Cycling of Matter in Living Systems 1.1 A Window on a New World

Early Microscopes and Microscopists Hans and Zacharias Janssen, Dutch lens-makers, invented the compound microscope in 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

Cycling of Matter in Living Systems 1.2 Development of Cell Theory

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 ( ) 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: The Compound Light Microscope – BLM 2 Pg 244 Skill Practice “Calculating Magnification” Pg 246 Check & Reflect, #1-8** Pg 252 Check & Reflect, #1-8 (omit 6)