Phylum Amnelida Flashcards
Phylum Annelida?
Annelids, arthropods and chordates are segmented.
Annelids are segmented from head to toe.
Segments of phylum annelida?
It’s also called Metamerism:- repeated segments.
If one segments fails the rest works.
Classification of Annelids?
It is based in segmentation, setae, and presence and absence of clitellum.
Clitellum?
Portion of reproduction.
Annuli of Annelids?
Annuli is each ring or circular groove outside of the animal.
Cephalization of Annelids (not earthworm)
Head is composed of two parts
- prostomium
- peristomium
Prostomium :- may or not be retractile (comes out and go back) and often bears eyes, tentacles and sensory palps. (Like planaria)
Peristomium :- surrounds mouth and may have setae, palps, or chitinous jaws.
Pygidium :- is the last segment bears Anus.
What is not part of segmentation or metamere in Annelids?
Peristomium and pygidium are not part of segmentation, New segments form from front of pygidium. (Opposite of tapeworms)
Where is the oldest and newest segment of annelids?
Oldest segments is toward the anterior portion (head) of the animal.
Newest one is toward the posterior end of the animal.
Coelom in Annelids comes from?
Mesoderm and shizocoel.
Circulatory system of Annelids?
Circulatory system of annelids is closed like Human.
It means that blood always stays within the vessels.
Heart take blood from Artery ➡️ capillaries ➡️ Venules ➡️ back to heart. Blood never leaves a vessel.
Open circulatory system:- Artery ➡️ sinuses (the openings) ➡️ venules ➡️ then back to heart.
Digestive system of Annelids?
Complete digestive system.
And they have regeneration.
Why are annelids coelomate animals?
Peritonea of adjacent segment meet to form the septa.
Muscles of Annelids?
Circulate muscles outside
Longitudinal muscles inside.
Annelids move by?
Peristalsis
Class polychaeta? Organisms
Poly = Many
Chaeta = bristles, hair
Nereis Virens ➡️ clam or sand worms.
Arenicola ➡️ lugworm.
Tubicolous polychaetas ➡️ Bristle worms.
Class polychaeta is?
Largest class, and mostly Marine
And have well developed Head.
They have parapodia:- paired appendages, all segments have it except the first and last.
Parapodia are Biramus.
No clitellum and many setae.
Tubicolous polychaetas?
Are sedentary
And spend much of their time in permanent burrows.
Head or prostomium have eyes, tentacles and sensory palps.
First segment is called peristomium.
They have pigments such as hemoglubulin.
Reproduction of Tubicolous polychaetas?
They have external fertilization and larva is called Trocophore.
Gonads swell during some time of the year.
Gametes go to coelom ➡️ gonoduct ➡️ Metanephridia ➡️ and then rupture from the body wall.
Other interesting facts of Tuberculosis polychaetas?
They are Active at Night (Nocturnal)
Chitinous jaws and sensory tentacles.
Each parapodia have two lobes:-
*Dorsal notopodium
*Ventral neuropodium
These both are used for creeping and swimming,
Palp and eyes of tuberculosis polychaetas?
Palp = are for sensing the environment.
They eyes but they cannot form image.
They have tentciles in head region.
Prostomium:- includes eyes, palp, pharynx, jaw and prostomial tentacles.
Peristomium :- includes tentacles and parapodia.
Parapodium of Neries virens?
Notopodium have a lot of capillaries for respiration. So, through their cuticle there is some respiration.
Setae help the animal propel.