Unit C: Cycling of Matter in Living Systems

Aristotle (384 BC – 322 BC) He was one of the first Greek philosophers who used the Scientific Method of observing, recording, reasoning, and interpreting in attempt to explain the world around him. Aristotle is known as “The Father of Biology.”

A compound microscope uses more than one lens to magnify objects.

Hooke’s three-lens system has two lenses in the ocular.

Robert Hooke (1635 – 1703) Robert Hooke coined the term “cells” when he observed cork under his microscope. He named the tiny chambers as such because they reminded him of the rooms that monks occupy in a monastery. Hooke’s drawing of cork cells

Antoni van Leeuwehoek (1632 – 1723) Leeuwenhoek was the first person to observe the movement of living cells. “animalcules”

1.Eye Piece or Ocular Lens. 2.Coarse Focus Adjustment 3.Arm 4.Stage Clip 5.Fine Focus Adjustment 6.Base 7.Lamp 8.Diaphragm 9.Stage 10.Objective Lenses 11.Revolving Nosepiece 12.Body Tube text pg. 478

The magnification tells us how much larger (or smaller) the picture is than the real size of the specimen under the microscope. magnification = (objective lens) (ocular lens) Skill Practice pg. 244 What is the magnification if the following combinations of lenses are used? a) a 2.5X low-power objective lens and a 10X eyepiece b) a 100X low-power objective lens and a 10X eyepiece 25X 1000X

UnitEquivalent Measurement centimetre (cm) 1/100 metre; 10 –2 m millimetre (mm) 1/10 centimetre; 10 –3 m micrometre - also called the micron (μm) 1/1000 millimetre; 10 –6 m nanometre (nm) 1/1000 micrometre; 10 –9 m angstrom (Å) 1/10 nanometre; 10 –10 m (see data booklet)

Micro-organisms like bacteria and viruses can range in size from 10 µm to just a few nanometres.

To convert from one unit to another, we use a conversion factor. It is a fraction where the numerator is equivalent to the denominator. Examples 1) 20 nm = ? m 20 nm = 2.0 × m 2) 400 pm = ? mm 400 pm = 4.00 × mm

The field of view is the entire area that you see when you look through the microscope. To compare different fields of view, we usually measure their diameters.

100 X1000 X Magnification increases the size of what you see BUT decreases the amount of the object in view.

Since the field of view decreases in size in direct proportion to the increase of the magnification, we can calculate the size of the other fields of view. For example: If the field of view is 4000μ at 40X, it will be 10 times smaller at 400X, or 400μ in size. Magnification Field of View (mm) Field of View (µm) 40X X X

text p µm

Actual SizeDiagram SizeScale 1.1 mm110 mm100:1 (or ×100) 2.6 mm5.0 cm (50 mm)19:1 (or ×19) To calculate actual size and scale of a diagram of a specimen under a microscope, you measure (or calculate) the diameter of the field of view (on the microscope) and the actual size of the finished diagram (on your page). must be in the same units!

read pages 242 – 246 C1.1 Check and Reflect page 246 #’s 1 – 8 Line Masters 1 and 2