Phylum Annelida

Question 1

What is the main feature of phylum annelida?

Answer 1

they are segmented worms and they are long and skinny

Question 2

What are 3 classes of phylum annelida?

Answer 2

1. Class Polychaeta
2. Class Oligochaete (earth-worm like worms)
3. Class Hirudinea (leeches)

Question 3

What are 4 characteristics of Annelids?

Answer 3

1. They are segmented and made up of repeated units that have similar internal and external anatomy and the segments are separated by septa
2. They are eucoelomates –> they have a body cavity completely lined with mesoderm ally derived tissues
3. Have closed circulatory system (blood is contain in vessels)
4. Complete digestive system with anus (this applies to all subsequent taxa after this)

Question 4

What are 3 characteristics of the Class polychaeta?

Answer 4

1. All are almost marine and few freshwater
2. Their body segments have fleshy lobes called parapodia (“not quite feet”) and each lobe has a chaetae which are bristles that help them move and swim
3. Clearly differentiated head with sensory antennae
   - they have many eyes; The sedentary species rarely move (live in tubes) and the errant species actively move with parapodia and head thats better developed

Question 5

What are some characteristics on Errant and Sedentary polychaeta?

Answer 5

1. errant species are usually predatory
2. sedentary polychaete usually ingest substrate and suspension feed (filter food particles out of their water columns) and deposit feed (put their sticky tentacles over substrate and lick off the adhering matter)
3. Sedentary polychaete dig and burrow and make tubes that they live in
4. Free-spawning species, where eggs and sperm released into water and fertilization occurs outside body of parent

Question 6

What are five characteristics on the Class oligochaete?

Answer 6

1. they are morphologically and ecologically less diverse
2. They lack parapodia and well developed head
3. they have few chaetae
4. Theres terrestrial and freshwater species, the terrestrial species are called earthworms
5. most feed by ingesting substrate and digesting organic matter

Question 7

How do oligochaete reproduce?

Answer 7

they are simultaneous hermaphrodites and transfer sperm by copulation (physical)

• each worm in the pair acts as both male and female AT THE SAME TIME
• temporary deposits sperm in partner’s seminal receptacle
• produces gelatinous cocoon with secretions from their clitellum
• repost eggs in cocoon and slides cocoon forwards and deposits stored sperm
• fertilization is external not internal
• they also go through direct development (they have no larval stage)

Question 8

What are the ecological importance of oligochaetaes?

Answer 8

• the terriristrial ones are good in maintaining soil fertility by turning over smaller fragments of organic matter and aerating the soil
• there species that feed on large organic debris and they are useful in composting

Question 9

What are 3 characteristics of the class Hirudinea?

Answer 9

• Mostly freshwater species but a few are marine and terrestrial
• very closely related to the earth worms (oligochaete) as they lack parapodia and have a clitellum
• they also lack chaetae, and thats why they suck and move with suckers

Question 10

What are some ecological importance of Class hirudinea?

Answer 10

• the are predators of the soft bodied invertebrates
• some of the feed on food of vertebrates and secrete a anesthetic and anticoagulant (causes vasodilation of blood vessels)
• medicinal leeches are for reliving blood congestion in haemotomas