In 1926 D'Ancona completed a statistical study of the numbers of each species sold on the fish markets of three ports: Fiume, Trieste, and Venice. His son-in-law, Humberto D'Ancona, was a biologist who studied the populations of various species of fish in the Adriatic Sea. Vito Volterra (1860-1940) was a famous Italian mathematician who retired from a distinguished career in pure mathematics in the early 1920s. However, we will ignore that in our subsequent development. In areas of Canada where lynx died out completely, there is evidence that the snowshoe hare population continued to oscillate - which suggests that lynx were not the only effective predator for hares. To be candid, things are never as simple in nature as we would like to assume in our models. On average, do the peaks of the predator population match or slightly precede or slightly lag those of the prey population? If they don't match, by how much do they differ? (Measure the difference, if any, as a fraction of the average period.).On average, what was the period of oscillation of the hare population?.On average, what was the period of oscillation of the lynx population?.The dominant feature of this picture is the oscillating behavior of both populations. Thus, the Hudson Bay data give us a reasonable picture of predator-prey interaction over an extended period of time. On the other hand, it is reasonable to assume that the success of trapping each species was roughly proportional to the numbers of that species in the wild at any given time. To be sure, trapping for pelts removed large numbers of both species from the populations - otherwise we would have no data - but these numbers were quite small in comparison to the total populations, so trapping was not a significant factor in determining the size of either population. To a first approximation, there was apparently nothing keeping the hare population in check other than predation by lynx, and the lynx depended entirely on hares for food. The following figure (adapted from Odum, Fundamentals of Ecology, Saunders, 1953) shows a plot of that data. Very few such 'pure' predator-prey interactions have been observed in nature, but there is a classical set of data on a pair of interacting populations that come close: the Canadian lynx and snowshoe hare pelt-trading records of the Hudson Bay Company over almost a century. Photo source: Rudolfo's Usenet Animal Pictures Gallery ( copyright disclaimer ).

there is no threat to the prey other than the specific predator.the prey species has an unlimited food supply, and.the predator species is totally dependent on a single prey species as its only food supply,.To keep our model simple, we will make some assumptions that would be unrealistic in most of these predator-prey situations. Which there are exactly two species, one of which - the predators - eats the In this module we study a very special case of such an interaction, in The study of populations that interact, thereby affecting each other's growth The 'carrying capacity' of the environment. In the study of the dynamics of a single population, we typically take intoĬonsideration such factors as the natural' growth rate and Part 1: Background: Canadian Lynx and Snowshoe Hares

Predator vs prey relationship