Chapter 18 Classification

18.1 Finding Order in Diversity

I. Assigning Scientific Names

□ Common names confusing=varies w/lang & location

□ Scientific name (latin) same worldwide

Puma Cougar Panther

Common names for a mountain lion:

The many names of Boletus

edulis

France:

Cepe

United

States:

King

Bolete

Italy:

Porcini

German

y:

Steinpilz

England

:

Penny

Bun

Sweden

:

Stensop

p

Poland:

Borowik

Finland:

Herkkut

atti

Spanish:

Rodelló

n

□ Dichotomous key: guide to ID unknown org

Uses paired statements with alternate choices

A. Binomial Nomenclature:

1. Linneaus (Swedish botanist) developed

2. 2-word naming system

□ Genus species or Genus species

□ Genus=type or group; species=unique description

B. Classifying species into larger groups

1. Systematics: organizing life into meaningful groups

2. Taxa: biological groupings

This poison arrow frog's scientific name,

Dendrobates azureus, means blue tree-walker!

The king vulture

Sarcorhamphus papa has a scientific name that means "father or leader with a fleshy, curved beak."

II. Linnaean Classification System A. Uses 7 hierarchical, ordered ranks-taxa

1. Largest to smallest: Kingdom, phylum, class, order,

family, genus, species

B. Problems with Traditional Classification

1. Used visible similarities/differences (barnacles look like

limpets but are more like crabs)

2. Today: use evolutionary relationships

Limpet:

gastropod mollusk Barnacle: crustacea

Crab: Crustacea

18.2 Modern Evolutionary Classification

I. Evolutionary Classification

□ Phylogeny: species grouped using evolutionary descent

A. Common Ancestors: taxa groupings show relationships

1. Larger, more diverse taxa=more ancient common ancestor

B. Clades-a monophyletic group: single common ancestor and all

descendants (living & extinct)

II. Cladogram

Cladistic analysis shows specific traits branch from comm ancestor

Links groups showing evolutionary relationships

A. Building Cladograms: branches (nodes) represent ancestral species

splitting in 2

1. Each node=last point species above line shared com ancestor

2. Root of node=common ancestor of those more recent

B. Derived Characters: trait arising in most recent ancestor of lineage

C. Losing Traits: tetrapods (4 limbs) include reptiles; snake still reptile

D. Interpreting Cladogram: character positions reflects order they arose

E. Clade vs Traditional grps: evol. links more accurate=clades connects

all species back to original ancestor (dinosaurs/ birds/reptile)

III.DNA in Classfication

A. Genes as Derived Characteristics

1. Gene homologies (similarities) determine evolutionry relationshps

2. Mutations=derived characteristisc

3. More recent commn ancestors = ↓ diffs in genes (more mutations

in common) =>closer related

B. New Evolutionary Trees

1. DNA=more accurate evolutionary tree

2. American vulture looks like African vulture yet DNA &

behavior more similar to stork (more recent comm ancestor)

3. Giant panda DNA more like bears; Red panda DNA more

like racoons (Pandas now in different clades)

African

Vulture Amercan

Vulture

Stork

Giant Panda

Red

Panda

Raccoons Red pandas Giant pandas Bears

Common Ancestor

18.3 Kingdoms (6) & Domains(3) I. Changing Ideas about Kingdoms

A. W/diversity of life: science moved from Linnaeus’s 2

kingdms to 5

B. Genetic data= bacteria Kingdom Monera divided into 2

C. Genome data=new taxonomic division: Domain (larger

than kingdom); now have 3

□ “Protista”: so diverse, > than 1 comm ancestr=not true clade

II. The Tree of Life

A. Domain Bacteria

1. Kingdom Eubacteria

2. Characteristics:

a) Unicellular

b) Prokaryotic

c) Thick Cell Wall

□Peptidoglycan

d) Diverse (majority)

1. Kingdom Archaebacteria

2. Characteristics:

a) Unicellular & anaerobic

b) Prokaryotic

c) Cell membranes contain unique lipids

d) Extreme Env’t

B. Domain Archaea

C. Domain Eukarya w/4 Kingdoms

1. Kingdom Protista

a) Paraphyletic group (more than 1 com ancestor)

b) Plant-like, fungus-like, animal-like members

c) Now at least 5 clades

d) Most single celled

2. Kingdom Fungi

a) Feed on dead/decaying org.

b) Cell walls contain chitin

c) Digest externally

d) Most multicellular

3. Kingdom Plantae

a) Autotrophic=Photosynthesis

b) Cell Wall (cellulose)

c) All plants are sister group to red algae (protist)

4. Kingdom Animalia

a) Multicellular/hetero

b) No Cell Wall/Motile