-
Porifera (sponges)
- benthic - live at bottom of aquatic environment
- tubes/pores that create channels for water currents
- can remold their body if the water currents change
- have spicules (stiff spikes of silica that provide structural support)
- suspension feeders
-
Cnidaria (jellyfish, corals, anemones, hydroids)
- Four main lineages: hydrozoa, cubozoa, scyphozoa, anthozoa
- mesoglea = gelatinous material
- one opening for both ingestion and elimination of wastes
- sessile and medusa form
- cnidocyte = cells eject a barbed, spear into prey, which is coated in toxins
-
Ctenophora (comb jellies)
- planktonic (live near surface)
- long tentacles covered in cells that adhere to prey
- beat cilia to move
-
Acoelomorpha
- lack a coelem
- simple digestive tract
- some only have mouth for ingestion and excretion
- feed on detritus/small animals or protists that live in mud/sand
-
Rotifera (rotifers)
- lophotrochozoans
- damp, marine, and freshwater
- pseudocoelems
- corona = cluster of cilia at anterior end to create current to when feeding
- sessile
- parthenogenesis
-
Platyhelminthes (flatworms)
- lophotrochozoans
- live on substrates of freshwater/marine environments
- some parasitize other organisms
- high surface-area-to-volume ratio --> completely flat; diffusion across body wall
- must be completely surrounded by water
- blind digestive tract (one hole for ingestion and excretion)
-
Annelida (segmented worm)
- lophotrochozoan
- 2 major lineages: polychaeta and clitellata
- Polychaeta have bristle-extensions (chaetae) which extend from appendages (parapodia)
- marine
Clitellata lack parapodia
-
Bivalvia (clams, mussels, scallops, oysters)
- mollusc
- two hinged shells
- mostly sessile
- fossilize readily because they live on the ocean floor
- suspension feeding through gills (powered by cilia and siphons)
-
Gastropoda (snails, slugs, nudibranchs)
- mollusca
- large muscular foot underneath
- torsion - visceral mass rotates during development
- have either a shell or poison
- radula - scrapes away food
- some use drills to break through mollusc shells, others harpoon animals with proboscis
-
Polyplacophora (chiton)
- mollusca
- have plates on top to form protective shell
- radula to feed
-
Cephalopoda (nautilus, cuttlefish, squid, octopuses)
- mollusca
- well-developed head
- foot modified to form anus/tentacles
- highly reduced shells
- large brains and eyes with sophisticated lenses
- beak to bite
- jet propulsion or moving fins to fly through water
- spermatophore - encased sperm, fertilization occurs within female
-
Nematoda (roundworms)
- ecdysozoans
- unsegmented, pseudocoelem, tube-within-a-tube body
- gas exchange through body wall
- move through wriggling their hydrostatic skeleton
-
Myriapods (millipedes, centipedes)
arthropoda
|
|
