CELL THEORY makes 3 Claims
• 1. All living organisms are made of 1 or more
cells
• 2. Cells come only from other living cells
• 3. The cell is the basic unit of life ( smallest
structure which can carry out life processes )
Scientific claims must be based on
evidence.
• What is the EVIDENCE used to propose
the idea that
All living things are made of one or
more cells?
Evidence for claim #1 of cell theory begins with Robert Hookes
observation of Cork ( from a tree ) in 1665. his actual drawing
is on the lower left. Hooke used the word Cells for the small
boxes he saw.
Mathias Schlieden observes cells in all
plants he studies. He proposes the claim
that all plants are made of cells
Theodore Schwann observes animal
tissues. Proposes the claim that all animals
are made of cells
Animal cells
FUNGUS CELLS
Rudolph Virchow proposes the claim
that living cells come only from other
living cells when cells divide.
CELLS DIVIDING to form new
( daughter ) Cells
First Cell divisions of a Frog egg…
forming a small frog Embryo
Human Cell beginning to divide. You can see
chunks of DNA called chromosomes being pulled
to opposite sides of the cell as it divides
CELL THEORY
• 1. All living organisms are made of 1 or more
cells
• 2. Cells come only from other living cells
• 3. The cell is the basic unit of life ( smallest
structure which can carry out life processes