Commensalism: One partner living on the other with no obvious effect on the second. Parasitism: One partner living on the other with detrimental effect on the second. Mutualism (symbiosis in a strict sense): Advantages for both partners.
Predation Versus Parasitism Predators get their food from prey, but they do not take up residence on or in the prey.
Parasites get their food from hosts, and they live on or in the host for a good part of their life cycle; they may or may not kill the host. Common flea Heart worm
What type of symbiosis? Commensalism Parasitism
What type of symbiosis? Mutualism Parasitism Rhyzobia on plant roots
Dynamics of Predator-Prey Interactions Many of the adaptations of predators and their victims arose through coevolution. The dynamics depend on: the carrying capacity of prey population in the absence of predation, the reproductive rates of the prey and predator, the behavioral capacity of the individual predators to respond to prey density.
Carrying Capacity number of individuals who can be supported in a given area within natural resource limits Limiting factors -cause population growth to decrease Food availability Human disturbances Predation Disease
Example of a Limiting Factor In mountainous regions and high latitudes, timberline is the limit of tree growth. Trees cannot grow above the high timberline because water remains frozen at the low temperature for most of the year. In this case, timberline, or more specifically, temperature is the limiting factor for tree density and distribution.
ExponentialGrowth -unlimited resources, continuous growth Logistic Growth- carrying capacity of 700 cells is reached