BIOL 321 Lab Part II Flashcards
Lophotrochozoa tree
Bilateria - Protostomia - Lophotrochozoa - 2 branches
1- Mollusca s.g. to Nemertea and Annelida
2. Bryozoa s.g. to Rotifer and Platyhelminthes
Nemertea
previously proboscis/ribbon worm
soft-bodied, non-segmented, slight torso-ventral flattening, ciliated ventral surface, abundant mucous glands, apparent lack of secondary body cavity but coelomate
Nemertea are coelomates?
lateral blood vessels are shrunk down coelomic compartments
epithelial lining derived from mesoderm, face lumen of blood vessel
Nemertean digestion
tubular, one-way digestive tract with mouth and anus
Nemertea characteristics
1-way digestive tract
eucoelomic compartments- circulatory system
eversible proboscis
proboscis
eversible, enclosed in proboscis sac (rhynchocoel), dorsal to anterior part of gut
shot out of body through pore dorsal to mouth
wall of sac is mesodermally-derived, and wrapped in muscle
Nemertean habitat
mainly marine
few fresh, few terrestrial (low resistance to desiccation)
under rocks, burrow in sediment
Nemertean species
ca. 1200
Tubulanus polymorphus
local nemertean
can be over 1m long
thin, long body, easily torn
vivid orange color, conspicuous coloration = chemical
ejection of proboscis
circular muscles contract - fluid pressure in sac increases - proboscis shoots out - turns inside out
proboscis elaborations
some have calcified stylet and secrete neurotoxin
how does proboscis return to rhynchocoel
proboscis retractor muscle
Nemertea movement
mucco-ciliary gliding
muscular wave crawling and dorsoventral swimming
Lophophore
organ for capturing suspended food
circular/horseshoe-shaped fold of body wall that encircles mouth and bears ciliated tentacles
Lophophorates
former phylum that contained Bryozoans, Brachiopods, and Phoronids that all contain lophophore
convergence
Bryozoa habitat
marine, freshwater
attached to rocks, plants, animals, docks
marine Bryozoans
lophophore forms circle of tentacles with mouth in centre
Bryozoan characteristics
u-shaped digestive tract, anus outside lophophore
almost all colonial
various growth/body forms
Bryozoan body forms
erect, branching, flat, encrusting
individual bryozoan
zooids
freshwater bryozoans
horseshoe shaped lophophore
zooids secrete
zooecium exoskeleton
Bryozoan reproduction
sexual, asexual (budding)
zooecium material
chitinous
proteinaceous
calcareous
Membranipora
genus of marine bryozoan
flat, encrusting colonies, often on kelp
Bugula
marine bryozoan
erect, branching colonies
lophophore retracted into zooecium
with lophophoral retractor muscles
Bryozoan feeding
beat ciliary tracts on lophophore tentacles - water currents - bring in suspended particle - cilia capture particle - transfer down tentacle to mouth
formation of new Bryozoan colony
settlement and metamorphosis of a ciliated larva = original zooid of the colony
Membranipora Bryozoan colony
ancestor zooid metamorphoses to form double zooid = ancestrula
individuals of a colony are identical, no polymorphism
frontal membrane not calcified
Bryozoan polymorphism
autozooids - feeding, produce gametes
heterozooids - defense zooids
Bugle heterozooid
avicularium
non-feeding, look like bird beak, open and close jaw - prevent settling of microorganisms on them
lower beak of avicularium
mandible
homologous to operculum of autozooid
Membranipora energy use
no frontal membrane calcification
divert energy to rapid growth, differentiation, and sexual maturation b/c seasonal species
freshwater bryozoan class
all one class larger zooids, more lophophoral tentacles in horseshoe shape produce overwintering bodies
overwintering bryozoan body
statoblast - yolky mesothelial cells congregate - cohesive mass - surrounded by epithelium - secret chitinous covering - covering may have elaborate looks or air pockets
floating, freezing, desiccation protection
germinate in spring when conditions less harsh
Mollusca phylogeny
Aculifera s.g. Conchifera
Aculifera – Aplacophora, Polyplacophora
Conchifera – (Monoplacophora, Cephalopoda) s.g. (Scaphopoda (Bivalvia, Gastropoda))
Gastropoda phylogeny
Vetigastropoda s.g. Patellogastropoda
Neritimorpha s.g. Caenogastropoda s.g. Heterobranchia
Mollusca species
ca. 80,000
second only to arthropods (in Metazoa)
Mollusc basic body plan
2 regions: cephalopodium (head + muscular foot), visceropallium (visceral organs, mantle)
mantle
pallium
dorsal covering of epidermal epithelium
secretes calcareous exoskeleton (1+ hard shell pieces) or spicules
mantle cavity
where mantle epithelium folds inward around periphery of foot and delineates a pocket – open to surrounding water
In mantle cavity
Pallial organs: 1+ gills = ctenidia, 1-2 sensory organs = osphradia (s. um)
anus, nephridiopore, gonoduct
tongue-like mollusc structure
radula
ribbon of transverse rows of teeth repetitively protruded from mouth
-lacking in bivalves, secondarily lost in some gastropods
Mollusca sizes
1mm (snail) - 18m (giant squid)
gastropod larva
veliger
Polyplacophora
‘many shells’
chitons
live on hard substrate, intertidal-shallow subtidal
dorso-ventrally flattened
Polyplacophora movement
slow crawl with ventral, muscular foot
polyplacophora feeding
radula scrape algae, bacteria off rock surface
distinctive chiton feature
8 overlapping, articulating dorsal plates embedded in mantle tissue
plates
valves
chiton mantle tissue surrounding valves
girdle
chiton cephalization
minimal - sedentary lifestyle
chiton anus
pigmented orange-brown strips in roof of mantle cavity on either side of anus = osphradia
chiton osphradia
concentration of sensory cells
posterior sensory cells??? (unknown why)
molluscan gills with filaments on both sides of the central axis
bipectinate ctenidia
how chitons cling so well
grip hard surface with peripheral edge of muscular girdle - elevate roof of mantle cavity - create suction
water flow through mantle cavity of chiton
enters pallial groove – down pallial groove, through gill chambers – exits pallial groove at anus
smooth area of chiton valve embedded in girdle tissue
articulamentum - hard, white, CaCO3
rough, exposed area of chiton valve
tegumentum - brown, rough, mostly conchiolin protein
canal cells in chiton valves
canals run through articulamentum in to tegumentum, house sensory cells (aesthetes)
some are photoreceptors
chiton muscle groups for flexing shell valves
rectus muscles - slender bundles of longitudinal muscle extend down side of midline
transverse muscle - thick muscle pads at junction between shell valves. from dorsal side of one articulamentum to ventral side of next most articulamentum
chiton salivary glands
branched, yellow, open into buccal cavity
secrete mucus to lubricate radula
esophageal glands
large, paired, ‘sugar glands’, secrete amylase to initiate food digestion
Chiton gonads
dioecious = gonochoristic = either testis or ovary not both
Radular teeth mounted on
basal strip of chitin
radular teeth deep in radular sac
small, incompletely formed, translucent
new teeth continuously secreted at distal end of radular sac - move forward in conveyor belt fashion
new teeth secreted by
odontoblasts
why are new teeth continuously secreted
continuously worn/abraded off, need to be replaced
radular teeth organization
transverse rows of 17 teeth - central tooth + 8 lateral on each side of central
1 lateral on each side is larger and black = tricuspid
why is radula tricuspid black
magnetite cap
tissue beneath radula
2 cartilage-like rods = odontophoral cartilages
protracted from mouth with radular ribbon to press teeth firmly against substrate
odontophoral cartilage + radular ribbon
buccal mass
buccal mass muscles
myriad muscles
execute feeding motion, red (contain myoglobin) - supply hard working muscles w/ O2
characters of chitons shared with other molluscs
CaCO3 shells secreted by mantle tissue ribbon of radular teeth mantle cavity containing ctenidia, osphradia, and receives anus, nephridiopores, gonopores bipectinate ctenidia muscular foot on ventral side
bipectinate
branched like a feather on both sides of a main shaft
distinctive characters of chitons
8 overlapping valves - change body shape for unflat surface sugar glands magnetite capped teeth straight digestive tract can suction body to rock
Class Gastropoda
largest class of molluscs in species and diversity
Gastropoda distinctive character
torsion
torsion
brings anus, mantle, pallial organs to anterior position over back of head
180º rotation of visceropallium relative to cephalopodium
gastropod shell coil
asymmetrically around central axis
gastropod shell central axis
columella
aids in protection shell provides gastropod
operculum - hardened plate of protein, secreted by back of foot, seals aperture shut
Vetigastropoda
keyhole limpet
vetigastropoda characteristics
bipectinate ctenidia, perforated shell, 2 ctenidia, 2 osphradia, 2 hypobranchial glands
broadcast spawn, external fertilization
Caenogastropoda
dog whelk
monopectinate ctenidium, gill axis fused along length to roof of mantle cavity, shells not perforated, 1 ctenidium, 1 osphradium, 1 hypobranchial gland
internal fertilization, eggs deposited in benthic egg capsules, veliger larvae
monopectinate ctenidium
gill filaments arise from only one side of central gill axis
Heterobranchia
sea slugs, pond snails
Heterobranchia characteristics
reduction/loss of calcified shell, minimal torsion, true ctenidium often absent replaced by gas exchange structures
internal fertilization, eggs deposited in benthic egg capsules, veliger larvae
torsion in vetigastropods
full extent of torsion
mantle cavity fully anterior
anus mid-dorsally over back of head
torsion in caenogastropods
anterior mantle cavity
anterior anus towards right side rather than mid-dorsal
heterobranchia torsion
little evidence of torsion in adult stage
importance of directing water into mantle cavity
oxygen over ctenidia filaments
flush feces and urine out of mantle cavity
Heterobranch ctenidia
lost altogether
Gastropod perforation gas exchange
vetigastropods - 1+ shell perforations, 2 ctenidia on either side of anus
water enters mantle cavity on both sides of head, flows between filaments, exits mantle cavity by passing out of shell perforation
Caenogastropod gas exchange strategy
1 ctenidium and osphradium located on left side of anterior mantle cavity
anus toward right side
water enters left side - passes over osphradium - flows between ctenidia filaments - out right side of mantle cavity picking up waste
osphradium
patch of sensory epithelium
may monitor possible contaminants or silt levels
Heterobranchia gas exchange
many lack ctenidium, mantle cavity may be lacking in adult, replaced ctenidium with various other gas exchange structures - anal branchiae, cerata
Pulmonates
mostly terrestrial and freshwater heterobranchs
usually breathe atmospheric O2
mantle cavity almost entirely sealed-off
pulmonate mantle cavity opening
pneumostome
pulmonate internalized mantle cavity
lung - muscles pump air in and out via pneumostome
gastropod shell mineral
CaCO3
calcite or aragonite
keyhole-limpet shell
well-developed, heavily calcified, secondarily lost coiling, very wide aperture, no operculum
Nudibranch shell
only present in larval stage
adult defense by defensive chemical
mollusc larva
veliger- planktonic, swim, some feed, coiled shell, foot, operculum, velum
velum
two lobes extending from either side of head
2 tracts of cilia around peripheral edge of each lobe
prototroch + metatroch
veliger prototroch
long cilia power swimming and bring phytoplankton toward veliger
Veliger effective stroke
prototrochal cilia down
veliger metatroch
runs parallel to prototroch, shorter cilia, power stroke is upward toward prototroch
veliger feeding
food particles caught between 2 ciliary bands and collected within food groove (also ciliated) - carry food particles to mid-ventral mouth
gill filaments arising from only one side of central axis of ctenidium
monopectinate
dorsal lateral outgrowths on the anterior surfaces of nudibranchs
cerata
cerata function
anal branchiae
aid in resperation
also attach and defense
nudibranch dorsal outgrowths (some nudibranchs)
cnidosacs
central axis of gastropod shell
columella
Class Bivalve phylogeny
Protobranchia
Autobranchia - Pteriomorpha, Heteroconchia
Pteriomorpha includes
mussels, scallops, oysters
Heteroconchia includes
all other bivalves
bivalves are primarily adapted for
life buried in sediment
bivalve burial adaptations
laterally flattened foot
bi-valve shell, hinged dorsally
sensory structures
bivalve foot adaptation
thrusting into sand/mud during burrowing
bivalve shell adaptation
enclose to protect soft tissues from abrasive sediment, prevent collapse of
bivalve sensory structure adaptation
concentrated along periphery of mantle fold bordering edge of shell valves rather than on head
why are bivalve sensory structures around valve periphery and not on head
head lies deep within spaced enclosed by shell valves
Protobranchia characteristics
deposit feeders, single pr. bipectinate ctenidia, short gill filaments for gas exchange only, taxodont hinge dentition
protobranchia deposit feeding
use tentacle-like feeding appendages extending from either side of mouth - collect, deliver particles to mouth
protobranchia feeding appendages
palp proboscis
vast majority of extant bivalves
Autobranchia
vast majority of Autobranchia have
lamellibranch ctenidia
lamellibranch ctenidia
greatly elongated ctenidia filaments, arising from either side of central axis, elongated to extent that filaments on each side fold back on themselves
how is water drawn in to mantle cavity of most molluscs
beating of lateral cilia of ctenidia filaments
lamellibranch ctenidia function
used for gas exchange and suspension feeding - phytoplankton captured, delivered to mouth by cooperative activities of specialized ciliary tracts
Autobranchia hinge dentition
heterodont
Pteriomorphia characteristics
epibenthic, anchor to sediments/rocks w/ byssal threads or directly cement shell valve to substrate
much reduced foot
mantle margins not fused
why do pteriomorphs have reduced foot
absence of burrowing activity (also why mantle margins not fused)
most extant bivalves are in which auto branch clade
Heteroconchia
2 sections of lamellibranch ctenidium
demibranchs
demibranchs formed by
long row of folded gill filaments arising from either side of gill axis
byssal thread characteristics
proteinaceous, secreted by gland at base of foot, present in most bivalve juveniles, mussels retain gland while most bivalves lose as adults
bivalve shells
outer periostracum (tough protein)
underlying biomineral
periphery corrugated to form 3 lobes
how bivalve shells are enlarged
secretion of periostracum and bxomineral by the peripheral edge of each lateral mantle fold
bivalve shells, outer lobe
secretes periostracum and biomineral
bivalve shell, middle lobe
sensory structures
row of light-reflecting eyespots
bivalve shell, inner lobe
muscular
pallial muscles from lobe to inner wall of shell
forms broad flap projecting into gape of shell
Pteriomorph eye
only bivalves with differentiated eye structures w/ lens, retina, pigment cells
bivalve shells are held together by
hinge ligament + adductor muscles + pallial muscles
adductor muscles
anchored on inner valve surface
extend between 2 valves
pull valves closed
most bivalves have 2 (A&P), same size
Mussel adductor muscles
anterior smaller than posterior
bivalves with single adductor muscle
oyster, scallop
single muscle is the posterior, becomes centralize
pallial muscles
inner lobe of mantle fold - shell along a line parallel to peripheral shell margin (pallial line)
deep burrowing bivalves
have very long siphons
draw water into inhalant siphon along w/ O2, food
exhalant siphon delivers H2O back after O2, food extracted
siphon
elaboration of muscular lobe of mantle fold
pallial sinus
incursion of pallial line that creates space to accommodate the retracted siphons, if present
muscle scars
of A/P adductor muscles
hinge ligament
tough proteinaceous sheet that binds the 2 shell valves together at their dorsal margin
relaxed position = shell open
pallial line
where the pallial muscles attach to the shell
hinge dentition
interlocking teeth that prevent the shell valves from slipping sideways
Heterodont
1+ central cardinal teeth, flanked on 1/2 sides by lateral teeth
chondrophore
cavity or process that supports the internal hinge cartilage of the shell of a bivalve
Taxodont
many similar peg-like teeth in a row on either side of umbo
umbo
most prominent, highest part of each valve of the shell of a bivalve
heterochonch shell dentition
heterodont
shipworm
elongated, reddish, wormlike body, enclosed in tunnel in floating or submerged timber, two anterior triangular calcareous plates, survive in extreme T’s and without O2
cementing bivalves
oysters, thorny oysters, kitten’s paws, jingle shells
cement lower valve to hard substrate using shell material as cement, fixed permanently
lower valve often more deeply cupped
giant clam
surface-dwelling, harbours intracellular photosynthetic symbionts, tropical/semi-tropical
bent-nose clam
surface deposit feeds with incurrent siphon
bivalve reproduction
most free-spawn gametes (broadcast spawn)
eggs develop into veliger larvae
bivalve veliger
look like tiny bivalves - have 2 shell valves
velum w/ ciliary bands for swimming, food capture
freshwater mussel larvae
glochidia larvae
unique, parasitic on fish
shell valves clamp onto fish gills
Class Scaphopoda
‘tusk shells’
marine, elongated (A-P), sell and mantle tubular and open at both ends
no ctenidia, heart, circulatory system
burrowing scaphopods
selective deposit feeders
unique food-gathering tentacles = captacula
what causes water to flow through a scaphopod mantle cavity
cilia
no continuous water flow - exhaled back out
how is hemal fluid pumped through scaphopod body
by the rhythmic action of the foot
Class Cephalopoda phylogeny
Nutiloidea s.g. to Coleoidea
what are coleoids
octopods, squids, cuttlefish
squid external features
fusiform body, muscular mantle, posterior dorsal fins, large image-forming eyes, olfactory crests, mouth w/ stiff jaws (beak), arms, tentacles, funnel, chromatophores
fusiform
having a spindle-like shape that is wide in the middle and tapers at both ends
squid tentacles
paired, suckers only at tips, used for capturing prey
squid arms
4 prs., suckers along length, used for holding and manipulating prey while beak tears off chunks, also for walking, courtship
modified squid arm
hectocotylized - terminal suckers reduced, basal area swollen and elongated
lower left arm in males - transfers spermatophores
Internal squid structures
siphon retractor muscles, cephalic retractor muscle, stellate ganglia, non-ciliated ctenidia, 2 branchial hears, systemic hearts ink sac, esophagus - stomach, digestive gland, caecum, rectum
squid respiration
deoxy blood from body – collects in branchial hearts – pumped through ctenidia for oxygenation – leave ctenidia - enter systemic heart - pumped to tissues and organs
how is water pumped in squid
through mantle cavity by muscular contractions of mantle
squid residual shell
pen
chitinous, non-mineralized
nautilus shell
external, heavily calcified shell, internal chambers, septa btw chambers perforated for siphuncle, gas filled chambers
siphuncle
cord of tissue that replaces fluid in chambers with gas (buoyancy)
Spirula shell
could, calcified, embedded w/i mantle tissue, retains internal chambers separated by septa w/ perforations for siphuncle
Sepia shell
cuttlefish, porous calcareous shell surf-board shaped, pores filled w/ gas by modified siphuncle = cuttlebone
Loligo shell
narrow, chitinous rod (pen), not mineralized, does not provide buoyancy, helps maintain conical shape of visceropallium
shared characters of Ecdysozoa
periodically moult a cuticle
no motile cilia or flagella
Ecdysozoan cuticle
covers all ectodermally-derived epithelia
outer layer of organic material
important skeletal roles
does not expand to allow animal to increase in size
Ecdysozoan cuticle skeletal role
maintains shape, protects from damaging external forces, transmits force of muscle contraction
How Ecdysozoans grows
undergo succesive cuticle moults, each moult followed by construction of new larger cuticle
Ecdysozoan moulting controls
hormonally by steroids called ecdysteroids
Phylum Nematoda
1 of largest animal phyla, most species not yet formally described, abundant in all habitats including parasites of animals/plants, mostly less than few mm
Nematode ecologic importance
degradation of OM, nutrient cycling
Nematode movement
need dense medium to push agains, no circular muscle or ciliary-mucus gliding, long muscles contract to bend the body into sin waves; dorsal/ventral muscles antagonize each other
how do Nematodes prevent kinks/telescoping of the body
very highly pressurized, hydrostatic pressure
collagenous cuticle resistant to pressure
Nematode coelomic condition
pseudocoel
Parasitic nematode reproduction
most are dioecious, eggs only fertilized if host is invaded by both m and f
Ascaris nematode life cycle
live in pigs/humans, pass form feces to soil, last in soil for years, 200,000 eggs/day, resistant to low T and desiccation , no intermediate host
Ascaris morphologic features
mouth encircled by 3 lips
m strongly curved posterior end, f straight
gut = mouth, pharynx, intestine, anus
nematode reproductive system
long, convoluted tubes, regionally differentiated into testis and sperm duct or ovary, oviduct, uterus
nematode hypodermis
syncytial epidermis
Hookworm
nematode that parasitizes human, anchor to intestine wall w/ sharp teeth-like thickenings of oral cuticle, make wound in intestine, feed on blood/tissue, cause anemia and death. Prevalent in areas of poor sanitation
hookworm cycle
eggs in feces - larvae hatch in moist soil and become infective to humans after 2 moults, if walk barefoot through contaminated soil larvae burrow in to humans foot, larvae undergo complex migration through heart - lungs- trachea- esophagus - intestine - moult stages - adult stage
Onychophorans
velvet worms
velvet worm characteristic
damp terrestrial habitat in tropic, similarities to annelids and arthropods, many predators, worm-like metamerism, pre-antennae, oral papillae, jaws, lobe-like paired appendages terminating double claws, metanephridia, tracheal tubules
velvet worm nervous
dorsal brain, circumesophageal connective, ganglionate ventral nerve cord
Phylum Arthropoda subphyla
Trilobitomorpha
Chelicerata
Mandibulata
chelicerate examples
horseshoe crabs, spiders, scorpions, ticks, mites, sea spiders
mandibulate examples
centipedes, millipedes, insects, copepods, barnacles, lobsters, shrimp, crabs, branchiopods
Phylum Arthropoda characteristics
75% of described extant species
almost 90% are insects - only invertebrate able to fly
1mm (mite) - 4m (spider crab)
exoskeleton, jointed appendages
bilateral symmetry, metamerism, tagmatization, open circulatory system, nervous system, complete digestive system, reduced eucoelom
what does arthropod stand for
arthros = joint podos = foot
details of arthropod exoskeleton
exosk. of body proper is regionally thickened into hardened plates
exosk. of each appendage is subdivided into linear series of hollow tubes
hard parts joined together by thin flexible areas of exoskeleton
sections of arthropod appendage
articles /podomeres
benefits of arthropod exoskeleton
rigid = transmit muscle force for locomotion/manipulation of objects
protects organs, supports/maintains body shape
waxy surface helps maintain water balance
exoskeleton challenges
restricts body growth
reception of environmental stimuli
tagmatization
grouped adjacent metameres into larger functional units, tagma, responsible for performing specialized tasks
segmentation of body in to fused sections
arthropod nervous system
dorsal brain in head, serially repeated ganglia along paired ventral nerve cords
Trilobite characteristics
oval, flattened metameric body, trunk divided in to 3 lobes, jointed antennae, paired biramous trunk appendages
trilobite appendages
gnathobase, exopodite, endopodite
Subphylum Chelicerata
1st append. modified feeding structures = chelicerae 2nd - pedipalps, various fn 3-7 - 4prs walking legs all from anterior tagma - prosoma posterior tagma = opisthosoma no mandibles, antennae
Class Merostomata
horseshoe crab - 3 extant genera, abundant in Palaeozoic, Mesozoic, prosoma+opisthosoma, compound eye, telson (tail), chelicera, coxa, gill books, chilarium, epitome
horseshoe crab eating
walking legs transfer food up to mouth
gnathobases at the base of walking legs grind up food
chelicera pushes the food in to the mouth
telson
not a true segment
helps horseshoe crabs ‘right’ themselves when flipped over
chelate
pincer-like
Class Arachnida
scorpions, spiders, mites, ticks largest class of extant chelicerates, majority terrestrial
scorpion chelicerae
small claw-like structures that protrude from the mouth
pull small amounts of food off the prey item for digestion
pedipalp
second paired apendage
spider-sensitive chemical detectors and function as taste and smell organs
scorpion-prey immobilization, defense and sensory
tick anchoring
hypostome - central mouth structure, blunt harpoon, sharp barbs, cement, penetrate skin and anchor
scorpion opisthosoma
stinger – stings, ejects poison
spider opisthosoma
spinneret - silk-spinning organ
scorpion stinger likely homologous to
horseshoe crab telson
Class Pycnogonida
sea spiders, all marine, anterior sucking tube (proboscis) - suck body fluid from prey
prosoma metameres clearly distinct
opisthosoma reduced to insignificant looking papilla w/ anus
Subphylum mandibulata
myriapods (centipede, millipedes), hexapods (insects, entognaths), marine crustaceans
mandibulate appendages
arise from head magma
1pr antennae (sensory)
1pr mandibles (feeding)
1st pair maxillae (accessory feeding appendages)
2nd pair of maxilla (accessory feeding appendages)
-crustaceans have 2nd pair antennae
Superclass Myriapoda
2 body magmata - head, trunk
head has characteristics mandibulate append.
trunk - morphologically similar pos on uniramous walking legs
Myriapod dessication
less able to resist desiccation because cuticle does not have waxy superficial layer
Myriapoda orders
Chilopoda - centipedes
Diplopoda - millipedes
centipedes
fast running carnivores, longer legs than millipedes, first pr trunk appendages specialized poison claws
millipedes
slow-moving, mostly herbivorous, bulldozed through leaf litter, trunk segments fused in duets = diplosegments
Mandibulata groups
Myriapoda
Pancrustaces
Pancrustacea
Hexapoda, Copepoda, Branchiopoda
Ostracod, Malacostraca, Cirripedia
Pancrustacea
‘new group’, replaces previous paraphyletic group crustacea, includes all ‘crustacean’ groups + hexapoda
Hexapoda
Insecta, Entognatha
Basic insect body plan seen in
crickets
‘without wing’ insects
Apterygote
e.g. silverfish
Cricket body tagmata
Head, thorax, abdomen
Cricket head
5 fused segments, compound and simple eyes, antennae, mouth parts,
cricket mouth parts
upper lip, pair of hard mandibles, pair maxillae, lower lip
cricket upper lip
labrum
cricket lower lip
labium
derived from ancestral pair of 2nd maxillae fused together along midline
have sensory palps
‘with wing’ insects
pterygote (2 wing prs)
cricket hypopharynx
tongue-like organ in centre of mouth used for tasting, lubricating, food
Cricket thorax
3 segments: pro- meso- metathorax
each division has pr of walking legs
meso, metathorax each bear pr of wings
cricket abdomen
11 segments
2 long posterior cerci
spiraces along each side of abd.
1st segment = tympanum
terminal segments = egg laying, copulation
f/m have long ovipositor extending from abdomen
tympanum
organ of sound reception
cerci
sensory appendages
spiracles
breathing pores
Malacostraca groups
Isopoda, Amphipoda, Decapoda, Euphausiacea, Stomatopoda
housefly mouthparts for
sponging
butterfly mouthparts
sucking
mosquito mouthparts
piercing and sucking
insect adaptation to dessication
tracheal tubules with closable spiracles
ability to convert ammonia to uric acid - excretion w/ minimal water loss
tracheal tubules
invaginations of epidermis, internally lined w/ cuticle w/ ring-like thickenings to prevent collapse of tubules
types of insect life cycles
ametabolous
hemimetabolous
holometabolous
young insect somewhat resembles adult and uses same kind of food
hemimetabolous
young insect resembles adult except for smaller size and undeveloped sex organs
ametabolous
hemimetabolous development
exopterypote
somewhat resemble adults - wings are first small pads
exopterygote
holometabolous
worm-like larvae, unlike adults, feed and grow by successional moults
grasshopper development
hemimetabolous
holometabolous last larval stage
followed by pupal stage - profound alteration of tissues and organs for complete metamorphosis
silverfish development
ametabolous development
flies, beetles development
holometabolous
Decapoda groups
Caridea, Anomura, Brachyura, Astacidea
Non-hexapod pancrustaceans
mostly aquatic, 2 pos antennae, usually at least some biramous/polyramous appendages
Branchiopoda
phyllopods, paddle-shaped exopods/endopods, exites/epipods, thin exoskeleton, maintain shape w/ pressurized hemal fluid,
phyllopods
distinctive leaf-like thoracic appendages
gas exchange, feeding, locomotion (swimming)
branchiopod example
fairy shrimp
fairy shrimp
swim upside down, 11 prs phyllopods from 11 thoracic appendages, prs move in unison
Copepoda
largest animal biomass on earth, pelagic usually have longer 1st antennae than benthic forms, torpedo-like body, 7 segments, paired biramous appendages move in unison for rapid forward movement
caudal furca
forked tail of copepod 1st antennae - sensory function
copepod swimming
burst of movement, abrupt stop
rapid thrusting appendages + low Re #
holoplanktonic
entire life in plankton
Cirripedia
barnacles, sessile, cement glands in 1st pr antennae, body encloses in calcareous plates, secreted by mantle
main contributor to secondary productivity
copepods
Cirripedia life stages
being as nauplius larvae - cypris larvae - attach to substrate - metamorphose, sessile juvenile/adult form
top of Cirripedia
opercular plates cover cirri
cirri
thoracic appendages, rake surrounding water for suspended food (small zoop.)
Cirripedia moult
exoskeleton of cirri but not calcareous plates
Malacostraca basic body
head, thorax (8segments), abdomen (6segments + telson)
decapod body
dorsal carapace extends posteriorly to cover thoracic segments
decapod head + thorax
cephalothorax
malacostracan thorax appendages
thoracopods
maxillipeds
malacostracan anterior thoracopods = accessory mouthparts
if maxillipeds present
rest of thoracopods are pereopods
malacostraca abdoment appendages
typically biramous
pleopods
may be specialized in to uropods
Isopoda
marine/terrestrial, dorso-ventrally flattened, lack carapace, non-stalked compound eyes, mostly herbivore/detritivore, terminal article is sharp, recurved hooks for hanging on to kelp/grass
isopod appendages
thoracopods = 1pr maxillipeds, 7pr pereopods - crawling, 5pr pleopods- gas exchange/swimming
Amphipoda
c-shaped body, laterally compressed, lack carapace, non-stalked compound eyes,
amphipod appendages
1pr maxilliped, first 2 pr pereopods have subchelate endings for grasping
abdominal appendages -3 prs pleopods, 3pr uropods
uropods heavily sclerotized, kicking, swimming, jumping, burrowing
amphipod examples
skeleton shrimp
beach hoppers
Euphausiacea
kill, look like small decapod shrimp, lack maxillipeds, bioluminescent, important fish/whale food
Euphausiacea appendages
8pr similar pereiopods (thoracopods) - biramous, setose (bristly) - function as filtering basket during feeding
Stomatopoda
mantis shrimp, dorso-ventrally flattened, carapace over fist 1/2 of thorax, massive tail fan, unique gilled abdomen pleopods
stomatopod appendages
enlarged 2nd pr thoracopods for prey capture
massive tail fan - broad, heavily sclerotized telson + pr lateral uropods -shield
Decapoda organisms
shrimp, crayfish, lobster, hermit crab, true crab
Decapoda characteristics
well-developed carapace covers entire thorax, anterior magma = cephalothorax, thoracopods give rise to gills
Decapod appendages
first 3pr thoracopods = maxillipeds
1st pr pereiopods may be highly enlarged and chelate = chelipeds
abdomen- 5pr biramous pleopods, 1pr uropods
Decapod gills
from thoracopods, within space formed by sidewalls of carapace = branchiostegites
Astacidea
crayfish, lobsters
powerful elongate abdomen, tail fan = uropods+telson, body, appendages covered in thick exoskeleton
Astacidea tagmata
cephalothorax
abdomen
Astacidea cephalothorax
head w/ antennules (1st pr antennae)
2nd pr antennae, mandibles, 2 pairs maxillae
thorax w/ 3 pos maxillipeds, 1pr chelipeds, 4prs walking legs/pereopods
Astacidea abdomen
5prs biramous pleopods, 1 pr uropods, telson
uropods+telson = tail fan
Astacidea exoskeleton
divided into dorsal tergum, 2 lateral pleuron plates, ventral sternum
Astacidea appendages made up of
3 parts: protopod - basal, 2 branches - endopod (inner), exopod (outer)
Astacidea atennules
1pr, biramous, many joints, balancing organ/statocyst on flattened dorsal surface of basal joint
Astacidea antennae
1pr, long, slender, many joints, excretory openings on basal segment
Caridea
shrimps, primarily adapted for swimming, laterally compressed, slender legs, well developed biramous pleopods, rostrum, paired compound eyes, some holopelagic
Brachyura
true crab, abdomen reduced and tucked under carapace, pleopods great reduced and specialized not for swimming, loss of uropods, no tail flip response, chelipeds = raptorial feeding, 4pr walking legs
Brachyura 1st pr pleopods
m- sperm transfer
fm - hold egg mass while brooding
Anomura
mud shrimp, hermit crab, lithodid crab, ONLY 3 PR walking legs, 4th pr reduced/tucked in gill to clean
hermit crab
long, curved abdomen, asymmetric coil, pleopods on one side only, uropods modified as grippers, might have enlarged right cheliped to close aperture
Deuterostomia phyla
Hemichordate
Echinodermata
Chordata
Echinodermata taxa groups
Crinoidea s.g. to
Asteroidea s.g. to Ophiuroidea) and (Echinoidea s.g. Holothuroidea
Chordata taxa groups
Cephalochordata s.g. Urochordata s.g. Craniata
Echinodermata characteristics
‘spiny’ ‘skin’, bilateral larvae, pentamerous adult (mostly), WVS
WVS
water vascular system - fluid-filled tubes (canals) connect to tube feet, eucoelomic - lined internally by mesothelium, linked to external seawater by porous ossicle
tube feet
internal ampulla, external podium, extend from body at ambulacral zones
specialized ossicle in echinoderms
madreporite
endoskeletal element
not present in holothurian
WVS canals
stone, ring, radial, lateral (extend to tube feet)
Pollen vesicle
water reservoir for WVS
Tiedemnanns bodies
phagocytic cells clear foreign material from WVS that enters madreporite
Tube feet, functions
feeding
surface area for gas exchange
echinoderm skeleton
internal, individual calcite pieces
echinoderm skeleton pieces
ossicles
small, loosely interconnected or form larger plates that fit together tightly, some species projections into spines
true endoskeleton
true endoskeleton
secreted by cells derived from embryonic mesoderm, completely covered by epidermis epithelium
mutable connective tissue
echinoderm, tensile connective tissue, change rapidly, switch fro extensible to inextensible, under control of nervous system, hormones
echinoderm facts
not metameric, no brain, no parasitic, all marine, habits from intertidal - great depth, all latitudes, 1cm-2m
pedicellariae
small wrench- or claw-shaped appendage with movable jaws, called valves; sea stars, urchins
Crinoidea
oldest echinoderm record, most extant are tropical/deep sea, crawl w/ claw-like cirri, 10 arms w/ pinnule side branches and podia (tube feet), large amount of body full of ossicles, little flesh
Asteroidea
sea stars, usually 5 arms, central disc, gonads in each arm,
pyloric caeca
nutrient storage
Asteroidea digestive
short esophagus - saccular cardiac stomach – pyloric stomach – pyloric caeca (in each arm)
short intestine connected to pyloric stomach and anus
Asteroidea canals
stone canal joins madreporite to ring canal, radial canal extends into each arm, lateral canals lead from radial to ampullae of tube feet
Asteroidea tube feet
cylindrical tube (podium) w/ suction disc at external end, rounded ampulla at internal end, ampulla contraction = podia extension, podia muscles allow directional movement, contraction of all podium muscle = water back into ampulla
Steroid tube feet functions
walking, gas exchange, prey capture, release ammonia
Ophiuroidea
5 arms, central disk, more mobile, rowing motions of arms for movement not podia, podia for suspension feeding
Echinoidea
regular - sea urchin, irregular - heart urchin, sea biscuit, sand dollar. rigid test covered w/ tubercles that articulate w/ base of spine and stalk of pedicellaria
Echinoidea ossicles
interlocking plate-like ossicles in rows from aboral apex - mouth, plates in alternating double columns of ambulacra and interambulacra
ambulacral plates
have pairs of pores, tube foot extends from each pair of pores
Aristotles lantern
40 ossicles, interconnected by 60muscles, moves 5 teeth during feeding, teeth protrude from peristomial membrane surrounding mouth and scrape algal fails /bite chunks
Holothuroidea
elongate along oral-aboral axis, microscopic skeletal ossicles embedded in dermis, mouth surrounded by buccal podia tentacles - enlarged branched podia of WVS, sedentary suspension/deposit feeders
Holothuroidea reproductive system
single gonad- ovary or testis, suspended form dorsal mesentery, large # narrow tubules in 2 mop-like bunches
Holothuroidea gas exchange
2 respiratory trees, main trunk extend from cloaca, branch repeatedly w/i coelom, seawater sucked in to cloaca by contracting cloacal suspensor muscle
Holothuroidea diestive
mouth – pharynx – short esophagus - all in aqua pharyngeal bulb
5 pharyngeal retractor muscle bundles from aqua pharyngeal bulb to body wall midway down length of body
esophagus - muscular stomach - long narrow intestine - short wide cloaca
Holothuroidea WVS
ring canal large, encircles esophagus gives rise to: 2+ elongated pollen vesicles, mid dorsal stone canals lead to madreporites, 5 radial canals – ampullae of tube feet
Holothuroidea body wall
beneath epidermis thick layer connective tissue dermis w/ collagen, ecm, mesenchyme. ossicles embedded in dermis. long. muscles in 4 strongly developed bands within ambulacral zones, 5 pharyngeal retractor muscles connect to long. body wall muscles
Echinoderm gas exchange
thin-walled podia, papulae
papulae
small, thin-walled sacs over aboral surface
outer layer = epidermal epithelium, inner = mesothelium
sand dollar flower pattern
petaloid podia
holes for brand podia that function exclusively for gas exchange
dark brown, broad flaps lined-up side by side
10 small slits in central disc of ophiuroid
entrance to bursae - thin-walled, internal pouches that water circulates through for gas exchange
Phylum Chordata
vertebrates +invertebrates, urochordates s.g. to craniates
Chordata main characteristics
notochord
dorsal hollow nerve cord
pharyngeal perforations
post-anal tail
Subphylum Urochordata
Tunicates/ascidians/sea squirts (all the same)- sessile adults, solitary or colonial
Larvaceans, thaliaceans (sales)
notochord, nerve cord only in larval stage
body covered w/ tunic (protein+tunicin polysaccharide), all marine, no parasites
Class Ascidiacea
most urochordates, almost entirely suspension feeders, U shaped gut, endostyle, cerebral ganglion, tubular heart that reverses pumping direction, tadpole larvae w/ muscular tail
Ascidian feeding
draw water into buccal siphon- particles extracted by branchial basket (perforated pharynx) - water exits though atrial siphon
Ascidian feeding exception
deep ocean species, gaping 2-lobed buccal siphon that snaps shut on passing zoop.
Ascidian larval metamorphosis
larvae only 1day, no feeding - settles - secretions from adhesive papillae - metamorphosis - retract tail - loss of 3/4 chordate characters
