Science 9: Unit A – Biological Diversity Lesson 1-2 – Classifying Biological Diversity

Quick Review! 1. What is Biodiversity? 2. How many species do scientists estimate are alive on the planet right now? 3. What region has the greatest number of species on the planet? 4. What is a species?

Classifying Biological Diversity Video – Classifying Biological Diversity There are a wide range of life forms (about 30 million −100 million species) around us. These life forms have existed and evolved on the Earth over millions of years. Why do we try to classify them?

Why do we classify organisms? Suppose you had only 10 minutes to run into a supermarket to get what you needed. Could you do it? In most supermarkets this would be an easy task. You would probably head straight to the area where the items were located. But what if you had to shop for the same items in a market where things were randomly placed throughout the store. Where would you begin? You would have to search through a lot of things before you found what you needed! You could be there for a long time! Biologists have organized living things with similarities into groups so that the organisms are easier to study. This process is called classification.

Why do we classify? Classification is the process of grouping things based on their similarities. Biologists use classification to organize living things into groups so that the organisms are easier to study. The scientific study of how living things are classified is called taxonomy.

So…HOW do we classify organisms? History lesson! Bear with me… Before the advent of modern, genetically based evolutionary studies, biology consisted primarily of taxonomy , or classification of organisms into different categories based on their physical characteristics and presumed natural relationship.   The leading naturalists of the 18th and 19th centuries spent their lives identifying and naming newly discovered plants and animals.

Carolus Linnaeus One of the most important 18th century naturalists was a Swedish botanist and medical doctor named Karl von Linné.  He wrote 180 books mainly describing plant species in extreme detail.  Since his published writings were mostly in Latin, he is known to the scientific world today as Carolus Linnaeus , which is the Latinized form he chose for his name.

Carolus Linnaeus In 1735, Linnaeus published an influential book entitled Systema Naturae in which he outlined his scheme for classifying all known and yet to be discovered organisms according to the greater or lesser extent of their similarities.  This Linnaean system of classification was widely accepted by the early 19th century and is still the basic framework for all taxonomy in the biological sciences today.

Just about enough history… The Linnaean system uses two Latin name categories, genus and species , to designate each type of organism. A genus is a higher level category that includes one or more species under it. He further added groupings above these, called the family and order, to group together organisms that seemed to share broader features… Ex. He used the term “primates” as the order which humans, monkeys and apes belonged. (from the Latin primus meaning "first”)

Linnaeus’s System

System The Linnaean scheme for classification of living things lumps organisms together .  The assumption is that the more traits two organisms share, the closer they must be related. The result is a hierarchical system of classification with the highest category consisting of all living things.  The lowest category consists of a single species.  Each of the categories above species can have numerous subcategories. .

Very tiny sample of the system

Little more info Major Characteristics of the 5 Kingdoms

SO…how does it work? Think about it like this, if we were put in a big room with a bunch of other Canadians and tried to group us, we would look like this: Canadians - Everybody Albertans – quite a few Grande Prairie – some Hillcrest Drive – (my street) a few My house – just me and my kids

Actual groupings for naming organisms: The higher up we go, the more we have in common…(ie. Higher up in the groupings) Actual groupings for naming organisms:

It’s waaaaaay more complicated than that… But we don’t need to know it all for grade 9 science! You need to know, - the system is based on PHYSICAL features - 2 name system – genus and species - Classification hierarchy – Kingdom, Phylum, Class, Order, Family, Genus, Species

Some ways to remember the last one: Pnemonic device – Kinky people Chew On Funky Green Saliva (created by my class when we were in Grade 8 science…still what I think of every time!) Can you come up with one yourself? Classification Rap – nerdy but good!

So how do you know if you found a new species? Well, you’d look it up in a dichotomous key – a tool based on a series of questions, generally with opposites as their answers. You would work your way down to the end, (kind of like a choose your own adventure story) until you either find the name of the species, or find it hasn’t been classified yet!

Assignment Today: 1. Answer questions page 15 # 3, 4, 8