2. There are eight large groups or
subgroups of invertebrates:
-Porifera
-Coelenterates
-Platyhelminthes
-Nematoda
-Annelida
-Mollusca
-Echinoderms
-Arthopods
3. 1. Porifera
The Poriferans are marine
animals full of pores or holes.
These holes serve as passage
for water which carries
nutrients and gases.
Sponges or pore-bearing
animals belong to this group.
5. 2. Coelenterata (Coelenterates)
The Coelenterate or
Coelenterates are hollow-bodied
or soft-bodied animals. Their
bodies are made up of two layers
of cells which form a hollow
tube. Examples of animals in this
group are the fresh water
hydras,hydroids, jellyfish, sea
fans, sea anemones, and corals.
8. 3. Platyhelminthes
Platyhelminthes have bodies
that look like ribbons. They
have no space inside so they
have no digestive system.
Flatworms belong to this
group.
9. The tapeworm and flukes are
examples of flatworms. The
tapeworm lives in the human
intestine and feeds
completely on the digested
food of its host. Flukes stay
in the liver. They are
parasites.
11. 4. Nematoda (Nematodes)
Nematoda or Nematodes consist
of animals called roundworms. They
are long, thin, round, and pointed at
one or both ends. Some of them are
also parasites. The ascaris lives in
the intestines of the human beings.
The hookworm, another parasite,
enters the human body by boring
through the skin
in the feet.
13. 5. Annelida
Animals belong to this group
are segmented worms. They
are the most complex among
the worms. Their bodies
are divided into segments.
Examples of the animals in
this group are the
earthworms and leeches.
15. 6. Mollusca (Mollusks)
Mollusca or Mollusks are
softbodiedor shelled animals.
Snails, slugs,clams, mussels,
oysters, squids and
octopuses are mollusks. Most
animals like the clams,
oysters and snails have
shells that protect their soft
bodies.
17. 7. Echinodermata
(Echinoderms)
Echinodermata or Echinoderms
are spiny-skinned sea animals.
They have hard shells covered
with prickly spines or needles.
Starfish, sand dollars, sea
urchins, and sea cucumber
are the most common
examples of this group.
19. 8. Arthropoda (Arthropods)
Arthropoda or Arthropods are
joint-legged animals. They
make up the largest group in
the animal kingdom. Their
legs are jointed. Their bodies
and legs are made up of
sections. They have an
outside shell called the
exoskeleton.
20. There are four groups of
animals (Arthropods)
in this group. These are:
a. Crustaceans have a hard
outer body covering divided
into sections. Crabs,
lobsters and shrimps belong
to this group.
22. b. Insects are small, six-legged
animals or have three pairs of walking
legs, one or two pairs of wings and a
pair of antennae. Their bodies
are divided into three parts: the head,
the thorax, and the abdomen. They
change their form as they grow. They
are the most numerous animals on
earth. Bees, ants, wasps, butterflies,
cockroaches, ladybugs, fireflies,
termites, moths and grasshopper are
insects.
24. c. Arachnids have four pairs
of walking legs. They have
possess spinnerets with
which they spin silk thread
into webs, cocoons and
nests. Examples of arachnids
are scorpions, mites, ticks
and spiders.
26. d. Myriapods are animals
with many legs. They are the
millipedes(diplopods) which
have two pairs of legs in
every segment of their
body and the centipedes
(chilopods) which have one
pair of legs in every segment
of their body.
28. Identify the characteristics of the
different invertebrates by completing
the Chart using the following
descriptions.
Classification - arthropods, mollusks,
echinoderms, coelenterates
Movement - fly, crawl, swim
Description - with exoskeleton, spiny skin,
soft and segmented body,enclosed in a shell,
hollow-body stinging cells or tentacles
