The egg will smash on the ground, preventing the baby warbler from hatching and competing for precious food. In photograph b the small mama warbler is shown feeding her big baby, the cuckoo. Mama warbler thinks the cuckoo is her baby and tends it faithfully while Mama cuckoo is out seeing the town. Parasitism occurs in any symbiotic relationship where one organism benefits at the expense of another. In addition to symbiosis, species in a community may interact with one another through a predator-prey relationship.
Predators feed on other living organisms - their prey .
The records of the Hudson Bay Company, a fur-trading company that operated in the U.S. and Canada in the 1800's and early 1900's, provide a classic study of the interaction between predator and prey. Hudson Bay operated when furs were a major source of clothing, paying trappers for their pelts. Of interest to biologists are the extensive records the Hudson Bay Company kept from 1845 to 1925. Observe the graph associated with Figure 47.8. Biologists analyzing this data make the assumption that the number of furs traded was proportional to the population of animals at that time.