CLASSIFICATION OF LIVING THINGS

Classification (taxonomy) can be described as sorting, ordering and grouping of living

things. In the present day classification, all characteristics of plants and animals are used. Hence,
similar plants and animals are grouped together. This makes the study for each group easier. The
grouping of living things into their kind is called Taxonomy or Classification. The system of
classification we use today is based on that introduced by Swedish scientist Carl Von Linne
(1707-1778). He is better known by his Latin name which Carlous Linnaeus. He published a
classification of plants in 1753 and that of animals in 1758. Linnaeus proposed 7 main categories
or taxonomic group or classification known as Hierarchy of Classification. These are;

Kingdom

Phylum (Animal) /Division (Plant)

Class

Order

Family

Genus

Species

1. Specie: This is basic unit of classification containing members which have the largest
number of features in common which have the largest number of features in common.
The members of a specie are similar and so can mate or interbreed with each other to
produce offspring. E.g. human beings belong to specie sapiens.
2. Genus: Genus is made up of group of species which have many things in common. Such
that they are believe to be closely related. For example, Horse, Donkey, Zebra belong to
different species but are so much in common that they are placed in the same genus.
Lions, Cat, Dog belong to the same genus.
3. Family: Family is made up of genuses that have many things in common. Chimpanzees,
Human beings and Apes are Hominidae.
 4. Order: They are also made of family that shares same characteristics. For examples all
primates belong to the same order.
5. Class: This is made up of order that share same characteristics in common. E.g.
mammalian they have mammary gland.
6. Phylum/Division: Classes with common characteristics are placed in the same phylum.
E.g. phylum Chordata are made up of notochord e.g. Mammalia, Aves (bird), Amphibian,
Reptilia.
7. Kingdom: This is the highest level of classification and it is made up of phylum or
division common characteristics.

Assignment: write out the classification of 2 animals and 2 plants.

Nomenclature

This is the science of naming living things. In Linnaeus system, each organism was
named to indicate the genus and specie. This is called binomial system of nomenclature.

It is the science of naming living organism in which each organism is given two names.
The first name is the generic name from the genus while the second name is the specific name
from the specie. In binomial nomenclature, the generic name starts with capital letter while the
specific name starts with small letters. The names are written and underlined separately except
when they are typed in italized form.

For example: Zea mays or Zea mays

Systems of classification

According to Linnaeus classification, he placed all organism into two system kingdom i.e. two
system of classification (kingdom plantae and kingdom animalia). While, the five kingdom
system of classification which most biologists favour place all living organism into five
kingdoms, which are;

- Kingdom Monera
- Kingdom Protista
- Kingdom Fungi
 - Kingdom Plantae
- Kingdom Animalia

Kingdom Monera

The organism in this kingdom include bacteria (single bacterium) and blue green algae
(cynobacterium). They have the following characteristics;

1. They are uni-cellular organism (single cell) though some form filament
2. The cell is prokaryotic (a prokaryotic cell is a simple cell that doesn’t have true nucleus)
3. They are either motile or non-motile
4. The cells have no mitochondrion, endoplasmic reticulum, chloroplast and other double
membrane bounded organelles
5. They may be autotrophic or heterotrophic in their mode of feeding
6. Their cell wall does not contain cellulose but it contains peptidoglycan (mixture of
polysaccharide and amino acids)
7. They do not have complex chromosomes (they have a single strand DNA)
8. They carry out asexual reproduction

Draw the Diagram of a Bacterium Cell

Kingdom Protista

1. They are eukaryotic organisms (cell with true nucleus)

2. They are unicellular organism or simple multicellular organisms
3. They are found mostly in watery areas like rivers, ponds, streams, moist places and body
fluid of living organisms
4. Some of them are heterotrophic in their mode of feeding while some are autotrophic and
some are both heterotrophic and autotrophic
5. Reproduction is usually asexual by mitosis but in some, sexual reproduction is by fusion
of gamete
6. Movement maybe by Cilia in Paramecium, Flagellum in Chlamydomona and Euglena,
Pseudopodia in Amoeba.

It is divided into four phyla:

 Phylum Protozoa
 Phylum Pyrrophyta (also called Dinoflagellata)
 Phylum Chrysophyta
 Phylum Euglenophyta
 Phylum Protozoa: This are animal like protist, they cannot manufacture their food themselves,
their mode of feeding is basically holozoic, parasitic and saprophytic. Holozoic are the feeding
methods in which an organism feeds on food substances that needs to be digested (bulky
materials), while parasitic mode of feeding is a type of feeding in which organism derive its
nutrients from its host causing harm to it (the host). Saprophytic is a mode of feeding in which an
organism feeds on dead organism or their remains. , they can reproduce sexually and asexually,
they may live individually or in groups called colonies, and they can be free-living or act as
parasites of other organisms.

Comparison of the locomotion of the classes belonging to phylum Protozoa, with example of organisms

Class Sarcodina Ciliophora Flagellata Sporozoa

No special
Move by temporary extensions Move by cilia Move by flagella
Locomotion organellel for
called pseudopodia surrounding the cell extending from the cell
locomotion

Example Genus Amoeba Paramecium Trypanosoma Plasmodium

Some of the above named protozoan species can be harmful to humans. For example, some
species of Plasmodium, such as Plasmodium falciparum, cause the disease malaria.
The Plasmodium parasites are carried by Anopheles mosquitoes and are transmitted to humans
via a bite. Malaria is a flu-like illness and can be fatal; the parasitic Plasmodium species are
common in sub-Saharan Africa.

Trypanosoma brucei is a species of the class Flagellata that causes the tropical disease “sleeping
sickness.” This disease causes fevers, swollen lymph nodes, and headaches and can be fatal if
left untreated. This parasitic protist is carried by the tsetse fly, which spreads the infection by
biting humans.

Phylum Chrysophyta: Organisms belonging to the Chrysophyta phylum include diatoms.

Diatoms have a unique and fascinating cell wall. Their cell walls are made up of silicon dioxide
(silica) surrounded by an organic matrix, which gives the appearance of a glass-like structure.
This structure allows diatoms to withstand huge amounts of pressure, up to 1.4million kg/m2!
Diatoms are hugely diverse and numerous and are particularly important as a food source for
marine organisms. An example of a diatom is shown in the micrograph below.

Phylum Pyrrophyta (also called Dinoflagellata): The Pyrrophyta phylum, also referred to as
the dinoflagellates, are important species of phytoplankton (microscopic algae) in marine
ecosystems. Dinoflagellates are motile organisms and possess two flagella, which they use for
locomotion. Dinoflagellates often contain photosynthetic pigments, such as chlorophyll which
gives them their greenish coloration. They have cellulose cellwall. Examples are
chlamydomonas, chlorella. Others may contain photosynthetic pigment like carotenoids, which
give them a reddish-brown color. When coastal areas of oceans or seas are particularly nutrient-

rich, dinoflagellates build up around the coast leading to a phenomenon called a “red tide. The
rapid population expansion of dinoflagellates can release a large amount of toxins into these
areas and kill other aquatic organisms like fish.

Phylum Euglenophyta: These are protist that possess both animal like and plant like features.
Examples of the member is euglena

Plant-like features of Euglena

 It has chloroplast which contains chlorophyll, so it can manufacture it food by itself

 They possess pyrenoids for the storage of starch

Animal-like features of Euglena

 They possess eye sport (it is sensitive to light but cannot form image)
 It possesses pellicle (it is a structure similar to the cell membrane)
 It possesses gullet
 Presence of flagellum for movement

Make a well labelled diagram of Euglena

Kingdom Fungi:

1. Some fungi are unicellular while some are multicellular

2. All fungi except slime mould are non-motile
3. The body of a fungus is made up of filaments called Hyphae. All the hyphae of a
single organism are collectively called mycelium.
4. The cell wall is composed mainly of chitin, a polysaccharide which is not found
in plant (plant cell wall is made up of cellulose)
 5. All fungi are heterotrophic in their modes of feeding because they lack
chlorophyll
6. They are mainly saprophytes while, others are parasitic
7. They reproduce asexually by means of spores
Examples: Rhizopus, Mushroom, Slime moulds

Economic importance of Fungi

 They bring about food spoilage.

 They cause diseases, especially in crop plant
 They breakdown dead remains of plants and animals, hence improving soil
fertility
 Useful in fermentation industries.
 They are used to produce antibiotics
 Source of protein

Make a well labelled diagram of Rhizopus

Kingdom Plantae:

1. They are non-motile multicellular organisms whose cell walls are made up of cellulose
2. They have an organelle which contain green pigment called chlorophyll
3. The presence of chlorophyll enables them to make their food themselves through a
process called photosynthesis

Kingdom plantae is divided into 4(four) phylum, namely;

 Thallophyta
 Bryophyta (hepaticae, musci)
 Pteridophyta
 Spermatophyta (monocotyledoneae and dicotyledoneae)

N.B
  Pteridophyta and spermatophyta are also known as Tracheophyta.
 Thallaphyta and Bryophyta are non-vascular plant, i.e. lack conducting vessels or tissues
(xylem and phloem).
 The phloem tissues transport manufacture food away from the leave while the xylem
tissues transport water, mineral salt from the root to various part of the plant.
 Pteridophyta and spermatophyta are vascular plant.
 Pteridophyta are seedless plant while spermatophyta are seed producing plants.

Division Thallophyta:

1. They are also known as algae

2. They are simple green plant that are all aquatic
3. They have thread like (filamentuos) or flat (thalus) bodies, i.e. their bodies are not
divided into roots, stem and leaves
4. Their group is made up of the brown algae (phaeophyta), the red algae (rhodophyta),
green algae (chlorophyta). The brown and red algae are larger that green algae.
5. The red and brown possess some other colouring pigment in addition to chlorophyll
6. Reproduction is asexual by cell division, fragmentation, spore formation and sexually by
conjugation
7. Some members show alternation of generation with the gamete producing generation
(gametophyte) being the dominant phase.

Examples of Thallophyta includes; Spirogyra (occurs in filaments), Kelp, Volvox (occurs in

colony).

Diagram showing alternation of generation of algae

Make a well labelled diagram of Spirogyra

Division Bryophyta:
 1. They are green plants found mainly in moist (wet) habitats such as tree trunks, damp
places, walls of open drains, sides of ponds.
2. Their vegetative body part is divided into:
 Leaves
 Stems
 Rhizoids instead of roots
3. Chloroplast are present as in higher plants
4. They are non-vascular plants, i.e. they don’t have conducting tissues, e.g. (xylem and
phloem). They depend on osmosis and diffusion to transport water, mineral salts etc.
5. They exhibit a distinct alternation of generation in their life cycle. The sporophyte
generation is attached to the gametophytes generation rise to another organism

Examples of Bryophyta include: Liver worth , Moss

Diagram showing life cycle of a moss plants

Division Pteridophyta:

1. They are found in damp places on land.

2. Their body is divided into roots, stem and leaves (fronds).
3. They have an underground stem called rhizomes.
4. They are non-flowering plants; hence they don’t produce seeds.
5. Spores are borne or carried in sporangia which occur under the surface of leaves.
6. They show distinct alternation of generations.
7. Sexual reproduction requires water.

Examples of Pteridophyta is Ferns

Diagram showing the life cycle of fern

Make a well labelled diagram of fern

Division Spermatophyta
 1. They are seed producing plant.
2. They are vascular plants with well developed vascular tissues.
3. They have true roots, stems and leaves.
4. The division is divided into two (2) sub-division;
 Gymnospermea
 Angiospermea

Characteristics of Gymnosperma

1. They have distinct roots, stems and leaves

2. They produce naked seeds borne on special structures called cones
3. Leaves may be needle-like in shape, broad or scaly
4. They are found in temperate regions or at high altitude in the tropics.

Examples are: Conifers, Cycads, Pines

Characteristics of Angiosperma

1. They are flowering plants

2. Seeds are born in fruits
3. They have well developed conducting systems
4. They are divided into two groups;
 Monocotyledons
 Dicotyledons

Differences between Monocotyledons and Dicotyledons

MONOCOTYLEDON DICOTYLEDON

They are one seed leaf or one cotyledon They have two seeds leaves

They have narrow needle-like shape leaves They have broad leaves with net veination
with parallel veination*

They have fibrous roots system They have tap root system

The floral part are in threes (multiples of The floral parts are in fours or fives
 three) (multiples of four or five)

Vascular bundles are scattered in the stem Vascular bundles are arranged in rings

They do not undergo secondary growth They undergo secondary growths

Kingdom Animalia

All animals belong to this kingdom. They are motile, multicellular organisms whose cell has no
cell wall and chloroplast. Their cell is made up of cell membrane of plasma membrane. They
take in ready-made food from their surrounding (they are heterotrophs). Animals are
put/classified into two main groups, namely;

 Vertebrates (animals with backbone)

 Invertebrates (animals without backbone)

There four characteristics features which are used to group animals into their phyla. These are;

 Body symmetry
 Body design
 Body cavity
 Body layer; An organism may lack body symmetry, so those that lack are called

Body symmetry: A symmetry is a line drawn through an object to cut it surface into two equal
halves. Animals are classified into three groups on the basis of their body symmetry. These
include;

 Asymmetrical: These are animals with no body symmetry. E.g Amoeba

 Radically symmetrical: These are organisms with radial symmetry
 Radial symmetry: This is a type of symmetry in which the body can be divided into
two equal halves along any plane or axis. E.g Hydra
 Bilaterally symmetry: This is a type of symmetry in which the body can be divided
into two equal halves along a single plane. E.g Earthworm, mammals
Body Design:

 Sac like body design: The organism has only a single opening
 Tube-like: The organism has two opening, the mouth and anus

Body Cavity:

 Acoelomate: organisms without body cavity

 Pseudocoelomate: organisms with false body cavity
 Coelomate is gotten from coelom meaning body cavity

Body Layer: Is the space between the gut wall and body wall.

 Monoblastic: organism with single body layer

 Diploblastic: organisms with two bod layers
 Triploblastic: organisms with three body layers

The main phyla in Subkingdom invertebrates:

1. Phylum Porifera
2. Phylum Coelenterata/Cnidarian
3. Phylum Platyhelminthes
4. Phylum Nematoda
5. Phylum Annelida
6. Phylum Mollusca
7. Phylum Arthropoda
8. Phylum Echinodermata

Phylum Porifera

Characteristics of phylum porifera:

 They are simple aquatic organisms that do not move around (sessile or sedentary)
 They have sac-like body structure.
  Their body have two layers (diploblastic) of cell, an outer, pinacoderm and inner,
choanoderm.
 Their body has many holes or pores through
 which water carrying food particles enters the gastric cavity (gut, alimentary canal) Their
inner layer has many flagellated cells called collar cells.
 They reproduce asexually by budding. A bud is an out-most growth from the parent plant.
 Most of them are hermaphrodites (an organism with the male and female gamates).
 They reproduce asexually by budding.
 They are primitive multicellular animals with asymmetrical bodies

Example of Porifera is sponges.

Make labelled diagram of Sponges

Phylum Coelenterata /Cnidarian

 They are aquatic animals most of which are marines but few are found in fresh water
(river, pond)
 They are diploblastic organisms. The outer layer is called ectoderm, while the inner layer
is called endoderm
 They have sac-like body structure
 They are radially symmetrical (their body can be cut along its axis in any plane to give
two identical halves)
 They possess tentacles which are used in picking food, catch food and push food into
their gut
 They have stinging cells called nematocysts or nematoblast on their tentacles. It is used
for offence and defence.
 Asexual reproduction is by budding while sexual reproduction is by fusion/union of
gametes
 They are hermaphrodites
 They exist in two forms, namely; polyps (sessile) and the medusa (motile).
 Phylum coelenterate is divided into three main classes;
Hydrozoa e.g. Hydra
 Scyphozoa e.g. Jelly fish
Anthozoa e.g. Sea Anemone

Examples of Phylum Coelenterata; Hydra, Jelly fish, Obelia, Sea anemones, Coral polyps

Make a labelled diagram of Hydra

Phylum Platyhelminthes (Flat Worms)

 They are dorsal ventrally flattened (the front view and back view are flat) and
unsegmented.
 The body has a single opening into their alimentary canal (they are sac like body
structure).
 They are bilaterally symmetrical.
 They are triploblastic organisms (i.e. they have three body layer) and other ectoderm,
middle mesoderm and inner endoderm.
 They are Acoelomate (i.e. animals with not body cavity).
 Circulatory or respiratory system are absent.
 They possess excretory, digestive and nervous system.
 They are mostly hermaphrodites.
 They may be free living or parasitic.
 Reproduction is asexually and sexually

These phylum is divided into three classes;

 Turbelleria e.g planaria

 Trematoda e.g. Liver fluke
 Cestoda e.g. Tapeworm

Examples of organisms under Phylum Platyheminthes: Planaria, Tape worm, Flukes like Liver
Fluke
Make a labelled diagram of tapeworm

Phylum Nematoda (Round Worms)

 They are bilaterally symmetrical.

 They are triploblastic organisms.
 Body is elongated, pointed at both ends.
 They have tube-like body structure.
 They are pseudocoelomate (have false body cavity).
 They produce sexually and sexes are usually separate.
 They possess well developed excretory, digestive, reproductive and circulatory systems.

Examples of Round worm are; Hookworm, Filarial worm, Thread worm

Make a labelled Diagram of a Round Worm

Phylum Annelida

 They are bilaterally symmetrical.

 Body is elongated and cylindrical.
 They are coelomates (true body cavity).
 They are mostly marine; others live in fresh water or damp soil.
 They are metametrically segmented (i.e. made up of repeating unit of segments)
 Their alimentary canal has two openings i.e. mouth and anus
 Presence of excretory organ or tube called nephridia or nephridium in each segment
 They are triploblastic organisms
 Gaseous exchange is through the moist curticle skin covering their body
 They possess clitellum
 They have well developed nervous and circulatory systems

The phylum is divided into three classes;

 Polychaete e.g. Sea worm
Oligochaete e.g. Earthworm
Hirudinean e.g. Leech

Make a labelled diagram of Earthworm

Advantages of body cavity to the Coelomate

1. The Coelom separates digestive and circulatory function from the body wall; each specialises so
each improves efficiency.
2. Supports larger size.
3. The fluid inside cushions the organs suspended within it, helping to prevent internal
injuries.
4. The cavity allows internal organs to grow and move independently of the outer body
wall.
5. A fluid filled cavity acts a hydrostatic skeleton for soft bodied animals
6. It allows the animals to grow bigger.
7. The fluid in the coelom can transport food, oxygen and wastes.
8. The body wall and gut wall can work independently as they are separated by the coelom.
9. Provides space for the organs inside the body to enlarge.

Phylum Mollusca

 Some members are aquatic while some are terrestrial

 They are bilaterally symmetrical
 They are triploblastic organisms
 They are coelomates
 Their body consists of head, muscular foot and visceral mass
 Body is covered by soft tissues called mantle which secretes the shell
 Gaseous exchange is through the gills (aquatic) and lungs (in terrestrial ones) which is
found in the mantle cavity (the space between the mantle and body mass)
 Reproduction is sexual and sex(es) are separate (they are not hermaphrodites)
The phylum is divided into three (3) classes;

 Class Gastropoda (Snail)

 Class Pelecypoda (Mussel)
 Class Cephalopoda (Octopus)

Examples of phylum Mollusca are Snail, Mussels, Squids, Bivalves, Slugs, Octopus

Make a well labelled diagram of a Land Snail

Phylum Arthropoda

 They are bilaterally symmetrical.

 They are coelomates.
 They are meta-metrically segmented.
 They have an exoskeleton made up of chitin.
 They have jointed appendages in each segment.
 Those phylum is the largest phylum and the most successful.
 These phylum is divided into 4 classes;

Class Insecta

Characteristics of Class Insecta

 Their body is divided into three segments/distinct part; head, thorax and abdomen.
 Their head has a pair of jointed antennae, a pair of compound eye and a segmented mouth
part.
 They have three (3) pairs of jointed walking legs, the legs are each distributed on each
segment.
 They have three thorax; prothorax, mesothorax, metathorax.
  The second and third thoracic segment may have a pair of wings each for flight.
 They respire by the means of trachea which has an opening to the exterior called spiracle.
 They undergo metamorphosis

Examples: Grasshopper, Cockroach, Butterfly, Housefly

Make a well labelled Diagram of Grasshopper

Class Arachnida

 They have two body division; prosoma and opisthosoma or cephalothorax and abdomen.
 They have 8 simple eyes or 4 pairs of simple eyes.
 The cephalothorax bears two pairs of appendages namely; pedipads and chelicerae which
are used for feelings.
 They respire by means of lung book.
 They have 8 jointed walking legs or 4 pairs of jointed walking legs

Examples are: Spiders, Scorpion, Tick

Make a well labelled Diagram of Spider

Class Crustacea

 They are aquatic, living free organisms.

 Their body is divided into two, namely; cephalothorax and abdomen.
 Their head bears a pair of antennae, a pair of stalked compound eyes with jointed mouth
parts.
 They respire by means of gills.
 They have 5 pairs of jointed walking legs.
 The thorax and abdomen bears jointed appendages which are modified for swimming,
walking or reproduction.
  They have chitinous exoskeleton which maybe impregnated with hard calcareous
materials.

Examples; Prawn, Crab, Lobsters, Barnacles, Water fleas

Make a well labelled Diagram of a Crab

Class Myriapoda

 They are land animals found under logs and rocks.

 Body is divided into two parts; head and a long segmented abdomen.
 They have a pair of simple eyes and a pair of short antennae.
 They respire by means of trachea.
 Centipedes have a pair of appendages (walking legs) on each body segment while
millipedes have two pairs of jointed walking legs on each segment. Centipedes are
carnivorous, millipedes are herbivorous. Centipedes have 10s to 100s of walking legs,
millipedes have over thousands of walking legs.

Make a well labelled Diagram of a Millipede & Centipede

Phylum Echinodermata

 They are aquatic animals that live on seabed and seashores

 They are triploblastic organisms
 They are radially symmetrical
 They have no head and are not segmented
 They have an endoskeleton made up of calcareous plates
 The organs for locomotion are sucker or tube fluid
 Sexes are separate

Examples include; Sea cucumber, Urchins, Starfish

Make a well labelled Diagram of Starfish

Phylum Chordata

All vertebrates belong to phylum Chordata and sub phylum Vertebrata. These Chordata have a
notochord, a flexible rod of tightly packed cells, a tubular nerve cord (dorsal) and gill slits at
some stage in their life histories. A backbone or vertebral column replaces the notochord in
vertebrates.

Characteristics of Vertebrates

 They are bilaterally symmetrical

 Their body is divided into head, trunk, tail
 They have an internal skeleton or endoskeleton that is made up of bones and cartilages
 They have a well developed nervous system with a brain and a spinal cord
 They have well developed sense organs
 They have a close circulatory system made up of muscular heart
 They have 2 pairs of limbs (tetrachord)
 The skin may be naked or have a covering of scale, features or hair
 The sub-phylum vertebrate is divided into six (6) classes. They are;
Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia
N.B. both chondrichthyes and Osteichthyes are grouped together as Pisces

Characteristics of Chordata

 They have notochord

 They have dorsal-hollow nerve cord (tubular)
 They have close blood circulatory system
 They have limbs

Characteristics of Chondrichthyes

 They are cartilaginous fishes (their skeletal material is made up of cartilage)

 Their gills are not covered by operculum
 Mouth is ventral
 Their fins are fleshy
  They typically have a heterocercal tail (the dorsal lobe of the tail fin is usually much
longer than the ventral lobe).
 Reproduction is oviparous
 They are coldblooded animals (Poikilothermic)

Example is a shark, dogfish, skate, ray fish etc.

Characteristics of Osteichthyes

 They are bony fishes.

 They have operculum or gill cover.
 They have swim bladder for buoyancy.
 They are coldblooded.
 They have terminal mouth which can often be protruded.
 The skin usually contains scales (bony plates covered with skin).
 They have typical homocercal tail (the dorsal and ventral lobes of the tail fin are usually
same size).
 They have fins supported by rays.

Example of Osteichthyes is tilapia fish, Titus, Mackerel

Make a labelled Diagram of a Tilapia fish

Class Amphibia

 They partly live in water and on land.

 They have naked and moist skin.
 They are poikilothermic organisms.
 They have gills at larvae stage and lungs at adult stage.
 They can also breath with their moist skin and mouth (mouth; buccal, skin; cutaneous).
 They have a pair of fore and hind limb. The fore limb is short and it is used for landing.
They have powerful hind limb with webbed digit which is used for swimming in water
and hopping (jumping) on land.
  They have sticky tongue which can be protruded and retracted quickly.
 Some have poison glands on their skin.
 Fertilization is external.
 They have inner and middle ears.

Examples are; Frog, Toad, Salamander

Make a well labelled Diagram of a Toad

Class Reptilia

 Most of them live on land while others live in water.

 They have their skin covered with dry, horny scale which prevent desiccation (loss of
water on their body).
 Fertilization is internal (union of the egg and the sperm cell takes place in the female),
while fertilisation is external in amphibian and Pisces.
 They are cold blooded animals (poikilothermic).
 They respire through the lungs.
 Their fore and hind limbs end with 5 (five) toes or digits and each ending with claws.
 They have a well-developed tongue which can protrude and retract quickly.
 They have inner and middle ears.
 They have incompletely developed four chamber heart.

Examples are; Lizard, Crocodile, Snake

Make a well labelled Diagram of Agama Lizard

Class Aves

 They are warm blooded animals (homoiothermic), which means their body temperature is
kept relatively constant.
 They carry out internal fertilisation.
 Their head, neck and trunk are covered with feathers while their hind legs are covered
with scales.
 Their fore limbs are modified into wings for flight. The hind limb have feet each with
four digits ending with claws.
 Their jaws are drawn out to form toothless beak.
 They lay eggs with hard shell and large yoke (amniotic).
 They have streamlined body which helps to reduce effect of opposing air during flight
 They respire with the aid of lung
 They have light bones and acute sense of vision.
 They four chambered heart.
Examples; Domestic fowls, Pigeon, Duck, Swallow bird

Make a well labelled Diagram of a Bird

Class Mammalia

1. They are warm blooded animals

2. They have mammary gland which is used in feeding young ones
3. They have external ear called pinnae
4. Their skin is covered with hair or fur and a sweat and sebaceous gland is present on the
skin.
5. They have heterodont dentition.
6. Fertilisation is internal.
7. They are mostly viviparous (they give birth to young ones alive rather than laying eggs).
8. They have lungs.
9. They are homoeothermic organisms.
10. Their heart is divided into four chambers heart .
11. Mammals are divided into orders e.g. the egg laying mammal or monotremes, the
pouched mammals /marsupials and the placenta mammals to which most mammal belong
to.
Examples are; Man, Rats, Bats, Dolphins, Kangaroos, Chimpazees.
Make a well labelled diagram of a Rat