Biology Lab Practical

Class Staurozoa

"stalked jellyfish" Only polyp stage, and use an adhesive disk to attach to plant life. The top of their polyps resembles a medusa, reproduction is sexual or asexual, and larvae develop directly to a new polyp.

Hemiptera

"true bugs", cicadas, aphids

Class Scyphozoa

"true jellyfish", dioecious, medusa stage most common, polyps are very small. Enlarged mesoglea (acellular cavity) underlying the epidermis, and no velum. Rhopalia (singular rhopalium) along the margin of the medusa that has statocysts and ocelli.

Subclass Oligochaeta

(In Sedentaria) •Earthworms •Lack eyes or tentacles in the anterior region •Nephridia—excretory structures, one pair in each segment -Highly vascularized to reabsorb some nutrients -Nephridiopore on each segment •Clitellum—reproductive structure, band near anterior -After mating, clitellum secretes a cocoon, eggs and sperm are deposited into cocoon as it is shed from the anterior •Hermaphrodites—require another worm to mate •Crop—stores food •Gizzard—used to grind food

Subclass Hirudinae

(In Sedentaria) •Leeches—mainly freshwater, some marine •Fixed number of segments in a species •Anterior and posterior suckers—pulls itself forward after attaching sucker •Septa are absent •Generally parasitic—feed on blood •Hirudin—anti-clotting enzyme secreted into host's bloodstream •Clitellum only visible during breeding season

Class Arachnida

(Phylum Arthropoda Subphylum Chelicerata) -Scorpions, spiders, (ticks, and mites have own subclass called Acari) -Most are terrestrial; none are marine. The chelicerae are modified as a claw or fang (these are homologous structures). The second appendages are the pedipalps for sensory use/grasping, and four pairs of walking legs.

Class Merostomata

(Phylum Arthropoda Subphylum Chelicerata) Horseshoe crabs and water scorpions. Marine animals with abdominal book gills, and one pair of lateral compound eyes.

Class Pycnogonida

(Phylum Arthropoda Subphylum Chelicerata) Sea spiders, small marine spider-like animals with a greatly reduced abdomen and long cephalothorax. Suction feeding on soft-bodied prey. Males possess ovigers, appendages for carrying eggs.

Class Malacostraca

(Phylum Arthropoda Subphylum Crustacea) -Includes lobster, shrimp, crayfish, crabs, isopods and Amphipoda -usually large animals with a 5-segmented head and a trunk consisting of fourteen segments (8 in the thorax, 6 or sometimes 7 in the abdomen, plus a posterior telson). Note that all segments bear appendages including maxillipeds on the thorax for locomotion and abdominal swimmerets.

Class Thecostraca

(Phylum Arthropoda Subphylum Crustacea) Barnacles, adults are sessile attached directly to the substrate or on a stalk. The carapace (mantle) covers the body in calcareous plates. No abdomen, long thoracic appendages and many jointed cirri with hair-like setae for filter feeding.

Class Branchiopoda

(Phylum Arthropoda Subphylum Crustacea) Small critters with trunk appendages flattened and antennae leaf-like, often modified for filter feeding and respiration. Common in temporary ponds and pools, most species live in freshwater. Examples are water fleas and brine shrimp - also sold as sea monkeys (image)

Class Oligostraca

(Phylum Arthropoda Subphylum Crustacea) Subclasses Ostracoda, which produce a bivalved carapace and resemble tiny clams (shown to right), while Branchiura and Pentastomida are parasites.

Class Insecta

(Phylum Arthropoda Subphylum Hexapoda) •Ectognathous—mouthparts not contained inside of the head—they stick out •Biting/chewing mouthparts -mandibulate •Piercing/sucking mouthparts -haustellate •Usually have wings -1 pair or 2 pairs •Respiratory system of tracheal tubes •One pair antennae •Body divided into head, thorax, and abdomen

Class Cilopoda

(Phylum Arthropoda Subphylum Myriapoda) Centipedes, have elongate flattened bodies with many similar segments, one pair of antennae, and each trunk segment has a single pair of walking legs.

Class Diplopoda

(Phylum Arthropoda Subphylum Myriapoda) Millipedes, have elongate cylindrical bodies with a distinct head and many similar trunk segments; one pair of short antennae, and two pairs of walking legs per trunk segment in adults.

Subphylum Chelicerata

(Phylum Arthropoda) -Distinct prosoma, which is a fused head and thorax -Antennae are absent -There are six pairs of uniramous appendages that include one pair of chelicerae, pincer-like appendages for feeding (may look like fangs), one pair maxillae/pedipalps, and 4 pairs of legs.

Class Asteroidea

(Phylum Echinodermata Subphylum Eleutherozoa) sea stars •Arms extending from central disc •Tube feet have suckers and are used for locomotion and feeding •Cardiac stomach—can be protruded out of the mouth to feed •Pyloric stomach—smaller, on top of cardiac -Connects to pyloric ceca in arms—digestion takes place in pyloric ceca •Anus on aboral side (side away from mouth)

Class Ophiuroidea

(Phylum Echinodermata Subphylum Eleutherozoa) •Brittle Stars •Arms extend from central disc •Tube feet lack suckers -Locomotion by movement of arms •Bursae for gas exchange

Class Holothuroidea

(Phylum Echinodermata Subphylum Eleutherozoa) •sea cucumbers •worm-like body—elongated along oral/aboral axis •ossicles are reduced in size and embedded within soft tissue of the body wall •some tube feet are modified to form oral tentacles •highly branched respiratory system •no spines or arms

Class Echinoidea

(Phylum Echinodermata Subphylum Eleutherozoa) •sea urchins, sea biscuits, sand dollars •ossicles joined to form a rigid test—holes in test for tube feet (5 of them, bearing suckers) •Aristotle's Lantern—cone-shaped feeding mechanism, used by urchins to chew food

Subphylum Pelmatozoa

(Phylum Echinodermata) Class Crinoidea •Sea lillies and feather stars •main part of the body is supporting above the substrate by long stalks or cirri •Oral surface points up •suspension feeders •can move—not sessile

Class Monogenea

(Phylum Platyhelminthes) -Single host, egg hatches and larvae attaches to host •Mostly ectoparasites of fish—attach to scales and gills •Opisthaptor—hooked organ at posterior for attachment

Class Turbellaria

(Phylum Platyhelminthes) •Mostly free-living; ~5mm-50cm •Marine, freshwater, some terrestrial •Ventral mouth in the middle of the body -Protrusible, muscular pharynx -Only opening to the gut •Gut may be simple or with branches -More branching associated with larger size body, and more efficient digestion •Movement by muscular contractions and cilia •Larvae resemble miniature adults; ciliated in marine forms •Can reproduce asexually through fission

Class Cestoda

(Phylum Platyhelminthes) •~4000 species •Tapeworms •Parasites of vertebrate digestive tracts -Usually 2 hosts, one may be and invertebrate •Scolex—head segment with hooks and suckers for attachment to host digestive tract •Proglottids—reproductive segments behind the head, make up the strobila •No digestive system—all nutrients absorbed from host (already digested) through tegument -Flat body allows efficient diffusion to all cells -Microtriches—modified cilia covering the outside, further increase surface area for absorption. •Monoecious •Strobila—chain of body made of proglottids -New, immature proglottids added behind the head (Germinative zone)

Class Trematoda

(Phylum Platyhelminthes) Liver flukes; all are parasitic, nearly all as vertebrate endoparasites as adults. Mouth is anterior, high reproductive capacity, syncytial tegument. Special organs for attachment, oral and ventral suckers, hooks. Glands to produce cysts. Also have a complex reproductive cycle with multiple hosts.

Trichonympha

(called Termite Flagellates for where they were first commonly found) - These protozoans house bacteria that actually break down cellulose.

Spherical Symmetry

A body form in which any cut through the organism's center results in identical halves.

Paramecium

A ciliated (it propels itself via cilia) protist that lives in fresh water and eats other tiny organisms for food.

Closed Circulatory System

A circulatory system in which the oxygen-carrying blood cells never leave the blood vessels. Seen in all vertebrates.

Open Circulatory System

A circulatory system that allows the blood to flow out of the blood vessels and into various body cavities so that the cells are in direct contact with the blood. Seen in insects and spiders.

Volvox

A green, single-celled aquatic organism that forms minute, free-swimming spherical colonies.

Amoeba

A type of protist characterized by great flexibility and the presence of pseudopodia.

Class Demospongiae

All live in a marine environment. This group is the most varied in shape and size, appearing as fans, vases, cushions or balls, and all of the bath sponges belong to this group.

Hymenoptera

Ants, bees, wasps

Class Hydrozoa

Asexual polyp stage and sexual medusa stage, polyp stage more common. Mostly marine and colonial. Freshwater hydra (image) have no medusa stage, Portuguese man-of-war are colonial. Medusa can be distinguished from those of true jellies by the smooth margin or ring outlining the bell of the lip of the medusa, called a velum which helps direct water currents in movement.

Coleoptera

Beetles (largest order of animals)

Biradial Symmetry

Body plan in which body components are arranged with similar parts on either side of a central axis, and each of the four sides of the body is identical to the opposite side but different from the adjacent side. (Example is comb jellies)

Radial Symmetry

Body plan in which body parts repeat around the center of the body (arrangement of body parts around a central axis) Examples include most cnidarians and echinoderms.

Bilateral Symmetry

Body plan in which only a single, imaginary line can divide the body into two equal halves.

Class Cuboza

Box jellies, sea wasps, cube jellies. Medusa stage most common. Their tentacles occur at the corners rather than emanating along the margin of the animals. Active predators and strong swimmers. Rhopalium at each corner, with 6 eyes can detect pictures.

Lepidoptera

Butterflies and moths

Class Calcarea

Calcareous sponges, all of these species are small, ranging from 10 cm or shorter in height; all are tubular or vase shaped.

Class Polyplacophora

Chitons •Shell made of 7-8 calcareous, hinged plates on the dorsal surface •Radula scrapes algae from rocks •Mantle forms a girdle around the edges of the plates •Foot extends across the ventral surface •Gills are found along sides of the foot •Primitive photoreceptor in pores in shell •Osphradia—chemical sensors that sample water •Marine

Blattodea

Cockroaches

Sexual Dimorphism

Distinct difference in size or appearance between the sexes of an animal in addition to difference between the sexual organs themselves.

Pinacocyte

Epithelial-like cell that forms the outermost layer of sponges and encloses a jelly-like substance called mesohyl

Choanocytes

Flagellated collar cells that line cavities and canals of sponges. Maintain a current of water passing through the canals. Food particles (bacteria, Protozoan) filtered by collar, oxygen diffused in, and carbon dioxide and waste diffused out.

Class Hexactinellida

Glass sponges, the characteristic feature of these sponges is their six-rayed siliceous spicules, bound by a glass-like latticework.

Orthoptera

Grasshoppers and crickets

Metamerism

Having repeating segments, where most are identical.

Node

In phylogenetic trees, the point where a branch splits, representing the common ancestor from which the descendant species diverged.

Mantodea

Mantids (praying mantis)

Difflugia

Produces shells or tests from mineral particles or other elements and they are commonly referred to as testate amoebae or shelled amoebae. Particularly common in marshes and other freshwater habitats.

Euglena

Protist that moves by a flagellum, known for its eye spot

Chilomonas

Protist, Flagellate

Choanoflagellates

Protists that are the closest living relatives of animals

Stentor

Protozoan, heterotrophic and motile by cilia

Class Homoscleromorpha

Small, the spicules do not form around a central filament and some have no spicules at all, reduced skeleton.

Ascaris

Species in phylum Nematoda, common parasite.

Diptera

True flies, mosquitoes

Porocyte

Tubular cells that allow water to flow from the outside of the sponge to its central cavity

Arcella

Typically enclosed in a chitinous, umbrella-shaped test that has a single central aperture through which the pseudopods, which are used for locomotion, extend out.

Splanchnocranium,

•"facial skull" •Derived from branchial arches -Endochondral bone •Supports gills •Contributes to jaws and mammal inner ear bones •Meckel's cartilage -Main part of lower jaw in chondrichthyes -Ossified in bony fish and descendants -Forms bone of mandible that articulates with skull in non-mammal tetrapods -Forms malleus (inner ear) in mammals

Characteristics of Phylum Rotifera

•"wheel bearing" -Ciliated corona resembles a wheel •40µm to 3mm long -Smaller than many protists •Mostly freshwater, some marine and terrestrial -Some live on animals or plants, some parasitic •Omnivores, herbivores, carnivores •Some form colonies •Some planktonic •Some live in interstitial spaces •Complete Digestive system •Some are sessile—attach with foot •Some have spines or appendages used for swimming •Some move by undulating movement with longitudinal and circular muscle •Some use a "looping" motion, like and inchworm Alternately attach with foot and mouth

Phylum Echinodermata

•All are marine •Deuterostomes •Calcareous skeleton -Spines, plates/ossicles (small bony plates) •Water-vascular system •Pedicellariae -Tiny jaws w/muscles -Aid in food capture, cleaning body surface, protecting papulae •Dermal branchiae (papulae) -'skin gills'—extend between ossicles to increase surface area for respiration—projections of coelom •Pentaradial symmetry -Often have 5 'arms' (or multiples of 5) •bilateral symmetry as larvae-free-swimming using cilia

Monophyly

•All individuals in a group share a common ancestor •All descendants of this ancestor are present in the group •Common ancestor shares characteristics that define the group

Paraphyly

•All members in the group share a common ancestor •However, not all of the descendants of the common ancestor are present in this group •Often a result of naming groups based on one or a few morphological characters alone

Chondrocranium

•Base of the skull •Cartilaginous -Surround nasal, optic, and otic organs •Forms the braincase in Chondrichthyes •Become ossified in most vertebrates -Neurocranium

Class Bivalva

•Clams, mussels, scallops •Marine and freshwater •Hinged shell with right and left halves (valves), closed by adductor muscles •Laterally compressed body and foot •Large mantle cavity •Lack cephalization and radula •Muscular foot used to burrow in substrate •Some attach to substrate with byssal threads •Filter feeders -Incurrent and excurrent siphons

Dermatocranium

•Covers brain, eyes, nostrils •Dermal bones forming the skull -Most of the skull, including the braincase •Facial—nasal, premaxilla, maxilla •Vault—frontal, parietal, postparietal •Orbital—around the eye •Palatal—roof of the mouth •Mandibular—lower jaw

Pseudocoelomate

•Fluid-filled cavity, not completely lined with mesoderm -Provides space for organs, allows for a hydrostatic skeleton -Circulate materials (gases, nutrients) throughout the body

Coelomate

•Fluid-filled, internal cavity within mesoderm, suspended by mesenteries •Allows for muscular digestive tract, less crowding of organs •Mesenteries provide space for blood vessels •Allows for a larger body size •May be used as a hydrostatic skeleton

Acoelomate

•Lacking a coelom (body cavity) •Triploblastic—possess 3 tissue layers -Endoderm, mesoderm, ectoderm •Possess a body wall and digestive tract -Space between is filled with mesodermal tissue (parenchyma) -Organs are found in this space •Members include Platyhelminthes and several small, obscure groups

Class Scaphopoda

•Long, thin, cylindrical shell open at both ends •Foot burrows into substrate •Ciliated feeding tentacles at posterior end •Water flow created by cilia in mantle cavity •Feed on detritus and protists •Marine

Polyphyly

•Members of the group share common features •However, they are descended from different ancestors

Class Polychaeta (Errantia)

•Motile •< 1 mm to 3 m in length •Prostomium (anterior) •Eyes, antennae, sensory palps •Parapodia—paired appendages on most segments, highly-vascularized respiratory structures -Increased surface area -May be used for locomotion—swimming/crawling •Notopodium (dorsal) •Neuropodium (ventral) -Highly developed sensory organs •Eyes can be simple to well developed with retina and rodlike cells •Statocysts •Reproduction -No permanent sexual organs •Gonads are temporary -External fertilization

Unique features of Cnidarians

•Named for the stinging cells they possess -Cnidocytes—contain stinging organelles •Radial symmetry/biradial symmetry •Possess two layers (diploblast) of true tissue •Most common in shallow, warm water -Mostly marine, some freshwater •Free-swimming and sessile forms •May harbor symbiotic algae or have symbiotic relationships with other animals •Sexual and asexual reproduction

Characteristics of Phylum Nematoda

•Pseudocoelomates •Free-living and parasitic forms •Covered by a nonliving cuticle secreted by the epidermis -Contains hydrostatic pressure, giving the round shape -Mostly collagen; flexible but does not stretch much •Ecdysozoans—the cuticle is shed (molting) at certain life stages •Lack respiratory structures—diffusion through cuticle -Limits body size •Possess only longitudinal muscle—dorsal and ventral -Successive contractions lead to sinusoidal movement •Complete digestive system •Mostly dioecious

Class Clitellata (Sedentaria)

•Sedentary and tube worms •Terrestrial and marine -Fan worms, lugworms, -Anterior of body can be modified into fan like structures for filter feeding •Tube worms inhabit burrows composed of mucus or CaCO3 •Terrestrial: -Notably: earthworms and leeches

Class Monoplacophora

•Single, cone-shaped shell •Similar in appearance to limpets, but have serial repetition of gills and gonads •<1mm-37mm •Marine, found up to 2000m

Class Cephalopoda

•Squid, octopus, cuttlefish, chambered nautilus •Means "head foot"—head and foot become indistinguishable •Foot and mantle cavity modified into jet-propulsion device (siphon) •Large, complex brains—some show problem-solving abilities •Complex eyes—can form an image •Chromatophores—color-changing cells in the skin of most cephalopods -Can be used for camouflage, communication •Shell has become internalized in most •Radula modified into beak for tearing flesh from prey •Ink glands can release a cloud of ink to evade predators •Closed circulatory system -Allows for higher metabolism—active predators

Class Gastropoda

•Terrestrial and aquatic forms •Snails, slugs, limpets, sea slugs, abalone •Torsion—twisting of the digestive system in larval gastropods, mouth and anus open above the head •Open circulatory system •4 sensory tentacles—possess eyes •The head is well developed, with a radula, a large flat foot, one or two gills, and the mantle is modified into secondary gills or a lung. Both dioecious and monoecious types are common.

Symplesiomorphy

•shared ancestral trait -Shared with an ancestor that is not the MRCA -Multicellularity in vertebrates, vertebral column for mammals (an earlier ancestor evolved multicellularity and a vertebral column than the MRCA of these groups) -In other words, the trait was already present when these groups evolved

Synapomorphy

•shared derived characteristics -Derived from the most recent common ancestor (MRCA) -Mammalian hair; notochord in chordates/vertebral column in vertebrates; Multicellularity in metazoans

Analogous traits

•traits that are similar but are not derived from a common ancestor (convergent evolution) -Evolved independently among multiple groups -Wings (bird, bat, insect); Complex eyes (cephalopods, cnidarians, vertebrates); Insect sucking mouthparts (overall mouthparts are homologous, but several adaptations for sucking mouthparts)

Class Aplacophora

•~320 species name means "plates bearing" •vermiform (worm-shaped) •exclusively marine -many come from Antarctic waters •most are small -< 5 mm •body lacks a true shell -but has calcareous spines/spicules •some lack a muscular foot •some lack a radula -some only use it for attachment •many feed on coral or hydras •some are detritivores •head and excretory organs are absent