Write 2 biologists and what they did thats facinating

Probably the most famous naturalist of all time, Darwin's contribution to biology and society is beyond imagination. He established that all species of life have descended over time from common ancestors, the existence of new species occuring via the process of natural selection. His theory of evolution was published in On the Origin of Species in 1859 and it caused quite the stir – Darwin was disputing the longheld belief that all species had been created by God at the beginning of the world. Evolution by natuaral selection combined with Mendelian genetics is now accepted as the modern evolutionary synthesis and forms the foundations of much biological scientific endeavour. 

Mendel's extraordinary contribution didn't receive its just recognition until long after the friar's death – you could call him the Van Gogh of the biological world. Mendel used peas to discover and demonstrate the laws of genetic inheritance, coining the terms dominant and recessive genes in the process. The laws were rediscovered at the turn of the 20th century and provided the mechanism by which Darwin's theory of natural selection can occur. The two theories combine to form our current understanding of the evolutionary process.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

a symbiotic relationship with the mitochondria