sekilas tentang amniote ( bagian 4 )
T-REC semarang-komunitas reptile semarang
Adaptasi untuk kehidupan di darat
Fitur Amniota berevolusi untuk bertahan hidup di darat termasuk cangkang telor yang kasar kokoh namun berpori atau keras dan allantois berevolusi untuk memfasilitasi respirasi sambil memberikan reservoir untuk pembuangan limbah. Ginjal dan usus besar juga sangat cocok untuk retensi air.
Nenek
moyang Amniota , seperti Casineria Kiddi , yang hidup sekitar 340 juta tahun yang lalu
, berevolusi dari amfibi reptiliomorphs dan mirip kadal kecil . Telur mereka
yang kecil dan ditutup dengan membran kasar , bukan cangkang keras seperti
burung-burung atau buaya . Nenek moyang dari Amniota mungkin meletakkan telur
mereka di tempat-tempat lembab , di
bawah kayu jatuh atau tempat-tempat lain yang cocok di hutan kuno . Memang
banyak Amniota modern tergantung pada kelembaban untuk menjaga telur mereka
dari desiccating .
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Casineria adalah genus punah tetrapod yang hidup sekitar 340 juta tahun yang lalu di zaman Mississippian. Casineria adalah hewan kecil dengan panjang total diperkirakan 15 sentimeter. tinggal di lingkungan yang cukup kering di Skotlandia. Campuran karakter dari primitif (amfibi) dan berkembang (reptil) , sangat dekat dengan asal Amniota.
Nama Casineria, dari latinization Cheese Bay, sebuah situs dekat Edinburgh, di mana ia ditemukan.
Text asli :
Adaptions for a terrestrial life
Features of amniotes evolved for
survival on land include a sturdy but porous leathery or hard eggshell and an allantois evolved to facilitate respiration
while providing a reservoir for disposal of wastes. Their kidneys and large intestines are also well-suited to water
retention. Most mammals do not lay eggs, but corresponding structures may be
found inside the placenta.
The ancestors of true amniotes,
such as Casineria kiddi, which lived about 340
million years ago, evolved from amphibian reptiliomorphs and resembled small lizards. Their eggs were small and covered with a
leathery membrane, not a hard shell like those of birds or crocodiles. Although
some modern amphibians lay eggs on land, with or without significant
protection, they all lack advanced traits like an amnion. This kind of egg
became possible only with internal fertilization.
The outer membrane, a soft shell, evolved as a protection against the harsher
environments on land, as species evolved to lay their eggs on land where they
were safer than in the water. The ancestors of the amniotes probably laid their
eggs in moist places, as such modest-sized animals would not have difficulty
finding depressions under fallen logs or other suitable places in the ancient
forests; and dry conditions were probably not the main reason the soft shell
emerged.Indeed, many modern day amniotes are
dependent on moisture to keep their eggs from desiccating.
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The allantois, along with the amnion and chorion (other embryonic membranes), identify humans, and other mammals, as amniotes. Other amniotes include reptiles, dinosaurs, and birds. Of the vertebrates, only Ichthyopsidas (fish and amphibians) lack this structure.
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Casineria is an extinct genus of tetrapod which lived about 340 million years ago in the Mississippian epoch. Casineria was a small animal with a total length estimated to have been 15 centimeters. It lived in what was then a fairly dry environment in Scotland. It is noted for its mix of primitive (amphibian) and advanced (reptilian) characters, putting it at or very near the origin of the amniotes. The sole find is lacking key elements (most of the skull and the whole lower body is missing), making exact analysis difficult.
Its name, Casineria, is a latinization of Cheese Bay, the site near Edinburgh, where it was found.
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