Essential idea: There is an unbroken chain of life from the first cells on Earth to all cells in organisms alive today.
Above you can see fossilised images of cells. We know from such evidence that cells have always worked using the same basic principles.
Understandings, applications and skills:
| 1.5.U1 | Cells can only be formed by division of pre-existing cells. [Students should be aware that the 64 codons in the genetic code have the same meanings in nearly all organisms, but that there are some minor variations that are likely to have accrued since the common origin of life on Earth.] |
| 1.5.U2 | The first cells must have arisen from non-living material. |
| 1.5.U3 | The origin of eukaryotic cells can be explained by the endosymbiotic theory. [Evidence for the endosymbiotic theory is expected. The origin of eukaryote cilia and flagella does not need to be included.] |
| 1.5.A1 | Evidence from Pasteur’s experiments that spontaneous generation of cells and organisms does not now occur on Earth. |
[Text in square brackets indicates guidance notes]
Starters
Presentation and notes
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The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
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Quick quiz Use the BioK Quick Quiz on 1.5 The origin of cells (as directed) to check your understanding of the topic.
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Weblinks
Evidence against spontaneous generation
Science as a process: arriving at scientific insights by Sumanas Inc. looks at Pasteur's experiments
Rejecting spontaneous generation a simulated lab by PH School
Evolution of the first cells
Learn about the Miller-Urey experiment from Stanley Miller himself.
The origin of complex life: it was all about energy by Ed Yong
Endosymbiosis
The evolution of organelles by Sunamas Inc.
Endosymbiosis by McGraw and Hill
Evolution of the cell by learn.genetics
Science as a process: arriving at scientific insights by Sumanas Inc. looks at Pasteur's experiments
Rejecting spontaneous generation a simulated lab by PH School
Evolution of the first cells
Learn about the Miller-Urey experiment from Stanley Miller himself.
The origin of complex life: it was all about energy by Ed Yong
Endosymbiosis
The evolution of organelles by Sunamas Inc.
Endosymbiosis by McGraw and Hill
Evolution of the cell by learn.genetics
Nature of science:
Testing the general principles that underlie the natural world - the principle that cells only come from pre-existing cells needs to be verified. (1.9)
Theory of knowledge:
Biology is the study of life, yet life is an emergent property. Under what circumstances is a systems approach productive in biology and under what circumstances is a reductionist approach more appropriate? How do scientists decide between competing approaches?
This Science 2.0 article Reductionism And Systems Thinking: Complementary Scientific Lenses is a good accessible read on how systems thinking complements the more traditional reductionist approach
This Science 2.0 article Reductionism And Systems Thinking: Complementary Scientific Lenses is a good accessible read on how systems thinking complements the more traditional reductionist approach
