Differentiate between: a. Open and clos | Class 11 Biology Chapter Animal Kingdom, Animal Kingdom NCERT Solutions

a. Open circulatory system: Blood is directly circulated in the cells and tissues without any network of vessels. Example: Mollusca, Arthropoda.

Closed circulatory system: Blood is circulated through a proper network of vessels (arteries, veins and capillaries). Example: Annelida and Chordata.

b. Oviparous: Oviparous are the animals that lay eggs. Oviparous animals or organisms look after their eggs after laying them.

Example: Birds, Reptilia.

Viviparous: are those animals that gives birth to the live young ones. They show parental care after their birth.

Example: Mammals.

c. Direct development: In this development larval stage is not present. An embryo develops into a mature individual without involving larval stage. Example: Human beings.

Indirect development: In this development sexually immature larval stage is present. Example: Butterflies.

d. Acoelomate: The animals in which the body cavity is absent. Example: Poriferans, Ctenophores.

Pseudocoelomate: The animals in which the body cavity is not lined by mesoderm layer and mesoderm is present in scattered pouches in between ectoderm and endoderm. Example: Aschelminthes.

e. Notochord: It is mesodermally derived rod- like structure formed on the dorsal side during embryonic development.

Nerve cord: Nerve cord is a strand of nervous system.

f. Polyp: Poly is sessile and cylindrical form. Example: Hydra, Adamsia.

Medusa: Medusa is free swimming and an umbrella shaped structure. Example: jelly fish.