metozoa v umetozoa
umetozoa are animals with true tissue
metozoa animals no true tissue
Protostomes
- distinguished by embryonic development
- 1st opening is mouth
Platyhelminthes
- aka Flatworms
- Triploblastic
- acoelomate
- bilateral symetry
- hermaphroditic
- one whole for mouth and anus
- “U” shaped gut
- eyespots deter predators
Platyhelminthes Parasitic example
Tapeworm
- lack mouth and gut
- absorb nutrients through skin
- less structures for parasites
- reproduce by exiting feces and infecting others usually through a water source
Rotifera
- minor group of lophotrochozoan
- have alimentary canal means a tube with a mouth and anus
- pseudo coelom
- crown of cilia draw vortex of water in and internal jaw called trophi grinds up the food
Ectoprocts and Brachiopods
- minor group of lophotrochozoan
- lophoporates= have lophophores which are feeding structures ciliated by tentacles
- coelomates
Mollusca
- minor group of lophotrochozoan
- all have: radula, nerve cords, heart, coelom, gills, TROCHOPHORE LARVAEA
- most have a mantle which secretes a shell and are benthic
- HAM= hypothetical ancestral model
Common characteristics of Mollusca
- mantle secreting shell
- muscular foot
- chambered heart
Phylum Mollusca
1. Monoplacophora
2. polyplacophora
- Monoplacophora = limpets
- polyplacophora= chitons
- both make home scars
- home scars: make indents in the rock that they keep coming back to so once the indent is perfect there is nothing that can lift it up off the rock
- clamp down with foot
Phylum Mollusca
3. Gastropoda
- means belly foot
- ctenidia= respiratory organ
- disadvantage is dump feces on head
- torsion: strait canal to flipped shell which benefited them by not being uneven so they are stable, head can go in first to protect from predator, keeps moisture in shell
Phylum Mollusca
4. Bivalvia
- 2 shells
- suck in clean water eat things then deposit clean water below them
- all have trocophore larvae
- cilia crown
- simple bivalve cycle
- benthic
Phylum Mollusca
5. Cephalopoda
- use jet repulsion for swimming
- chambered natulises are the only living cephalopods with an external shell
- ex: octopus, squid, nautilus
- COOLEST is the octopus
Phylum Annelida
- lophotrocozoa
- segmented body
- trocophore larvae
- segmented body
- aka segmented worms
- 2 types
- oligochaeta
- polychaetes
- oligochaeta
- leeches
Oligochaeta
Oligarchaeta = terrestrial worm
- Bilateral symmetry
- Triploblastic,
- coelomate
- Cephalization
- Respiration, circulatory, excretory,
reproductive organs (gonochoric)
17k spp.; marine and terrestrial
- Special features : Repeated body segments,
Collagenous cuticle; not molted
Polychaetes
Polychaetes = mostly marine
Each body segment has a pair of fleshy
protrusions called PARAPODIA that bear
many bristles, called CHAETAE, which are
made of chitin
Leeches
- use bladelike jaws to slit the skin
of the host - host is often oblivious because
the leech secretes an anesthetic - after incision, the leech secretes
hirudin, which keeps the blood of
the host from coagulating - parasites
Phylum Nematoda
- long, thin, threadlike “worms” with a thick cuticle.
- Head is small and possesses only small sense organs, it is small
- Use pseudo coelom as a hydrostatic skeleton secreted by epidermis.
- complete gut: mouth, muscular pharynx, intestine, rectum, and anus
- layer of longitudinal muscles that “play against” the cuticle to yield alternating movement.
- found in all environments
ex: hook worm
hook worm
a Nematoda
- large plates in mouth cut intestinalis lining
- adds anti clotting factors
- can cause anemia or death because it sucks more blood than they can use
- larvae hatches then penetrates skin of person
Guinea Worms
a Nematoda
- get when drink water
- penetrates gut wall
- leaves through foot causing blistering
- no cure must unwind it on a stick slowly for weeks
Filarial Worms
Nematoda
- attacks lymphatic system so you don’t have enough fluids
- can lead to elephantiasis
- common in tropical regions and spread by mosquitos
- often in dogs heart and lungs and up to 40cm long
