Binomial classification

KEY CONCEPT

Organisms can be classified based on physical similarities.

Why do we classify living Organisms?

To make this great biodiversity easier to

study!

• Classification is the grouping of organisms based on similarities of features.

• Taxonomy is the science of studyingclassification. It looks at features and tries to arrange them in a logical order.

Two main types of classification

Artificial classification: in which easily

observable characteristics are used.

such as colour, mode of locomotion,

habitat etc

Natural classification: which reflects

possible evolutionary relationships,

based on ancestry (phylogeny)

Early Classification – Aristotle (384 to 322 BC)

• Greek Scholar

• Divided animals into three groups

• Those that fly

• Those that swim

• Those that crawl or walk

Linnaean Classification System Developed in the mid 1700’s

by Swedish botanist named

Carolus Linnaeus.

Classifies all organisms as

animals or vegetable (plant)

Gave all organisms a two part

Latin name.

• Why did Carolus Linnaeus develop this system?

The yellow and white

flower with many

small petals

The yellow and

white flower with

no obvious scent

Carl Linnaeus – Chrysanthemum leucanthemum

The pretty flower with a

fuzzy yellow center

surrounded by white

petals which attracts

small bees.

How it’s organized

• Linnaean

classification

system has seven

levels.

• Each level is

included in the level

above it

• Levels get

increasingly specific

from kingdom to

species.

A taxon (taxa – plural) is a group of organisms in a

classification system.

A ‘species’ is the fundamental taxon

Groups of similar species form the next largest taxon

called a ‘genus’.

Groups of similar genera form the next largest taxon

called a ‘family’

…and so on, up to the largest taxon = Kingdom.

Seven Levels of classification

1. Kingdom

2. Phylum

3. Class

4. Order

5. Family

6. Genus

7. Species

King Phillip Called

Others From Germany,

Singapore.

Limitations of Linnaean Classification

• Physical similarities are not always a result

of a species being closely related

• Unrelated species can evolve similar traits.

Modern classifications uses genetic similarities.

Recent DNA research has changed

some long standing classifications.

Binomial nomenclature

• A naming system that gives each

species a unique two part name.

• Uses Latin and Greek words.

• Uses the Genus and Species as first

and last name.

White oak:

Quercus alba

• Scientific names help scientists to communicate.

– Some species have very similar common names.

– Some species have many common names.

Advantages over common names:

• Genus - includes one or more physically similar species

that are closely related.

– Always written in italics and Capitalized

• Species – a group of organisms that can successfully breed

and produce offspring.

– Always written in italics and lowercase

Tyto alba

Binomial NomenclatureFamily

Family Felidae (Cats)

Tiger - Panthera tigris Lion - Panthera leo Kitten – Felis domesticus Cougar – Felis concolor

Genus and species

are always italicized

OR underlined if

hand written

First letter of the

genus is capitalized First letter of the

species is lowercase

Let's try some simple naming - Latin

The brown caterpillar Noun first descriptor second.

i.e. caterpillar brown

Eruca castane

Let's try some simple naming - Greek

The spotted reptile

Herpeto halio

Let's try some simple naming - Greek

Reptile with a flat nose.

Herpeto platyrhino

Types of Invertebrates

The invertebrates are a group of animals (and animal-

like organisms) that do not have a backbone.

♦ The group of invertebrates without specific organs

is referred to as the lower invertebrates. For

example, Protozoans and Porifera, while the higher

developed invertebrates have a true coelom like

mollusks, annelids, echinoderms, and arthropods.

♦ Generally, the invertebrates are divided into four

groups, based on their cellular composition and

organization, namely Protozoa, Mesozoa, Parazoa

and Metazoa

Protozoa

• They are for the most part of their lives

unicellular, i.e. made up of one cell

• They are also described as being acellular i.e.

not divided into cells (non-cellular).

• Their vital functions are carried out by

organelles.

Mesozoa (Greek: mesos =

middle; zoon = animal)

• The name was given because mesozoans are

thought to be intermediate between true

multicellular animals and protozoans (single-

celled/acellular organisms).

• Their bodies are cellular.

• They do not have more than two cell

‘layers’; the outer layer ciliated and the

inner reproductive.

Mesozoa

• They are bilaterally symmetrical.

• They have no organs.

• They have no body cavity.

• Gametes and agametes are produced from special

cells, which form the central mass of the body.

Parazoa

• Multicellular invertebrates, which possess

collared flagellated cells that make them

unique among the other multicellular

invertebrates.

• The many cells in their body are not

organized into tissues and organs.

• They are therefore at the cellular level of

organization.

Metazoa

• Invertebrates with marked cellular differentiation.

• There are two levels of organization in this group:

Diploblastic – includes animals with two cell layers showing

tissue level of organization, where the body is composed of an

inner endoderm and outer ectoderm.

Triploblastic – includes animals with three layers showing

organ level of organization; they possess a third body layer, the

mesoderm between the outer ectoderm and inner endoderm.

Characteristic features of

Protozoa

1. SMALL, MICROSCOPIC.

2. PROTOPLASMIC GRADE OF

ORGANIZATION.

3. UNICELLULAR, MULTINUCLEATED

(MONOMORPHIC OR DIMORPHIC).

4. SOLITARY, FORMING LOOS COLONY.

5. SYMMETRY – NONE

Characteristic features of

Protozoa

6. SUBCELLULAR PHYSIOLOGICAL

DIVISION OF LABOUR.

7. LOCOMOTION BY LOCOMOTORY

ORGANS LIKE CILLIA,FLAGELLA OR

THROUGH PSEUDOPODIA.

8. NUTRITION HOLOZOIC OR

HOLOPHYTIC OR PARASITIC OR

SAPROZOIC

DIGESTION

9. DIGESTION : INTRACELLULAR

THROUGH FOOD VACUOLES.

10. RESPIRATION AND EXCRETION:

THROUGH GENERAL BODY SURFACE

OR TROUGH CONTRACTILE

VACUOLES.

11. REPRODUCTION – ASEXUAL –

BINARY OR MULTIPLE FISSION.

SEXUAL – CONJUGATION

ENCYSTMENT MAY BE.

Classification of the

Protozoans

They are broadly divided into four subphyla based mainly on their organelles

and modes of locomotion as follows:

♦ Sub-Phylum: Sarcomastigophora

♦ Sub-Phylum: Sporozoa

♦Sub- Phylum: Cnidospora

♦Sub- Phylum: Ciliophora

SubPhylum

Sarcomastigophora

Uses flagella or pseudopodia as a means of

locomotion. Ex Amoeba, Entamoeba,

Euglina,Volvox single nucleus(monomorphic),

Asexual reproduction is by longitudinal binary fission.

A. Superclass MASTIGOPHORA

B. Superclass OPALINATA

C. Superclass SARCODINA

A. Superclass

MASTIGOPHORA

• Body is covered by pellicle; locomotory

organelles are flagella;

• Asexual reproduction by longitudinal

binary fission.

• It includes two classes –

Phytomastigophora and

Zoomastigophora

Superclass MASTIGOPHORA1. Class

Phytomastigophorea

• Some are with chlorophyll

bearing chloroplasts

• Nutrition is holophytic

• Reserve food is paramyl-

um

• Includes euglenoids and

dinoflagllates

2. Class

Zoomastigophorea

• Mostly parasitic;

• Chloroplasts are absent;

nutrition is holozoic

• saprozoic or parasitic,

Reserve food is glycogen

or volutin.

Class Phytomastigophorea

(Phytoflagellates): 6

orders

• Order 1.

Cryptomonadida-

Cryptomonas

• Order 2.

Dinoflagellida-

Noctiluca.

Class

Phytomastigophorea• Order 3. Euglenida -

Euglena

• Order 4.

Chrysomonadida -

Dinobryon

• Order 5. Volvocida -

Volvox

• Order 6.

Chloromonadida -

Chattonella

Class

Zoomastigophorea (Zooflagellates)- 2

orders

Order 1. Choanoflagellida –ProterospongiaOrder 2. Kinetoplastida-Leishmania, Trypanosoma.

B. Superclass OPALINATA

• Commensals or

parasites in the gut of

anurans.

• Body is covered by

oblique rows of cilia

but without

infraciliary system.

• Some are binucleate,

others are

multinucleate but

homokaryotic.

• Examples Opalina

C. Superclass SARCODINA

(=RHOZOPODA)

•Locomotion is brought about by pseudopodia.• It includes three classes –

• Rhizopodea

•Piroplasmea

• Actinopodea

Class Rhizopodea•It includes amoebas, foraminiferans.

• Amoebas have lobopodia or filopodia

• Foraminiferans have reticulopodia.

•In amoebas body is soft.

• Foraminiferans have a calcareous porous shell.

Class Piroplasmea

Parasitic; locomotory structures absent; spores are

absent.

Example: Babesia (causes red water fever in cattle)

Class Actinopodea

These are the ray footed protozoans.

• Locomotory structures are axopodia.

• Skeleton consists of siliceous shell (Radiolaria)

or strontium sulphate spines (Acantharea) or siliceous

shell or radiating needles (Heliozoa).

• Silicious shells of radiolarians form ooze

.

Examples: Collozoum (radiolarian) Actinophrys

(heliozoan) Acanthometra, Actinosphaerium

Sub-Phylum: Sporozoa

Locomotory organs absent, spores usually

present, endoparasitic) eg. Eimeria, Monocystis,

Plasmodium

It includes three classes - Telosporea,

Toxoplasmea and Haplosporea.

Class: Telosporea

•Spores without polar capsules and filaments

•Sporozoites are long

• Subclass Gregarinea (Monocystis; Gregarina).

• Subclass Coccidia (Plasmodium).

Class: Haplosporea

•Spores are present and are amoeboid,

•Reproduction is only asexual, by multiple

fission.

• Each spore contains singl e sporozoite o

Example: Haplosporidium

Class: Toxoplasmea

Body covered by two layered pellicle

• Only asexual reproduction, by endodyogeny.

• It is internal budding wherein two daughter

cells are produced within a mother cell and the

mother cell is destroyed in the process,

Example: Toxoplasma

Sub- Phylum: Cnidospora

• Parasitic.

• No special locomotory structures.

• Spores are provided with one or more polar filaments,

which are useful for attachment to the host.

• It includes two classes - Myxosporidea and

Microsporidea

Sub- Phylum: Cnidospora

Class Myxosporidea

• Extracellular parasites of

cold blooded vertebrates.

• Spores with typically two

capsules each with single

polar filament.

• Example: Myxidium

Class Microsporidea

• Intracellular parasites in

fish.

• Spore with one

intrasporal or 1 -2

intracapsular filaments.

• Example: Nosema

bombycis

Sub- Phylum: Ciliophora•Complex protozoans.

• Cilia are useful in locomotion and food capture.

• Dimorphic nuclei - macronucleus (vegetative and polyploid) and micronucleus (reproductive and diploid),

•Sexual reproduction by conj ugation, which brings about nuclear reorganization.

•Only class under this subphylum is Class Ciliata. o

Example: Paramecium, Balantidium.

Class Ciliata

Subclass Holotricha (Paramecium; Balantidium).

Subclass Peritricha (Vorticella).Subclass Suctoria (Ephelota; Podophrya).Subclass Spirotrichia (Stentor)

Class Ciliata

Subclass Holotricha

• Buccal cillia absent.

• Body cillia simple and

uniform.

• Orders- 6

1.Gymnostomatida

2.Trichostomatida (Balantidium)

3.Chonotricha

4.Apostomatida

5.Astomatida

6.Hymenostomatida

(Paramecioum)

Subclass Peritricha

• Adult wothout body cillia.

• Apical end with buccal

cillia.

• Oreder

• Peritrichida (Vorticella)

Subclass Suctoria

Subclass Suctoria

• Sessile and stalked body.

• Young with cillia, adult

with suctorial tentacle

• Order- Suctoria

• ex Podophyra

Subclass Spirotrichia

• Reduced body cillia.

• Buccal cillia well marked.

• Ex Nyctotherus

• Orders- 3

• Hetertrichida

• Oligotrichida

• Hypotrichida