Quiz 6- poriferans, cnidarians, annelids, molluscs Flashcards
Use your understanding of poriferan biology to assemble a marine sponge, and identify the major cells, structures and forms.
pinacocytes
mesenchyme
archeocyte cells
choanocytes
flagellum and microvilli collar
pinacocytes
exterior “skin” cells of sponges- some become porocytes
mesenchyme
jelly-like middle layer of sponges
***made of archeocyte cells: move around in mesohyl- reproduce, transport + store food, secrete spicules
spicules
mesenchyme/ archeocyte cells called SCLEROCYTES secrete skeletal elements called spicules that can be made of CaCO3, silica, or spongin
variable shapes
choanocytes
in sponges
flagellum and microvilli collar
line inner layer of sponges
drive water movement in thru pores for filter feeding
Explain how water & nutrients move through, and are utilized by, poriferans.
water flows in thru porocytes + out thru osculum opening
brings in food + o2, removes wastes
3 major porifera body forms
ascon
sycon
leucon
all have pores, choanocytes, and at least one osculum
major difference btwn ascon + sycon sponges
sycon has folds called radial canals that are lined with choanocytes
ascon are simplest, LEAST common
porocytes called ostia
Differentiate between sexual and asexual reproduction in Poriferans.
most monoecious- (both sexes on 1 individual)
do NOT self fertilize bc eggs and sperm are ready at different times
sperm cell is a modified choanocyte- engulfed by a choanocyte on egg, fertilized, planktonic larva, settles/attaches to substrate + develops
leucon sponge
no spongocoel cavity
pores lead water thru choanocyte chambers
several osculi openings
four major classes of Cnidarians.
anthozoans
scyphozoans
cubazoans
hydrozoans
gen chars of cnidarians
nettles!
have 2 tissue layers:
epidermis and gastrodermis
mesoglea
radial symmetry
blind gut
well formed digestive system
often dioecious
nervous system
mesoglea
in cnidarians
jelly-like substance btwn 2 tissue layers (epidermis + gastrodermis)
cnidarian digestion
extracellular
dioecious
separate sexes
like cnidarians (generally)
cnidarian excretion
diffusion
cnidarian nervous system
network of nerve cells
major cnidarian stages
sessile polyp
stinging medusa
both have stinging cells + tentacles
anthozoans
anemones, corals, + sea fans
CARNIVOROUS
(may have symbiotic zooxanthellae)- supplement diet
no medusa stage
solitary or colonial
stony corals excrete calcium carbonate
anthozoan stages
polyps produce gametes that develop into swimming planular larvae that then settle + develop
scyphozoans
true jellies!
carnivorous
outside of body covered in sensory structures
move via muscle contraction (rings)
scyphozoan stages + life cycle
short benthic polyp stage, long planktonic stage
medusae shed gametes that develop into (planular) larvae then develop benthic stage
benthic stage undergoes STROBILATION
strobilation
in true jellies (scyphozoans)
during benthic stage
little developing ephyra pop off the end + swim off!
smaller ephyra develop into larger medusae
cubozoans
box jellies!!
carnivorous
well developed eyes
unusually strong swimmers compared to other cnidarians
chironex fleckeri
australian box jelly/sea wasp
weirdly do not develop benthic stages in reefs- only in estuaries of rivers on undersides of stones
cubozoan life cycle stages
benthic polyp stage, medusae
hydrozoans
simplest cnidarians
benthic colony + medusa stages
planktonic hydrozoa- eg: velella velella + portuguese man’o’war (spend most of life in medusa stage)
also hydrozoans that spend most of their life in benthic stage
hydrozoan benthic colony stage
polymorphic- feeding and reproductive cells all attached to one another
***called gastrozooids and gonozooids
Explain how cnidocytes function, and be able to label their major structures (nematocysts, thread, barb, cnidocil).
nematocysts- actual stinging systems (organelles)
barb holds thread
cnidocil- hair-like projection
How does scyphozoan reproduction differ from hydrozoan reproduction?
scyphozoans have individual benthic polyps while hydrozoans have colonies
hydrozoan colonies have specialized gastro- + gonozooids
benthic scyphozoan polyps undergo strobilation
both have medusae
annelids
segmented worms
NOT including/discussing phyla of flatworms or roundworms
bilateral symmetry
3 tissue layers
complete gut
body cavity
can free burrow, live in substrate, on top of substrate, or construct tubes
3 major classes of annelids
polychaeta (we’re focusing on these bc they’re the best duh)
oligochaeta (earthworms)
hirudinea (leeches)
feeding types of annelids
carnivores, deposit feeders, suspension feeders (can be one or more of these)
infaunal vs epifaunal
referring to annelids
living IN vs ON TOP OF substrate
body cavity in annelids
coelom
Describe the major biological and ecological characteristics of the Polychaetes.
have distinct segments w separate pairs of parapoida (containing setae)
free + tube-living
setae
bristles attached to parapodia in polychaetes
used for burrowing, swimming, crawling
most have swimming larvae
bobbit worms
longest known polychaete
ambush predator
5 antennae
large mandibles
no eyes, no brain
christmas tree worm
tube builders
2 bright crowns composed of hair-like radioles attached to a central spine- used for respiration + filter feeding
sedentary- anchored in burrows bore into coral
How do siboglinids differ from typical polychaetes? Explain how they utilize symbiotic bacteria for nutrients.
Important points - how is hydrogen sulfide used, where does it come from, how is it transported within the worm?
live in constructed tubes
near hydrothermal vents (underwater volcanoes), whale falls, sunken plant material
riftia
siboglinids
no mouth, gut, or anus
symbiotic chemosynthetic bacteria within their trophosome- depend entirely on these for their diet
red plumes that absorb o2, hydrogen sulfide
Be able to differentiate between the processes of chemosynthesis and photosynthesis.
chemosynthesis
co2 + h2s + o2 –> sugar + s + h20
photosynthesis
co2 + h20 –> sugar + o2
energy for chemo reaction comes from interaction of oxygen + hydrogen sulfide
Osedax worms:
Where are they primarily found?
How and why do they bore into whale bones?
What is their relationship with bacteria?
How do they get oxygen?
Explain how they differentiate into males vs females, and the roles of each.
- whale falls!
- larvae travel on the current + develop when the right nutritional environment is found (when they land on whale falls)
- feast on bone- unoccupied niche, arrive after all flesh has been eaten
- acid bores into bone, symbiotic (chemosynthetic) bacteria help them digest the fat from the bone
- o2 taken in from fan structure on the opposite end of the side that bores into the bone
- males are basically parasites within females- larvae that land later or on top of others- never grow past larval stage
mollusca
mostly shelled (calcium carbonate)- shell often secteted from mantle
complete gut
3 tissue layers
coelom
gill within mantle cavity used for respiration + feeding
mollusca feeding
suspension feeding thru gill in the mantle
major classes of the Phylum Mollusca.
cephalopoda
scaphopoda
gastropoda
bivalvia
monoplacophora
polyplacophora
cephalopoda
phylum mollusca
complex eyes
carnivorous
arms with suckers
all have photophores that change color
swim, but somewhat benthic
ink
squid
feed on large fish to krill
8 arms lined w suckers
2 long tentacles
hypnome
beak
hypnome
in mantle of squid
shoots out water to propel squid towards prey
giant + colossal squid
largest invertebrates
can be over 50ft long omg
colossal squid comparable in size but higher mass
octopus
beak
2 eyes
soft bodies allow it to squeeze thru really tight spaces
8 appendages
most intelligent invertebrates
chambered nautilus
ancient
2 pinhole eyes- only see light + dark
perceive water depth, current speed + direction
no suckers, but over 90 arms
highly developed sense of smell
use maneuverable siphon in mantle to propel water + push them in any direction
cuttlefish
internal shell aka cuttlebone
cephalopoda reproduction
males transfer spermatophore to female
internal fertilization
eggs free float or attach to substrate
photophores
in cephalopoda
scaphopoda
phylum mollusca
tusk shells
infaunal (buried in substrate)
probe into sediment looking for small prey, radula brings them to mouth
gastropoda
phylum mollusca
most have a cap-shaped cell
torsion
mouth with teeth (radula) that scrape against food (eg algae)
flattened muscular foot
subclasses of gastropoda
caenogastropoda
patellogastropoda
vetigastropoda
heterobranchia
caenogastropoda
subclass of gastropoda
contains grazers, carnivores, filter feeders
eg: periwinkle + moon snails, conches, cone snails
cone snails
caenogastropoda
venomous + predatory
some venoms can be fatal to humans
use chitinous harpoon loaded with venom to capture to prey
some venoms have a pain-reducing venom- medical uses (eg: ziconotide which is 1000x stronger than morphine!!!)
moon snails
caenogastropoda
drills thru bivalves using radula (teeth) + acid
use proboscis to scoop out insides of bivalves
lay egg masses- “sand collars”
patellogastropoda
limpets! (true limpets)
muscular foot to stick to rocks, use radula to scrape algae
badasses that live in the intertidal zone
vetigastropoda
keyhole limpets + abalone- both have opening/”keyhole” that makes them different from true limpets
heterobranchia
nudibranchs!!!! also sea hares, pteropods
no shells except sea hares that have an internal shell
DETORSION- reverses torsion process
glaucus atlanticus
heterobranchs
blue sea dragon
pokemon!
pelagic- float upside down, use gas-filled stomach sac
eat portuguese man’o’war + velella + store nematocysts
leaf sheep
cute green heterobranchs
2 eyes + 2 rhinophores
rhinophores used for sensing chemicals in the water
capable of kleptoplasty
kleptoplasty
capability of leaf sheep
retaining chloroplasts from their algae diet that are able to keep photosynthesizing- give the leaf sheep their green color
2 most common suborders of nudibranchs (heterobrachia)
aeolidacea
doridacea
aeolidacea
nudibranch suborder
cerrata on dorsal side- extension of digestive tract + used in respiration
can store nematocysts form hydroids they eat
doridacea
nudibranch suborder
single gill plume near anus
bivalvia
class
phylum mollusca
2 valves hinged together by calcified feet
mantle lines the valve
muscular foot
infaunal or epifaunal
many use filter feeding
byssal threads
crassotrea virginica
bivalve (oyster)
important for filtering water + habitat for crabs, etc
monoplacophora
class
phylum mollusca
believed to be most similar to ancestral mollusks
one cap shaped shell
flattened foot
radula
polyplacophora
class
phylum mollusca
oval-shaped, flattened, have 8 chitonous dorsal plates
flattened foot that suctions to rocks
radula- mostly feed on algae but sometimes graze on seaweed + small invertebrates
Understand the biological role of chromatophores, and which group of organisms is primarily known for having them.
in cephalopods, used for camouflage
specialized pigment cells
controlled neurally
rapidly expand + contract via muscles
