Differentiate between:

a. Open and closed circulatory system

b. Oviparity and viviparity

c. Direct and indirect development

d. Acoelomate and pseudocoelomate

e. Notochord and nerve cord

f. Polyp and medusa

Open in App

Solution

a. Open and closed circulatory system

Criteria Open circulatory system Closed circulatory system

Route of blood flow Sinuses Blood vessels

Exchange of material Directly Through capillaries

Transport of gases Does not take place through hemolymph Takes place through blood

Examples Present in arthropods, molluscs Present in annelids, fishes, amphibians, reptiles, birds and mammals

b. Oviparity and viviparity

Criteria Oviparous Viviparous

Nature of birth Lays eggs Birth to young ones

Development Usually in external environment Inside mother’s body

Nourishment Egg yolk provides nourishment Nourishment from mother’s body

Survival rate Low High

c. Direct and indirect development

Criteria Indirect development Direct development

Definition Development in which organisms do not develop into an adult directly from an embryo, rather follow larval stages and perform metamorphosis to get into the adult stage Development of an adult from embryo without any intervening larval stages

Presence of larval stages It involves one/ multiple sexually immature larval stages It does not involve intervening larval stages

Metamorphosis Metamorphosis is present Metamorphosis is absent

Examples Most of the invertebrates and amphibians show indirect development Direct development occurs usually in fishes, reptiles, birds and mammals

d. Acoelomate and pseudocoelomate

Criteria Acoelomate Pseudocoelomate

Presence of coelom Absent Present between endoderm and ectoderm

Mesodermal lining Absent Mesoderm is present as scattered pouches, complete lining is absent

Examples Platyhelminthes
(Fasciola) Aschelminthes
(Ascaris)

e. Notochord and nerve cord

Criteria Notochord Nerve cord

Nature Solid Hollow

Occurence Ventral to the nerve cord in chordates Nerve cord is present in both chordates and non-chordates

Origin Mesodermal Ectodermal

f. Polyp and medusa

Criteria Polyp Medusae

Reproduction Asexual Sexual

Shape Cylindrical and fixed Umbrella-shaped and free

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