Similarities And Differences Between Lamarck And Darwin

The cave fish is a curious object of study. One of which has many scientist rushing to discover exactly why this fish developed that cannot see. The cave fish live in dark caves and have evolved to life without vision. Both Lamarck and Darwin had excellent theories about evolution. Darwin believed that natural selection had the biggest impact on the evolution of a species. Darwin theorized each population had variations, these variations caused the individual to either have a greater or lesser chance of survival. The individual that had the disadvantaged genes would be less likely to live or reproduce and therefore be killed off by predators, or lack offspring. Those that had characteristics more suited for the environment were more likely to live and mate, therefore passing their genes onto the next generation.

Lamarck however held the belief that if you don’t use it you lose it, or more commonly called use and disuse theory. The idea that the characteristics used most by the species will grow stronger and these strengths will be passed on to successive generations. Those traits that were used less would get progressively less pronounced, eventually disappearing completely if they are not needed. But Lamarck also held the idea of acquired characteristics. The evolution of giraffes is a common example of this theory. Lamarck theorized at

Consequently, a mutation in a pleiotropic gene may have an effect on some or all traits simultaneously. An example is phenylketonuria, a human disease that affects multiple systems but is caused by one gene defect” (google) Pleiotropic genes that effect more than one trait may be to blame for the loss of vision in the cave fish. It is evident a change in the pleiotropic gene responsible for the eye size and the size of taste buds has been responsible for the shrinkage of the eye and the enhancement of the olfactory