Skip to main content

EVOLUTION



origin of species is written by Charles Darwin in 1859


Herbert Spencer coined the term 'survival of the fittest.'


Lamarck gave the theory of progressive use and disuse of organs and believed in the inheritance of acquired characters.


an experiment to prove that organic compounds were the basis of life was performed by Stanley Miller.


nucleoproteins gave probably the first sign of life.


a single chromosome contains hundred to thousands of genes.


genetics is the study of inheritance.


Y chromosome does not have any allele linked to it


Three botanists - Hugo DeVries, Carl Correns and Erich von Tschermak ,independently rediscovered Mendel's work in the same year, a generation after Mendel published his papers.


Evolution can be described as generation and shaping of diversity by environmental selection


extinct species must have existed at some time:- this statement describes evolution


java man, peking man and heidelberg man are the fossils of "homo erectus".


crow magnon is the fossil of an early homo sapien that lived about 40000 years ago.


allopatric speciation is speciation that happens when 2 populations of same species become isolated from each other due to geographical changes.

it is also known as geographic speciation.


the swan neck experiment by louis pasteur disapproved the spontaneous generation theory which stated that life was generated from inanimated matter.


this theory was set up to prove that particles in the air(germ theory) rather than the air itself(spontaneous generation) led to fermentation.


bar eye character in "DROSOPHILA" is by duplication in X-chromosome.


monohybrid ratio is 3:1

dihybrif ratio is 9:3:3:1


Planaria has rudimentary eyes.


primitive earth had a reducing atmosphere because of the absence of free oxygen.

free oxygen first evolved due to the presence  of blue green alga and later on plants which release free oxygen as by product which made the atmosphere oxidizing later on


blood group O is a recessive trait.


adaptations can either be temporary or permanent.


analogous organs indicate convergent evolution.


PARAPATRIC SPECIATION:- in this type of speciation,2 subpopulation of a species evolve reproductive isolation from each other while continuing to exchange genes.


PERIPATRIC SPECIATION:- in this type of speciation, 2 subpopulations are geographically isolated from each other.its primary characteristic is that one of the populations is much smaller than the other one.genetic drift takes place.





Labels:

Comments

Post a Comment

Popular posts from this blog

The ABC Murders Vs Murder On The Orient Express. Which one should you buy first ?

Agatha Christie is often regarded as the best author of murder mysteries till date. During her time, she has written countless masterpieces such as And Then There Were None , The Murder Of Roger Ackroyd , The ABC Murders , Murder On The Orient Express , Peril At End House , etc. On seeing 2 great murder mystery novels, a reader often gets confused about which one to buy and read first. Should it be this one or that one ? Thoughts like these linger in the reader's mind and trouble him for hours. But we are here to help you guys. And that's why, in this article, will take a look at 2 great murder mysteries; Murder On The Orient Express   and The ABC Murders and we will help you determine which one is more suitable for you and should be bought first. So, without any further ado... LETS GET STARTED ! Before we begin our comparison, let us have a basic introduction of each book: 1) The ABC Murders : 'LET US SEE, MR. CLEVER POIROT, JUST HOW CLEVER YOU CAN BE...' Murder is...
Post a Comment
Read more

LIST OF PHOBIAS A-Z

Phobias, almost every person in the present world has one phobia or the other .And those weird names of different phobias don't make it any easier. Keeping this in mind, lets have a look at some of the common and '' not-so- easy to remember " phobias:- Acrophobia:- fear of heights Aerophobia:- fear of flying Agoraphobia:- fear of public space Ailurophobia:- fear of cats Amathophobia:- fear of dust Arachnophobia:- fear of spiders Astraphobia:- fear of lightning Claustrophobia:- fear of closed-in spaces Emetophobia:- fear of vomiting Ereuthophobia:- fear of blushing Haematophobia:- fear of blood Microphobia:- fear of germs/small things Nyctophobia:- fear of the dark Mysophobia:- fear of dirt Ochlophobia:- fear of crowds Ornithophobia:- fear of birds Pathophobia:- fear of disease Pnigophobia:- fear of choking Pteronophobia:- fear of feathers Pyrophobia:- fear of fire Xenophobia:- fear of strangers Zoophobia:- fear of animals
Post a Comment
Read more

READING AGATHA CHRISTIE'S "AND THEN THERE WERE NONE"

"AND THEN THERE WERE NONE " . .. If you are a fan of Agatha Christie and like her stories very much than you probably know this book which I am talking about( or writing about ). And since you are a fan of Agatha Christie I will presume that you had probably read one or more of Agatha Christie's books before reading this one. So I will also assume that you had at least a little idea about what to expect from this book and its plot... BUT WHAT ABOUT ME ? COZ THIS WAS MY FIRST AGATHA CHRISTIE BOOK AND I HAD NO IDEA ABOUT WHAT TO EXPECT ! And when I read this book, believe me, it just blew my mind away ! I had literally never ever read such a mind blowing book before. How could I , because before reading this book, the only author's books which I read were of Enid Blyton, and if you have ever read an Enid Blyton book, you probably know the difference in the level of their stories and you might be able to imagine the amount of joy and thrill which I got from readin...
Post a Comment
Read more