👉Phylum-Mollusca🦑🐙🐚🐌🦑🐙🐌
👉Characteristic Features of Phylum Mollusca👇👇👇👇
1 They are bilaterally symmetrical.
2 They are triploblastic, which three layers.
3 They show organ system grade of organisation.
4 The body is soft and unsegmented.
5 Body is divisible into three regions – head, a visceral mass, and ventral foot.
6 Body is covered by a mantle and shell.
7 They can be found in different habitats, both aquatic and terrestrial.
8 The body cavity is a haemocoel, through which blood circulates.
9 The digestive system is well developed and complex. It has a radula, which is a rasping structure that has chitinous teeth. It is used in feeding.
10 The nervous system is made up of paired ganglia, connectives, and nerves.
11 The circulatory system is open, with heart and aorta.
12 Respiration occurs through gills called ctenidia.
13 The ventral muscular foot helps in locomotion.
14 They have a pair of kidneys (metanephridia)
15 Sexes are separate and reproduction is through sexual reproduction.
16 Fertilisation can be internal or external.
Eg.-Clams,
Mussels,
Octopus,
Pila ( Snail),
Oyster,
Cuttlefish,
Squid
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