Archaeopteryx is a fossilised reptile found in Germany which has feathers and is considered the link between reptiles and birds.
Reptile eggs usually have a soft membrane which allows moisture and gasses to pass through the membrane, this is a cleidoic egg.
Avian eggs have a hard (moisture impervious) shell and an amniotic sac containing amniotic fluid in which the embryo develops and a yolk sac for the nutrients used by the developing embryo, these are called amniotic eggs. (While amniotic eggs fit within the definition of cleidoic eggs, the amniotic egg is more advanced and so are frequently considered different definitions)




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Thanks for that, I know heaps of good stuff now!!!!

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