KINGDOM ANIMALIA
MAIN FEATURES OF SOME GROUPS
GENERAL FEATURES
 MULTICELLULAR
 HETEROTROPHS
 ANIMAL CELLS WITHOUT CELL
WALL
 MAJOR PHYLA SUBDIVIDED BASED
ON BODY SYMMETRY,
DEVELOPMENT OF COELOM (fluidfilled body cavity that is completely
lined by tissue to hold organs) AND
INTERNAL AND EXTERNAL
STRUCTURES.
SYMMETRY IN ANIMALS
COELOM IN ANIMALS
PHYLUM: PORIFERA
 Commonly known as SPONGES
 Sessile (attach to ocean floor)
 Aquatic (mostly marine)
 LACK ORGANS AND BODY SYMMETRY
 Asexual reproduction by budding
 LACK A NERVOUS SYSTEM
 LACK MOUTH AND ANUS
 Capable of regeneration
PHYLUM: CNIDARIA
 RADIAL SYMMETRY (symmetry around a central
point).
 Aquatic (mostly marine).
 SACLIKE BODY WITH ONE OPENING (MOUTH/ANUS).
 Two cell layers making up the body: endoderm and
ectoderm.
 THEY HAVE TISSUES BUT NO ORGANS.
 They have two body forms:
 Both body forms posses mouths surrounded by tentacles
that bear CNIDOCYTES, cells containing “darts” called
nematocysts.
 Different types of cnidarians have a predominant body
form (medusa or polyp).
 Sexual and asexual reproduction.
PHYLUM: PLATYHELMINTHES
 Commonly named FLATWORMS
 Animals
with
BILATERAL
(symmetry about a central line)
SYMMETRY
 They have an incomplete digestive system, with
a mouth but no anus.
 Posses a simple brain and nervous system with a
head area and eyespots that are able to sense
light (FIRST GROUP TO SHOW CEPHALIZATION)
 They lack a respiratory and circulatory system.
Gas exchange occurs by diffusion.
 They have three layers of tissue but lack a body
cavity (coelom).
 Many are hermaphroditic and parasitic.
MARINE
FLATWORMS
TAPEWORM
FLUKE
PHYLUM: ANNELIDA
 Known as ringed or segmented worms.
 Cylindrical body with chaetae (bristles)
 Have bilateral symmetry
 They have a brain that connects to a nerve cord that
runs the length of the body.
 In the head area, there is a mouth and sensory
organs.
 They have a circulatory system that moves blood,
nutrients and oxygen.
 With a CONTINUOUS/COMPLETE DIGESTIVE
TRACT THAT ENDS IN AN ANUS.
 They HAVE A COELOM.
Phylum: MOLLUSCA
As it is a very diverse group, there are few
characteristics that all mollusks share.
 They have three main parts in their bodies:
A) Mantle. Thin sheet of tissue that encloses the
internal organs as a glove. It can secrete hard shells
made of calcium carbonate that work as an
exoskeleton.
B) Visceral mass. Solid mass of tissue where internal
organs are embedded.
C) Muscular foot. Used by the bivalve to dig in the
sand, used by the snail to creep along rocks, and
(divided into tentacles) used by the octopus to catch
prey.
 They have a well developed excretory system
 Open circulatory* system with a 3-chambered heart.
 Nervous system consisting of a pair of ganglia and
nerve cords.
 Sexual reproduction.
hermaphrodites
Both
dioecious
and
Phylum: ARTHROPODA
Class
Crustacea
Class
Arachnida
Class
Insecta
Myriapod
FEATURES ALL
ARTHROPODS SHARE:
 Segmented bodies
 Jointed legs or appendages
 Exoskeleton made of chitin
 Grow in stages after molting
 Heart on dorsal side of the
body
 Open circulation* system
 Most have compound eyes
*Open circulation happens when there are no vessels to contain the
blood and it flows freely through the cavities of the body.
 Arthropods have a REDUCED AND DIVIDED
COELOM.
 Digestive system is arranged not so
differently from that of a human: foregut
(pharynx and esophagus), midgut (stomach),
and hindgut (colon, anus).
 Sexual reproduction with separate sexes in
most organisms, and very few
hermaphrodites.
 Complex respiratory system adapted to each
organisms way of life.
 Arthropods have a well developed nervous
system with a wide variety of sense organs
that make them very responsive to the
environment.
SUMMARY OF KEY FEATURES IN ANIMALS
SYMMETRY
GUT OPENINGS
SEGMENTATION
FEATURES
EXAMPLES
PORIFERA
NONE
0
NONE
Use spicules for
support
Sea sponge
CNIDARIA
RADIAL
1
NONE
Cnidocytes
(stinging cells)
present
Coral, jellyfish,
hydra
PLATYHELMYNTHES
BILATERAL
1
NONE
Flattened body
Tapeworm
ANNELIDA
BILATERAL
2
YES
Use peristals for
moving
Leech, earthworm
MOLLUSCA
BILATERAL
2
NON-VISIBLE
Some have a shell
made by mantle
Octopus, snail,
slug, oyster
ARTHROPODA
BILATERAL
2
YES
Have exoskeleton
made of chitin
Spider, crab, bee