TOK What is the unit of life baby
TOK: What is the unit of life, baby Ms. Willson or her cells? Be prepared to justify your answer. IB Bio dance for LIFE : )
What are three parts of the cell theory?
Lets do some disection….
The Modern Cell Theory 1. All living things are composed of cells 2. The Cell is the Basic Unit of Life 3. All Cells come from Preexisting Cells
What is a theory? How do we use it in everyday speech? Is this the same as a scientific theory?
Add a definition of a scientific theory at the top of your notes. . FIN ON ITI AD E DD H E. . R E
Find a definition for theory that you like Using a cellular device (or the cellular device of a neighbor) find a definition for scientific theory that you think is fitting for this class. Be prepared to share (both the source and some keywords/ phrases)
If it’s called the cell theory… that means: • “Well substantiated”= lots of evidence • “Explanation of the natural world” = why natural things are they way they are • “Based on a body of facts” = not opinion • “Repeatedly confirmed” = shown over and over again • “Through observation and experiment” = rigorous testing and use of the scientific method • “Not a guess” = Not a guess.
The Modern Cell Theory 1. All living things are composed of cells 2. The Cell is the Basic Unit of Life 3. All Cells come from Preexisting Cells
Why are “trends” useful in the study of biology? - Trends lead to the development of a theory - Trends allow us to make predictions for what we expect to observe If you knew that there was a cell in the mystery box, would you be able to predict what features would be present?
Features of cells that would be considered a “trend” Cell membrane separating the cell contents from the outside Genetic material storing instructions for the cell Machinery for creating proteins Cytoplasm with enzymes to catalyze metabolism Energy release systems to power the cell’s activities
What was the trend Hooke observed? Answer here
Evidence for Cell Theory: All Living things are composed of cells ●From 17 th century on ●Tissues of plant and animals ○ Later Fungi, Bacteria and Protists ●Every specimen had one or more cells
Implications? If it’s not a cell, is it alive? What about VIRUSES? Some interesting articles: https: //www. livescience. com/58018 -are-viruses-alive. html https: //www. khanacademy. org/test-prep/mcat/cells/viruses/a/are-viruses-dead-or-alive
The Modern Cell Theory 1. All living things are composed of cells 2. The Cell is the Basic Unit of Life 3. All Cells come from Preexisting Cells
Evidence for the Cell Theory? The Cell is the Basic Unit of Structure and Organization in Organisms Any part smaller than a cells (for example, any organelle) is not capable of independently carrying out all of the characteristics of life.
The Modern Cell Theory 1. All living things are composed of cells 2. The Cell is the Basic Unit of Life 3. All Cells come from Preexisting Cells
Evidence for the Cell Theory? All Cells Come from Preexisting Cells We observe mitosis, meiosis and binary fission, not spontaneous generation.
What implications are there from all cells being formed from preexisting cells? If we consider all the trillions of cells in our body, each one was formed when a previously existing cell divided into two!
What implications are there from all cells being formed from preexisting cells? That means that: ● We can trace the origin of cells in our body back to the first cell- the zygote produced by the fusion of a sperm and egg.
What implications are there from all cells being formed from preexisting cells? ● The sperm and egg that formed us were produced by our parents. We can trace the origins of all cells back through billions of years of evolution to the earliest cells on Earth.
What observations and experiments would provide evidence that supports the cell theory? ? ? ? ? ?
Stay Tuned for the Exceptions. . .
Discrepancies do not necessarily disprove a theory. For example, the cell discrepancies we discussed are just not “typical” cells. It is unlikely that the cell theory will ever be discarded.
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