1. pets
2. reptiles

Biology 171
Practical 3 Study Guide
This practical will focus on organisms from each of the Phyla below, with emphasis on key characteristics (review
Table 1 on page 224 and character definitions on pg 181 – 183 in your manual)
Be familiar and able to identify organisms from each of the below Phyla/ Divisions (in bold). Some specimen
examples are provided in parentheses.
METAZOA
Parazoa
Phylum Porifera (sponges, glass sponge, including Grantia sp.)
Eumetazoa
Radial Symmetry
Phylum Cnidaria (Hydra sp., corals, jellies, sea anemones, Portuguese men-of-war)
Bilateral Symmetry
Protostomes
Lophotrochozoa
Phylum Annelida (clamworms [Nereis sp.], earthworm dissection & slide XS [Lumbricus
terrestris], leeches)
Phylum Mollusca (clams, snails, squids, octopus, chambered nautilus, clam dissection)
Phylum Platyhelminthes (Planarians = flatworms [Dugesia sp.], other flatworms &
tapeworms)
Phylum Rotifera living and prepared slides
Ecdysozoa
Phylum Nematoda (roundworms, including Ascaris sp. (dissection & slide XS) and Trichinella
sp. (encased larvae slide))
Phylum Arthropoda
Subphylum Cheliceriformes (horseshoe crabs, spiders, scorpions, ticks
[Dermacentor andersoni, slide WM],
mites)
Subphylum Myriapoda (millipedes, centipedes)
Subphylum Hexapoda (insects [grasshopper, Romalea sp., mouthpart
dissection, external morphology], springtails)
Insect Orders:
Ephemeroptera (mayflies)
Odonata (dragon/damselflies)
Orthoptera (grasshoppers, crickets)
Hemiptera (true bugs)
Homoptera (cicadas, aphids)
Coleoptera (beetles, weevils)
Lepidoptera (butterflies, moths)
Diptera (flies, mosquitoes)
Hymenoptera (ants, bees, wasps)
Subphylum Crustacea (crabs, lobsters, crayfish [Cambarus sp.], shrimp,
Biology 171
Practical 3 Study Guide
isopods, barnacles, Daphnia sp. (living, slide WM & WM with
parthenogenic eggs)
Deuterostomes
Phylum Echinodermata
Class Asteroidea (sea star)
Class Echinoidea (sea urchin, sand dollars)
Class Holothuroidea (sea cucumber)
Class Ophiuroidea (brittle sea star)
Class Crinoidea (feather sea star, sea lilies)
Class Concentricycloidea (sea daisy)
Phlum Chordata
Subphyla Urochordata (tunicates [sea squirts, sea pork])
Subphyla Cephalochordata (lancelets)
Subphyla Vertebrata (cyclostomes, bony fish, sharks [dogfish] and rays, amphibians
[bullfrog], reptiles [Anole], mammals [pig], and birds)
Important things to know:
1. Understand how phylogenetic trees show relationships.
2. What is a derived trait? What are they for each phylum?
3. What is phenotypic plasticity?
4. Know the relationships and relatedness of organisms we’ve looked at in lab (e.g. Are rotifers more closely
related to manatees or green algae?)
5. Uses/significance of anatomical parts (e.g. What is the clitellum and what does it do?)
6. What are the differences between acoelomate, pseudocoelomate, and eucoelomate body types? What is an
example of each?
7. What are the two types of symmetry? What is a sponge? Know anterior/posterior/dorsal/ventral.
8. What’s the difference between a protostome and deuterostome? What are some examples of each?
9. Why are females often larger than males?
Biology 171
Practical 3 Study Guide
Animal Terminology
(an abbreviated list)
Heterotrophic – obtaining food by eating other organisms or substances derived from them
Radial symmetry – symmetry in which the body is shaped like a pie or a barrel (i.e. lacking a left and right
side) and can be divided into mirror-image halves by any plane through its central axis; ex. hydra
Bilateral symmetry – symmetry in which a central plane divides the body into two equal but opposite
halves; ex. earthworms, clams, grasshoppers
Protostomes – one of the two major groups that the organisms that fall within Eumetazoa are divided into
(the other being deuterostomes); protostome development is characterized by development of the mouth
from the blastopore
Deuterostomes - one of the two major groups that the organisms that fall within Eumetazoa are divided into
(the other being protostomes); deuterostome development is characterized by development of the anus from
the blastopore
Blastopore – in a gastrula, the opening of the archenteron that typically develops into an anus in
deuterostomes and a mouth in protostomes.
Gastrula – an embryonic stage in animal development encompassing the formation of 3 layers: ectoderm,
mesoderm and endoderm
Epidermis – the outermost layer of cells in an animal; also can refer to the dermal tissue system of nonwoody plants, usually consisting of a single layer of tightly packed cells
Ectoderm – the outermost of the three primary germ layers in animal embryos; gives rise to the outer
covering and, in some phyla, the nervous system, inner ear and lens of the eye
Mesoderm – the middle primary germ layer in an animal embryo; develops into the notochord, the lining of
the coelom, muscles, skeleton, gonads, kidneys and most of the circulatory system in species that have these
structures
Endoderm – the innermost of the three primary germ layers in animal embryos; lines the archenteron and
gives rise to the liver, pancreas, lungs and the lining of the digestive tract in species that have these structures
Ecdysis – shedding or casting off of an outer coat such as a cuticle (in nematodes) or exoskeleton (in insects)
Cuticle – tough coat that covers the body of a nematode; exoskeleton of an arthropod, consisting of layers of
protein and chitin that are variously modified for different functions
Exoskeleton – a hard encasement on the surface of an animal, such as the shell of a mollusk or the cuticle of
an arthropod, that provides protection and points of attachment for muscles
Body cavity – a fluid or air-filled space between the digestive tract and the body wall
Acoelomate – a solid-bodied animal lacking a cavity between the gut and outer body wall
Pseudocoelomate – an animal whose body cavity is lined by tissue derived from mesoderm & endoderm
Eucoelomate (Coelomate) – an animal that possesses a true coelom (a body cavity lined by tissue
completely derived from mesoderm)
Osculum – a large opening in a sponge that connects the spongocoel to the environment
Spicules – needle-like structures that are found in many organisms; in sponges they provide structural
support and deter predators
Spongocoel – the central cavity of a sponge
Choanocyte – a flagellated feeding cell found in sponges; also referred to as a collar cell, it has a collar-like
ring that traps food particles around the base of its flagellum
Spongin – supportive material that consists of a soft, proteinaceous substance
Gastrovascular cavity – a central cavity with a single opening in the body of certain animals that function
in both the digestion and distribution of nutrients
Gastrodermis – lines the gastrovascular cavity
Biology 171
Practical 3 Study Guide
Cnidocytes – a specialized cell unique to the phylum Cnidaria; contains a capsule-like organelle housing a
coiled-thread that, when discharged, explodes outward and functions in prey capture or defense
Nematocyst – in a cnidocyte of a cnidarians, this is the specialized capsule-like organelle containing a coiled
threat that when discharged can penetrate the body wall of prey
Pharynx – in flatworms, the muscular tube that protrudes from ventral side of the worm & ends in the
mouth; can also refer to an area in the vertebrae throat where air & food passages cross
Nervous system – the fast-acting internal system of communication involving sensory receptors, networks
of nerve cells & connections to muscles and glands that respond to nerve signals; func-tions in concert with
the endocrine system to effect internal regulation & maintain homeostasis
Auricle – projections on the head of a planarian that contain sensory cells, mainly for touch and chemical
sense
Parapodia – paired, unjointed lateral outgrowths (hint: recall the structures on the segments of the
clamworms we looked at)
Seta (plural: setae) – in animals it generally refers to a bristle or hair-like structure
Clitellum – a structure that secretes a cocoon that holds eggs in earthworms and some other annelids
Prostomium – fleshy, dorsal, pre-oral protuberance
Nephridia – excretory organs of many invertebrates
Esophagus – a channel that conducts food, by peristalsis, from the pharynx to the stomach
Crop – a chamber or pouch in foregut of arthropods & annelids for holding & partly crushing food
Foot – one of the three main parts of a mollusc; a muscular structure usually used for movement
Mantle – one of the three main parts of a mollusc; a fold of tissue that drapes over the mollusc’s visceral
mass and may secrete a shell
Visceral mass – one of the three main parts of a mollusc; the part containing most of the internal organs
Gonads – the male and female sex organs; the gamete-producing organs in most animals
Carapace – large, expanded, exoskeletal plate;
Green glands – refers to the excretory organs in crayfish
Cecum (plural: ceca) – the blind pouch at the beginning of the intestine
Malpighian tubules
Ventral nerve cord
Madreporite – small, porous plate that serves to take water into the vascular system
Aboral surface – surface away from the mouth; e.g. the upper surface of a sea star
Endoskeleton – a hard skeleton buried within the soft tissues of an animal, such as the spicules of sponges,
the plates of echinoderms, and the bony skeletons of vertebrates
Spiracles - small, circular openings into elastic air tubes of certain invertebrates
Tracheae – air tubes (aka windpipe)
Invertebrate – an animal without a backbone
Vertebrate – a chordate animal with a backbone; includes the mammals, reptiles (including birds),
amphibians, sharks and rays, ray-finned fishes and lobe-fins
Rostrum – nose-like projection that extends over the mouth region
Post-anal tail – extension of the body beyond the anus
Notochord – a longitudinal, flexible rod made of tightly packed mesodermal cells that runs along the
anterior-posterior axis of a chordate in the dorsal part of the body
Open circulatory system – a circulatory system in which fluid called hemolymph bathes the tissues and
organs directly and there is no distinction between the circulating fluid and the interstitial fluid
Closed circulatory system – a circulatory system in which blood is confined to vessels and is kept separate
from the interstitial fluid (i.e. the fluid filling spaces between cells in an animal)