Other than domesticated animals killed for consumption by other persons involved in that concerned career, if a number of animals, as a whole, are taken their lives by humans, the balance of ecosystem would be greatly debilitated. Carnivores, herbivores, and omnivores have to depend on each other on the basis of food chain. Nevertheless, due to an increase of advanced technology and a number of growing population, we are infringing and disturbing the ecosystem by default. At least killing tiny pests by all means can have a negative chain impact on the ecosystem. For instance, if we intend to kill any kinds of pests or bugs by using pesticides, such as DDT, the toxic residues of this chemical will fall to the ground and is dissolved into the river, and then the plankton collects this DDT, which will then be eaten by the fish. Afterwards, the birds will be exposed to this toxin by eating fish in turn. Finally, the ecosystem will be detrimental to all kinds of creatures on earth. Another example related to this cause is hunting animals for their skins or furs, which is usually illegal. Killing these rare animals means destroying the food chains as well. When some types of animals such as bears or tigers are hunted in a vast number, other types of creatures would be increasing at an imbalanced rate. This imbalanced condition is very dangerous for the whole animals including humans and nature. The number of deer population can increase drastically if the tigers in the wild are hunted for their fur. Then the leaves and plants in the forest will be surprisingly depleted successively. So, the whole environment will get negatively impacted by these cruel acts.