Which of the following is an example of natural selection? A. Two species of cichlid become less and less alike in the lake environments they both share B. A variety of dogs are bred for their ability to hunt animals that dwell in the ground C. Peacocks are selected for mating by females due to their bright plumage. D. The venom of a certain salamander species becomes more poisonous as predation by snakes increases. E. Sharks and dolphins share similar body shape and living environments
Hint: In order to first arrive at the correct answer one must know the true meaning of natural selection. In simple words, nature selects the best fit of the species in consideration to make it survive and reproduce. Let us look at the whole concept in the answer.
Complete answer: The theory of natural selection was proposed by Charles Darwin. For example let us consider two bacterial species growing in a culture media. When abundant nutrients are present, they grow and divide well. But when the nutrient is diminishing these two bacterial species fight among them for survival. This leads to the death of one of the bacterial species. The species which survives the competition and the fight for survival has actually depicted the survival of the fittest. Thus it lives and continues to grow and divide by giving rise to more stronger individuals. From the above mentioned options it is seen that as the predation of snake increases, the venom of certain salamander species becomes more poisonous. The salamander species becomes more poisonous so as to combat the increase in the predation of snakes. This depicts the true meaning of natural selection.
So, the correct answer is option D The venom of a certain salamander species becoming more poisonous as predation by snakes increases.
Note: There are generally weak and healthy people in a population. As a disease strikes, the healthy people and the weak people both fall sick but the healthy people recover fast and most of the weak people die or some survive. This is designed in such a manner so that only the healthy population is carried forward eliminating the weak individuals.