Unit C: Cycling of Matter in Living Systems

Unit C: Cycling of Matter in Living Systems

Background information Science 10 • Chemistry, Physics, Biology, and Climate/Earth • Half the class will be taught with Mr. Peters and the other half will be taught with Mrs. Procee • Chemistry and Physics- Mr. Peters • Biology and Earth Sciences- Mrs. Procee

Science 10 • What to expect: • Lots of material • Quizzes, chapter exams and unit exams (at least one a week) • Labs

Science 10 Survival Guide • To survive and do well in Science 10, you must do the following: • Keep up with readings and assignments • Turn in assignments, labs, and projects on time (there are penalties) • Show up- don’t be late and don’t skip • Get to know each other and help each other out- you are each other’s best resources! • Get help- don’t wait until it’s too late • Ask questions and lots of them

Class Expectations • RESPECT • Respect for your fellow classmates • Respect for the learning environment and school • Respect for your teacher • Be in class and on time • Lates- wait outside until I get to the door- will owe me time! • Unexcused absences – lose make up privileges • No phones • Unless otherwise stated by teacher

Class Expectations • iPods • Privilege- may use ONLY during individual work (if disruptive, class loses privilege) • NOT during lecture, exams, group work etc • Food and water • If you make a mess clean it up. • Assignment late policy • Missed exams • Make up privilege for excused absences only

Homework Policy • If don’t finish work in class, will need to bring it home • NEED to take responsibility for own learning! • There will be a homework folder, and it is your responsibilty to check it if you missed a class

Evaluation • Activities, Labs • Chapter Tests • Unit Exams • Final Exam

Materials for Class • Science 10 – Addison-Wesley • Notebook • Pen or Pencil

Questions?

What is Science? • Thoughts?

Exploring • As a class, read pages 240-241

Chapter 1.1 A Window on a New World

The cell is the unit of structure of all living things. This means that living organisms including plants, animals, bacteria, protists and fungiare composed of at least one cell. • Hundreds of years ago, no one knew this because cells were too small to be seen with the unaided eye. It wasn’t until the development of the light microscope that people realized the existence of cells.

Cell Theory and the Microscope • The invention of the microscope made it possible for scientists to see objects otherwise unseen and allow them to answer many questions about the structure of organisms • One such discovery was that living organisms are composed of small units called cells. • Over time, new technologies and new discoveries led to the development of a theory on cells (more on this in 1.2)

Early Microscopes and Microsopists • It is believed that Hans and Zacharias Janssen, Dutch lens-makers invented the microscope in about 1595. • They used a two lens system of an eyepiece, or ocular lens, and an objective lens. • This would have been the first compound microscope, meaning that it made use of more than one lens • Had a magnifying power of approximately 20x

Robert Hooke • Robert Hooke was a 17th Century scientist from England • Used a three lens system, that used illumination from a beam of light concentrated on the specimen. • He examined slices of cork under the microscope and noticed that the cork was made up of several tiny rooms • These rooms he called “cells”

Antoni van Leeuwenhoek • Leeuwenhoek, a Dutch merchant, studied cells with a more powerful microscope (500x magnification as opposed to Hooke’s 30x) several years after Hooke’s discoveries • He studied scrapings from his teeth and discovered many microscopic organisms he called “animalcules, which later were identified as single celled organisms • He was the first to see the movement of different types of single cells we now know as bacteria, sperm, and unicellular protozoa • He is considered the father of the microscope

The Modern Microscope • Since the time of the Jensen brothers and van Leeuwenhoek microscopes have improved greatly. Stronger lenses and improved mechanical parts have been developed.

Since modern microscopes use ordinary light to produce an image, they are called light microscopes. • In a light microscope, light passes through a cell or other thin object and then through glass lenses. • The lenses bend the light in such a way that the image of the specimen is magnified as it is projected into the eye. • If an object under a light microscope is too thick for light to pass through, the object cannot be seen.

The Lens • A modern light microscope contains several lenses. • One set of lens called the objective lens magnifies the object being viewed. • Different objective lenses give different magnifications. • Most high school microscopes have objective lenses that magnify 4, 10 or 40 times. • A second lens called the ocular lens then magnifies the image produced by the objective lens. • The ocular lens or the eyepiece is the part of the microscope that the observer looks through and usually has a magnification of 10X.

The total magnification of microscope is then calculated by multiplying the magnification power of the two lenses. • Therefore the most commonly used microscopes magnify objects from 40 to 400 times. • With special lens, a total magnification of 1000-1500 times can be reached. • Modern technology allows the manufacture of lens that can magnify greater than 1500X. However the nature of light limits how much a compound light microscope can enlarge an image or magnify an object clearly.

When light passes through each set of lenses, the light rays are spread apart. The greater the magnification, the greater the spreading or bending of the rays. The more the light is spread, the poorer the resolution of the image. • Resolution is the microscopes ability to deliver a visible image with clear detail. Therefore light microscopes can only magnify effectively to about 1 000-1 500 times the size of the actual specimen because greater magnifications increase blurriness.

Calculating Magnification • Magnification= (power of objective lens)(power of eyepiece) • What is the magnification of a system that has a 4x objective lens and a 10x eyepiece? • (4)(10)x= 40 x

Skill Practice • Work on Skill Practice: Calculating Magnification on the bottom of page 244.

Parts of a Microscope • In your workbook, label the microscope as well as fill in the role of each of the parts on the chart. • Use Student Reference on page 478 and the Compound Light Microscope write up in your workbook to help fill in all the information. • This is important information for labs as well as for quizzes and the unit final. Make sure you know the parts and functions.

Estimating an Object’s Size with the Microscope • Lab on page 245 • In your data table, include medium power as well

Unit C: Cycling of Matter in Living Systems