Animal Diversity
Exploring the
Categorization of
Animal Species
The Tree of Life
The three domains of life represent the
earliest branches in evolutionary history
Characteristics of Animals
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Eukaryotic
Multicellular
Heterotrophic
Most are capable of sexual reproduction.
Animal cells lack a cell wall.
Motile during some stage of their life
Respond to external stimuli as a result of
nerve and/or muscle action
Classification Scheme
Kingdom
Phylum
Class
Order
Family
Genus
Animalia
Animalia
Chordata
Chordata
Mammalia
Mammalia
Carnivora
Primates
Felidae
Hominidae
Felis
Homo
Species sylvestris
sapiens
Skeleton
Segmentation
Surface Features
or Appendages
Ways to Distinguish
Between Animal Groups
Development Patterns
Body Cavities
Body Symmetry
Body symmetry
Phylum Porifera
Sponges
 Asymmetrical
Loosely structured
collection of cells
Cell specialization
Lack tissues
Non-motile as
adults
Filter feeders
 Radial symmetry
Phylum Cnidaria
 Cells organized into
two tissue layers
 Lack true organs
 Nerve network and
contractile tissue
 Body plans
Polyp- attached
Medusa- motile
Coral, Hydra, Anemones
and Jellyfish
 Mouth and anus are
same opening
 Asexual and sexual
reproduction
Body Cavities
Coelom: body cavity lined on all sides
by a layer of mesodermal cells
Phylum Platyhelminthes
Tapeworms, Flukes , Flatworms
 Bilateral symmetry
 Acoelomate
 Three tissue layers
 Excretory and
Reproductive Organs
 Move by use of nerve
cells, ganglia
 Many are free-living;
some are parasitic
Phylum Nematoda
Roundworms
 Bilateral symmetry
 Pseudocoelomate
 Three tissue layers
 Tubular gastrovascular
cavity; two openings
 “Ganglionic Brain”
 Gas exchange by
diffusion
 A few species are
parasitic
Phylum Annelida: Segmented Worms
 Bilateral symmetry
 Coelomate, fluid filled
cavity allows movement
 Three tissue layers
 Segmented body
 Closed circulatory
system: 5 pairs of hearts
 Excretory organs:
nephridia
 Digestive system with
specialized areas
 Segmented muscles for
movement
Phylum Mollusca
 Bilateral symmetry
 Coelomate
 Three tissue layers
 Soft body in a calcium
containing shell
 3-chambered heart,
blood vessels
 Ciliated digestive tract
 Excretory organs: nephridia
 Head-foot has sensory and
motor organs
 Gills for oxygen absorption
 Tooth-bearing strap: radula
Classes of Phylum Mollusca
Class Bivalvia
clams, mussels,
oysters, scallops
Class Gastropoda
snails, slugs
Class Cephalopoda
squid, octopus
Class Polyplacophora
 chitons (ancestral)
 eight plates on back
Phylum Arthropoda
 Bilateral symmetry
 Coelomate
 Three tissue layers
 Distinct body regions:
head, thorax, abdomen
 “joint-footed”
 Exoskeleton, moved at
joints by muscles
 Open circulatory
system
 Complex nervous
system, compound eye
 Efficient gas exchange
system
Classes of Phylum Arthropoda
 Class Arachnida
 spiders, ticks, scorpions
 Class Crustacea
 crabs, lobsters, shrimp
 Class Insecta
 insects
 Class Diplopoda
 millipedes
2 pairs of legs/segment
 Class Chilopoda
 centipedes
1 pair of legs/segment
 Class Meristomata
 horseshoe crabs
Protostome: mouth forms first during embryonic
development
Deuterostome: anus forms first and then mouth
forms
Phylum Echinodermata
 Radial symmetry, 5-part
body plan
 Coelomate
 Deuterostome
 Three tissue layers
 “Spiny Skin”
 Modified coelom forms a
water vascular system to
move tube feet
 Nervous system: central
nerve ring with branches
Classes of Phylum Echinodermata
Class Asteroidea
sea stars
Class Echinoidea
sea urchins, sand dollars
Class Holothuroidea
sea cucumbers
Class Ophiuroidea
brittle stars
Phylum Chordata
 Bilateral symmetry
Coelomate
Deuterostome
Three tissue layers
Four common features
Notochord
Dorsal, hollow nerve cord
Pharyngeal gill slits
Post-anal tail
Sub-Phylum Vertebrata
Notochord replaced by
vertebral column
Endoskeleton
Development of brain
Closed circulatory system,
heart with 2 or more
chambers
Use of gills, skin or lungs
to obtain oxygen
waste removal by kidneys
Separate sexes, internal
or external fertilization
Classes of Sub-Phylum Vertebrata
Class Agnatha
jawless fishes
Class Condrichhthyes
 cartilaginous fish
Class Osteichthyes
bony fish
Classes of Sub-Phylum Vertebrata
Class Amphibia
frogs, toads, salamanders
Class Aves
birds
Class Reptilia
lizards, snakes,
turtles, alligators
Classes of Sub-Phylum Vertebrata
Class Mammalia
most bear live young
milk from mammary glands
hair
endotherms
monotremes: egg laying
platypus
marsupials
kangaroo
placentals
bat, rabbit, dog,
cattle, whale, human
Worksheet
• Complete pages 123-124 from lab
manual
– Record your answer and reasoning for
any 8 specimens, making sure to write the
answer on the line that matches the
specimen number
• Be sure your instructor checks your
completed worksheet before you leave
the lab.
CLEAN UP!
• Leave animal specimens and their
skeletons in orderly arrays
Thank you!