Essential Idea:  There is an unbroken chain of life from the first cells on Earth to all cells in organisms alive today.

• Outline answer to each objective statement for topic 1.5
• Quizlet study set for this topic

At SHS, Topic 1.5 is taught in the following class unit(s):

• Cell Theory (unit 1)
• Prokaryotic Cells (unit 3)
• Eukaryotic Cells (unit 4)

1.5.U1  Cells can only be formed by division of preexisting cells.

• Discuss implications of all cells being formed from preexisting cells.​​

1.5.U2  The first cells must have arisen from non-living material.

• Outline the four processes needed for the spontaneous origin of cells on Earth.
• Outline the experiments of Miller and Urey into the origin of organic compounds.
• Define polymerization, monomer and polymer.
• Outline two properties of RNA that would have allowed it to play a role in the origin of life.
• ​Outline why fatty acids were likely the primary component of the membrane of early cells.

1.5.U3  The origin of eukaryotic cells can be explained by the endosymbiotic theory.

• State the endosymbiosis theory.
• Outline the major events in the origin of eukaryotic cells.
• Describe the evidence for the endosymbiotic theory.​

1.5.A1  Evidence from Pastuer’s experiments that spontaneous generation of cells and organisms does not now occur on Earth.

• Define spontaneous generation.
• Describe Pasteur’s experiments about spontaneous generation.
• ​Explain why Pasteur’s experiments did not support the idea of spontaneous generation. ​

1.5.NOS  Testing the general principles that underline the natural world- the principles that cells only come from pre-existing cells needs to be verified.

• ​Outline historical thinking about spontaneous generation.
• Summarize the Redi experiment.
• Summarize the Spallanzani experiment.
• List reasons why biologists now universally accept that cells only come from preexisting cells.

In the News:

• Searching high and low for the origins of life (2020-07-21)
• Cell-Bacteria Mergers Offer Clues to How Organelles Evolved (2019-10-03)
• A New Clue to How Life Originated (2019-08-12)
• New insights into the origin of life (2019-08-07)
• Scientists discover new chemistry that may help explain the origins of cellular life (2019-07-23)
• Key early steps for origin of life occur under a variety of conditions (2019-07-08)
• Life thrived on Earth 3.5 billion years ago, research suggests (2019-03-08)
• How biologists are creating life-like cells from scratch (2018-11-07)
• The rocky road to biomolecules (2018-11-07)
• Chemists find a recipe that may have jump-started life on Earth (2018-10-18)
• The End of the RNA World Is Near, Biochemists Argue (2017-12-19)
• ​The origin of life: labyrinths as crucibles of life (2015-01-27)
• Ancient rocks show life could have flourished on Earth 3.2 billion years ago (2015-02-16)
• Researchers may have solved origin-of-life conundrum (2015-03-16)
• Building blocks for 'RNA world' made from simple ingredients (2016-05-12)
• Scientists take big step toward recreating primordial 'RNA world' of 4 billion years ago (2016-08-15)
• World’s Oldest Fossils Found in Greenland (2016-08-31)
• Protein-like structures from the primordial soup (2016-09-12)
• On the origin of life: Studying how the first biomolecule self-replicated (2016-11-02)
• Oldest evidence of life on land found in 3.48 billion-year-old Australian rocks (2017-05-09)
• Chemists may be zeroing in on chemical reactions that sparked the first life (2017-05-19)
• ​​Genetic Struggles Within Cells May Create New Species (2017-09-27)
• ​'Solar-powered' sea slugs can survive in the dark (2013-11-20)
• Missing link microbes may help explain how single cells became us (2015-05-06)
• On the origin of eukaryotes: When cells got complex (2016-02-03)