UNIT 4 – TAXONOMY AND CLASSIFICATIONCHAPTER 13 IN TEXT

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4.0 CLASSIFICATION AND TAXONOMY

• 4.1 Define taxonomy

• 4.2 Discuss the reasons for classifying organisms

• 4.3 Define species and binomial nomenclature

• 4.4 Describe Carolus Linnaeus’ classification system

• 4.5 Define taxon and list the levels in order from broadest to the most specific

• 4.6 Describe the five kingdom system and the characteristics associated with each kingdom

• 4.7 Discuss the problems with the five kingdom system and the recent taxonomic solution

• 4.8 Describe the three domain system and the characteristics associated with each domain

• 4.9 Define dichotomous keys and their importance in identifying organisms

Taxonomy is the science of classifying all species of

organisms, extinct and living.

It is important because of the great diversity of

organisms. Some organisms appear similar, some have

similar functions, and some are genetically related but

look different.

SPECIES

•One definition for a species is a related group of organisms

that share a more or less distinctive form and are capable of

interbreeding.

• This is the most popular definition in Biology, however, even

this definition is under debate since a large number of

organisms do not interbreed but rather reproduce asexually.

NAMING AND CLASSIFYING ORGANISMS

• There are well over 2 million different

types of organisms known.

• Biologists place the organisms into

groups based on their characteristics.

• By classifying, biologists can organize

living things into groups.

The system of

naming we use today

was created over

300 years ago by

Carolus Linneaus

(Father of Classificatrion)

• The Linnean system is very simple

to use and became popular as a

result

NAMING ORGANISMS

• Many of the names are based on the

Latin or Greek since that is what was

used when the naming system was

created.

• Scientists are required to give new latin

scientific names when they discover new

species

• The names often reflect the

characteristics of the organisms, or in

some cases honour the discovering

scientist

BINOMIAL NOMENCLATURE

• Binomial = 2 terms

• Nomenclature = naming

• System of naming species using a

two-term name

• First term is the genus name

• Second term is species name

• Rules for naming

1. The genus name is capitalized

2. The second name is the species

and is entirely lower-case

3. The name must be either in

italics or have each term

separately underlined

BINOMIAL NOMENCLATURE EXAMPLES

CORRECT WAY

• Canis familiaris – house dog

OR

• Canis lupus – Wolf

• Many species may be in the same

genus because they are related, in

this case dog-like animals

WRONG WAY

• Canis Familiaris

• canis lupus

• Canis latrans - Coyote

• Canis lupus

• The wolf Canus lupus is not endangered.

• Canus lupus has 39 subspecies. Some of these

subspecies are threatened.

Canus lupus lupus Canis lupus familaris Canis lupus dingo

Domestic Dog

BENEFIT OF UNIVERSAL NAMING

• A universal system of

naming allows us to avoid

the confusion associated

with common names, and

tells us something about

evolutionary

relationships.

Eg. A plant species May have 2 common names – dependant

where you live…

• Bullrush – cattails

• Ptarmigan – grouse

• Larch - tamarack

Eg. Common names give you misleading info on species

classification, causes confusion.

• Catfish shellfish

• Starfish crayfish

Eg. This system uses Greek and Latin – this avoids

miscommunication = no matter what language you speak –

every scientist will know what a Homo sapien is.

The genus name can be abbreviated to its initial letter, but never

omitted, (as H. sapiens) when repeated or when several species

from the same genus are being listed or discussed in the same

paper or report.

EACH ORGANISM IS FIRST CLASSIFIEDINTO A DOMAIN…….

1. Domain Bacteria

• Kingdom Bacteria

• Earliest living organisms, 1000’s of

species exist today

2. Domain Archaea

• Kingdom archaea

• Evolved later, through a series of

changes in bacteria

3. Domain Eukarya

• Kingdoms protista, plantae,

animalia and fungi

• Early protists branched away from

bacteria, giving rise to all the

other kingdoms

These 3 domains are divided

by cell plan type:

• Prokaryotic

• Eukaryotic

ANIMATION: CLASSIFICATION SCHEMES

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video

2 KINGDOMS TO THE 6 KINGDOM CLASSIFICATION SYSTEM WE USE TODAY……

With increased travel, increased technology – scientists have

discovered new species that did not fit nicely into Aristotle's

2 kingdoms ----- changes needed!

ROAD TO 6 KINGDOM CLASSIFICATION

• We often tend to organize things based on

physical characteristics

• Music, clothing, books

• The groupings reflect the patterns we see in

the world around us

• Aristotle first grouped over 1000 organisms

into 2 large kingdoms, then subdivided each into

smaller groups

• 1. KINGDOM ANIMALIA

• Grouped based on movement:

• on land

• in the air

• in water

• 2. KINGDOM PLANTAE

• Grouped based on physical

characteristics

• Reproductive structures

• Types of external tissues

CLASSIFICATION: A WORK IN PROGRESS

• In the mid-1900s, the two-kingdom system was replaced by a five-kingdom

system that

• placed all prokaryotes in one kingdom and

• divided the eukaryotes among four other kingdoms.

• ** with technology – scientists have discovered single cellular prokaryotic

organisms living in extreme environments ( salt, acidic and volcanic

environments) – prokaryotes now 2 kingdoms. (Monera and Archeabacteria)

• **The domain Eukarya is currently divided into kingdoms, but the exact

number of kingdoms is still under debate. (Protista)

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ROAD TO 6 KINGDOMS

• 3. KINGDOM PROTISTA

• Discovery of micro-

organisms forced

scientists to reconsider

Aristotle’s system of

classification

• Some organisms move

like animals, but

photosynthesize like

plants

ROAD TO 6 KINGDOMS

• 4. KINGDOM FUNGI

• Were originally included in the

plant kingdom

• Were placed in their own

kingdom because they do not

photosynthesize, and absorb

nutrients from their

environment

INVENTION OF MICROSCOPE – NEW KINGDOM

Entirely made up of prokaryotic cells (lacking a nucleus and

membrane-bound organelles)

Obtain energy from a wide range of environments, but thrive

between 10 and 40 degrees celcius

Also called: Monera, eubacteria (true bacteria)

5. Kingdom Bacteria

ROAD TO 6 KINGDOMS

6. KINGDOM ARCHAEA

• Also made up of prokaryotic cells, but with specialized structures

allowing them to live in extreme environments

• Hot vents, acidic lakes, high pressure, low oxygen, etc.

• Also called: archaebacteria

Today, the above five kingdom system is not ideal or realistic for the diversity of organisms. There

exist two problems, Kingdom Monera and Kingdom Protista.

Kingdom Monera is the group of organisms that have

been around since four billion years and, as a result,

their long existence has led to evolutionary

adaptation and the greatest metabolic diversity.

Scientists have added a taxon broader than Kingdom

and, therefore, placed above Kingdom. This grouping is

called the Domain, of which there are currently three

recognized.

1. Domain Eubacteria include "true" bacterial

organisms that are prokaryotic and contain cell walls

composed of peptidoglycan.

2. Domain Archaea include bacterial prokaryotic

organisms whose cell walls are composed of a

different substance. By adding these two domains, the

bacteria and prokaryotic organisms are better

classified based on their overwhelming characteristics.

3. The third domain is Domain Eukarya and includes all

organisms composed of eukaryotic cells. For example,

Kingdom Fungi, Plantae, and Animalia.

Copyright © 2010 Ryan P. Murphy

FIGURE 14.26

Earliest

organisms

Domain Bacteria

Domain Archaea

Domain Eukarya

The protists

(multiple

kingdoms)

Kingdom

Plantae

Kingdom

Fungi

Kingdom

Animalia

Paradigm Shift – 5 to 6 Kingdom Classification System

•1. Kingdom Monera (Bacteria): Unicellular prokaryotic organisms that are the simplest in structure

but display the greatest metabolic diversity.

•2. Kingdom Fungi: Mostly multicellular eukaryotic organisms that contain cell walls and are absorptive

heterotrophs (consume organic molecules)

•3. Kingdom Plantae: Multicellular eukaryotic organisms that contain cell walls and are autotrophic

(consume CO2)

•4. Kingdom Animalia: Motile multicellular eukaryotic organisms, without cell walls, and are ingestive

heterotrophs.

•5. Kingdom Protista: Multicellular or unicellular eukaryotic organisms with diversity in their nutrition.

6. Kingdom Archaebacteria : unicellular prokaryotic organism – living in extreme environments.

Kingdom

Bacteria

DomainBacteria

Kingdom

ProtistaKingdom

FungiKingdom

PlantaeKingdom

Animalia

DomainEukarya

Kingdom

Archaea

DomainArchaea

Living Things

Problems with Kingdom Protista – latest divide and problems with kindgoms!The protists are eukaryotic and, therefore, are included under Domain Eukarya.

However, the problem with the protists is that they are a "dumping ground" for any eukaryotic organisms that

does not fit as a Fungus, plant or animal.

The result is a large group of organisms making up Kingdom Protista with no specific characteristic except that

they are eukaryotic.

For example, they may be unicellular or multicellular, autotrophic or heterotrophic, with cell walls or without.

Scientists have patched this problem by dividing Kingdom Protista into several new and different Kingdoms. They

are:

• Kingdom Archaezoa

• Kingdom Euglenozoa

• Kingdom Alveolata

• Kingdom Stramenopila: the brown algae

• Kingdom Rhodophyta: the red algae

Even this is not a fix because current debate exists over the green algae. Should they be in their own Kingdom as

the brown algae and red algae are, or should they be placed with Kingdom Plantae because of their close

relationship with green plants?

Hierarchy of Taxa

Still a changing science, the taxonomy of today is shown below.

Domain Archaea Eubacteria Eukarya

Kingdom Numerous Numerous 1. Archaezoa

2. Euglenozoa

3. Alveolata These are new!

4. Stramenopila

5. Rhodophyta

6. Fungi

7. Plantae Older Taxa

8. Animalia

TAXONOMY

Carolus Linneaus

(Father of Classification)

HIERARCHY OF GROUPS

• Each kingdom is subdivided into

smaller and smaller groups called

taxa (one taxon)

• Kingdoms are the largest taxa,

containing 1000’s of species

• Species are the smallest taxa,

containing only one type of organism

• The Taxa

• Domain

• Kingdom

• Phylum (plural – Phyla)

• Class

• Order

• Family

• Genus (plura – genera)

• Species

• Each taxon may have subtaxa

LINNAEUS CLASSIFICATION

• The groupings or taxa from most general to most specific are:

• Domain

• Kingdom

• Phylum (animals) or Division (plants)

• Class

• Order

• Family

• Genus

• Species

Did King Philip cried out “For Goodness sakes?”

HUMANS

• Kingdom Animalia

• Phylum Chordata

• Class Mammalia

• Order Primates

• Family Hominidae

• Genus Homo

• Species sapien

PHYLOGENY & CLADISTICS

• Phylogeny – The whole evolutionary history of a species or other taxonomic group. • At the base of the tree is the oldest ancestor• Forks in branches represent divergences of new species• The top of the tree represents the most recent time, so from

the base to the top of a branch is a progression through time.

• Cladistics – A classification scheme based on phylogeny and the idea that any one group of related organisms was derived from a common ancestor

PHYLOGENETIC TREES

Cladogram – A diagram similar to a phylogenetic tree that does not

take into account the time of a divergence.

PHYLOGENETIC TREE OF LIFE

DICHOTOMOUS KEYS

• A tool used by biologists to identify

unknown organisms

• Consists of a series of paired

comparisons of characteristics used to

sort organisms into smaller and smaller

groups

Dichotomous Keys Using Smiley Faces

Instructions: Use the key below to identify the species name of each of the smileys below.

1. Teeth visible ....................go to 2 6. Smiling, happy face ...... Smilus traditionalis

.....Teeth not visible .................go to 4 .....Not happy, frowning or other .....go to 7

2. Has a wide, toothy smile .......Smilus toothyus 7. Mouth curved down, frowning .... Smilus saddus

....Is not smiling ......................go to 3 .... Mouth is a small circle .................Smilus suprisus

3. Visibly crying .................Smilus dramaticus 8. Has a pirate eye patch ...............Smilus piratus

.... Frowning .......................Smilus upsettus ....Does not have eye patch ............ go to 9

4. Eyes are symmetrical .... go to 5 9. One eye is much larger than the other eye ...... Smilus mutatus

....Eyes not symmetrical .....go to …One eye is winking .................Smilus winkus

5. Eyes shaped like hearts ..... Smilus valentinus

....Eyes are shaped as ovals .....go to 6

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8

Genus: Aliens

Be sure to use Genus &

Species name

Be sure to use proper

formatting rules for

writing scientific

names!!

H. Precede the description with the part that is being described (leaves are red…. Instead of leaves present)

I. Start the choices in a couplet with the same word, if possible.

J. Start each couplet with different words, if possible.

Assignment #4