1. Unit 3 – Biology and Environment
Science 10 - Leinweber

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

3. 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 see the movement of single cells that we now know as bacteria.

4. The Microscope

5. 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
When using a compound microscope the magnification can be calculated:
Magnification = (power of objective lens)(power of eyepiece lens)

6. Magnification of Objects
M = is magnification ratio
hi = height or length of the image
ho = height or length of the object
* any units can be used for the measurement as long as they are consistant
M = hi ho

7. Example
A 1.5um bacterium appears to have a length of 52.0um through the microscope lens. Calculate the magnification power of the microscope.

8. Homework Read pg 242-246 in text Section 1.1
Pg 244 Skill Practice “Calculating Magnification”
WB pg Q 1-13
The Compound Light Microscope WS (in notes)

9. 1.2 Development of Cell Theory
Cycling of Matter in Living Systems

10. 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"

11. 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.

12. Major Contribution – Scientific Methods
Variables –
Controlled
Manipulated
Responding

13. Pasteur’s Experiments
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

14. 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

15. 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

16. 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

17. Homework:
Read pg in text Section 1.2
WB pg Q 1-14

18. 1.3 Developments in Imaging Technology and Staining Techniques
Cycling of Matter in Living Systems

19. Contrast
Scientist discovered that they could manipulate the light source to alter the contrast between structures in the cell and improve the image.
Experiments with stains and coloring agents showed that particular stains could attach to particular parts of the cell, improving the contrast between internal structures and producing better images
A disadvantage to staining is that it kills the cells making it impossible to view living cells.

20. Microscopes We are going to be looking at 4 types of microscopes:
Light Microscopes
Electron Microscopes
TEM
SEM
Confocal Laser Scanning Microscope
Scanning Tunneling Microscope

21. Light Microscope Think of the compound microscope as a good friend
It is relatively inexpensive, reliable, but it has its limitations.
Maximum magnification ~2000X

22. Electron Microscopes
The “go to” reliable microscope with lots of power, and just a hint of mystery
Engineered in the 1930s. Specimens are illuminated with a beam of electrons instead of light. Makes electron micrograph.

23. Transmission Electron Microscope
Works like a slide projector. Electrons go through a thin sample to give the micrograph
Magnifies X

24. Scanning Electron Microscope
Sweeps a beam of electrons over object to get a 3D image.
Magnification of up to 300,000x

25. Confocal Laser Scanning Microscope
Has very powerful observation abilities
Invented in the 1960s.
Can study thick specimens, measures 2D slices in order to form a 3D image.

26. Scanning Tunneling Microscope
Very technologically advanced. It seems like it can do ANYTHING.
Developed in the 1980s, can obtain an image of atoms on an object’s surface. Can produce images of DNA. Uses an electron probe to make a 3D image

27. Homework:
Read Section 1.3 pg
Complete pg Check & Reflect, #1-6
WB pg Q 1-6