Phylum : Annelida General Characters & Example, Multiple Choice questions : NEET
🌑Defination
Annelids are first Coelomate, Triploblastic, bilateral symmetrical, metamerically segmented animals with organ system level of organisation.
🌑General features
🔴They are aquatic and found in marine and fresh water and also live in terrestrial habitat.
🔴They are free-living some are parasite like Pontobdella, Acanthobdella etc.
🔴They have organ-system level of body organisation and bilateral symmetry. They are triploblastic, metameric segmented and coelomate animals.
🔴Their body surface is distinctly marked out into segments or metameres. Hence the phylum name Annelida has been given.
🔴They possess longitudinal and circular muscles which help in locomotion.
🔴Aquatic annelids like Nereis possess lateral appendages, parapodia, which help in swimming.
🔴A closed circulatory system is present in which blood is flown in network of blood vessels.
🔴Nephridia help in osmoregulation and excretion.
🔴Nervous system consists of paired ganglia connected by lateral nerves to a double ventral nerve cord.
🔴Nereis is dioecious, but earthworms and leeches are monoecious. Reproduction is sexual.
🟡Nereis
🔴It is commonly called as Calm worm or Rag worm.
🔴Prostomium and Peristomium are two parts of Head of Nereis. First one is triangular and second one is ring like.
🔴Mouth is located at anterior of Peristomium with fine tentacles.
🔴It use parapodia for locomotion and swimming.
🔴It usually live in burrow of sand and carnivores and nocturnal in nature.
🔴It can maintain its internal body environment with respect to surrounding.
🔴Alimentary canal is in form of straight tube and include mouth to rectum.
🔴The number of body segments are 200.
🔴It has four pairs of simple and round eyes.
🔴It reproduce sexually because it is dioecious. Male and female are different.
🟡 Pheretima
🔴It is commonly called as Earth worm.
🔴Earthworms have microscopic fine hair like structure called setae that help in locomotion and Anchorage. Setae are present in body except first, last and clitellum region.
🔴Earthworms have a closed circulatory system with a heart, capillaries, and vessels. Their blood is red and contains hemoglobin which is dissolved in plasma.
🔴Earthworms have a dark band of glandular tissue called the clitellum, which is located between 14th and 16th segment. Clitellum has mature eggs of Earthworm.
🔴Earthworms have blood glands in segments 4-6 that produce hemoglobin and blood corpuscles.
🔴Earthworms are hermaphrodites or Monoecious . They have both male and female sex organs.
🔴Earthworms have nephridia that help them excrete nitrogenous waste and regulate osmoregulation.
🔴Alimentary canal is in form of straight tube and include mouth to rectum.
🟡 Hirudinaria
🔴It is commonly called Leech. Leeches has an anterior sucker at the front of the body and a posterior sucker at the back of the body
🔴The number of body segments are 33.
1. Which of the following statement is not correct with respect to Annelida.
5. Consider the following statement and select the correct code:
Comments
Post a Comment