A species that will destroy itself due to unchecked technological advancement.
Humans have a level of intelligence sufficient enough for them to discover how to exploit environmental resources, leading to a subsequent increase in population. This increase in population requires more exploitation of environmental resources, leading to another population increase, resulting in a feedback
loop of overpopulation and significantly altering the environment. As competition is naturally selected for its success in securing resources and reproduction, the human species is instinctually inclined to fight over resources, whether it be land,
water, shelter,
food, or mates. As
humans discover how to extract more energy from resources, this fighting over resources, or war as we call it in modern times, gets more and more brutal as
time goes on, going from arrows to
guns to dynamite to atomic and thermonuclear warheads, to name a few examples. Overall, as
humans become more advanced, they will not only lead to the suffering of their brethren, they will lead to the suffering of life all across the globe in their destruction of it.