IT IS A FASINATING STORY OF GRADUAL CONVERSION OF AMPHIBIANS INTO FIRST AMPHIBIAN AND THEN TERRESTRIAL TETRAPODS DURING CARBONIOUS PERIOD OF PALEOZOIC ERA .
Use of mutants in understanding seedling development.pptx
Transitional forms chapter 4.1 amphibian ancestors of reptiles -introduction to hylonomus
1. Amphibian Ancestors of Reptiles
It surprises us to no end to know
that small lizard like amphibians
of Paleozoic carboniferous times
were ancestors of successor giant reptiles
and fossils of proto reptiles or para reptiles
makes us eager to know more and more
about this fascinating transformation .
2.
3. Transitionalforms
CarboniferousCradle
Of
Ancestors of Reptiles
It was a period in which the earth was lush green
with flourishing ferns and tall Gymnosperms unseen,
lakes ,ponds and puddles were live with noisy frogs
swimming or hopping in and out of water in funny ways
and salamander like creepy creatures were in abundance;
vast jungles were full of giant scorpions & dragon flies
when some of the braver amphibians tried to remain
more & more on dry land and even lay eggs there, almost
experimenting how to make them survive on ground and
came up with the idea of amniotic eggs with hard shells
to save them from dessication ,gradually adapting to
terrestriallife pattern in hot and humid climate at that time.
let us see, one by one, who were these innovation loving
bold creatures which became the transitional forms leading
to evolution of reptiles in due course of time ,
5. Transitionalforms
Lizzae theLizard
We are small longish long tailed fellows
a bit Salamander likea bit lizard like
insectgulpinggentleguys
but don’t underestimateus please
for we are grand ancestorsof a ‘ race’
known for its fearsomelooks and largesize.
We are slenderfellows with small legs ,long tails
and a bodyfull of scales on back as well as belly
livingin fresh water lakes in carboniferousdays
called as Lizziethe lizard but not a lizardat all
we are actually reptiliomorph leposopondyli
close to both amniotesand amphibianguys.
6.
7. Transitionalforms
Proterogyrinus
( Earlier tadpole !)
We looklike our terrestrial friends
with fivefingersand lateral eyes
longishhead ,long tail and strongfeet
able to hunt whileon the move
more at homein water than on land
we are reptiliomorpha Anthracosaurus
Embolomeri- amphibian guys.
We had slenderbodies,stronglimbs,long tails
black& whitestripesrunningdown our spines
splayed out legs ,and five digits on each foot
small needlesharp teeth ,largejaws ,yelloweyes
We were top predatorsof our time
with thin skinwe mostlylivedin water
but were capableof dashing out of water
and wander on land to grab the prey even
as big as car sized millipedelike Arthropleura
and eagle sized dragon flies.– Meganeura.
8.
9. Transitionalforms
Solenodonsaurus
( Singletoothlizard)
Small amphibiansresembling
both didectomorphs!and amniotes ,
were carnivorous / insectivorous
reptiliomorpha with triangularfaces;
felt moreat ease on land than in water.
They had a hearingsystem
Similar to moderntetrapods
And sharp slightlycurved teeth
A build likethat of Didectomorphs
They were sisterlyto Anthracosaurs
10.
11. Transitionalforms
Hylonomus
( Forest dweller )
These tinycreatures of hardlyeight inches
were ,unbelievably, the very firstreptiles
which roamed in jungles eatinginsects
living/dying in hollow trees trunks
were ancestorsof both synapsids& sauropsids
in ‘Canada’during hot humid carboniferousdays ..
Looking morelike a modernlizard
eatingmillipedes & snailsby smallteeth
they were fullyadapted to lifeon land
and were closelyrelated to Diapsids .
