Marine Animal

What is a marine animal?

A marine animal is any animal (and bird) that lives in and around the ocean and its waters (saltwater). 

A marine animal can have gills (to breathe air when they are underwater) or lungs (to breathe air at the surface of the water). 

A marine animal can have fins or be finless. It can live in the middle of the ocean or on the bottom of the sea. It can fly and live around ocean coasts. 

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What is an instar?

An instar is the development stage of an insect between each stage of moulting, or shedding its skin. 

For example, each stage from egg to larvae (grub) to pupa (chrysalis or cocoon) to an adult insect, as an insect undergoes metamorphosis, is called an instar.

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Plantigrade Locomotion

What is plantigrade locomotion?

Plantigrade locomotion is the way some animals walk with their toes and metatarsals (heels) flat on the ground.

Terrestrial (land) mammals have three ways of walking:

(1) digitigrade (walking on their toes with their heels permanently raised),

(2) unguligrade (walking on the nail of their toes – the hoof – with the heel permanently raised), and 

(3) plantigrade (walking with their toes and heels on the ground).

The leg of a plantigrade mammal includes the bones of the upper leg, called the femur and humerus, and the bones of the lower leg, called the metatarsals and metacarpals. 

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Frog Eyes

A frog has bulging eyes.

A frog has three eyelid membranes. One is transparent (see through) to protect the eyes when the frog is underwater. The other two eyelid membranes vary from translucent (clear) to opaque (cloudy).

Its eyes are at the top of its head, and may be the only part of a submerged frog that is seen above the water. 

A frog’s iris can have a range of colours and its pupil can be a variety of shapes. 

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