Kingdom Animalia – all animals are multicellular
heterotrophs that lack cell walls and share the first
few steps of early embryology
Animals are very diverse in form, organization, and
complexity from the simplest invertebrates to more
complex vertebrates
– Most animals (>95%) are inverts
– Aside from very successful insects, most animals are marine
– Diverse morphologies, habitats, and adaptations
• Prokaryotes
– Domain Bacteria
– Domain Archaea
• Eukaryotes
– Domain Eukarya
• Kingdom Protista
• Kingdom Plantae
• Kingdom Fungi
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Chytridiomycota
Phylum Zygomycota
Phylum Basidiomycota
Phylum Ascomycota
• Kingdom Animalia
• Kingdom Animalia
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Phylum Porifera
Phylum Cnidaria
Phylum Ctenophora
Phylum Platyhelminthes
Phylum Nemertea
Phylum Nematoda
Phylum Rotifera
Phylum Mollusca
Phylum Annelida
Phylum Arthropoda
Phylum Echinodermata
Phylum Chordata
Phylum Porifera
• Sponges
• Habitat
– Mostly marine, few
freshwater
– sessile
• Suspension filter feeders
• Cellular level (lacks true
tissues and organs)
• Body plan = asymmetrical
Although sponges lack true tissues they still carry out
specific functions – at the cellular level
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Porocytes: water canal
Pinacocytes: flat protective cells
Choanocytes: “collar cells” capture food (plankton)
Amebocytes: transport food; differentiate into other cells
Spicules: siliceous or calcareous skeletal structures
Poriferan body plans
Sponges, like many organisms, can reproduce asexually
and sexually.
– Asexual budding
– Sexual broadcast spawn
Sponges, as simple as they are, show diverse
adaptations and organization to varied environments
Examples of these varied body plans include:
– Tropical to temperate encrusting
– Subtropical bath sponges
– Deep water glass sponge
Phylum Cnidaria (nigh-dare-ia)
Are nearly all marine and
include jellyfish, sea
anemones, & coral which all
share radial symmetry and
specialized cells for
predatory feeding
Cnidarians are at the tissue level of organization
…yet only two true derived tissues.
• 2 layers
– Epidermis and
gastrodermis
– Mesoglea is middle jelly
layer rather than a true
tissue
Closer, but not yet…
• Recall: Gastrulation (Infolding
of the blastula)
• Forming a primitive gut &
embryonic tissues
– Endoderm lining of
gut/organs
– Mesoderm  muscle, bone,
connective tissue
– Ectoderm  skin, hair, nails,
nervous tissue
Cnidarian gut is described
as gastrovascular cavity
w/extracellular digestion
Cnidarians exhibit two basic body forms: medusa
(swimming) and polyp (attached)
Furthermore…
• Polyp forms can be
either solitary
(individual polyps) or
colonial (integrated
of many polyp types)
• Cnidarian life-cycles
can include
alternations of
medusa and polyp
generations.
Phylum Cnidaria is
organized into 4 classes:
• Class Hydrozoa
Greek: multi-serpent-headed water beast
– Individual polyps
Sessile colonies
– colonies of
specialized polyps
• Feeding
• Reproductive
• Defense
Drifting colonies
• Class Scyphozoa
with dominant
medusae stage
– Examples
• Sea Nettle
• Moon Jelly
• Upside-down Jelly
• Class Cubozoa
– Tropical
– Potent toxins
Class Anthozoa
• Solitary or colonial
polyps w/out medusae
stage
– Sea anemones
• Some with zooxanthellae
symbionts
– Photosynthesizing
protists
– Corals
• CaCO3 skeletons
• Environmentally valuable
reefs
• Extremely susceptible to
negative impacts
– Pollution, increased
temp., etc
Phylum Ctenophora
Comb jellies
• Marine planktonic
predators that use 8
rows of ciliary combs
or ctenes to swim
• Instead of cnidocytes,
have tentacles with
colloblasts to capture
prey
– Adhesive, non-stinging
cells
Phylum Platyhelminthes
Flatworms
• Bilateral symmetry
• Organ level
– Except no circulatory
• Cerebral ganglia
– Simple brain
• Reproduction:
– Asexual (simple
regeneration)
– Sexual
• Most are hermaphrodites
• Include free-living (self
foraging) & parasitic
lifestyles
Flatworms have 3 distinct tissue layers – gave rise
to a more complex digestive system
• This closed digestive system is described as an
incomplete gut rather than a complete gut
• Acoelomic (w/out coelom or protective gut cavity)
Parasitic flatworms find a host to feed from than
spend much of their resources on reproduction
Chinese liver fluke - Opisthorchis sinensis
Opisthorchis lifecycle
Schistosoma
Female
Similar to this mammal tapeworm example, marine
tapeworms are internal parasites to fish and marine
mammals.
“…as dense as seaweed forests, that live in the guts of sharks.”
Cestoda
Cestoda scolexes
Cestode
proglottid 2
Testes
Ovary
Yolk gland
Phylum Nemertea
• Ribbon worms
“not flat, nor round”
• Advanced organ system
over flat worms
– Circulatory system
– Complete gut
– Between Acoelomates &
Pseudocoelomates
• Rhynchocoel: partial cavity
around proboscis
• Eversible proboscis
Phylum Nematoda
• Roundworms
Bit more space for more
complex development
• Complete gut
• pseudocoelomates
• Varied environments,
size, & lifestyles
– Aquatic to terrestrial
– Free-living to parasitic
• Marine sediments (feed
on bacteria)
• Parasitic to most
marine animals & many
others
• Reproduction
– Primarily sexual
One of the biggest marine parasites
measures 13 meters and is two
centimeters in diameter …found in
the placenta of the sperm whale.
Trichinella
Enterobius
female
Ascaris
Censored
Ascaris female x.s.
Ascaris male x.s.
Phylum Rotifera
• Microscopic, yet
multicellular, organ-level
aquatic animals
• Ciliated crown (“wheel”) to
funnel food
• Pharyngeal grinding
structure (mastax)
• Complete gut
• Pseudocoelomates
• Reproduce
– Sexually …or…
– Parthenogenesis (“virgin birth”)
• Females  eggs  female
offspring (w/out fertilization)
Phylum Mollusca
Very diverse group of soft body inverts
that include Gastropods (Snails,
slugs), Bivalves (oysters, clams,
mussels), and Cephalopods (squid,
cuttlefish, octopus)
•
examples within this phylum are found
in diverse environments: Marine,
freshwater, moist land
and, share characteristics such as…
• Open circulatory system
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Mantle for protection
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central blood cavity rather than highly
branched blood vessels
Secretes shell, provides space for gills
and siphons
Locomotive muscular “foot”
Well developed Nervous system
…in most
Class Gastropoda
• “stomach footed”
• Mantle
– Tissue that
secretes shell
• Radula
– Rows of rasping
teeth for grazing
– Modified in
predators
Cone shells
• Single harpoon
tooth
– evolved from rowed
ancestors
– filled with paralyzing
venom
• Conotoxins
– Medical value for
specific neural &
muscle treatment
– Addictive-free pain
killers
Class Bivalvia
• Clams, oysters,
mussels…
• Suspension filter
feeders
– Incurrent & excurrent
siphons
• Spade-foot for
locomotion
• Two valves (shells)
secreted by mantle
– Held closed by
powerful adductor
muscles
• Class Polyplacophora
– Chitons
• Graze on microalgae
• 8 overlapping plates
• Class Scaphopoda
– Tusk shells
• Open at both ends
• Deeper benthic
sand/mud
Class Cephalopoda
• Squid, octopus,
cuttlefish, nautilus
• Shell: internal, external,
or lacking
• Well developed nervous
system
• Most adapted for active
predatory lifestyle
Class Cephalopoda (cont.)
• Muscular foot modified to
arms &/or tentacles
– Siphon for locomotion
• Hydropropulsion
• Ink sac or gland
– defense
• Chromatophores
– Adjustable pigment cells
• Conotoxins in some
Reproduction
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•
Most are separate sexes
Some free spawners
– bivalves
•
Most develop from:
– Trochophore larva
• Ring of cilia
– Veliger larva
• Ciliated mass
•
Some parasitic larva
– Glochidia larva of some fresh water clams
Phylum Annelida
• Segmented worms
– Earthworms
– Polychaetes
– Leeches
• Repetitive body parts
• Hydrostatic skeleton
– Flexibility and strength
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Coelomates
Longitudinal & circular muscles
Closed circulatory system
Excretory organs
Marine, moist land, and some
freshwater
• Bilateral symmetry
• Some parasitic
Earthworm
dissected
Nereis
• Class Polychaeta
• Adaptations to
predatory lifestyle
– Eyes, tentacles, jaws,
etc
• Coelom
– Protective gut cavity
• Parapodia
– w/setae
– Respiratory, nervous,
and locomotion
Phylum Annelida
• phylogenetically placed
between Mollusca and
Arthropoda
– Trocophore larva
– segmentation
Phylum Onychophora
• “walking worms”
… or velvet worms
– Tropical predator
• Link between
annelids and
arthropods
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Walking appendages
Lacks exoskeleton
Antennae
Soft segmented body,
yet chitinous
– Arthropod-like
circulatory system
Phylum Arthropoda
Examples (whether aquatic or
terrestrial) include Insects,
spiders, crabs, shrimp,
centipedes – all of which
possess a hard chitinous
exoskeleton
– Replaced via molting
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Jointed bilateral appendages
Segmented body
Open circulatory system
Many marine crustaceans
– Two pairs of antennae
– gills
Subphylum Trilobita
Subphylum Chelicerata
• Chelicera
– First pair of oral
appendages
• Scorpion pinchers
• Spider fangs
• Lack antennae
• Book gills or book
lungs
• Typically four pairs
of walking legs
• 2 body regions
– Cephalothorax &
abdomen
Class Merostomata
Class Arachnida
Order Scorpiones
Order Uropygi
Order Aranae
Order Opiliones
Order Acari
Order Acari
Subphylum Crustacea
• Includes: fairy shrimp,
copepods, barnacles,
decapods (shrimps,
lobsters, crabs), isopods,
and amphipods
• Two body regions
– Cephalothorax & abdomen
• Two pairs of antennae
• At least 4 prs of walking
legs
Class Branchiopoda
• “gill feet”
• Many thoracic
appendages
– Swimming
– …and modified as gills
• Primarily freshwater
• Examples
– Fairy shrimp
– Water flea
Class Copepoda
• Very abundant plankton
• Biramous appendages
• Long first antennae
Class Cirripedia
Barnacles
• Suspension feeders
– Cirri (also for respiration)
• Protected by calcareous
plates
• Free-swimming larvae
– Nauplius
Other Crustaceans…
Class Malacostraca
Order Decapoda
• Shrimps, crabs,
lobsters…
• 5 pairs walking legs
– Thoracic pereopods
– 1st pr as cheliped
• 5 pairs abdominal
appendages
– Pleopods or
swimmerets
Crayfish dissection
Order Amphipoda
• Laterally flattened
• Shrimp-like
&
Order Isopoda
• Dorsal-ventrally
flattened
Subphylum Uniramia
• Unbranched appendages
• Or… 2 Subphylums:
– Myriapoda
– Hexapoda
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•
•
Class Insecta
Very diverse and abundant
Head, thorax, abdomen
Compound and simple
eyes
• Spiracles rather than lungs
– Open canals – “ram
respiration”
Development & Metamorphosis
Feeding maggot larval
stage; pupa; adult
Gradual development
sub-adults to adults
Order Anoplura (head louse and nit)
Anoplura (crab louse)
Order Coleoptera
• Beetles
• Sheath wing
– Forewings hard and leathery
– Hindwings membranous
Order Dermaptera
• Earwigs
• “skin-fasten”
– Ear shape of
hindwing
• Are not known to
crawl into ears
Order Diptera
• Flies; mosquitos
• Dominant forewings
• 2nd pair very different
– Reduced to tiny
halters or vibrating
balancers
– For equilibrium
Order Hymenoptera
• Bees; wasps; ants
• “membrane-wings”
– Hindwings reduced
and attached to 1st
• Male ants keep
wings, mate with
queen
• Female ants are
wingless, sterile,
workers
Order Hemiptera
• True bugs
– Stink bugs;
waterstriders
• “half-wing”
– Forewing is leathery
in the front but
membranous in the
rear
Order Homoptera
• Aphids; leaf
hoppers; cicadas
• “same-wings”
– Both pairs
membranous
– Folds parallel over
abdomen
Order Isoptera
• Termites
• “equal-wing”
– 2 pair of equal size
– Lost at maturity
Order Lepidoptera
• Moths and
butterflies
• “scaly or roughwing”
– 2 pair covered in
scales
Order Odonata
• Dragonflies and
damselflies
• 2 pr elongated
membranous wings
– perpendicular to
thorax
– parallel to thorax
• Dominant aquatic
nymph stage (“seeswimming)
Order Orthoptera
• Grasshoppers;
crickets; cockroach;
praying mantis
• “straight or correctwing”
– Forewings leathery
Order Siphonaptera
• Fleas
• Wings absent
• Piercing/sucking
parasitic mouthparts
Subphylum Myriapoda
Class Chilopoda & Diplopoda
• Centipedes
• 1 pair of appendages per
segment
• Dorso-ventrally flattened
• Predatory lifestyle
• Millipedes
• 2 pair of appendages per
segment
• Circular rather than flattened
• Herbivorous
Deuterostomes
• Anus first, mouth second
• Radial cleavage
• Enteroceoelous rather than
schizoceolous
• Indeterminate blastomeres
• Ventral heart
• Dorsal nerve cord
Phylum Echinodermata
“Spiny skin”
• All marine; mostly benthic
(sea floor)
• Radial symmetry
• Some regenerate asexually
• 5 classes
– Crinoidea--feather stars and
sea lilies
– Asteriodea--sea stars
– Ophiuroidea--brittle stars and
basket stars
– Echinoidea--sand dollars and
sea urchins
– Holothuroidea--sea
cucumbers
• Water vascular system
– Tube feet
Water vascular system w/ tube feet
Lophophorates
• Lophophore =
unique ciliated
feeding structure
• Bryozoans
– Colonial moss
animals
– Secrete CaCO3
• Brachiopods
– Two valves (shells)
• Chaetognaths
– Lophophore
modified
– Aggressive pelagic
predators
• (plankton)
Phylum Chordata
Invertebrate chordates examples
– Subphylum Urochordata
• Tunicates, sea squirts, ascidians
– Subphylum Cephalochordata
• Lancelets
Share 4 “chordate” characteristics
• Notochord
– Flexible rod-like structure
• Dorsal nerve cord
– Tube for nerves
• Pharyngeal gill slits
– Respiration and feeding
• Post-anal tail
– Reabsorbed in some species