1.7a KINGDOM ANIMALIA

CHAPTER 1 : BIOLOGY SB025
BIODIVERSITY SEMESTER 2

SESSION 2020/2021

1.7 DOMAIN EUKARYA: KINGDOM ANIMALIA

Learning outcomes
At the end of the lesson, students should be able to:
a) Describe unique characteristics of Kingdom Animalia.
b) State classification of Animalia into 9 phyla.

CHAPTECRH1A.0P:TER 1 : BIOBLIOOLGOYG2YSSBB020525
BIODIVEBRIOSIDTYIVERSITY SEMESSTEEMRE2STER 2
SSEESSSSIIOONN 22002109//22002210

c) Discover the unique characteristics of the following
phyla:

i. Porifera (e.g. Leucosolenia sp.)
ii. Cnidaria (e.g. Obelia sp.)
iii. Platyhelminthes (e.g. Taenia sp.)
iv. Nematoda (e.g. Ascaris sp.)
v. Annelida (e.g. Pheretima sp.)
vi. Arthropoda (e.g. Valanga sp.)
vii. Mollusca (e.g. Achatina sp.)
viii. Echinodermata (e.g. Asterias sp.)
ix. Chordata (e.g. Amphioxus sp.)

CHAPTER 1 : BIOLOGY SB025
BIODIVERSITY SEMESTER 2

SESSION 2020/2021

Explain evolutionary relationships of Animalia based on
their:

i. level of organization
ii. Germ layers
iii. Body symmetry
iv. Body coelom
v. segmentation

UNIQUE CHARACTERISTICS OF
KINGDOM ANIMALIA

• Multicellular eukaryotes

• Ingestive heterotroph

• Carbohydrate reserves: glycogen

• Lack cell walls
• Most reproduce sexually with dominant diploid

stage
 Involves small flagellated sperm that
fertilizes a large, non-motile egg

UNIQUE CHARACTERISTICS OF
KINGDOM ANIMALIA

• Most have nervous and muscle system

• Most are capable of locomotion, some are
sessile

• Development of transport system
- Blood carrying oxygen, carbon dioxide,
nutrients and excretory materials is pumped
throughout the body in vessels.

CLASSIFICATION OF KINGDOM ANIMALIA

• Kingdom animalia is divided into 9 phyla:-

 Phylum Porifera
 Phylum Cnidaria / Coelenterata
 Phylum Platyhelminthes
 Phylum Nematoda
 Phylum Mollusca
 Phylum Annelida
 Phylum Arthropoda
 Phylum Echinodermata
 Phylum Chordata

Multicellularity

No true tissues True tissues
Parazoa Eumetazoa

Radial symmetry; bilateral symmetry;
diploblastic triploblastic

Radiata Bilateria

No body cavities Body cavities

Acoelomates Completely lined
by mesoderm
Not completely lined
by mesoderm Coelomates

Pseudocoelomates
PORIFERA
CNIDARIA

PLATYHELMINTHES

NEMATODA
MOLLUSCA
ANNELIDA

ARTHROPODA

ECHINODERMATA

CHORDATA

CLASSIFICATION OF KINGDOM ANIMALIA

1) BASED ON TISSUES

 No true tissues  Parazoa
 Sponges lack tissues

 True tissues  Eumetazoa
 But all other animals have different
tissues which perform different function

Parazoa (No true tissues)

CLASSIFICATION OF KINGDOM ANIMALIA

2) BODY SYMMETRY

• Sponges lack body symmetry
• Some animal exhibit radial symmetry

Has top and bottom region
No anterior end and posterior end
No left and right side

• Some animal exhibit bilateral symmetry
Has top and bottom region
Has anterior end and posterior end
Has left and right side

2) BODY SYMMETRY

Any imaginary slice
through the central axis
divides the animal into
mirror images

Only one imaginary
slice divides the animal
into mirror images

Radial symmetry
Bilateral symmetry

CLASSIFICATION OF KINGDOM ANIMALIA

3) GERM LAYERS

Diploblastic
• Two germ layers:

- Ectoderm
- Endoderm

*Mesoglea
- gelatinous non-cellular layer between endoderm and ectoderm
(coelenterates) which are do not form any tissue or organ.

CLASSIFICATION OF KINGDOM ANIMALIA

3) GERM LAYERS

Triploblastic
• Three germ layers:

- Ectoderm
- Mesoderm
- Endoderm

3) GERM LAYERS

Ectoderm • The outermost layer
Endoderm • Covers the surface of embryo
Mesoderm • Give rise to outer coverings and central nervous

system

• The innermost layer
• Lines the developing digestive tract @

archenteron
• Give rise to lining of digestive tracts and organs

(e.g. liver, lungs)

• Lies between the ectoderm and endoderm
• Develops into muscles and other organs

between the digestive tract

Archenteron:
• A cavity within an

animal embryo
(gastrula stage).

• All part of
archenteron cavity
form a gut which
become either mouth,
mouth & anus or anal
opening.

CLASSIFICATION OF KINGDOM ANIMALIA

4) COELOM (BODY CAVITY)

Acoelomates • NO coelom @ body cavity

Pseudocoelomates • Coelom is NOT completely
Coelomates lined by mesoderm

• Coelom is completely lined
by mesoderm

CLASSIFICATION OF KINGDOM ANIMALIA

4) COELOM (BODY CAVITY)
Acoelomates such as planarians lack a body
cavity (between digestive tract and outer body wall )

CLASSIFICATION OF KINGDOM ANIMALIA

4) COELOM (BODY CAVITY)
Pseudocoelomates such as roundworms have
coelom which the coelom is NOT completely
lined by mesoderm

CLASSIFICATION OF KINGDOM ANIMALIA

4) COELOM (BODY CAVITY)
Coelomates such as earthworm have coelom
which the coelom is completely lined by
mesoderm

PHYLUM PORIFERA

UNIQUE CHARACTERISTICS OF PORIFERA

• Porifers mean “ pore bearing”. Sponge bodies
perforated by tiny holes
- e.g. Sponge (Leucosolenia sp.)

• Most are marine, some lives in freshwater
• Do NOT have true tissue

- consists of only differentiated cells

pore

UNIQUE CHARACTERISTICS OF PORIFERA

• Sessile (non-motile)
• Lack nerves or muscles
• Asymmetry body plan (lack body symmetry)

UNIQUE CHARACTERISTICS OF PORIFERA

• Most: hermaphrodites
- Each individual functions as both male and
female in sexual reproduction by producing
sperm and eggs (produced at different times)

• Reproduction :
- Asexual (fragmentation & regeneration)
- Sexual

UNIQUE CHARACTERISTICS OF PORIFERA

• Body of a simple sponge; sac perforated with
holes

• Body wall consist of porocytes (specialized tube-
like cells) that
form pores (ostia)

•Suspension feeder
 Capture food particles suspended in the
water that passes through their body.



UNIQUE CHARACTERISTICS OF PORIFERA

• Body of sponge consists of 2 layers of cells
separated with mesohyl region.

UNIQUE CHARACTERISTICS OF PORIFERA

• Choanocytes (Collar cells)
– Line the spongocoel

– Each with a flagellum ringed
by a collar

– Flagella : generate water
current @ create the flow of
water in through the pores
(ostium) and out through the
osculum

– Collar : trap food particles
and digest it or transfer to
amoebocyte



UNIQUE CHARACTERISTICS OF PORIFERA

• Amoebocytes
– Lies in mesohyl

– Absorb food from water
and choanocytes digest
the food transport
nutrients to other cells by
phagocytosis

– Secrete :

Calcium carbonate to form

sharp spicules * Food particles are digested
Collagen protein to form within choanocytes and
amoebocytes by phagocytosis
spongin



UNIQUE CHARACTERISTICS OF PORIFERA

• Has water system:
– Water is drawn
through the
porocytes to the
spongocoel (central
cavity)

– and flows out
through the larger
opening called
osculum



PHYLUM CNIDARIA

UNIQUE CHARACTERISTICS OF CNIDARIA

• Eumetazoa (true tissues)
• Solitary or colonies
• Most are marine (Obelia sp.), some freshwater

species (Hydra sp.)
• Sessile or motile

UNIQUE CHARACTERISTICS OF CNIDARIA

• Basic body plan:
– Diploblastic
– Outer layer (epidermis) and inner layer
(gastrodermis) are separated by mesoglea
– Radial symmetry

Body symmetry of hydra, sea anemone and jellyfish

UNIQUE CHARACTERISTICS OF CNIDARIA

• Has central digestive compartment;
gastrovascular cavity:
 Single opening, functions as both mouth &
anus
 Mouth surrounded by tentacles

• Have two body shape:
(i) Polyp
(ii) Medusa

UNIQUE CHARACTERISTICS OF CNIDARIA

POLYP MEDUSA

Cylindrical form Bell shape

Sessile (adhere at rock) Motile

Mouth and tentacle Mouth and tentacle point
point upward downward

Thin mesoglea Thick mesoglea

Big gastrovascular Small gastrovascular
cavity cavity



Mouth, tentacles and gastrovascular cavity of hydra, jellyfish and
sea anemone

UNIQUE CHARACTERISTICS OF CNIDARIA

• No brain

• Nerve net is associated with simple sensory
receptors that are distributed radially around
the body (to detect and respond to stimuli
equally from all directions)



UNIQUE CHARACTERISTICS OF CNIDARIA

• Carnivores:
- Have tentacles for defense and feeding

- Have cnidocytes on tentacles

- Cnidocytes:
 cells containing cnidae called
nematocysts (stinging structure)

- Nematocysts:
 contain stinging thread (coiled) that
can penetrate the body wall of the
cnidarian’s prey







UNIQUE CHARACTERISTICS OF CNIDARIA

• Dimorphism in body plan
• The existence of 2 different forms of
individual within same animal species
– Polyp (sessile)
– Medusa (floating)

Obelia sp.
(polyp)

Obelia sp. (medusa)

Dimorphism in Obelia sp.

• Exist in colonies
• Dimorphism: exist in both polyp and medusa

forms
• Has 2 types of polyps:

- Reproductive polyp (lack of tentacles)
- Feeding polyp (has tentacles)

Dimorphism in Obelia sp.

• Polyp reproduce asexually by budding
 Reproductive polyp produce medusa
by budding asexually.

• Medusa reproduce sexually
 Producing gametes

**EXTRA: Life Cycle of Obelia sp.

2. Feeding polyps 3. Reproductive polyps are 4. The
are equipped with lack of tentacles and medusa
tentacles produce tiny medusa by swims off,
asexual budding. grow and
1. A colony of reproduce
interconnected s sexually.
polyps-produced
from asexual
reproduction by
budding.

6. The planula eventually 5. The zygote develops
settles and develops into into a solid ciliated
new polyp. larva (planula).