I don’t see any labels, but remember that humans are a great example of a k-selected species. High rates of parental care leads to high survivorship of offspring, and thus negates the need to have large amounts of offspring.
R-selected species are quite the opposite. They produce large amounts of offspring at many intervals in an attempt to maximize survivorship, as they don’t have strong parental involvement with their young. Think of insects.
The terrestrial food web is a food web that is characterized by all land animals and is largest terrestrial food chain on earth as the farmer tends to introduce a rat poison in this food web the rat may get killed by the medicine but if the same rate may be eaten by a snake the poison that killed the rat may infect the snake.
Hence the pollutant may climb up the ladder and intoxicate the hawk that depends on small animal for prey which may be further eaten by a man or other animal like a cat may then spread this disease or the infection to other upwards in the food chain and thus the process of Biomagnification takes place in the ecosystem.