1.1 A Window on a New World
Cycling of Matter in
Living Systems
Early Microscopes and
Microscopists




Hans and Zacharias Janssen, Dutch lens-makers,
invented the compound microscope in 1595.
Compound microscopes use more than one lens to
magnify the object
Robert Hooke, in 1665, used a three lens
microscope to view cork cells
Around the same time Antoni van Leeuwenhoek,
using only a single lens microscope was the first to
seethe movement of single cells that we now know
as bacteria.
Skill and Practice: Calculating
Magnification p. 244

To use a compound microscope to estimate
the size of an object you need to be able to
calculate the magnification of certain
combinations of lenses

Magnification = (power of objective lens)(power of eyepiece)
The Microscope
1.2 Development of Cell Theory
Cycling of Matter in
Living Systems
Spontaneous Generation
Abiogenesis is a theory that states that
nonliving things can be transformed into
living things.




Proposed by Greek philosopher, Aristotle
Implied that fish and frogs came from mud, and flies
came from rotten meat
Scientists accepted this theory for nearly 2000 years
At times referred to as "spontaneous generation"

Francesco Redi, an Italian physician in 1668 set out to
prove flies do not come from meat, by conducting an
experiment








Pieces of meat were placed in 4 different jars not covered
(experimental)
Pieces of meat were placed in 4 different jars sealed (control)
Experimental group -> attracted flies -> laid eggs -> maggot ->
fed on meat -> turned to flies
Control group ->no fly attraction -> no flies produced
Redi concluded flies did not come from rotting meat
But...Air was claimed to be the active ingredient to the rotting
meat to produce flies
So... Redi used an experimental test, this time covering the
container with a very fine mesh, allowing for air flow, but no fly
contact
Conclusion... Meat cannot be transformed into flies.
Louis Pasteur (1822-1895)
Boiled broth for a long time -> clear broth
->swan-necked flask -> microbes trapped in
curve of the flask
Conclusion: microbes could not be created
from non-living broth
The Cell Theory
No one scientist developed the cell theory.
Robert Hooke

First described cells in 1665, while looking at a piece of
cork under a primitive microscope.
 He saw honeycomb shaped structures and described
them as cells.
Anton van Leeuwenhoek

Observed living blood cells, bacteria, and single-cell
organisms
–
Robert Brown

–
1820, described the tiny sphere in the plant cell as the
nucleus
Theodor Schwann (zoologist) and Mathias
Schleiden (botanist)

concluded plant and animal tissues are composed of cells
 prepared the foundations of the modern cell theory
The modern Cell Theory states:
 All
living things are made up of one or
more cells and the materials produced
by these cells.
 All life functions take place in cells,
making them the smallest unit of life
 All cells are produced from pre-existing
cells through the process of cell division
Homework:



Pg 244 Skill Practice “Calculating Magnification”
Pg 246 Check & Reflect, #1-7
Pg 252 Check & Reflect, #1-8 (omit 6)