Invertebrates - Phylum Annelida

annelida

segmented worms

what types of species are in annelida

marine, terrestrial, and freshwater species

body plan

bilateral, but very minimal cephalization

tissue types

triploblastic, eucoelomate

protosome or deuterosome

protosome

annelida have a _______________ digestive system

complete

annelida have what type of segmentation

metamaric

each segment...

has repeated internal or external features

what class are the marine species

polychaetes

what class are the terrestrial species

olgiochaetes

how is the epidermis protected

by a chitinous cuticle

setae

chitinous bristle-like structures that help segmented worms move

parapodia

Paddlelike appendages that assist polychaetes annelids in locomotion.

digestive system

mouth, pharynx, esophagus, crop, gizzard, intestine then anus

circulatory system

closed, with dorsal and ventral blood vessels

respiratory system

none, gas exchange occurs across the epidermis

metabolic waste is excreted by

nephridia

nervous system

well developed, ventral nerve cord and ganglia

general reproduction - monecious

— both male and female in same animal
— permanent gonads
— self fertilization or cro fertilization

general reproduction - dioecious

- some are dioecious
— male animal or female animal
— temporary gonads

polychaetes reproduction

- external fertilization, larvae produced, metamorphosizes into adult
— can reproduce asexually by fragmentation

oligochaetes reproduction

internal fertilization, eggs develop, worm hatches from egg