A BRIEF ACOUNT OF EVOLUTION Flashcards
(31 cards)
About ____________ years ago , 1st cellular forms of life appeared on earth.
2000 million
What is the mechanism of non-cellular aggregates of giant macromolecules evolving into cells?
Not known
Some of these earliest cells had the ability to ___________
release O2
The reaction to release O2 could have been similar to ____________
light reaction in photosynthesis
By ________ , invertebrates were found and active
500 mya
________________ existed probably around 350 mya
Jawless fish
Sea weeds and few plants existed probably around ____________
320 mya
1st organisms that invaded land were __________
Plants
Fish with ____ could move on land and go back to water
Strong fins
350 mya
In ________, a ____________ fish was caught in South Africa which was thought to be extinct
1938, Coelcanth
Coelcanth called ________ evolved into the _________
Lobefins, 1st amphibians
There are only 3 specimens of lobefins left with us
True/false
False
No specimens
Amphibians evolved into ____________
reptiles
Difference between reptile and amphibian eggs is ___________
Reptiles lay thick-shelled eggs which do not dry up in sun unlike those of amphibians.
In the next 200 million years, ________ dominated earth
reptiles
Giant ferns(pteridophytes) fell to form __________
coal deposits slowly
Some of the land reptiles went back into water to evolve into ________ probably ____ mya(eg. - Ichthyosaurs)
fish like reptiles, 200
Land reptiles were ________
Dinosaurs
Biggest dinosaur with huge dagger like teeth was ________ and was ________ feet high
Tyrannosaurus rex, 20
When did dinosaurs suddenly disappear from earth?
65 mya
What are the probable reasons of disappearance of dinosaurs?
2
Climatic changes killed them
Evolved into birds
Small sized reptiles of dinosaur era are also extinct
True/false
False
Still exist
1st mammals were like ________ with large/small fossils
Shrews, small
Mammals protected their unborn young _________________
inside the mother’s body
