Cell Theory
and how life on Earth began
Presentation is brought to you by;
Ed Lester V. Cagatan
How life on Earth began?
• Spontaneous Generation Theory
Life can be generated from inanimate objects
Was already around since the time of Aristotle
Quest to find out how life began!
• Francesco Redi
Disprove the spontaneous generation
theory.
Meat in jars.
Muslin
is a cotton fabric of plain weave. It is made
in a wide range of weights from delicate
sheers to coarse sheeting.
Considered as the father of parasitology.
Quest to find out how life began!
• Lazaro Spallanzani (Late 1700s)
• Also disproved spontaneous generation theory
• Broth and flask (sterilized)
• He concluded that;
• The microorganism did not come from the broth.
• Microorganism came from the air.
• It is impossible for microorganism to come from nonliving things.
Quest to find out how life began!
• Alexander Oparin (1953)
• Atmosphere of the primitive earth contained
methane, ammonia, hydrogen and water
vapor.
• Ultraviolet rays, rain and hot seas.
• Complex organic molecules
Quest to find out how life began!
• Stanley Miller
• Performed an experiment as suggested by
Oparin.
• Introduced sparks to the mixture of gasses
• Amino acids
• Living things on Earth may have arisen
through a series of chemical combinations of
this organic molecules.
Cellular Theory
1. All living things are structurally made up of cells.
2. The cell is the fundamental unit of organizations for
all organism.
Cell – Tissues – Organs – Organ System – Organism
3. Cells came from the division of preexisting cells.
Contributors to the cell theory
Robert Hooke
-Coined the term cell (cellulae meaning small rooms).
- The first two principles was derived from his
observations.
Antonie van Leeuwenhooek
-First to see individual cells and recognized them as
living unit.
Contributors to the cell theory
Matthias Schleiden and Theodor Schwann
-All plants and animals are made up of cells.
Rudolf Virchow
-Cells divide to form new cells.
Robert Brown
- Presence of nuclei in cells.
Additional information.
Cytology
- study of cells
Chemical basis of life
-4 elements constitute the 98% of living matter.
- Hydrogen (63%), oxygen (25.5 %), carbon (9.5
%) and nitrogen (1.4 %).
- The remaining 2 %
- P, K, Mg Na, S and Cl and few others in minute
amounts
Animal vs Plant Cell