini-star.CARMENES observed Teegarden's star over three years, watching for the wiggles and tugs produced by any orbiting planets. In the end, more than 200 measurements suggested that two small worlds are jostling the star, each weighing in at approximately 1.1 times Earth's mass. The team calculates that one of the planets, called Teegarden's star b, completed an orbit in a mere 4.9 Earth-days; the other world, Teegarden's star c, has a rotation of just 11.4 days.

Eerily quiet

Before they could report that those planets likely exist, the team had to rule out intrinsic stellar phenomena, like starspots and flares, that can masquerade as orbiting worlds. Sometimes, this can be quite tricky for red dwarf stars, which are notoriously turbulent and prone to erupting in massive flares. But Teegarden's star is almost eerily quiet, making it much more comfortable than usual to tease out planetary signals.\

"The number of measurements is so high, and the star is so well-behaved that there is very little room for an alternative explanation," Ribas says. "So, this is, to me, a clear-cut case of planet detection. I would bet both my little fingers that they are there."

“These are very plausible-looking planet candidates,” agrees Lauren Weiss, of the University of Hawaii.

“I am impressed by the quality of the data. However, Weiss notes, a few points cause her to hesitate. First, scientists don’t know the exact time it takes for Teegarden’s star to rotate on its axis, and that type of motion could be masquerading as one of the planet signals.

Still, “stellar rotation would probably only mimic the orbit of one planet, not two planets, so at least one of the planets is probably real,” she says. Second, she says, the planets might be zipping around the star more speedily than inferred, which might knock down their potential habitability.

"This technical concern is minor, though," Weiss says. "If there are planets around the star, and the authors got their orbital periods wrong, the planets are still planets."

• Characteristics of the Two Planets that made them have the potential to Sustain life

• Weak Characteristics of the Two Planets that might Reject the Claim

REFERENCES

Book

Aileen C. Dela Cruz et. al., Earth and Life Science, Quezon City, EC-TEC Commercial, 2016, 24-39

Website

Dave Jarvis, “ROTATION OF PLANETS INFLUENCES HABITABILITY”, July 30, 2008, https://www.astrobio.net/alien-life/rotation-planets-influenceshabitability/#:~:text=New%20research%20has%20revealed%20that,and%20ultimately%20influence%20cloud %20formation.

N a d i a D r a k e , ” Two potentially life-friendly planets found orbiting a nearby star”, National Geographic, J u n e 1 8 , 2 0 1 9 , https://www.nationalgeographic.com/science/2019/06/two-potentially-life-friendlyplanets-found-12-light-years-away-teegardens-star/

Tony Greicius, “In the Zone: How Scientists Search for Habitable Planets”, NASA, July 17, 2013, https://www.nasa.gov/mission_pages/kepler/news/kepler20130717.html

G. H. Rieke , “Properties of the Planets and Habitable Zones”, http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/habzone.htm

Images

Freida Mcmurtrie, “EARTH ROTATION AND NORTH STAR, NAVIGATION, ILLUSTRATION”, PIXY#ORG,

Alec Baravik, "File:Solar Wind and Earth's magnetic field - SVGu1.1.svg”, WIKIMEDIA COMMONS, July 9 2012,

eo.ucar.edu, “File:Atmosphere layers.jpg”, WIKIMEDIA COMMONS, January 1 2015,

needpix.com 2019, “Drip Rain Drop Free Photo”, pixabay.com, https://www.needpix.com/photo/421053/driprain-drop-water-wet-nature-liquid-blue-droplet

A loose necktie, “File:Star-sizes.jpg”, July 12 2019,

Amanda Doyle, “ATMOSPHERE LAYERS INFOGRAPHICS VECTOR ILLUSTRATION”, ASTROBIOLOGY MAGAZINE, August 7, 2014, https://pixy.org/2395648/

“File:Atmosphere layers.jpg”, CC0 Public Domain, eo.ucar.edu, “EARTHS LAYERS OUTER CORE”, January 1 2015, https://pixy.org/1075328/

LadyofHats, “File:Timeline evolution of life.svg”, CC0 Public Domain.

Karen Arnold , “Bamboo Frame Clipart” , PublicDOmainPictures.net.

https://www.publicdomainpictures.net/en/view-image.php?image=251547&picture=bamboo-frame-clipart