2“Just as populations contain interacting members of a single species, communities contain interacting populations of many species.” – Holt Modern Biology – Ch 20
3Probably the most interesting predatory aspects is that of the Lizardfish / Goby interaction. The lizardfish that prey on gobies are not much larger than the food they eat. In fact, a 5 cm lizardfish can eat a 3 cm Hawaiian Shrimp Goby!
4PredationIn predation, an individual of one species, called the predator, eats all or part of an individual of another species, called the prey.Many types of organisms can act as predators or prey.
5A predator’s survival depends on its ability to capture food, but prey’s survival depends on its ability to avoid being captured.
6The predator species (in the illustration below, the Lion (Panthera leo) kills and consumes the prey species (in this case, a Cape Buffalo (Syncerus caffer).
10Plants cannot run away from a predator, but many plants have evolved adaptations that protect them from being eaten.Physical defenses such as sharp thorns, spines, sticky hairs, and tough leaves can make plants more difficult to eat.
14If two species compete for a resource, the result may be a reduction in the number of either species or the elimination of one of them.More often, one species will be able to use a resource more efficiently than the other. As a result, less of the resource will be available to the other species.
15Competition – Anole lizards The Green Anole (Anolis carolinensis) is native to the southern United States In the 1960's, The Brown Anole (Anolis sagrei) was introduced from Cuba.The two species vie for habitat and food resources, and it appears that the exotic Brown Anole has displaced the native Green Anole in some physical spaces, such as lower shrubbery and grass.The Green Anole generally lives higher up in the trees and foliage than the Brown Anole does. This result of competition is known as resource partitioning.
16SymbiosisA symbiosis is a close, long-term relationship between two organisms.Three examples include:parasitismmutualismand commensalism
17ParasitismParasitism is similar to predation in that one organism, called the host, is harmed and the other organism, called the parasite, benefitsascarustapeworm
19MutualismMutualism is a relationship in which two species benefit from each other.Some of these relationships are so close, that neither species can survive without the other. (It is sometimes called obligate mutualism - Ex:termite and trichonympha)
20The Clown Fish and its Sea Anemone partner both benefit from the relationship: The fish gets a safe home that protects him from predators, and he fiercely protects his sea anemone. He also feeds the anemone. (It is also called Protocooperation because each can survive without the other.)
22Pollination is one of the most important mutualistic relationships on Earth.
23Ants & Acatia Trees in Central America. The ants live in the thorns and gain food from the acacia. The ants defend the acatia from insect herbivores.
24CommensalismCommensalism is an interaction in which one species benefits, and the other species is not affected. (from english “sharing of food” or from latin “sharing a table”)Originally, the term was used to describe the use of waste food by second animals (scavengers), like the carcass eaters that follow hunting animals, but wait until they have finished their meal.
25Cattle egrets eat insects and lizards that are forced out of hiding by the movement of Cape buffaloes in Tanzania. (The birds occasionally feed on ectoparasites on thebuffalo, but generally the buffalo do not benefit from the egrets)