Frog metamorphosis
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Transcript of Frog metamorphosis
Frog Metamorphosis
The Life Cycle of Frogs
What is Metamorphosis?
A typically marked or more or less abrupt developmental change in the form or structure of an animal occuring subsequent to birth or hatching
How does it Work?
Metamorphosis in amphibians is regulated by thyroxin and prolactin
Development is subject to many adaptations due to specific ecological circumstances
They also make use of the lateral line organ
Redundant organs are reabsorbed via apoptosis after metamorphosis
A Frog’s Life Cycle
The Egg
The egg begins as a single cell
It becomes surrounded by a jellylike covering, which protects the egg
The female may or may not stay with the eggs to take care of the young after she had laid them
The Embyo
The mass of cells in the egg come to form an embryo
Organs and gills begin to form, and the embryo lives off the internal yolk
This supplies it with nutrients for 21 days
The Tadpole
After its 21 day development period, the embryo leaves its jelly shell, and attaches itself to a weed in the water
It has external gills like a fish to absorb oxygen and feeds on algae
It is extremely vulnerable, and must rely on its camouflage to protect it
The Changing Tadpole
About five weeks, the tadpole begins to change
It starts to grow hind legs, which are soon followed with forelegs
Lungs begin to develop, preparing the frog for its life on land
The Froglet
Over time, the tadpole becomes even more froglike
Its mouth widens, it loses its horny jaws, gills are lost
The tail becomes much smaller, and the legs grow
The lungs are almost functioning at this point
The Frog
Eleven weeks after the egg was laid, a fully developed frog with lungs, legs, and no tail emerges from the water
Eventually, it finds a mate
The female lays the eggs, the male fertilizes them, and the whole process begins again