lab practical 1 .docx · web viewarthropoda most diverse phyla exoskeleton, paired jointed limbs,...

PHYLUM = LATIN NAME OF GROUP (Platyhelminthes)CLASS = LATIN NAME of specific group (Tubelleria)

Lower Metazoans:Porifera (sponges) – Parazoans Cnideria – Metazoans

Hydrozoans (Hydra) Scyphozoa (Jellyfish) Anthozoa (Anemones + Corals)

Worms:Platyhelminthes (Flatworms, acoelomate, unsegmented)

Turbellaria (Planaria) – free living Trematodes (Flukes) – free living AND parasitic Cestoidea (Tapeworms) – parasitic

Nematoda (Roundworm, molt, pseudocoelomate, unsegmented)Annelida (coelomate, segmented)

Oligochaeta (Earthworms) Hirodinea (Leeches) Polychaeta (Clamworms)

*Hirodinea and Polychaeta make up Clitellata

Molluscs:Bivalvia (clams, oysters)Gastropoda (snails, slugs)Cephalopoda (squid, octopus)

Arthropoda:Trilobitomorpha (Trilobites)Chelicerata:

Merostomata (horseshore crab) Arachnida (spiders, mites, tickets)

Crustecea (lobsters, crabs, crayfish)Myriapoda:

Diplopoda: Millipede Chilopoda: Centipede

Hexapoda (Insects)

Echinodermata:Crinoidea (Feather stars)Asteroidea (Sea stars)Ophiurodea (Brittle stars)Echinodea (Sea Urchins, sand dollars)Holothuroidea (Sea cucumbers)

Porifera and Cnideria

- Metazoans: multicellular - Metazoans are polyphyletic (multiple lines if lineages or from Choanoflagellate ancestor?) - Metazoans:

Parazoans: no true tissue, cell aggregates Eumetazoans: true tissue, organ systems

Porifera (Sponges)- Choanocytes/Collar cells: drive water through sponge for filter feeding (derived from protozoan

Choanoflagellate?)- Sponges divided based on spicules (calcium, skeletal remains of sponges)

1) Bony2) Glass3) Spongin

- Mesohyl: loose filling on sponge wall - Porocyte

Cnideria (Hydra, Jellyfish, Anemones/Corals) - Diploblastic - Nerve net - Scyphozoa + Anthozoa have gastric cavity divided by septa but not in hydra

Hydra:- asexual polyp and sexual medusa (can alternate/suppress one)- Hydra have Cnidocyte with Nematocyst- Epidermis and gastroderm with mesoglea in between - Gastric cavity not divided

Scyphozoa (Jellyfish)- medusa only- gastric cavity divded by septa - Life stage: Planula -> Scyphistoma -> Strobila -> Ephyrae (young medusa) -> Adult medusa

Anthozoans (Anemones + Corals)- polyp only - gastric cavity divided by septa - changes shape by slowly inflating, cilia drives water inside, close mouth, grows in height; open mouth, expels

water

Worms- body cavities originally for locomotion using hydrostatic skeleton - pseudocoelom made from blastocoel and not completely lined with mesoderm; true coeloms not made from

blastocoel and completely lined with mesoderm - diseases: Trematodes (snail, fish, human), Nematode (elephantiasis and trichinosis)

Worms similar to parasites:Size: large for egg productionReproductive organs: elaborate to make many gametesShape: dorsally ventrally flattened to cling onto hostsOrgans of attachment: suckers and hooks Complex life cycles: 2/more hosts (especially trematodes (flukes) which have snail, fish, and human hosts)Digestive Tract: no digestive tract, nutrients absorbed across wall*General Reduction/elimination of circulatory, respiratory, loco and nervous systems

Platyhelminthes- no body cavity other than digestive system - Cephalization and ladder like nervous system with ventral nerve cords- Flame cell (many protonephridia) – cilia creates currents to draw fluid inside

Tubellaria (Dugesia)

Freshwater vs Marine Tubellaria (Planaria) PharynxGastrovascular CavityEyespot

Trematodes (Flukes) - 2/more hosts – snail, fish, humans

1. Adult Fluke2. Eggs in feces3. Miracidium 5. Rediae

2. Sucker6. Intestine 8. Uterus9. Testes

Cestoidea (Tapeworm) - Scolex (complex head) + proglottids (ribbon like body with segments to package gonads) - NO TRUE segmentation

Scolex (complex head attaches to intestine) – SCOLEX HAS HOOKS AND SUCKERS Mature Proglottid Gravid Proglottid (swollen and eggs are visible)

Nematodes (Round worms) – Ascaris - Free living AND parasitic – in human gut - Trichinosis and elephantiasis - Males and females differ in shape (females longer with straight tail)- Cuticle

Annelida (Coelomate, segmented)- increased cephalizaton- closed circulatory system - classes divided using SETAE (bristles)

Oligochaeta (Earthworms)- no parapodia (distinguishes from Clitellata: Polychaeta/clamworms)

Seminal Vesicles (white circles)Dorsal Blood Vessel (runs along middle)Septa (segments)Crop comes before gizzard (hard)

Cross section of Earth worm

Clitellata (with parapodia): includes Hirudinea (leech) and Polychaeta (Clamworm)

Hirudinea (leech)- no septa (false annulation=external but no internal septa), cutting jaws, posterior and anterior suckers- lack of septa allow rapid movement of blood and helps locomotion

Polychaeta (clamworms)- marine, burrow in mud or live in CaCO3 tubes - Filter feed (flowerlike) on reefs or predators

Parapodia of Polychaeta Setae Circular + Longitudinal muscle

Tubellaria Trematoda Cestoidea Nematodes Oligochaeta Hirudinea PolychaetaDigestive System

*Platyhelminthes don’t have digestive system (absorb thru wall)

*nematodes and annelids have digestive system

Feeding Free living Parasitic (many hosts)

Parasitic (scolex with hooks and suckers on gut)

Parasitic on gut (Elephantiases and Trichinosis)

Filter feeder

Mode of feeding

Oral sucker Scolex with suckers and hooks

2 oral suckers, cutting jaw

Parapodia,Jaws

* nematodes live in almost all habitats

Molluscs

- mantle, shell (bivalve + gastropoda), head (gastropoda + cephalopoda), radula - molluscs are 2nd largest phyla - coelomate, lost segmentation from annelids - diverged from flatworm through specialization of dorsal to mantle, ventral to foot - Trocophore (larvae of molluscs) and annelids are similar -> common ancestor?

Bivalva (clams, oysters)- no head/radula- foot for burrowing, 2 shells - gills fill mantle cavity and act as sieve (filter materials)

Anterior: short round; Posterior: pointed with siphons 1. Gills (brown wrinkly) 2. Anterior adductor 3. Anterior food retractor (behind adductor)5. Posterior adductor6. Posterior foot retractor 7. Foot (For burrowing)

8. Excurrent Siphon9. Incurrent Siphon11. Labial Palp (connects to mouth) 12. Mouth 13. Mantle (shell) – has pallial line that connects adductor scars

18. Visceral Mass (gills removed)

Umbo: swollen junctionHinge Ligament: long and black connects shells Pallial line: connects adductor scars

Gastropods (snails, slugs, nudibranches) - torsion: during larval development, anus brought above head to empty - nudibranches: detorsion, secondary unwinding - many have gills but some have lungs - prefer moist habitats (freshwater) but some are terrestrial

Dart Sac: Big white bulbBuccal Mass (bulb contains radula, beak, pharynx, glands): smaller white bulb near antennae

Shell: apex at top, spire is spiral, aperture is front larger partMantle is thicker near head Anterior tentacles shorter than posterior tentacles (posterior tentacles have eyes) Genital pore – below right antennaePneumostome (lung) – below right of shell

Cephalopoda (Squid, Octapus) - rapid predators because tentacles- no shell except for in Nautilus - cephalization and highly developed senses (vision same as humans)- Chromatophores controlled by muscle cells allow colour changes - Females have ovaries that look like tapioca

4.Siphon retractor muscles Siphon on posterior end 6.Gills 8.Ink sac 11. 2 Branchial hearts 13. Stomach 19. Pen (remnant of shell) 8 arms, 2 tentacles (grasp food)

Bivalves (clam, oyster) Gastropoda (snails, slugs) Cephalopoda (Squid, oysters)

Symmetry Bilateral Torsion causes asymmetry BilateralFeeding Adaptations Filter Feed (can detect env

pollution)Radula (Scrapes) Radula

Beak8 Arms + 2 tentacles

Locomotion Burrow using foot Foot moves TentaclesSkeleton Mantle Mantle Pen (remnant of shell)Circulatory Open Open ClosedNervous system Chemoreceptors Inc cephalization

Chromatophores controlled by musclesEyes + large brain

Habitat Water Water/ some land snails have lungs

Water

Consumer Filter feeder Predator, scavenger, filter feeder

Mobile Predator

Defense Adductor muscles close shell

Shell Ink sac

Arthropoda- most diverse phyla- Exoskeleton, paired jointed limbs, high cephalization, neural and respiratory advances- metamerism in ancestors -> tagmosis (fusion of segments for specialized functions)- metameric organisms have serially homologous appendages (came from common ancestor)- Monophyletic or Polyphyletic? - Evolved from Annelids and share clade with nematodes and Onychophora because:

Moulting Same Hox genes No cilia

Exoskeleton Advantage: attachment point for internal muscles, protection, structural support, extensions used as powerful levers for locomotion Disadvantage: growing body size -> Ecdysis/Molting

Locomotion- Locomotion concentrated on legs so body can move forward without affecting organs - Appendages joined with flexible membranes for strength without sacrificing mobility- Striated fibre bundles instead of long/circular muscles

Nervous and Sensory coordination- Highly evolved brain with antennae, compound eyes, simple/ocellar eyes

Food Acquisition- anterior mouth, esophagus, pharyngeal pump, forgut (process foodstuffs), midgut (absorption and digestions)

hindgut (form feces) rectum, anus

Excretion and water balance 1) waste diffuses across walls and tubules (both within haemocoel) to excretory pores at base of appendages 2) Nephrocytes: strategically placed cells that accumulate and break down waste

3) MALPHIGIAN TUBULES: waste in blood passes to tubules and transported to hintgut

Circulation and Respiration- reduced coelom, fatty acids occupy most area - ostia allows blood into heart, arteries pump blood into haemocoel (interconnected spaces) that reach all tissues - Gills/Lungs evolved (rather than diffusion) because increased body size, mobility, movement onto land -> needs

more efficient system - Terrestrial arthropods have tracheal systems (chitin tubes) with external openings (spiracles), tubes are beside

cells and exchange gas

Trilobitomorpha (Trilobites)

- unspecialized except for head region, each segment with a pair of appendages

Chelicerata Merostomata (horseshoe crab)

- Shieldlike cephalothorax, 5 pairs of legs, book gills, and chelicerae (tear food apart)

1. shield like cephalothorax2. abdomen 5. 5 pair walking legs

Arachnida (spiders, mites, ticks) - book lungs + sucking mouth apparatus - Spiders: cherlicerae -> fangs- Scorpions: pedipalps -> pincers- Ticks/mites: cephalothorax + abdomen fused

Mandibulata: crustaceans and insects were grouped together because they both have: antennaes. mandibules, maxillae(however crustaceans primarily marine, insects are terrestrial and freshwater) - both groups are successful because modification of appendages for diff functions

Crustacea (lobster, crab, crayfish)

13. Maxilliped 14. Mandibules Maxilla (below mandibules)

Gastric mill (in stomach) – grinds foodDigestive gland – secretes digestive enzymesGreen Gland – works as kidney, removes waste and retains salt

Ventral View

1.Stomach (on dorsal)2. Mandibular muscle x2 (Side of head) 3. Digestive Gland 4. Heart (dorsal) 6. Gills 9. Green glands (Green) on ventral

Myriapoda (Diploda: Millipede; Chilopoda: Centipede) - one pair of antennae- metameric with little tagmosis except for in head - Diploda (millipede) cylindrical, 2 pairs of legs/segment- Chilopoda (centipede) flat, 1 pair of legs/segment, fangs

Insects- given rise to more species than any other organism - 3 pairs of legs, 2 pairs of wings, head, thorax, abdomen- trachea for gas exchange

Grasshopper

Mandible (below labrum flap)

1. Compound eye4. ProthoraxFemur – big back legForewings (top); Hindwings (bottom)Spiracles (black spots on top of pink spots in abdomen)Ovipositor (end in females to bury into ground and lay eggs)

Arachnida (spider) Crustacea(crayfish)

Diplopoda (Millipede)

Chilopoda(centipede)

Hexapoda(Grasshopper)

Body Division Cephalothorax+abdomen

Cephalothorax+abdomen Head, thorax, abdomen

Head, Thorax, Abdomen

Antennae None 2 pairs (Antennule–shorter, Antenna–longer)

1 pair 1 pair 1 pair

Mouth Parts Chelicerae with fangsPedipalps with pincers

1 pair Mandibles (teeth)1 pair Maxillae (below teeth)3 pairs Maxillipedes

Fangs Mandibules (teeth)Maxilla

Legs 4 pairs WALKING LEGS

2 pairs/segment 1 pair/segment 3 pairs legs, 2 pair wings

Respiration Book gills Book lungs Traechae (Chitin tubules)

Echinodermata

Crinoidea (Feather stars)

- Mouth/oral surface upwards- 5 arms with ambulacral grooves (with cilia and tube feet to carry food into mouth)- often stalked, sessile

Asteroidea (Sea Stars)

Bipinnaria (1st stage in larvae) – CILIA bands for moving and feeding

Brachiolaria (later stage) – ARMS Metamorphosis occurs after Brachiolaria and turns into sea star

1. Madreoporite (white spot)

2. Stone Canal (white hard, connects madreporite to ring canal) 3. Ring canal (around stomach) 4. Radial Canal 5. Gonad (clear, jellylike makes gametes) 7. Stomach

8. Mouth9. Ambulacral groove

Sea Arm cross section 6. Ampulla 10. Tube feet 13. Ossicle 14. Pyloric Caecum

Ophiuroidea (Brittle Star)

- no ambulacral grooves- tube feet not for locomotion but ossicles form joints - moves quickly unlike ophiuroid

Echinoidea (Sea Urchin, Sand Sollar, Heart Urchin)

1. Aristotle’s Lantern2. Teeth

7. Gonad

4. Tube feet5. Madreporite - ambulacral plates extend along surface of test- lack arms - locomotion by TUBE FEET AND SPINES

Holothuroidea (Sea Cucumbers) - elongate and lie on their side (secondary bilateral symmetry) - tube feet only on substrate side (SOLE)- mouth with tentacles (modified tube feet) for feeding - RESPIRATORY TREE for gas exchange - CUVERIAN TUBULES through anus – have sticky secretions for entangling predators - Evisceration – expulsion of one or both respiratory trees in response to stress for defense