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

– Chytridiomycota

– Phylum Zygomycota

– Phylum Basidiomycota

– Phylum Ascomycota

• Kingdom Animalia

• Kingdom Animalia– 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

– 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 HydrozoaGreek: multi-serpent-headed water beast

– Individual polyps

– colonies of specialized polyps

• Feeding• Reproductive• Defense

Sessile colonies

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 MolluscaVery 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

– central blood cavity rather than highly branched blood vessels

• Mantle for protection– 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

• 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• 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– Walking appendages– Lacks exoskeleton– Antennae– Soft segmented body,

yet chitinous– Arthropod-like

circulatory system

Phylum ArthropodaExamples (whether aquatic or

terrestrial) include Insects, spiders, crabs, shrimp, centipedes – all of which possess a hard chitinous exoskeleton– Replaced via molting

• 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 CirripediaBarnacles• 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 & Order Isopoda

• Laterally flattened• Shrimp-like

• Dorsal-ventrally flattened

Subphylum Uniramia

• Unbranched appendages• Or… 2 Subphylums:

– Myriapoda– Hexapoda

• 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 rough-wing”– 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 (“see-swimming)

Order Orthoptera

• Grasshoppers; crickets; cockroach; praying mantis

• “straight or correct-wing”– Forewings leathery

Order Siphonaptera

• Fleas• Wings absent• Piercing/sucking

parasitic mouthparts

Subphylum MyriapodaClass 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 ChordataInvertebrate 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