Grades 9-12 or Adult Sophisticated Learner
As the early Earth settled down from its formation and continued the evolution of its crust, oceans, and atmosphere, many unique environments were taking shape – places like beaches, icy areas, rocky surfaces, hot springs, lakes and lagoons, seas, volcanoes, and even small hot water volcanoes on the ocean’s floor called hydrothermal vents (hydro=water; thermal=heat). Many of the raw materials of life (small, organic [aka carbon-containing] molecules such as carbon dioxide and methane) were available in these environments, and in order to for life to get started, they needed to interact with each other in the presence of energy. In today’s biology, enzymes help lower the activation energy needed for biochemical reactions to take place. But on the prebiotic Earth (pre=before; biotic=life), none of those enzymes existed yet. In order to get small molecules to interact with each other, they had to be brought into close proximity so chemical reactions could occur. This may have happened in a variety of ways on the early Earth.
In hydrothermal vent systems on the ocean floor, organic molecules in superheated water from below the crust could gush up through chimney-like structures (the vents) where there would be immediate interaction with the cold ocean water. Groups of molecules could have gotten caught in tiny pore spaces in the rock of the chimney (like a sponge made of rock) – spaces that may have emulated an early cell, in which prebiotic chemical reactions that gave rise to life could have taken place. Also, the interaction of the hot and cold water could have produced a temperature gradient in which the molecules could have sorted themselves and interacted in new ways.
On the ocean’s surface, hydrophobic (“water-fearing”) molecules could have formed in pools like small oil slicks floating on the water. Raw materials in ocean water that splashed up onto rock surfaces in early tide pool environments would have been condensed and concentrated as the ocean water evaporated, forcing interactions. As sea ice froze, small pockets of salty water containing organic molecules would have gotten progressively smaller, bringing the molecules closer together. Even the surfaces of some minerals like calcite can provide a platform for prebiotic chemical reactions, especially reactions which bind monomers of the same kind into longer chains (like a string of pearls).
There were many different kinds of environments on the early Earth that may have provided the conditions and energy needed for prebiotic chemistry to occur and to potentially evolve into biochemistry.
Disciplinary Core Ideas
LS1.C: Organization for Matter and Energy Flow in Organisms: The process of photosynthesis converts light energy to stored chemical energy by converting carbon dioxide plus water into sugars plus released oxygen. (HS-LS1-5) The sugar molecules thus formed contain carbon, hydrogen, and oxygen: their hydrocarbon backbones are used to make amino acids and other carbon-based molecules that can be assembled into larger molecules (such as proteins or DNA), used for example to form new cells. (HS-LS1-6)
LS4.C: Adaptation: Changes in the physical environment, whether naturally occurring or human induced, have thus contributed to the expansion of some species, the emergence of new distinct species as populations diverge under different conditions, and the decline – and sometimes the extinction – of some species. (HS-LS4-6)
ESS1.C: The History of Planet Earth: Continental rocks, which can be older than 4 billion years, are generally much older than the rocks of the ocean floor, which are less than 200 million years old. (HS-ESS1-5) Although active geologic processes, such as plate tectonics and erosion, have destroyed or altered most of the very early rock record on Earth, other objects in the solar system, such as lunar rocks, asteroids, and meteorites, have changed little over billions of years. Studying these objects can provide information about Earth’s formation and early history. (HS-ESS1-6)
ESS2.A: Earth Materials and Systems: Earth’s systems, being dynamic and interacting, cause feedback effects that can increase or decrease the original changes. (HS-ESS2-1) Evidence from deep probes and seismic waves, reconstructions of historical changes in Earth’s surface and its magnetic field, and an understanding of physical and chemical processes lead to a model of Earth with a hot but solid inner core, a liquid outer core, a solid mantle and crust.
ESS2.B: Plate Tectonics and Large-Scale System Interactions: Plate tectonics is the unifying theory that explains the past and current movements of the rocks at Earth’s surface and provides a framework for understanding its geologic history. Plate movements are responsible for most continental and ocean-floor features and for the distribution of most rocks and minerals within Earth’s crust.
ESS2.C: The Roles of Water in Earth’s Surface Processes: The abundance of liquid water on Earth’s surface and its unique combination of physical and chemical properties are central to the planet’s dynamics. These properties include water’s exceptional capacity to absorb, store, and release large amounts of energy, transmit sunlight, expand upon freezing, dissolve and transport materials, and lower the viscosities and melting points of rocks. (HS-ESS2-5)
ESS2.E: Biogeology: The many dynamic and delicate feedbacks between the biosphere and other Earth systems cause a continual coevolution of Earth’s surface and the life that exists on it. (HS-ESS2-7)
PS1.B: Chemical Reactions: Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy. (HS-PS1-4, HS-PS1-5)
PS3.A: Definitions of Energy: Energy is a quantitative property of a system that depends on the motion and interactions of matter and radiation within that system. That there is a single quantity called energy is due to the fact that a system’s total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms. (HS-PS3-1),(HS-PS3-2)
PS3.B: Conservation of Energy and Energy Transfer: Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system. (HS-PS3-1) *Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems. (HS-PS3-1, HS-PS3-4)
PS3.D Energy in Chemical Processes: The main way that solar energy is captured and stored on Earth is through the complex chemical process known as photosynthesis (HS-LS2-5)
Systems and System Models: Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions — including energy, matter, and information flows — within and between systems at different scales. (HS-LS2-5) Stability and Change: Much of science deals with constructing explanations of how things change and how they remain stable. (HS-ESS1-6) Change and rates of change can be quantified and modeled over very short or very long periods of time. Some system changes are irreversible. (HS-ESS2-1)
Big Ideas: The conditions that existed on the young Earth made the start of life possible. The beginning of life on Earth was likely a result of a complex combination of available energy from the Sun, lightening, and ocean floor volcanoes as well as the presence of the building blocks of life in liquid water. While most life on Earth now relies on primary production derived from energy from the Sun through the process of photosynthesis, it is possible to convert chemical energy in lieu of solar energy. Hydrothermal vents on the ocean floor are a highly likely place for the first life to have developed because of the presence of energy and building blocks from the water and vented material. While the process was likely very slow, given enough time, the building of each building block of life is possible and would have slowly given rise to more complex molecules. The complex chemistry of life can be broken down into simple components seen throughout the world’s oceans.
Boundaries: Emphasis is on using available evidence within the solar system to reconstruct the early history of Earth, which formed along with the rest of the solar system 4.6 billion years ago. Examples of evidence include the absolute ages of ancient materials (obtained by radiometric dating of meteorites, moon rocks, and Earth’s oldest minerals), the sizes and compositions of solar system objects, and the impact cratering record of planetary surfaces. (HS-ESS1-6)
5-12 Astrobiology Graphic Histories. Issue 7: Prebiotic Chemistry and the Origin of Life. These astrobiology related graphic books are ingenious and artfully created to tell the story of astrobiology in a whole new way. This issue illustrates prebiotic chemistry and the Origin of life on Earth. NASA. https://astrobiology.nasa.gov/resources/graphic-histories/
6-12 Astrobiology Math. This collection of math problems provides an authentic glimpse of modern astrobiology science and engineering issues, often involving actual research data. Students explore concepts in astrobiology through calculations. Relevant topics include The Origin of Life (page 3) and The Largest Known Extraterrestrial Molecules (page 11). NASA. https://www.nasa.gov/pdf/637832main_Astrobiology_Math.pdf
6-12 Virtual Field Trips: Ancient Records of Life on Earth: Australia.VFT’s are topic-based interactive and educationally rich experiences captured during real expeditions with scientists doing current research. The Trezona Formation is a group of sedimentary rocks found in southern Australia. This “field trip” is highly immersive and full of interactive material and rich scientific content covering early organisms on Earth, evolution and Earth’s properties. Arizona State University. http://vft.asu.edu/ and
6-12 Microbes@NASA. The website has activities, visualizations, videos and more about microbial mats and why NASA is interested in them. The site includes a photo gallery, interactive web features in which students can conduct remote experiments on a real microbial mat in a NASA laboratory, numerous classroom activities, and a seven-minute animated film taking you for a ride through a microbial mat. These microbial mats can be used to understand the origin and early life on Earth, how the Earth and life co-evolve and the search for life beyond Earth. NASA. https://spacescience.arc.nasa.gov/microbes/
Cyanobacteria Races: Cyanobacteria Motility Experiment for a classroom. By studying fossil records of cyanobacteria motility on Earth, scientists are better able to identify fossil records in their search for life in the universe and beyond. In this experiment, students expose cultures of freshwater cyanobacteria to a directional light source, measuring their movement toward this light source with a ruler and recoding measurements https://spacescience.arc.nasa.gov/microbes/download/pdf/Cyanobacteria_Races.pdf
Microbial Mat Web Lab. Profiles of oxygen concentration reveal a great deal about what is going on inside a microbial mat. Using this activity, classes can remotely operate an experimental setup containing an oxygen microsensor in a lab at Ames Research Center. https://spacescience.arc.nasa.gov/microbes/learn/weblab.html
9-10 Voyages through Time: Origin of Life. Through the Origin of Life module, students address questions such as: What is life? What is the evidence for early evolution of life on Earth? How did life begin? Sample lesson on the website and the curriculum is available for purchase. SETI. http://www.voyagesthroughtime.org/origin/index.html
9-12 SpaceMath Problem 350: Estimating the Temperatures of Exoplanets. Students review the basic properties of ellipses by exploring the orbits of newly-discovered planets orbiting other stars. They also use a simple formula to determine the temperatures of the planets from their orbits.[Topics: equation of ellipse; evaluating functions] https://spacemath.gsfc.nasa.gov/astrob/7Page14.pdf
9-12 SpaceMath Problem 338: Asteroids and Ice. Students calculate how much ice may be present on the asteroid 24-Themis based on recent discoveries by NASA [Topics: mass=density x volume; volume of a spherical shell] https://spacemath.gsfc.nasa.gov/astrob/6Page154.pdf
9-12 SpaceMath Problem 287: LCROSS Sees Water on the Moon. Students use information about the plume created by the LCROSS impactor to estimate the (lower-limit) concentration of water in the lunar regolith in a shadowed crater. [Topics: geometry; volumes; mass=density x volume] https://spacemath.gsfc.nasa.gov/moon/6Page66.pdf