evolution and cladistic interpretation of 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.