This week our topic is the diversity of living things on our planet.   This is just a brief introduction to diversity, and we will delve more deeply into some components in lecture.

Introduction

    Why should you care about the diversity of life on the planet?   There are many reasons to care.  One reason is that we depend on other living things to survive for our food and water sources, so we should know what is available to us.  Another reason is that it is the unique combination of living things on Earth that creates our atmosphere that provides us with oxygen; every organism on this planet interacts with other organisms and is necessary for our planet.  It is also the case that living things can cause infections in our bodies... it is only by understanding those living things that we can fight infection.  And, the last reason I'll give you is that because all living things share certain characteristics, it is possible that we can use other living things to create cures for human ailments.

    Of all of these reasons, the notion that the variety of life creates our atmosphere is the main one that relates to the concept of global warming.  We'll return to this in a later chapter.

What is in store for you in this lesson?

    You will be learning about the classification system for all living organisms.  Such a classification system is necessary in order to identify each organism, and to understand how similar each organism is to one another.  Then, you will be learning about characteristics of each of the major classification groups.   You have done some of this in your diversity lab, but I'll expand on those ideas here.

    Meanwhile, although we haven't specifically studied evolution in this course (it is a major part of Principles of Biology II), it relates to the diversity of life.  You see, the more similar two organisms are, the more likely they were to have arisen from a common ancestor, evolutionarily, in the more recent past.  If organisms only became distinct more recently in evolutionary history, they will have very similar DNA.  In fact, humans are over 98% identical in our DNA to certain apes.  So, I might say that two organisms are closely related... because similar organisms are more evolutionarily-related.  And you might see some similar terminology used on web sites.

© 2006 STCC Foundation Press, content by Dawn A. Tamarkin, Ph.D.

Last changed: January 21, 2007