Animal diversity unit 2 Flashcards
what are staurozoa
sessile polyps; look like attached medusae
what are Cubozoa
Sea wasps, box jellies; Deadly neurotoxins
what are Myxozoa?
Microscopic unicellular parasites; Long thought to be protozoans
what is the common name for Ctenophores?
comb jellies
ctenophore characteristics
Gelatinous, radially symmetrical marine diploblasts; No gas exchange, excretory or circulatory organs; All are hermaphrodites; most free spawn
what do ctenophore synapomorphies include?
8 rows of ciliary “combs” (ctenes) along body; Colloblasts (often on 2 retractile tentacles)
What do colloblasts do?
secrete adhesive to capture prey
What is sister group to rest of Metazoa?
Until recently, ppl say Porifera; there is evidence from phylogenomic studies Ctenophora is sister to animals
Mollusca characteristics
Bilaterally symmetrical coelomate protostomes; Second to Arthropoda in # of described species (~100,000 living species); Amazing body plan variation and size
what animals are in mollusca?
Clams, snails, slugs, squids
Some Molluscan Synapomorphies
Broad, muscular foot; Mantle w shell glands; Radula; Ctenidia; Anus and nephridia open into mantle cavity
what is a Radula?
ribbon of teeth, used for feeding
what are Ctenidia?
gills
what does Polyplacophora mean?
chitons
what are Polyplacophora?
Flat marine grazers; lifestyle similar to snails
Polyplacophora shell characteristics
8 shells (valves) along back; Secreted by glands in mantle; Made of calcium carbonate; have thin organic coating (periostracum)
what does the Flat creeping foot do?
secretes mucus; movement ciliary or muscular
What is space between foot and mantle edge called?
mantle groove
what do radula sit on?
odontophore
Chiton respiratory system charactersitics
several pairs of ctenidia (gills)
chiton circulatory system characteristics
Open; Heart in a sac called a pericardium, a few vessels, and a hemocoel
what is a hemocoel?
unlined blood sinuses that surround organs
what larva do chitons have?
trochophore
gastropoda common names
Snails, sugs, abalines, limpetets, many species
gastropoda characteristics
Most marine, many freshwater or terrestrial; Some pelagic; most have a single coiled shell; Spacious MC over head; Food often w operculum
what does pelagic mean?
lives in water column
what does operculum do?
protects snail when withdrawn into shell
Gastropod Internal Anatomy
Radular apparatus w variable tooth pattern; Gut loops thru VM, empties over head; Dorsal heart pumps blood from gills to hemocoel; Water flows thru MC from left to right, passing thru gill before anus/nephridiopore
What types of snails have a poison dart radula?
cone snails, Conus
Nervous System of gastropods
2 lateral cords that loop into MV, w pairs of ganglia (cerebral, pedal, visceral); System looks like it have been twisted into a figure 8
why do gastropods nervous system look like it has been twisted into a figure 8?
torsion - MV is twisted ~180 during development
Balance sensory receptors that some animals have called?
statocysts
what are the 2 steps to gastropod torsion?
- Large muscle (velar/foot retractor muscle) contracts, Twists MV around ~90 counterclockwise
- Contraction followed by asymmetric growth
what does detorted mean? →
VM has rotated back clockwise to some extent, reversing torsion
what are the Effects of Torsion?
Gut empties in rear before torsion but empties over head after torsion
what is an implication of torsion?
Anus/nephridiopore empty over head; Effects mollified by unidirectional water flow
Why did torsion evolve?
don’t know, protection or helps water flow
Bivalvia animals?
Clams, oysters, scallops, mussels
Bivalvia characteristics
Marine and freshwater; Laterally compressed, w 2 lateral shells (valves); no radula
how do bivalves feed?
suspension feeders; Cilia, muscles pump water into incurrent siphon and out thru gill and out via excurrent siphon, Food captured in mucus on gill; mucus passed to palps
what are some bivalve anatomy characteristics?
Mantle, gills are large lateral sheets; Poorly developed nervous system → “eyes” on mantle edge
how do bivalves reproduce?
Most shed gametes into outgoing current, Females may bring sperm in for internal fertilization; marine bivalves release juveniles or trochophores; freshwater bivalves produce parasitic larvae called glochidia
common name of scaphopoda?
tusk shells
Scaphopoda characteristics
All marine; live buried in sediment; use tentacles to gather food; microorganisms
what are Scaphopoda tentacles called?
captacula
Aplacophora characteristics
marine “worms” w calcareous scales or spicules
Monoplacophora characteristics
marine, limpet like; Known only as fossils until 1952; multiple pairs of gills, gonads, kidneys
Cephalopod characteristics
largest solitary invertebrates - Giant squids 18m+, up to ~1000 pounds (colossal squid); ~1000 living species; all marine predators
Nautiloidea →
nautiluses, 2 pairs of gills
Ammonoidea →
extinct; common fossils
Coleoidea →
internal or no shell, 1 pair of gills
Belemnoidea →
extinct; common fossils
Decapodiformes →
“squids” and cuttles, high diversity
Octopodiformes →
vampire squids and octopuses
what are some cephalopod synapomorphies?
arms, tentacles, siphon, beak, Chromatophores
what are Chromatophores →
cells w pigment sacs; signaling and crupsis
what do cephalopod arms and tentacles do?
used for prey capture, usually have suckers
what does a cephalopod siphon do?
direct water for propulsion
what happens in squid digestion?
beak rips up prey, radula moves chunks to esophagus
what happens in squid respiration/circulation?
2 gills, brachial hearts boost blood into gills, systemic heart sends blood to body; Closed circulatory system
what happens in squid nervous system?
Several cerebral ganglia around esophagus; Often have cartilaginous “skull”; Sophisticated sense organs; giant axons
what happens in squid reproduction/development?
gonochoric; Male packages sperm in spermatophores, specialized arm transfers them to females; Female lays egg masses; semelparous
what does semelparous mean?
breed once then die
Cephalopod Behavior: Crypsis →
matching color, pattern, texture of background (Octopus vulgaris)
Cephalopod Behavior: Mating →
colorful displays between mates, male-male interactions (Sepioteuthis sepioidea)
Cephalopod Behavior: Predation →
strobe displays in cuttlefish
Cephalopod Behavior: Bioluminescence →
firefly squid
What isn’t found in molluscan mantle cavity? →
operculum
what are some Cephalopod Phylogenies?
Vampyroteuthis sister to octopuses; Phylogenomic analyses seem to support clade of large decapodiforms including cuttlefish, myopsids and oegopsids
what are annelida?
coelomate triploblastic worms; mostly marine, many FW and terrestrial
what are some annelida synapomorphies?
metamerism; paired epidermal chaetae; nuchal organs; trochophores
what is a metamerism also known as?
segmentation
what are nuchal organs?
paired sensory organs on head
what are some “Polychaeta” characteristics
mostly marine; parapodia and many setae; many bristles
what are Oligochaetes?
earthworms/various aquatic worms; few bristles
what are Hirudinea’s?
leeches and allies
what are polychaete’s basic anatomy?
homonomous segments that bear parapodia; have prostomium, peristomium, and pygidium
what does prostomium mean?
before mouth
what does peristomium mean?
where mouth is
what is pygidium?
segment that contains anus
what does parapodia mean?
large flaps along sides of body
Polychaete Reproduction/Development characteristics
Have epitokes; teloblastic growth in pygidial growth zone
what are epitokes?
swimming forms for gamete dispersal
what is the life cycle of polychaetes?
zygote → trochophore → settlement → adult
what happens in teloblastic growth?
Mesoderm blocks split off and hollow out
what are characteristics of Polychaete burrowers?
small parapodia, tentacles; lots of hemoglobin
what are characteristics of Polychaete pelagic predators?
huge eyes, tentacles and parapodia
what are characteristics of Polychaete Tentacular suspension/detritus feeders?
Feather dusters (sabellids, serpulids)
what are characteristics of Polychaete mucus suspension feeders (Chaetopterus)?
makes U-shaped papery tube; Holds net w 2 parapodia, pumps water thru, particles trapped on net, worm eats net
what are characteristics of Polychaete Siboglinidae?
Weird deep sea worms; only part of body is segmented; no guts, have trophosome; Bacterial symbionts generate ATP
Siboglinidae used to be a phylum named what?
pogonophora
what are Clitellata?
Earthworms, many FW species and Hirudinida
Clitellata characteristics
No parapodia; Hermaphroditic; oligochaetes; terrestrial or FW; few setae, have clitellum
what does oligochaete mean?
have few (oligo) bristles (chaetae/setae)
how do Clitellata reproduce?
Clitellum makes cocoon that picks up eggs then sperm; Eggs fertilized in cocoon, direct development
what are Hirudinida?
Leeches and allies, many ectoparasites
what are some Hirudinida characteristics?
No setae; have suckers at both body ends; Segments not separated by septa, Annulations don’t correspond to segments, Constant segment number (usually 34)
Sipunculidae “peanut worms” characteristics
Unsegmented, ~250 species, all marine; Have retractable introvert, often w hollow tentacles
what are Echiuridae?
Unsegmented benthic marine worms; ~130 species
what are some Echiuridae characteristics?
have non-retractable ciliated proboscis that sweep substrate w proboscis to gather food
What is a Weird echiuran?
Urechis caupo → suspension feeds using mucus net
both Echiuridae and Sipunculidae have larvae like those seen in what?
annelids
lophophora are a clade of what 3 phyla?
Phoronida, Brachiopoda, Bryozoa
Putative synapomorphies of Lophophorata include:
Lophophore, Epistome
what is a lophophore?
ring of coelomic, ciliated feeding tentacles; water is drawn thru it
what is an epistome?
muscular lobe near mouth
what are characteristics of Phoronida?
Marine benthic tube-dwelling worms; Feed and breathe w lophophore; Have tripartite coelom
what are the parts of the tripartite coelom in Phoronida?
protocoel in epistome, mesocoel in tentacles, metacoels - main body cavities
how do Phoronida’s develop?
Mouth, coelom form like in protostomes; Cleavage, mesoderm formation like deuterostomes; Have unique larva (actinotroch)
Brachiopoda characteristics
Marine benthic clam-like suspension feeders; Superb fossil record; lifestyle similar to bivalve mollusks
what are the 2 groups of Brachiopoda?
Inarticulates and articulates
what are inarticulates?
burrow w muscular pedicle, no teeth
what are articulates?
sessile, attach w pedicle, if shells hinges have teeth, they articulate together
Bryozoa (Ectoprocta) characteristics
Marine and FW, many species; almost all colonial, polymorphic; each zooid lives in zoecium and has polypide and cystid
what does polymorphic mean?
Many forms
what is an autozooid?
feeding zooids w lophophore
what is an avicularium?
zooid modified into pinchers
what are Kenozooids?
stalks and stolons
what are Kleistozooids?
nutrient storage
what are Kamptozoa?
tiny sessile colonial polyp like animals
characteristics of Kamptozoa
have pseudocoel; Solid tentacles that cannot be retracted; no lophophores
how do Kamptozoa feed?
bring water up thru tentacles; anus on inside of tentacle rings (entoprocts)
what are Cycliophora?
tiny sessile animals
Cycliophora characteristics
marine, found on mouthparts of marine crustaceans; ectosymbionts; Feed on debris using ring of cilia around mouth; weird cloning
what are Nemertea?
ribbon worms or proboscis worms
Nemertea characteristics
marine benthic predators; proboscis for catching prey house in rhynchocoel; secretes sticky/toxic substance; have style and toxic gland
what are Xenacoelomorpha?
Group of worms sister to rest of Bilateria
Xenacoelomorpha characteristics
~350 species, <5 mm long, all marine; most free living; Some have blind gut, others have mouth but no gut
Platyhelminthes characteristics
~20,000 extant species; Triploblastic acoelomate animals; Bilaterally symmetrical and cephalized; Marine, FW, some terrestrial; Free living (“Turbellaria”) or parasitic (Trematoda and Cestoda)
what are major flatworm subgroups?
Tricladida (planarians); Polycladida (free living marine worms); Neodermata (all parasitic); Monogenea (mostly fish ectoparasites); Trematoda (flukes); Cestoda (tapeworms)
Turbellarian characteristics
Ciliated epidermis and mucus glands; members of clade Tricladida; Gut has 1 opening, muscular pharynx; No special respiration/circulation structures; Protonephridia for osmoregulation; Cephalized ladder-like nervous system; eyespots, chemoreceptors for detecting prey
what are Turbellarians?
planarians
what does Tricladida mean?
3 branched gut
What are parasite advantages?
free, large source of resources; few competitors; protection from environment/predation
what are Protonephridia?
flame bulbs
How do parasites deal w disadvantages?
cloning/sexual reproduction; specialized integuments; largely anaerobic metabolism; complex life cycles
What are disadvantages of being a parasite?
hosts fight back and hard to find
what are Trematoda?
flukes
Trematoda characteristics
Mostly parasitize mollusks, but also humans
what are blood fluke characteristics?
Cause human schistosomiasis; swimmers itch; Schistosomes infect ~200
what are Cestoda?
tapeworms
Cestoda characteristics
No mouth/digestive cavity; Bodies divided into repeated units (proglottids); Gut parasites of vertebrates as adults; Suckers or hooks on scolex attach worm to host
what are Chaetognatha?
arrow worms
where do Chaetognatha live?
all marine, most pelagic
what do Chaetognatha eat?
ambush predators, eat invertebrates and small fish
Chaetognatha characteristics
No respiratory, circulatory, or excretory structures; Transparent; All hermaphrodites
what are Micrometazoans?
Grade of animals less than 1 mm long; not a clade; pseudocoelomates
Micrometazoans characteristics?
vermiform; Low fecundity and weird sex - hermaphroditism/cloning are common; Eutely; “Reduced” organ systems; Physiologically tough
what does vermiform mean?
worm shaped
what does eutely mean?
cell constancy
Gnathifera: Rotifera and Acanthocephala characteristics
Found in all aquatic habitats; 1 diverse asexual group (Bdelloidea) - no male bdelloids; Includes Acanthocephala - spiny headed worms, vertebrate endoparasites
Gnathifera: Rotifera and Acanthocephala General anatomy
Ciliated corona on head for swimming/feeding; Adhesive toes w cement glands
Gnathostomulida characteristics
Tiny hermaphroditic marine worms w rotifer-like jaws; Marine, interstitial in low oxygen sediments, ~80 species
Micrognathozoa characteristics
Tiny, wormlike animals w complex jaws; 1 known species (Limnognathia maersk); FW, interstitial
