Phylum Annelida Flashcards
General characteristics
segmented permits specialization complete digestive track bilateral symmetry true coelom 3 germ layers
Advances over Nematodes
segmented
true coelom
more organs in the body cavity
classes and examples
oligochaeta-earthworms
polychaeta- marine worms( paired, paddle like appendages on each segment
digestion/feeding, digestion organ pathway
mouth-pharynx-esophagus-crop-gizzard-intestine-anus
mouth function
start of digestive pathway
Pharynx
contracts and swallows food and dirt
pumps food and soil into esophagus
Esophagus
food tube (contacts)
Crop
stores food (like stomach)
Gizzard
grinding food
Intestine
digesting and absorbing nutrients
Anus
eliminate
respiratory system
aquatic- has gills
nad(earthworms)- diffusion through moist skin
they also have secrete mucus to keep skin moist.
Circulation
- closed circulatory system-blood flow is in vessels
- have hearts (aortic arches) 5 hearts on dorsal side.
- heart is a thickened blood vessel which can pump blood
- dorsal blood vessel-runs the length of worm (on back)
- ventral blood vessel- on stomach; length of worm.
- blood has hemoglobin to carry oxygen, similar to ur blood
excretion
-solid waste- anus=digestive system
-liquid waste- nephridia
filter fluids & nitrogenous waste
nervous system: response
- brain-dorsal ganglion
- ventral nerve cords(down length of stomach)
- small ganglia and nerves in each segments
- sensory receptors-anterior
- tentacles
- chemical receptor
- eyes… can sense light or dark
- statocysts.. detect gravity
nervous system: movement
- longitudinal muscles stretch long, shorter or fatter
- circular muscles 00 contract to make thinner or thinker
- setae- on each segment; bristles anchor in soil, used for burrowing
- marine worms-paddles called parapodia for swimming
asexual reproduction
None
- may have regeneration when end of worm is broken off
- it can regrow
sexual reproduction
- most hermaphrodic (both sexes in the same )
- rarely fertilize their own eggs
- 2 worms exchange
- clitellum secretes a mucus “cocoon” eggs and sperm are released into it
- young worms hatch from “cocoon”
septum
wall separating each segment
longitudinal and circular
muscles allowing each segment to contract
setae
bristles found on each segment
what type of circulatory system do annelids have?
a closed system
what class do earthworms belong to?
oligochaeta
what class do marine worm belong to ?
polychaeta
what class do leeches belong to?
hirudinea
a thickened band of segments towards the anterior
clitellum
internal walls between each segment in an earthworm
septa
blood sucking organisms in this phylum
leeches
