A BRIEF ACCOUNT OF EVOLUTION......
#Biology...
About 2000 million years ago ( termed as 'mya' for brevity) the first cellular forms of life appeared on earth. The mechanism of how non cellular aggregates of giant molecules could evolve into cells with membranes envelop is not known. Some of these cells had the ability to release Oxygen.
This reaction could be have been similar to light reaction in photosynthesis where water is split with help of solar energy captured and channelled by appropriate light harvesting pigment. Slowly singled-celled organism became multi-cellular life forms.
By the time of 500 mya, invertebrates were formed and active.Jawless fish probably evolved around 350 mya .Sea weed and few plants were present probably around 320 mya.We are told that the first organism that invaded land were plant. They were widespread on land when animals invaded land. Fish with stout and strong fin could move on land and go back to water This was about 350 Mya. In 1938 , a fish caught in south Africa happened to be a Coelacanth which was thought to be extinct.
These animals called Lobefins evolved into the first amphibians that lived on both land and water .There are no specimens of these left with us
However, these were ancestors of modern day frogs and salamanders. The amphibians evolved into reptiles. They lay thick shelled eggs which do not dry up in sun unlike those of amphibians. Again we only see their modern day descenter such as the turtles, tortoises and crocodiles .In the next 200 million years or so , reptiles of different shapes and sizes dominated on earth . Giant ferns (pteridophytes ) were present but they all fell into form Coal deposit slowly.
Some of these land reptiles went back into water to evolve into fish like reptiles probably 200 mya (Example : Ichthyosaue.) The land reptiles were of course ,the dinosaur The biggest of them ,i.e., Tyrannosaurus rex was about 20 feet in height and had huge fearsome dagger like teeth. About 65 mya, the dinosaurs suddenly disappeared from the earth. We do not know the true reason. Some say climatic changes killed them Some say most of them evolved into birds The truth may live in between. Small sized reptiles of that era still exist today.
#sunday# Biology# curiosity #Topic of the day.
About 2000 million years ago ( termed as 'mya' for brevity) the first cellular forms of life appeared on earth. The mechanism of how non cellular aggregates of giant molecules could evolve into cells with membranes envelop is not known. Some of these cells had the ability to release Oxygen.
Invertebrates
This reaction could be have been similar to light reaction in photosynthesis where water is split with help of solar energy captured and channelled by appropriate light harvesting pigment. Slowly singled-celled organism became multi-cellular life forms.
Multicellular life forms...
By the time of 500 mya, invertebrates were formed and active.Jawless fish probably evolved around 350 mya .Sea weed and few plants were present probably around 320 mya.We are told that the first organism that invaded land were plant. They were widespread on land when animals invaded land. Fish with stout and strong fin could move on land and go back to water This was about 350 Mya. In 1938 , a fish caught in south Africa happened to be a Coelacanth which was thought to be extinct.
These animals called Lobefins evolved into the first amphibians that lived on both land and water .There are no specimens of these left with us
Jawless fish
Salamander.. ..
However, these were ancestors of modern day frogs and salamanders. The amphibians evolved into reptiles. They lay thick shelled eggs which do not dry up in sun unlike those of amphibians. Again we only see their modern day descenter such as the turtles, tortoises and crocodiles .In the next 200 million years or so , reptiles of different shapes and sizes dominated on earth . Giant ferns (pteridophytes ) were present but they all fell into form Coal deposit slowly.
Dianosaur
Some of these land reptiles went back into water to evolve into fish like reptiles probably 200 mya (Example : Ichthyosaue.) The land reptiles were of course ,the dinosaur The biggest of them ,i.e., Tyrannosaurus rex was about 20 feet in height and had huge fearsome dagger like teeth. About 65 mya, the dinosaurs suddenly disappeared from the earth. We do not know the true reason. Some say climatic changes killed them Some say most of them evolved into birds The truth may live in between. Small sized reptiles of that era still exist today.
#sunday# Biology# curiosity #Topic of the day.
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