The Animal Kingdom

True Body Cavity a body cavity is any

fluid filled space in a multicellular organism.

However, the term usually refers to the space, located between an animal’s outer covering (epidermis) and the outer lining of the gut cavity, where internal organs develop.

Cell LayersCells on the outside of the embryo (ectoderm) will become skin and nerve cells.

While inner groups of cells (endoderm) will give rise to the gut.

And the cells in between (mesoderm) will produce bone and muscle tissues, and the circulatory, excretory and reproductive systems.

Phylum Phylum Porifera Porifera

SpongesSponges

Definitions 1.1Endoderm

└ The inner germ layer that develops into the lining of the digestive and respiratory systems.

Mesoderm └ The middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue.

Sub Groups - Classes

Class Calcarea Class Demospongiae Class Hexactinellida

No openings to the digestive system – cells lining pores simply extract food from water passing through pores.

Two cell layers – outer ectoderm and inner endoderm (no mesoderm)

No true body cavity

Distinguishing Characteristics

All marineHave pores through which

food is filtered

Phylum Cnidaria

One opening to the digestive system for obtaining food and releasing waste -Internal sack for digestion called the gastrovascular cavity

3 cell layers-outer layer=epidermis, middle =mesoglea, inner layer =gastrodermis

No true body cavity

Subgroups Anthozoa=true corals. Anemones and

sea pens Cubozoa= box jellies with complex eyes

and potent toxins Hydrozoa=most diverse group with

siphonophores, hydroids, fire corals, and many medusae

Scyphozoa=true jelly fish

Distinguishing Characteristics Aquatic or marine organisms Have tentacles which are armed with

stinging cells named nematocysts Nematocysts eject barbed threads

tipped with poison Radial symmetry

Examples in Queensland Box jelly fish - Cubozoa Bulb-tentacle Anemone – Anthozoa Blue bottles -Hydrozoa

Phylum PlatyhelminthesFrom the Greek platy for flat and helminthes for worms, Hence Flat Worms

Have three cell layers (endo, meso and ectoderm)

Have only one opening to the digestive tract.

No true body cavity

Distinguishing CharacteristicsBilaterally symmetricalFlattened worm-shape bodyMany are hermaphrodites (both

male and female sexual organs)Have a simple nervous systemLive in aquatic environments or

within another organism (endoparasites)

5 classes Turbellaria Trematoda Aspidogastrea Monogenea Cestoda

Examples Planaria (Turbellaria)

Dugesia tigrina Liver Flukes (Trematodes)

Opisthrochis sinensis (human liver fluke) Fasciola hepatica (sheep liver fluke) Schistosoma mansonii (blood fluke)

Tapeworms (Cestoda) Taenia pisiformes (dog tapeworm) Taenia soleum (pig tapeworm) Taenia

soleum

South-East Queensland Lives a long distance from the sea water Found under rocks and rotting logs

around mangroves relatively thick, fleshy and oval body,

and is well camouflaged against the mud by its brown body and dark spots

Leopard Flatworm Myoramyxa pardalota

Blue-lined flatworms Pseudoceros sp.

Prostheceraeus, a flatworm of the class Turbellaria

NematodesRound WormsMelisa Chang and Angelique Burden

Three cell layersTwo digestive openings – mouth

and anusNo true body cavity

Subgroups Dipogasteria Rhabditia Spiruia Tylenchia

Distinguishing Characteristics

Live in soil or are parasites including humans. Unsegmented worms with long cylindrical

rounded body, pointed at both ends (round worms)

have reproductive, nervous and excretory systems,.

Bodies are bilaterally symmetrical Most are microscopic but can grow to 8 metres

in length

Examples of Roundworms

Pin worms

Annelids

Three cell layers Two openings to the digestive system –

mouth and anus True body cavity

Distinguishing Characteristics Segmented bodies Long cylindrical shaped bodies Some have small bristles along length of

body (not true appendages) Live in moist environments

Examples Earth worms

Polychaetes – pink bristle worm

Polychaete worm

Leeches

Arthropods

© Lauren and

India

Three cell layersTrue Body Cavity Arthropods have

body cavities; their main internal cavity is a hemocoel, which accommodates their internal organs and through which their blood circulates - they have open circulatory systems

Two openings to the digestive cavity

Distinguishing Characteristics

Segmented bodyBody made up of more than one

part. Spiders have two segments and insects have three segments.

Many jointed legs or limbs

Exoskeleton - external skeleton.

Examples (Classes) Crustacea Arachnida Insecta Chilopoda (millipedes) Diplopoda (centipedes)

Molluscs

The Mollusca have three cell layers The body cavity in molluscs is a true

body cavity Two openings to the digestive tract

Distinguishing Characteristics unsegmented soft body most have internal or

external shell have a mantle - a fold

in the body wall that secretes the hard protective shell

muscular foot and/or tentacles

have a radula - a toothed structure used to grate food

Examples of the Phylum Snails Slugs Octopi Limpets Nautiluses Cuttlefish Clam

Molluscs in South East QLD

Mud Whelks

Molluscs in South East QLD

Trochus Shells.

Phylum Echinodermata

Three cell layers Two openings to the

digestive system True body cavity

Characteristics Exclusively marine (only found in ocean) Endoskeleton – spiny Radial Symmetry -Five or more arms

Echinoderms exhibit a wide range of colours.

                             

Feather star                 Many snake stars

Sea Urchin

                    Zebracrab

           Urchin clingfishSea Cucumber

Sea urchin Spiny Cushion Starfish

Examples

Egyptian Sea Star Coleman shrimp

Toxic sea urchin

Shrimpfish

Chordata

• Includes vertebrates, urochordata and cephalochordata

• But not all chordata are vertebrates

Distinguishing features Chordates is defined by having at some stage

in their lives all of the following: A notochord - a fairly stiff rod of cartilage

that extends along the inside of the body. In fish and other vertebrates this develops into the spinal cord,

A dorsal nerve cord A pharyngeal slits - the part of the throat

immediately behind the mouth. A muscular tail - extends backwards behind

the anus. (missing in primates) They all have true body cavity, 3 cell layers

and two openings to the digestive system

Urochordata – sea squirts

Cephalochordata - lancelets Small, "vaguely fish-shaped" animals that

lack brains Usually found buried in sand in shallow

parts of temperate or tropical seas

Vertebrates – animals with backbone Includes:

• Mammals• Birds• Amphibians • Reptiles • fishes