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Biology 1st Secondary

Unit Four

Classification of Living Organisms

Chapter One (session 7)

Principles of classification of Living Organisms

Classification : Is the arrangement of living organism in groups according to their

similarities & differences to facilitate their study, identification & their relation to man.

Taxonomy: Is the science that concerns with the classification of living organisms in groups

on scientific bases.

Importance of classification:

1- It facilitates studying and identifying the living organisms.

2- It facilitates identifying the new organisms and adding them to their similar groups.

3- It benefits many other fields of science.

Species: Unit of classification being a group of individuals having similar morphological

characteristics, can mate with each other & produce fertile offspring similar to them.

Tigon Mule

It is produced from a female lion with a

male tiger (two different species),

It is sterile, unable to mate, reproduce and

produce a new generation of the same

species

It is produced from mating of a

female horse with a male donkey

(two different species)

It is sterile, unable to mate,

reproduce and produce a new

generation of the same species

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Naming of Living Organisms

Carolus Linnaeus

He developed a system for naming the organisms and gve it the name (binomial nomenclature

system)

The name is written in Latin language.

Each living organism has binomial name where:

- The 1st name represents the genus and begins with a capital letter.

- The 2nd

name represents the species and begins with a small letter.

Example:

The scientific name of the cat is (felis domesticus) or felis catus.

Taxonomy hierarchy:

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Dichotomous key:

It is a series of descriptions that are orders in pairs and lead the user to the identification of living

organism.

It starts with broad features then it gets more specific.

Through each step you can choose one of the 2 descriptions according to the

characteristics of the living organism.

At the end, you will reach a description that leads to the organism's name or the group to

which it belongs.

Examples of dichotomous key:

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Exercise (principles of classification)

Choose the correct answer:

1- Tigon is not given the term "species" because it ……………..

a- Is not similar to its parents b- Is unable to mate

c- Produces fertile individuals d- Is able to mate

2- Bean plant is from dicotyledons plants, which of the following expresses the

binomial nomenclature for it?

a- Vicia faba b- Vicia Faba

c- Vicia faba d- VICIA FABA

3- If the number of individuals in a phylum of Animalia is 3 million, so the number

of individuals in a class in this phylum may be ……………millions.

a- 9 b- 6

c- 3 d- 1

4- The arrangement of class in the classification hierarchy of living organisms is

……………..

a- Preceding the family and

following the genus.

b- Preceding the species and

following the phylum

c-

d- Preceding the order and

following the phylum

e- Preceding the kingdom and

following the family.

5- In the taxonomy hierarchy, which of the following levels contains the highest

number of living organisms?

a- Family.

b- species

c- order

d- kingdom

6- The scientific name of potato is Solanum tuberosum and the scientific name of

sweet potato is Ipomoea botatus. So, they are similar in…………..

a- phylum

b- subgenus

c- genus

d- species

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Chapter Two (session 8)

Modern classification of Living Organism Old system of classification

1- Kingdom Planta

2- Kingdom Animalia

Modern system of classification:

1-Kingdom Monera

2-Kingdom Protista

3-Kingdom Fungi

4-Kingdom Planta

5-Kingdom Animalia

Kingdom Monera

Unicellular

No nuclear membrane (prokaryotic)

Cell wall is devoid from cellulose or pectin

Cytoplasm is lack of many membranous organelles such as mitochondria, Golgi body, plastids

and endoplasmic reticulum.

a- Phylum Archaebacteria:

Survive in harsh environmental conditions.

b- Phylum Eubacteria:

Contain colored pigments mostly blue green.

Some are autotrophic as cyanobacteria ex.: Nostoc .

Others are heterotrophic.

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Kingdom Protista

Not complex in structure.

It is eukaryotic (genetic material is surrounded by nuclear membrane)

They are different from plants and animals as they are not complex and some of them have cell

wall and plastids.

a- Phylum Protozoa:

Free living or parasites on plants & animals causing diseases

It includes 4 classes:

1- Class Sarcodina: ex.Amoeba- move by pseudopodia.

2- Class Ciliophora: ex. Paramecium – move by cilia.

3- Class Flagellata: ex. Trypanosoma- causes sleeping disease –

move by flagella.

4-Class Sporozoa: ex. Plasmodium-causes malaria–have no

means of locomotion .

b- Phylum Euglenophyta:

Euglena

It contain green plastids & move by flagella.

c- Phylum Chrysophyta:

Diatoms

They are considered as source of fish food.

d- Phylum Pyrrophyta:

Phytoplankton algae in seas & oceans, red in color & move by flagella.

3) Kingdom Fungi

Have no chlorophyll so they obtain food from other organisms [saprophytes or parasites].

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a-Phylum Zygomycota: ex. Rhizopus [bread mould ] – produce enzyme used in cheese

industry.

b-Phylum Ascomycota: May be unicellular as yeast or multicellular as-penicilium used in

production of penicillin antibiotic.

c-Phylum Basidiomycota: ex. Mushroom.

bread mould

penicillium mushroom

yeast

4) Kingdom Planta

a-Phylum Rhodophyta: [red algae] ex. Polysiphonia.

Polysiphonia

b-Phylum Phaeophyta: [brown algae] ex. Fucus

c-Phylum Chlorophyta: [green algae] ex. Chlamydomonas [unicellular] & Spirogyra

[multicellular].

d-Phylum Bryophyta: Non – vascular plants – terrestrial. ex. Riccia (flat) &

Funaria (erect)

e-Phylum Tracheophyta: [vascular plants: have xylem

& phloem]

-Divided into 3 classes:

1- Class Filicatae: (ferns)ex. Adiantum

-Have stem, leaves, roots but no flowers or seeds.

2- Class Gymnospermae:(conifers) ex. Pinus

-Don’t produce flowers – Have naked seeds

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3- Class Angiosperm: (flowering plants)

Subdivided into:

Monocotyledons Dicotyledons

-Seeds have only one cotyledon.

-Flowers with trimerous whorls.

-Leaves are narrow & parallel veined.

-Fibrous roots.

-Ex.: wheat, onion & palm.

-Seeds have two cotyledons.

-Flowers are either tetramerous or

pentamerous.

-Leaves are pinnated or palmated

venation.

-Tap roots.

-Ex.: peas, beans & cotton.

Wheat onion

pea Cotton

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Exercise (Monera / Protista)

Choose the correct answer:

1- Which of the following pathogens is not classified, according to the modern

classification?

a- Sleeping sickness

b- Malaria disease

c- AIDS d- Elephantiasis

2- The basic standard in classifying this organism

among monerans is ………….

a- The number of cells

b- The type of nucleus

c- The absence of

mitochondria

d- The presence of

plastids

3- From the unicellular organism that doesn’t have a nuclear membrane is

………………

a- Nostoc

b- Euglena

c- Trypanosoma d- Amoeba

4- Trypanosoma and plasmodium are different in ……………….

a- The mode of nutrition

b- The phylum

c- The type of nucleus

d- The method of locomotion

5- Euglena and Dino-flagellates are similar in all the following, except …………..

a- The degree of complexity of

the body

b- The mode of nutrition

c- The method of locomotion

d- The type of pigments

6- From the Protists that can perform photosynthesis process is …………..

a- Dino-flagellates

b- paramecium

c- plasmodium

d- Trypanosoma

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Exercise (kingdoms fungi / Plantae)

Choose the correct answer:

1- All the following organisms have nuclear membrane except ………….

a- penicillium

b- Amoeba

c- bacteria

d- bread mold fungus

2- There are some multicellular saprophytic living organisms cause spoilage and

they are used in some food industries, these organisms belong to kingdom………………

a- Monera

b- Protista

c- fungi

d- Plantae

3- Which of the following doesn’t produce spores?

a- plasmodium

b- penicillium

c- polysiphonia

d- mushroom

4- From the opposite figure, letter (X) refers to ………………..

a- The mode of nutrition

b- The method of locomotion

c- The taxonomic level

d- The habitat

5- Which of the following doesn't contain xylem vessel?

a- Pinus

b- Bean plant

c- polypodium

d- Funaria

6- All the following plants form seeds except………………

a- Pinus b- Cactus

c- Cotton

d- Polypodium

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Session 9 5) Kingdom Animalia

a- Phylum Porifera: ex. Sponges

Aquatic, attached at the base to rocks.

b- Phylum Cnidaria: ex. Hydra, Jelly fish, Corals.

-Aquatic, some attached others move, some have tentacles with cnidocytes (stinging cells).

ex. Hydra, Aureli (jelly fish) & sea anemone

b- Phylum Platyhelminthus [flat worms] cause diseases to man & animals.

Ex. Planaria, Bilharzia & Tape worms

d- Phylum Nematoda: [round worms]ex. Ascaris , Flaria. Ascaris

- Free living, parasites on man, animals & plants.

e- Phylum Annelida [ring worms] ex. Earth worm.

- Free living – few are external parasites.

f- Phylum Arthropoda:

-Body divided into segments carrying jointed appendages.

-Covered by an exoskeleton.

-Divided into:

Class Crustacea: ex. Crabs & Prawn.

Class Arachnides: ex. Scorpions, spiders.

Class Insecta: ex. Cockroach, flies, mosquito,

moths, bees, ants & locust.

Scorpion Locust

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Class Arachnides Class Insecta

-Body divided into thorax &

abdomen.

-Four pairs of walking legs, simple eyes.

-Breath through trachea or lung books.

-Body divided into head, thorax,

abdomen.

-Head contains a pair of antenna & a pair of

compound eyes.

-Has 3 pairs of jointed legs & 2 pairs of wings

[one or none].

-Respire through trachea.

Class Myriapoda: ex. Scolopendra.

g-Phylum Mollusca: ex. Desert snail Oyster

Octopus.

-Body soft mass.

h-Phylum Echinodermata: ex. Star fish Sea cucumber.

-Most developed invertebrates.

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Session 10 i- Phylum Chordata:

-Most developed animals.

-Includes 7 classes:

Class: Agnatha [jawless fish] ex. Lamprey.

Class Chondrichthyes [cartilaginous fish] ex. Ray fish, sharks.

Class Osteichthyes: [bony fish] ex. Bouri, bolti.

Class Chondrichthyes Class Osteichthyes

- Cartilaginous endoskeleton.

- Mouth on ventral surface with strong teeth.

-Breath by gills with no operculum.

-Bony endoskeleton.

-Mouth terminal.

-Breath by gills with operculum.

Class Amphibia: ex. Frogs Salamanders

- Embryo in water-adult on land- return to water for fertilization.

- Cold blooded [temp of body varies with environment.].

Class Reptilia: ex.: Lizard, chameleon, gecko, tortoise, snake & crocodile.

- Cold blooded.

Class Aves: ex. Pigeon, hen, duck, hawk, eagle, sparrow & ostrich.

- Forelimbs modified to wings for

flying.

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- Warm blooded [constant body temp ] .

Class Mammalia:

- Warm blooded [constant body temp]

- Subdivided into 3 subclasses:

1) Protheria: ex. Duck-billed platypus.

- Lay eggs – young suckle milk.

2) Metatheria: ex. Kangaroo.

- Give birth to undeveloped young- kept in pouch to complete

development.

3) Eutheria:

- Give birth to fully developed youngs.

- Sudivided into :

a- Order Edentata: ex. Armadillo Sloth.

- Without teeth.

b- Order Insectivora:

ex. Hedgehog.

-Front teeth like pincers extending outwards.

c- Order Carnivora: ex. Lion , tiger, wolf, fox, dog,

cat.

-Large canines, premolars & molars .

d-Order Perissodactyla: ex. Horse, donkey, zebra & rhinoceros

-Big sized teeth to grind food.

-Odd-toed, each toe has horny hoof.

e- Order Artiodactyla: ex.Sheep, goats, giraffe,

deer & camels.

-Tips of toes protected by horny masses {hooves}

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f-Order Cetacea : ex. Whale, dolphin.

-Marine animals, respire atmospheric oxygen by lungs.

g-Order Rodenta: ex. Gerbo, rats.

- One pair of chisel-shaped incisors in each jaw.

h-Order Lagomorpha: ex. Rabbit.

- A pair of incisors in upper jaw & two pairs in lower jaw.

i-Order Chiroptera: ex. Bats.

- Weak eyes, fly at night.

j-Order Proboscida: ex.:Elephant.

-The two upper incisors grow to form the canines.

i-Order Primates: ex. Lemurs, monkeys, chimpanzee, gorilla, man.

- Most highly developed mammals with pentadactyle limbs.

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Exercise (kingdoms Animalia)

Choose the correct answer:

1- All the following statements are correct except……………….

a- All mammals suckle their young.

b- Some mammals lay eggs

c- All mammals have canines

d- All mammals breathe by lungs.

2- Bony fishes differ from the adult of amphibians in the …………….

a- Unisexuality b- type of fertilization

b- Way of respiration d- thermal equilibrium

3-The eggs laying trait in females indicates an example for the ……….traits

a- Sex linked b- sex influenced c- sex limited d- Mendelian

4- The following figures represent two types of living organisms, where they share

each other in…………………

a- The type of eyes b- The number of body regions

c-The number of walking legs d- The presence of exoskeleton

5- All the following statements are correct, except that ……………

a- All mammals suckle their young.

b- Some mammals lay eggs

c- All mammals have canines

d- All mammals breathe by lungs

6- The means of locomotion are varied in phylum …………..

a- Porifera b- Mollusca

c -Echinodermata d- all the previous