Download First Lab Practical

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) Bony
2) Glass
3) 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 production
Reproductive organs: elaborate to make many gametes
Shape: dorsally ventrally flattened to cling onto hosts
Organs 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)
Pharynx
Gastrovascular Cavity
Eyespot
Trematodes (Flukes)
- 2/more hosts – snail, fish, humans
1.
2.
3.
5.
Adult Fluke
Eggs in feces
Miracidium
Rediae
2. Sucker
6. Intestine
8. Uterus
9. 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
Digestive
System
Feeding
Mode of
feeding
Tubellaria
Trematoda
*Platyhelminthes
don’t have
digestive system
(absorb thru
wall)
Free living
Parasitic
(many
hosts)
Oral sucker
* nematodes live in almost all habitats
Cestoidea
Nematodes
*nematodes
and annelids
have digestive
system
Parasitic
(scolex
with hooks
and suckers
on gut)
Scolex with
suckers and
hooks
Parasitic on
gut
(Elephantiases
and
Trichinosis)
Oligochaeta
Hirudinea
Polychaeta
Filter feeder
2 oral
suckers,
cutting jaw
Parapodia,
Jaws
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 adductor
6. Posterior foot retractor
7. Foot (For burrowing)
8. Excurrent Siphon
9. Incurrent Siphon
11. Labial Palp (connects to mouth)
12. Mouth
13. Mantle (shell) – has pallial line that connects adductor scars
18. Visceral Mass (gills removed)
Umbo: swollen junction
Hinge 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 bulb
Buccal Mass (bulb contains radula, beak, pharynx, glands): smaller white bulb near antennae
Shell: apex at top, spire is spiral, aperture is front larger part
Mantle is thicker near head
Anterior tentacles shorter than posterior tentacles (posterior tentacles have eyes)
Genital pore – below right antennae
Pneumostome (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)
Symmetry
Feeding Adaptations
Bilateral
Filter Feed (can detect env
pollution)
Torsion causes asymmetry
Radula (Scrapes)
Locomotion
Skeleton
Circulatory
Nervous system
Burrow using foot
Mantle
Open
Foot moves
Mantle
Open
Chemoreceptors
Habitat
Water
Consumer
Filter feeder
Defense
Adductor muscles close
shell
Water/ some land snails
have lungs
Predator, scavenger, filter
feeder
Shell
Cephalopoda (Squid,
oysters)
Bilateral
Radula
Beak
8 Arms + 2 tentacles
Tentacles
Pen (remnant of shell)
Closed
Inc cephalization
Chromatophores controlled
by muscles
Eyes + large brain
Water
Mobile Predator
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 cephalothorax
2. 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 food
Digestive gland – secretes digestive enzymes
Green 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 eye
4. Prothorax
Femur – big back leg
Forewings (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)
Body Division
Cephalothorax+abdomen
Antennae
None
Mouth Parts
Chelicerae with fangs
Pedipalps with pincers
Legs
4 pairs WALKING
LEGS
Book gills
Respiration
Echinodermata
Crinoidea (Feather stars)
Crustacea
(crayfish)
Cephalothorax+abdomen
2 pairs (Antennule–
shorter, Antenna–longer)
1 pair Mandibles (teeth)
1 pair Maxillae (below
teeth)
3 pairs Maxillipedes
Diplopoda
(Millipede)
Head, thorax,
abdomen
1 pair
2 pairs/segment
Book lungs
Chilopoda
(centipede)
1 pair
Hexapoda
(Grasshopper)
Head, Thorax,
Abdomen
1 pair
Fangs
Mandibules
(teeth)
Maxilla
1 pair/segment
3 pairs legs, 2
pair wings
Traechae (Chitin
tubules)
- 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. Mouth
9. 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 Lantern
2. Teeth
7. Gonad
4.
5.
-
Tube feet
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