Classifying Organisms

Highlights you should have picked up!

1. Why do biologists organize living things into groups?

2. What do the levels of classification indicate about the relationship between the organisms?

3. How are taxonomic keys useful? 4. What is the relationship between

classification and evolution?

Key ideas to understand and learn:

Classification occurs so organisms can be more easily found when information is needed.

It is much easier to find information about one type of organism if it is placed in a group.

So, how are they grouped?

Scientists have identified more than one million kinds of organisms.

Classification: is the process of grouping things based on their similarities.

Classification is also used so organisms can be grouped and more easily studied.

Taxomony: The scientific study of how things are classified.

Grouping is based on similar ties.

He placed organisms into groups based on their observable characteristics. Each organism was given a two-part scientific name. This is

called the binomial nomenclature The first name is the genus. This grouping contains similar

closely related organisms. It is also the first word of the binomial nomenclature and is capitalized.

Felis would contain a puma, marbled cats, and house cats.

Carolus Linnaeus-Swedish naturalist– 1750’s

Sharp retractable claws

Hunting habits-nocturnal = night.

The different Felis all share:

The species is a group of similar organisms that can mate with each other and produce offspring that can also mate and reproduce.

Horses and Donkeys = Mule = no

The second scientific name is the species. (distinctive traits)

The complete scientific name is written in italics. The first letter of the first word in the scientific

name is capitalized. Latin was the most common language at the time

–that is why scientists have Latin meanings and names for the words. This is used everywhere in the world so no one is confused and the names are exactly alike everywhere.

Marmota monax has also been called a woodchuck, groundhog, or whistlepig.

Using Binomial Nomenclature

The system used today is based on Linnaeus’ system but has been organized into a series of levels to classify many organisms.

They are grouped according to shared characteristics.

The beginning group is very broad and as it goes down the line, it becomes more narrow and specific.

Open your book to page 21A.

Levels of Classification

Domain Kingdom Phylum Class Order Family Genus Species The more classification levels that organisms

share, the more characteristics they have in common.

The order:

The further down the levels you go, the fewer animals are still together.

By the time you get to genus there may only be two animals and at species you have only one.

That way, you can actually identify what type of bird you really want to see. (applies to whatever organism you want identify).

Did you notice that. . . . . . .

Taxonomic keys

Turn your book to page 22 A This is a key for use in identifying an insect.

Go through the steps and read to follow and discover the name of the insect shown there.

It is a. . . . . Pseudoscropion

What do we use to identify the organisms?

Charles Darwin—1859—published information he had studied and collected which was a theory on how organisms can change over time (evolution).

Keep in mind that the changes take place over a very long period of time. Animals can adapt to their environment or they will die.

Therefore, species with similar evolutionary histories are classified more closely together.

Evolution and Classification

They share many similar chemicals within their cellular makeup.

When scientists study the chemicals they may discover new information that changes the earlier ideas. Once this happens, organisms may be moved to a different classification.

This happened with the skunk. They have their own family now (Mephitdae = noxious gas).

If animals share many characteristics that means that:

Using the leaf pictures I will give you and page 25 A, your table will decide how to classify your leaves. You will write a key for your classification idea.

In about 15 minutes you will be asked to trade your key with another table and see if they can follow your key and identify the leaves correctly.

Let’s try a classification key