What are annelids?
- marine
- have bristles
- predators
- also called bristle worms
- characterized by their segments
- not flatworms or roundworms
What are the individual segments of a worm called?
metamerites
What is a bobbit worm?
- named after lauren bobbit
- has jaws thats snap or snip efficiently
What are the synapomorphies of annelida?
- epidermal setae
- usually two on both metamersism
- terrestrial: anchoring
- marine: breathing, swimming, sensing
- metamarism
Describe the external morphology of annelids?
-jaws on their eversible pharynx
-segementsL prostomium, perstomium, pygidium, parapodia
what Is the prostoimium
-first segment
-primary sensory organs to sense environment
-tentacle and palps: respiration but primarily sensory
what is there peristomium
first true body segment
what is the pygidium?
- last segment of the body
- tail
- has the anus
- has two sensory called cirrus
How does an annelid grow
from the pyrigidium up
what is a parapodia?
- have setae embedded in them
- has two nodes
- both have setae embedded
- neuropodium
- ventural lobe
- aciculum
- primary way of sensing the environment
- notopodium
- dorsal lobe
- has repsiratory capillaries
Describe the internal morphology of annelids?
- each metarite is covered in pareital peritoneum
- this tissue membrane made out of mesoderm
- every segement is separated by a septum
- means its compartmentalized
- when circular muscle contract: thinner & longer, causing the longitudual muscle
- when the longitudual muscle contracts, circlular muscles have to relax
- wide and narrow
- allows to burrow and anchor in the substrate
What are errantians?
- scale worm
- bristles can modify to either become protection at the top, or on bottom modify to the become legs
- benthic or pelagic
- pelagic worms can inflate themselves for buoyancy
How are errata’s important economically?
food source
What are the errantians most dangerous time?
reproduction time
how do errantians reproduce?
- reproduce without leaving their burrows
- forms two different forms of their bodies
- normal body part: atoke
- epitoke forms during reproduction
- when mature enough, it will swim away
- environmental cues where the epitokes are released at the same time
What are sedentarians?
-sessile
-filter feeder
-cilia that covers the surface
how do sendtarians eat?
ciliary feeders, desposit feeders, sand filtering, mutualistic bacteria trophosome
Ciliary feeders
- live above the sand
- makes a tube to protect from predators, made up of calcium, silica, or protein
- to filter feed they have radioles that have pinnules on them
- sort by size and composition
- cilia move the food the mouth
- on the dorsal side
- organic things to eat; inorganic to excrete, store, or help build its case
deposit feeders
- cilia on the ventral side of the tenetacles
- burrow into the sand for protection
- have tentacles that rummage on the ground for food
sand filtering
- burrows into the sand
- muscle contraction to create water current
- water follows over their body as they breathe
- nutrients get stuck on the sand, which they just eat
mutualistic bacteria trophosome
- use tentacles for respiration
- reply on bacteria to help them break down the caclium on the bones for food
- trophosome that harbors bacteria to eat for the worm
What are spoon worms?
- family echuridiae
- named because their mouth looks like a spoon
- sex is decided by how far away from the mother you can get
- if it doesnt get far away, it stays a male and the mother will keep it in a pouch where it will produce sperm
- primairly despsit feeders
- benline: changes larva into male or female
- no peripoda
- have epidermal epitae
- no internal contents
- breathe through their hind gut respiratory elements
What animals are in the order clitellata
- earthworms leeches
- size is retained by the underground
- earthworms respirate through their skin
syamorphy of clitellum
saddle
