MECHANISM OF EVOLUTION

• Evolution needs variations.
• Origin of variation and reason for speciation is inheritable factors influencing phenotype.
• Mendel explained the influence of inheritable actors on phenotype.
• Darwin mentioned that natural selection is the reason for evolution
• Hugo de Vries based on his work on evening primrose believe that mutation causes evolution.
• Evolution for Darwin was gradual while de Vries believed that mutation caused speciation and hence called it

fig. evening primrose