BIOL3007 Lecture Notes - Lecture 9: Dingo Fence, Red Kangaroo, Paramecium
Document Summary
Competition vs. predation: environmental conditions temperature as an example, bottom up availability of resources, top down predation level control distribution and abundance. Evidence of effects of predation: population effects of predation: lab trials with predator-prey protozoa. Lab results show extinctions, only unless prey refuges are available or immigration (of prey) is introduced. This is an unlikely ecosystem in the real world. Lab trials with parasitoid-prey system show stable parasitoid-prey oscillations. Real life example: looked at skunks and their effect on hatching rates of ducklings. You need something to compare your varied factor results with, otherwise you cannot draw conclusions. Nest hatchings doesn"t necessarily translate to population size (perhaps there is not enough food and the hatchlings die etc. ). When you have a closed population, there is a minimum 15% hatchling success needed to ensure population stability. So, the proportion in this experiment doesn"t show population stability.