Topic: Classification

Aim: Explain the classification system we use today.

Do Now: Take out test so we can finish going over it.

HW: Ditto – Microscope Review

Castle learning – Microscope due on Monday!

Microscope test is on Tuesday!

Describe one way all students in this class can be separated into groups, or classified.

Aristotle (384BC-322BC) developed the first classification system, which divided all known organisms into two groups: PLANTS and ANIMALS.

Aristotle then divided each of these main groups into 3 smaller groups.

Animal Subgroups: Land, Water, Air

Plant Subgroups: Small, Medium, Large

Scientists have identified more than 2.5 million different organisms. And their job isn’t even close to being finished! Some biologists estimate that there may be at least 7 million different kinds of organisms living in tropical rain forests and in the depths of Earth’s oceans. No wonder why we need to classify!

Classification•Grouping of different types of organisms based on similar characteristics

Taxonomy•Branch of biology that deals with classification of living things

Carolus Linnaeus (1707-1778) like Aristotle, classified organisms according to their traits. The classification systems of both Aristotle and Linnaeus started with the same two groups: Plants and Animals. Linnaeus called these groups kingdoms. But, unlike Aristotle, Linnaeus divided kingdom into 5 levels. Organisms were placed in these levels based on traits, including similarities of body parts , physical form such as size, shape, and methods of getting food.

Classification system used today

•Carolus Linnaeus (1700’s)

•All organisms are divided into 7 levels of classification

Kingdom

Phylum

Class

Order

Family

Genus

Species

•Largest group

•Very diverse

Smallest groups and most closely related to each other

Kings

Play

Chess

On

Fine

Green

Stools

Species•One kind of organism that can mate with each other & produce fertile offspring

Kingdom

Phylum Phylum Phylum Phylum Phylum Phylum

Naming organisms

Before Linnaeus developed his naming system, plants and animals were named by a series of Latin words that described the physical appearance of the organism. This was very confusing. For example, let’s look at the first name of the honey bee.

Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatus. This means “fuzzy bee, light

gray middle, brown body, smooth hind legs that have a small bag edged with tiny hairs.” Linnaeus named it Apis mellifera which means “honey-bearing bee.”

Binomial Nomenclature

•Method used to name organisms

•Devised by Linnaeus •2 names

–Genus species

Humans = Homo sapiens

Kingdom Animalia

Phylum Chordata

Class Mammal

Order Primate

Family Homoide

Genus Homo

Species sapiens

Kingdom Animalia

Phylum Cordata

Class Mammalia

Order Carnivora

Family Canidae

Genus Canis

Species Lupus (the wolf)

Canis lupus

Let’s summarize…

1. How are organisms classified in the classification system used today?

2. Explain the difference between a kingdom and a species.

3. Explain the method used for naming organisms.

4. In a dichotomous key, how many descriptive statements are found in each step?

5. When starting a dichotomous key, which step do you start with?

6. What do you do if the first statement is false?

Review:

1. Which of the following places the seven major classification groups in order from largest to smallest?

(1.) phylum, class, kingdom, order, family, genus, species

(2.) kingdom, phylum, class, order, family, genus, species

(3.) kingdom, phylum, order, family, class, genus, species

(4.) genus, species, class, order, kingdom, family, phylum

2. The scientific name for a lion is Panthera Leo. The word Panthera tells us the lion’s

(1.) kingdom

(2.) phylum

(3.) genus

(4.) species

3. Members of a population of gray squirrels, Sciurus carolinensis, are classified in the same species because they

(1.) obtain their food in the same manner

(2.) produce enzymes by synthesis

(3.) can mate and produce fertile offspring

(4.) live in the same area

4. In today’s classification system, 2 organisms would be most closely related if they were classified in the same

(1.) kingdom

(2.) phylum

(3.)genus

(4.)species

5. Which classification category contains the greatest number of different types of organisms?

(1.) kingdom

(2.) phylum

(3.) genus

(4.) species

Dolphin Tursiops truncatus

Raccoon Procyon lotor

Fruit flyDrosophila melanogaster