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the first amniotes

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This document summarizes key aspects of animal diversity by discussing amniotes. It describes amniotes as the first tetrapods to fully adapt to land using amniotic eggs equipped with membranes that protect embryos. The earliest amniotes resembled small lizards and evolved 312 million years ago. They diverged into synapsids and sauropsids, including modern reptiles, birds, and mammals. Amniotic eggs evolved adaptations like the amnion, yolk sac, chorion, and allantois membranes to protect embryos in harsh land conditions. The document also provides a cladogram illustrating the phylogeny of amniotes.

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the first amniotes
Submitted by :- Iqra Saeed, saira gulab and yasif uddin reg no# :- kiu-bs-583 dept :- biological sciences section:- plant sciences BS-2 submitted to:- ma'am sharishta subject:- animal diversity date:- 17 Aug. 2020
• Evolutionary Perspective • The first amniotes • Amniotic egg • The Cladistic Interpretation of the amniotic linage cotent
EVOLUTIONARY PERSPECTIVE • Amniotes are tetrapods that are characterised by having an egg equipped with an amnion, an adaptation to lay eggs on land. • Amniotes include synapsids (mammals) a nd sauropsids (reptiles and birds), as well as their ancestors, back to amphibians. • The first amniotes, referred to as "basal amniotes", resembled small lizards and evolved from the amphibian reptiliomorphs about 312 million years ago in the Carboniferous geologic period.
First amniotes • Very early in their evolutionary history, basal amniotes diverged into two main lines. • the synapsids and the sauropsids, both of which persist into the modern era. • The oldest known fossil synapsid is Protoclepsydrops from about 312 million years ago. • while the oldest known sauropsid is probably Paleothyris, in the order Captorhinida (306–312 million years ago).
Reasons of adaption of amniotic egg • As these animals are first organisms which completely adopt the land environment. From the harsh condition (dessication, high temprature and etc) organism will develop an amniotic egg. • Amniotic egg contain amnion fluid which protect an embroyo from harsh condition
Characters of amniotes • žAmniotes are the group of Tetrapods whose living members are the reptiles,including birds aand mammmal. • žAmniotes are named fir the major derived character of the clade,the amniotic egg,which contain memeberanes that protect the embryo. • žThe extraembryonic membranes are the amnion,chorion ,yolk sac,and allantois.
Contiiii………… • žAmniotes have other terrestial adaptations,such as relatively impermeable skin and the ability to use the rib cage to ventilate the lungs.
Yolk sac • žThe yolk sac contains the yolk. • žBlood vessels in the yolk sac membrane transport nutrients from yolk into embryo. • žLess water and more proteins than albumin.
Allantois • žBetween amnion and chorion. • The allantois help in gaseous exchange and wastes removal. • Membrane of alllantois function with chorion as a respiratory organ.
Chorion • žOutermost fetal membrane around embryo. • žExchange gases between embryo and air. • ž • žAMNION • žFluid filled cavity • žDue to amnion, egg is known as amniotic egg. • žPrevent from external shock. • žFluid prevent from dehydration.
Reptiles-lay shelled eggs on land • žThe reptile clade include the tuataras,lizard,snakes,turtles,crocodilians,bird s, and the extinct dinosaurs. • žReptiles have scales that creat a waterproof barrier. • žMost reptiles are ectothermic ,absorbing external heat as the main source of body heat. • žBirds are endothermic,capable of keeping the body warm through metabolism.
The cladistic interpretation of amniotes • The cladogram prese nted here illustrates the phylogeny (famil y tree) of amniotes, and follows a simplified version of the relationships found by Laurin & Reisz (1995)
the first amniotes
This Photo by Unknown author is licensed under CC BY-NC.

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the first amniotes

  • 2. Submitted by :- Iqra Saeed, saira gulab and yasif uddin reg no# :- kiu-bs-583 dept :- biological sciences section:- plant sciences BS-2 submitted to:- ma'am sharishta subject:- animal diversity date:- 17 Aug. 2020
  • 3. • Evolutionary Perspective • The first amniotes • Amniotic egg • The Cladistic Interpretation of the amniotic linage cotent
  • 4. EVOLUTIONARY PERSPECTIVE • Amniotes are tetrapods that are characterised by having an egg equipped with an amnion, an adaptation to lay eggs on land. • Amniotes include synapsids (mammals) a nd sauropsids (reptiles and birds), as well as their ancestors, back to amphibians. • The first amniotes, referred to as "basal amniotes", resembled small lizards and evolved from the amphibian reptiliomorphs about 312 million years ago in the Carboniferous geologic period.
  • 5. First amniotes • Very early in their evolutionary history, basal amniotes diverged into two main lines. • the synapsids and the sauropsids, both of which persist into the modern era. • The oldest known fossil synapsid is Protoclepsydrops from about 312 million years ago. • while the oldest known sauropsid is probably Paleothyris, in the order Captorhinida (306–312 million years ago).
  • 6. Reasons of adaption of amniotic egg • As these animals are first organisms which completely adopt the land environment. From the harsh condition (dessication, high temprature and etc) organism will develop an amniotic egg. • Amniotic egg contain amnion fluid which protect an embroyo from harsh condition
  • 7. Characters of amniotes • žAmniotes are the group of Tetrapods whose living members are the reptiles,including birds aand mammmal. • žAmniotes are named fir the major derived character of the clade,the amniotic egg,which contain memeberanes that protect the embryo. • žThe extraembryonic membranes are the amnion,chorion ,yolk sac,and allantois.
  • 8. Contiiii………… • žAmniotes have other terrestial adaptations,such as relatively impermeable skin and the ability to use the rib cage to ventilate the lungs.
  • 9. Yolk sac • žThe yolk sac contains the yolk. • žBlood vessels in the yolk sac membrane transport nutrients from yolk into embryo. • žLess water and more proteins than albumin.
  • 10. Allantois • žBetween amnion and chorion. • The allantois help in gaseous exchange and wastes removal. • Membrane of alllantois function with chorion as a respiratory organ.
  • 11. Chorion • žOutermost fetal membrane around embryo. • žExchange gases between embryo and air. • ž • žAMNION • žFluid filled cavity • žDue to amnion, egg is known as amniotic egg. • žPrevent from external shock. • žFluid prevent from dehydration.
  • 12. Reptiles-lay shelled eggs on land • žThe reptile clade include the tuataras,lizard,snakes,turtles,crocodilians,bird s, and the extinct dinosaurs. • žReptiles have scales that creat a waterproof barrier. • žMost reptiles are ectothermic ,absorbing external heat as the main source of body heat. • žBirds are endothermic,capable of keeping the body warm through metabolism.
  • 13. The cladistic interpretation of amniotes • The cladogram prese nted here illustrates the phylogeny (famil y tree) of amniotes, and follows a simplified version of the relationships found by Laurin & Reisz (1995)
  • 15. This Photo by Unknown author is licensed under CC BY-NC.