Annelids and Arthropods
What is an Annelid?
An Annelid is defined as a segmented worm in the Annalida phylum.
The Annalida phylum defining characteristics
- Symmetry and Size
- Body Wall
- Nervous system
- Sense Organs
- Circulation and respiratory structures
- Segmental organs
What is the primary way of feeding for these segmented worms?
They primarily feed on decomposed plants materials and this applies all of the species of segmented worms except leeches (freshwater segmented worm) that feed on blood.
Where are Neres Worms Typically found?
The Neres Worm or rag worm are common North American species is Nereis
Differences between Errant and Sedentary polychaetes
- Body Segments – A large number
2. Anterior appendages –
Few in number and differentiated into palps, antennae, tentacular cirri, etc
3. Life Habit – Free living and generally rapacious
4. Feeding: (breast mode) all have jaws; scavengers or predators (on plants and animals)
Learn more from the source : http://personal.cityu.edu.hk/~bhworm/sedentary/spoly.htm
- Body Segments – A limited number ; May be separated into different segments
2. Anterior appendages
May be absent or a few to many similar appendages
3. Life habit – Tubicolous or burrowing
4. Feeding: (animalistic) usually filter- or deposit-feeders (i.e. consume sediment)
Main Characteristics of Arthropods
All arthropods share a common set of characteristics that include having jointed limbs, an exoskeleton, good senses, and bilateral body symmetry. An exoskeleton is a hard, shell-like covering that protects an arthropod’s inside body parts.
Observing other Arthropods
Horse Shoe Crab
What does the animal use for respiration?
A horseshoe crab is not a crab- how does it differ from the “real” crabs?
What are the barnacle shells ?
How does this animal feed?
Barnacles feed through feather-like appendages called cirri. As the cirri rapidly extend and retract through the opening at the top of the barnacle, they comb the water for microscopic organisms. … Four more plates form a “door” that the barnacle can open or close, depending on the tide.
Locate and watch a video of barnacles feeding on youtube……