The Precambrian Era

Your Name: Kahli Veys

Concepts Addressed: Precambrian era, geologic time scale, evolution

Lab Goals: Students will become familiar with the Precambrian Era in relation to what time period(s) it spans and what occurred geologically and biologically during that time.

Lab Objectives:

Students will:

  • Describe the Precambrian era
  • Explain geologic time
  • Explore how early life first began
  • Work together in a team to create a game
  • Use art to deepen knowledge of the Precambrian era
  • Write out the rules of a game

Benchmark(s) Addressed:

2.4D.1 Use tools to construct a simple designed structure out of common objects and materials.

2.4D.2 Work with a team to complete a designed structure that can be shared with others.

4.2E.1 Compare and contrast the changes in the surface of Earth that are due to slow and rapid processes.

5.2L.1 Explain the interdependence of plants, animals, and environment, and how adaptation influences survival.

Materials and Costs:

List the equipment and non-consumable material and estimated cost of each

Scissors (12-pack) $7.49

Estimated total, one-time, start-up cost: $7.49

List the consumable supplies and estimated cost for presenting to a class of 30 students

Colored pencils (six 12-packs) $13.74

Crayons (one 96-piece pack) $7.20

Markers $4.79

Construction Paper $1.49

Heavy weight construction paper or cardboard $4.17

Clay (optional—for molding volcanoes, etc.) $6.99

Glue sticks (12-pack) $3.77

Index cards $1.07

Estimated total, one-time, start-up cost: $43.27

Time:

  • Preparation time: 30 mins. to purchase the supplies
  • Instruction time: 2 hours (1 hour 15 minutes or instruction and making the games, 45 minutes for each group to play at least a few other groups’ games.)
  • Clean-up time: 15 minutes to clean up supplies

Background:

The Precambrian is Earth’s first period of time. The earth took form about 4.5 billion years ago. For the first 4 billion years of that time, the Earth was growing and changing. The only living things during this time were one-celled organisms. The Precambrian era is an informal name for the supereon comprising the eons of the geologic timescale that came before the current Phanerozoic eon. It spans from the formation of Earth around 4500 Ma (million years ago) to the evolution of abundant macroscopic hard-shelled animals, which marked the beginning of the Cambrian, the first period of the first era of the Phanerozoic eon, some 542 Ma. It is named after the Roman name for Wales - Cambria - where rocks from this age were first studied.

To speak of "the Precambrian" as a single unified time period is misleading, for it makes up roughly seven-eighths of the Earth's history. During the Precambrian, the most important events in biological history took place. Consider that the Earth formed, life arose, the first tectonic plates arose and began to move, eukaryotic cells evolved, the atmosphere became enriched in oxygen -- and just before the end of the Precambrian, complex multicellular organisms, including the first animals, evolved.

The Hadean Time actually came first, but it is not a geologic time period. It was the time when the earth was molten and had not yet formed a crust. It is not a geologic time because there were no rocks yet.

After the Hadean time period came the Archaean and it was in this period that life first appeared on Earth. Our oldest fossils date to roughly 3.5 billion years ago, and consist of bacteria microfossils. In fact, all life during the more than one billion years of the Archaean was bacterial. Stromatolites, colonies of photosynthetic bacteria, have been found as fossils in Early Archaean rocks of South Africa and Western Australia. Stromatolites increased in abundance throughout the Archaean, but began to decline during the Proterozoic. They are not common today.

The last time period within the Precambrian era is the Proterozoic period. The proterozoic can be broken down into three, even smaller time periods within it. Many of the most exciting events in the history of the Earth and of life occurred during the Proterozoic -- stable continents first appeared and began to accrete, a long process taking about a billion years. Also coming from this time are the first abundant fossils of living organisms, mostly bacteria, by about 1.8 billion years ago. The first glaciations also occurred in this time period.

With the beginning of the Middle Proterozoic comes the first evidence of oxygen build-up in the atmosphere. This global catastrophe spelled doom for many bacterial groups, but made possible the explosion of eukaryotic forms. These include multicellular algae, and toward the end of the Proterozoic, the first animals.

Precambrian Board Game!

Materials:

  • Crayons
  • Markers
  • Colored Pencils
  • Glue Sticks
  • Colored paper
  • Scissors
  • Clay
  • Index cards
  • Heavy weight construction paper/cardboard (for game boards)

Procedure:

  • Students will get into groups of 3 and create a board game using the materials provided—the theme of the game is a journey through the Precambrian Era (almost like Candy Land), with the final stop the end of the Precambrian Era, which was the evolution of hard-shelled species (trilobites, etc.)
  • Using crayons, colored pencils, markers, and clay, decorate your game board (large pieces of construction paper or cardboard will serve as the game board)
  • Make “spaces” on the board for players’ pieces to land on out of cut-out paper or crayons/markers
  • Make sure to include each of the following:
  • Hadean, Archaean, Paleoproterozoic, Mesoproterozoic, and Neoproterozoic
  • Refer to the powerpoint for further information on each of these eras within the Precambrian era, to better help design your board game
  • Create the rules for your game and write them on a note card—making sure the game is for 3+ players
  • Once all groups have completed their games, the students will rotate around the room in their groups, playing each other’s games.

Assessment:

  • Student’s gameboards will be assessed for content and clarity.
  • Quiz:
  1. List the following eras within the Precambrian era in order of earliest to most recent: Archaean, Hadean, Proterozoic

Answer: Hadean, Archaean, Proterozioc

  1. In which time period within the Precambrian era did the first glaciation occur, Hadean, Archaean, or Proterozoic?

Answer: Proterozoic

  1. Which time period within the Precambrian era was the hottest, Hadean, Archaean, or Proterozoic?

Answer: Hadean