How are living things classified?

Part OneWhat is classification?PhylogenyBinomial NomenclatureDichotomous Keys

What is classification?

Whenever you place similar items together, you are classifying them.

Look at the images on the next page. What do they have in common? How many different ways can you divide these flying

things into groups? Choose a method to classify these objects. Start with

2 headings and then subdivide each group.

Phylogeny

The evolutionary relationships between organisms.

Used today to classify organisms into 6 Kingdoms: Plants –complex multicellular cells, make own food Animals – complex multicellular cells, heterotrophs (eat

other organisms) Fungi – complex multicellular cells, decomposer, ex.

Mushrooms, mold, & mildew Protists – complex unicellular, ex. algae Archaebacteria – one celled, live in extreme

environments Eubacteria – one celled, most bacteria

(Secondary Science Program: Rhode Island College)

KingdomsPhylum

ClassOrder

FamilyGenus

Species

Pneumonic Device: King Phillip can only find green socks!

Kingdom is the largest category and then it gets subdivided into smaller and smaller groups.

Species is the smallest group - only organisms that are the same species can mate & produce fertile offspring

How does all of this work?Kingdom Animalia Animalia Animalia Animalia

Phylum Chordata Chordata Chordata Arthropoda

Class Mammalia Mammalia Mammalia Insecta

Order Perissodactyla Perissodactyla Proboscidea Dictyoptera

Family Equidae Equidae Elephantidae Cryptocercidae

Genus Equus Equus Elephas Cryptocercus

species grevyi caballus maximus punctulatus

Common

Name Zebra Horse Elephant Cockroach

Questions

Which two organisms on the previous slide are most closely related?

Which are more closely related, the horse and cockroach or horse and elephant?

Binomial NomenclatureTwo word naming system. The first word is

the genus. A genus is a group of similar species. The second word is the species.

Example: Maple trees are in the genus Acer. There are many kinds of maple trees, so they have a species name also. Acer rubrum – Red MapleAcer saccharum – Sugar Maple

Why do we use Binomial Nomenclature?

Helps avoid mistakes. Example: Lizards

Green Iguana (Iguana Iguana)

(Myska)

Desert Iguana (Disposaurus doralis)

(Seaman)

Organisms with similar evolutionary histories are classified together.◦Question: Look at the names of these

organisms. Which are more closely related? Panthera onca jaguar Lynx rufus bobcat Panthera tigris tiger Puma concolor cougar

Gives descriptive information about the species.Example: Acer rubrum – Red Maple. Rubrum

is Latin for red.Allow information about organisms to be

easily organized into books, pamphlets, etc.

Question

• List, in order, the 7 categories used to classify a single organism?

Dichotomous Keys

• Detailed list of identifying characteristics and scientific names

• Example: page 26 in textbook

• PART TWO – A CLOSER LOOK INTO THE ANIMAL KINGDOM

Phyla of the Animal Kingdom

• Annelida• Arthropoda• Chordata• Cnidaria• Echinodermata• Mollusca• Nematoda• Porifera

Phylum Annelida

Bilateral symmetryUniformly segmented bodyParapodia – fleshy “legs”BristlesExamples: earthworms, bristle worms,

leeches

Phylum Annelida

Bristle Worm (Read)

Phylum Arthropoda

Bilateral symmetrySegmented bodyHard exoskeletonJointed legsExamples: insects, spiders, crustaceans

Phylum Arthropoda

(Sparks, 2007)

(FreeDigitalPhotos.net, no date)

(NOAA, 2005)

Phylum ChordataBilateral symmetryHave or had a tailNotochordEmbryonic gill slitsExamples: vertebrates, sea squirts

Phylum Chordata

(Elasmodiver.com, no date) (Fireflower Systems Limited, no date)

(Hicker, 2008)

Phylum Cnidaria

• Radial symmetry• Ring of tentacles around mouth• Stinging cells• Examples: jellyfish, sea anemones, coral

(Muller, 2001)

Phylum Cnidaria

(Chpt. 10)(BBC)

Phylum EchinodermataFive part radial symmetryTube feetSpiny skinExamples: sea stars, sea cucumbers, sea

urchins, sand dollars

Phylum Echinodermata

(Zubi, 2003)

(Zubi, 2005)

(Ditchburn, no date)

Phylum Mollusca

Bilateral symmetry Have or had a shell Soft bodied with a muscular “foot” Examples: snails, slugs, bivalves, squid,

octopus

Phylum Mollusca

(Xylem Elements, 2008)(Zander, 2007)

(Huston, no date)

Phylum Nematoda

Bilateral symmetry Round, unsegmented body Cuticle Example: round worms, hook worms, pin

worms

Phylum Nematoda

(Myers, 2001)

Phylum Porifera

Asymmetrical or radial symmetry Have many pores Made up of a group of cells that have

aggregated but do not form tissues Example: Sponges

Phylum Porifera

(Missouri Botanical Garden, 2002)

Follow-up Questions

Sketch an organism with bilateral symmetry and one with radial symmetry. Draw the lines of symmetry over your sketch.

Which of the following is an animal?a. Mushroomb. Spiderc. Maple treed. Bacteria