A Very Diverse Kingdom
Kingdom Animalia Characteristics
 All animals share the following
characteristics
1. Eukaryotic
2. Multicellular
3. Reproduce sexually
4. Heterotrophic
5. Motile, at least for part of their life
Kingdom Animalia Features
Animals are taxonomically grouped
based on three main features:
Number of body layers
Type of Body cavity
Body Symmetry
Feature 1: Number of body layers
The 3 main layers appear very early in
embryonic development. In humans the
layers are:
Endoderm – lungs, liver, gut lining
Mesoderm – muscles, blood, kidneys
Ectoderm – skin, nerves
Feature 2: Type of Body Cavity
The two main types of body cavities are:
Coelomates –have a fluid filled body
cavity that supports organ systems
Acoelomates – lack a fluid filled
body cavity like flatworms
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Feature 3: Body Symmetry
The three main types of symmetry are:
Bilateral – can be cut into two
mirror images through a central line.
Radial – body is organized around a
central axis. They are symmetrical
around any central cut.
Asymmetry – no distinctive
symmetry
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Animal Phyla
 Animalia phyla are spilt
into two major groups
based on the presence or
absence of a spinal cord
and vertebra
1. Non-chordates or
invertebrates
2. Chordates or vertebrates
Invertebrate Phyla
 These are animals without a notochord
(backbone)
 There are eight phyla of invertebrates
1. Porifera (Sponges)
2. Cnidarians (jellyfish)
3. Platyhelminthes (Flatworms)
4. Annelids (segemented worms)
5. Nematoda (Roundworms)
6. Mollusca (snails, clams)
7. Echinoderms (starfish)
8. Arthropods (insects, crabs)
1. Porifera: Sponges
 Asymmetrical (no symmetry)
 No coelom
 Sponges are the simplest animals,
lack defined tissues and organs
 Are hermaphroditic
 Fertilized eggs become freeswimming larvae, which then
attach to the ocean floor,
metamorphose and become fixed in
one place.
2. Cnidarians: Jellyfish and Corals
 Have radial symmetry
 No coelom
 Have tentacles with
stinging cells that they
use to capture food.
 Reproduce both
sexually and asexually
3. Platyhelminthes: Flatworms
 Have bilateral symmetry.
 No coelom
 Can be free-living or
parasites
 Free living worms are
hermaphrodites, they
generate a reproductive
system only during breeding
season.
4. Nematodes: Roundworms
 Have bilateral symmetry.
• pseudocoelomates (coelom
was lost or reduced)
 Have long thin, round worm
like bodies
 Simplest organisms to have
a complete digestive tract
 Most are free-living,
however some are parasitic
 Some reproduce sexually
some asexually
5. Annelida: Segmented Worms
 Have bilateral symmetry
 Have a coelom
 Have round, segmented
bodies which is beneficial
for movement, can move
different parts at a time,
increases flexibility.
 Can reproduce sexually or
asexually
6. Mollusca: Snails, Clams, Squid
 bilateral symmetry
 Have a coelom
 They are soft-bodied
animals. Most cover
their body with a
shell for protection.
 Reproduce sexually
or asexually
7. Echinodermata: Starfish
 Adults have radial symmetry
 Have a coelom
 Have spiny outer covering for
protection
 Move by changing water
pressure inside tubes in the
arms
 Can be stationary or
burrowing
 Reproduce sexually or
asexually
8. Arthropoda: Insects and Spiders
 Have bilateral symmetry.
 Have a coelom
 Ecologically important part of food chains
due to their abundant numbers
 Have simple respiratory, circulatory and
excretory systems
 Reproduce sexually or asexually
 There are four group of arthropods:
Arachnids (spiders), Centipedes & Millipedes,
Crustaceans (crabs, shrimp), Insects