Topic 1.5:  The Origin of Cells

Essential Idea:  There is an unbroken chain of life from the first cells on Earth to all cells in organisms alive today.
At SHS, Topic 1.5 is taught in the following class unit(s):

Statements & Objectives:

1.5.U1  Cells can only be formed by division of preexisting cells.
  • Discuss two 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.
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.
  • Explain historical thinking about spontaneous generation (what did people think and why did they think it?).
  • Define conformity bias and give an example of conformity bias in the historical study of life.
  • Outline the experiments of Redi and Spallanzani.
  • List reasons why biologists now universally accept that cells only come from preexisting cells.​
"When we try to pick out anything by itself, we find it hitched to everything else in the Universe."  -  John Muir,   1911