Animals of the Intertidal Zone Flashcards
what are examples of echinodermata?
- sea star - Pisaster brevispinus, Pycnopodia (typical)
- sand dollar - Dendraster
- sea cucumber - Apostichopus
what does echinodedrmata mean?
spiny skin
what are the characteristics of echinodermata?
- pentaradiate symmetry: 5 arms, 5 rows of tube feet - asymmetrical
- hydrostatic skeleton - water vascular system (tube feet)
- no brain
- nerves control all tube feet, sensing light, smell, gravity
- calcium carbonate skeleton - plates (ossicles) -> held together by collagen which is almost muscle
what is WVS?
system of hydraulics for locomotion, feeding, sensing
- controls tube feet
WVS parts
- stone canal - projects off ring canal and connexts to madreporite
- polian vessicles - bulbs to ring canal, holds water to maintain internal pressure
- radial canals - go down arms and it is a series of lateral canals
- ring canal - central canal
- lateral canals - off radial canals
- ampulla - pouch that expands or contracts to control water flow to tube feet
- mandreporite
MCT
mutable collagenous tissue
- stiffen spines
- autotomize arms or spines - loss of limbs
- contract in Crinoids
- changes mechanical properties fast
what is used for defense?
spines
- stimulus (touch) -> cross links collagen -> stiffen
describe MCT
- cross links ECM using calcium
- calcium is released from cells or taken up from cells
- by neuronal impulses
what is the steps for MCT?
- softening signal moves calcium into cells
- resting state
- stiffening signal moves calcium out of cells into ECM
-> stiffness progresses with each step
how do sea stars feed?
- hydraulic skeleton and MCT to pry open bivalves
1. grasp onto two valves with adhesive glues on their feet
2. lock collagen in places (use MCT to stiffen arms for traction)
3. use WVS to move water in radial canals and ring canals to pull tube feet and open valves enough to insert loose “cardiac stomach” - external digestion
what do purple urchins have and what makes them special?
- use spines and teeth to burrow into sandstone
- Aristotle’s lantern - 5 teeth help and moved by muscles
- graze algae off rocks
what is used for defence?
pedicellaria - small claw appendages
- biting jaws
- toxic jaws for protection
- Toxopneustes - pedicellaria with toxins - clamps onto and releases toxins
what belongs to phylum arthropoda?
“jointed legs”
- crabs
- decapod crustaceans (10 walking legs)
what is the skeleton made of for arthropoda?
chitin
calcium carbonate
how do crabs grow?
moult
- produce hormone to release old skeleton from tissue
- crabs slides out from old carapace and its soft
- inflates new skeleton with water and new chitin hardens over hours to days
what is the body of arthropoda like?
- thorax and abdomen which is tucked under body
- 5 pairs of legs on thorax
- 10 walking legs - decapoda
what is the hormone produced by arthropoda?
ecdysone
where do crabs live?
subtidal or intertidal
what do rock crabs eat?
snails
where do porcelain crabs live?
under rocks
how do Petrolisthes cinctipes eat?
filter feeds using antennae
how do Petrolisthes eriomerus eat?
deposit feeds using mops or setae on chelae
what is the point of appendages?
feeding
walking
sensing
mating
what is found on claws and legs?
sensory setae to feel motion and smell water
how do crabs eat?
specialized mouth parts and claws for crushing, tearing and deposit feeding or filtering
what is found on mole crabs?
sensory setae on tail fan
what do mole crabs do?
burrows in sand on wave-swept beaches and filters with antennae
- setae sense flow, chemicals, predators and mates
what do northern cling-fish eat?
limpets, shrimp and clingfish
how do northern cling-fish stay put?
sucker on ventral side with hairs
- adhesion like gecko feet by molecular attraction
how do pacific spiny lumpsucker adhere?
sucker derived from modified pelvic fins
what do pacific spiny lump sucker eat?
worms
snails
other sessile invertebrates
what is the species name for barnacles?
cirripedia
where are crustaceans?
barnacles
how do crustaceans settle?
on their heads
how do crustaeans feed?
with their feet
what are barnacle legs called?
cirri
- rake water for plankton
- hold cirri into strong flow
describe goose neck barnacle
- found on wave-swept shores - withstand wave action - flexible
- flexible muscular stalk - attach to substrate using stalk
what are the two main body regions for gastropod molluscs?
head and foot
viscera and shell
what is a mantle?
- molluscan character
- tissue that secretes shell
what is the purpose of the cephalic tentacle?
sensing chemicals/touch on head
how do molluscs feed?
radula -> ribbon on teeth capped with iron
- new teeth are constantly formed
what are predatory snails called?
drills
- drill into prey by boring a hole in the shell
- insert their proboscis into hole and inject enzymes to digest the prey
what is a proboscis?
mouth on end of long tube
how do herbivorous snails eat?
use radula to graze on algae
where do radula bore holes?
over main organs
what are bivalves?
mussels
- mollusc with two shells hinged at one point
- burrows in sand and attaches to rock with sticky protein threads - byssus threads
- feed by filtering water over gills
- no radula
what are some examples of chiton?
- carnivorous chiton
- mossy chiton
- gumboot chiton
what are sea anemones?
anthozoa - Gr flower animal
- cnidarians - feed with stinging cells “cnidocytes”
- sessile
- have symbiotic algae which photosynthesize - share nutrients
- capture prey with tentacles - upside down tentacles
cnidocytes
- specialized organelle that fires when a hair cilium is triggered, releasing stick, piercing, poison dart into prey
what are aggregating anemones?
anthopleura elegantissima
describe anthopleura elegantissima
colonial and clonal (sexual and asexual)
feed cooperatively
colonies fight - scouts and warrior clones
what do warrior clones have?
inflate special short tentacles called acrorhagi to sting other colonies
what is Nemerteans?
unerring
ribbon worms
special circular muscles
stretchy
elongate
Rhyncocoel: cavity at front with piercing weapon - stylet ejected rapidly to capture and poison prey
what are Platyhelminthes?
flat worms
no body cavity
some have pharynx - extrude from center of body and into prey
what are polychaetes?
many setae
segmented with gut
feet or appendages on each segment - walk, feed or respire
predators like Nereis - capture using pharynx
what are neresis parapodia?
specialize as paddles when it becomes reproductive and must swim
what do Halosydna have?
scales called Elytra on Halosydna
what are serpulids?
fan or feather worms
- polychaetes with anterior end specialized for suspension feeding
- sessile
- secrete tube of calcium or protein on rocks
- parapodia run up and down tube
- anterior appendages branch into two fans of feather-like structures that filter water with cilia
- one appendage acts as operculum - close top of tube and prevent desication
what are bryozoans?
moss animals
share a feeding organ
lophophore that is shaped like a loop and ciliated
what are Porifera?
- pore bearer
- encrusting or massive that is tube or vase-shaped
- pump cells - collar cells (choanocytes) that fraw water in through channels in body - decreasing in diameter until water slows so much that bacteria are plucked out by individual cells and eaten
- holes visible on surface are excurrent vents - oscula
what are urochordates?
- ascidians
- solitary
- compound
- colonial
- jacket out of tunicin (cellulose-like material)
- feed by pumping water into body via buccal siphon, over mesh the branchial basket, capturing plankton on mucus
- mucus spun across basket by cilia, captured on dorsal side, transported to mouth and eat
- water squirts out atrial siphone
- larval stage like tadpole
