Monday, November 16, 2009

Organisms that exhibit the ff: ecological relationship?

1.) mutualism


2.) predation


3.) scavenging


4.) competition


5.) commensalism


6.) parasitism


7.) amensalism





example:tree trunk-----orchid---mutualism





please list down as many as you can in each.......pls!!!

Organisms that exhibit the ff: ecological relationship?
1) MUTUALISM : mutualism is an interaction between two or more species, where both species derive benefit





e.g-


*In the acacia example, certain ants (e.g. Pseudomyrmex spinicola) nest inside the plant%26#039;s thorns. In exchange for food and shelter, ants protect acacias from attack by herbivores and competition from other plants. The ants reduce competition by trimming back vegetation that shades the shrub.





*Some species of ants also %26quot;farm%26quot; aphids, protecting them on the plant they eat, and eating the honeydew that the aphids secrete.





*A famous land version of symbiosis is the relationship of the Egyptian Plover bird and the crocodile. In this relationship, the bird is well known for preying on parasites that feed on crocodiles. To that end, the crocodile openly invites the bird to hunt on its body, even going so far as to open its jaws to allow the bird enter the mouth safely to hunt-literally plucking leeches from its gums. For the bird, this relationship not only is a ready source of food, but a safe one considering that few predator species would dare strike at the bird at such proximity to its host.





*Many plants will function in a voluntary mutualistic relationship as companion plants, providing each other with shelter, fertilization, the repelling of pests, et cetera. For example, beans may grow up cornstalks as a trellis, while fixing nitrogen in the soil for the corn, as exploited in the three sisters gardening technique.





2)PREDATION : predation describes a biological interaction where a predator organism feeds on another living organism or organisms known as prey.


e.g -


*Lion hunting buffalo, deer, wilbeest


*Baleen whales, eat millions of microscopic plankton at once, the unicellular prey being broken down well after entering the whale.


*Hunting by cat family members and other carnivores





3)Scavenging : it is consumption of already dead animals


e.g -


*raven feeding on dead fish


*vultures feeding on carrions


*hyneas feeding on carrions





4)COMPETITION : Competition within and between species is an important topic in biology, specifically in the field of ecology. Competition between members of a species (%26quot;intraspecific%26quot;) is the driving force behind evolution and natural selection; the competition for resources such as food, water, territory, and sunlight results in the ultimate survival and dominance of the variation of the species best suited for survival. Competition is also present between species (%26quot;interspecific%26quot;). A limited amount of resources are available and several species may depend on these resources. Thus, each of the species competes with the others to gain the resources.


e.g -


*a smaller tree will receive less sunlight from an adjacent tree that is larger than it in a rain forest. The larger tree is competing with the smaller one


* in a forest if it is occupied by more than one predator, they will compete with each other for getting prey





5) Commensalism : relationship between two living organisms where one benefits and the other is neither harmed nor helped.


e.g -


*use of waste food by second animals, like the carcass eaters who follow hunting animals, but wait until they have finished their meal.


*few bacteria live in our gut wall but do not harm us and they get nutition from the food we eat





6) Parasitism : one organism, usually physically smaller of the two (the parasite) benefits and the other (the host) is harmed.


e.g -


*Many endoparasites acquire hosts by gaining entrance to their tissue; others enter the host when it consumes certain raw foods, as in the case of the nematode Ascaris lumbricoides, an endoparasite of the human intestine. A. lumbricoides produces large numbers of eggs which are passed from the host%26#039;s digestive tract and pancreas into the external environment, relying on other humans to inadvertently ingest them in places without good sanitation


*Some aquatic leeches, for example, locate hosts by sensing movement and then confirm their identity through skin temperature and chemical cues before attaching


*Parasitoids are parasites that use another organism%26#039;s tissue for their own nutritional benefit until the host dies from loss of needed tissues or nutrients. Parasitoids are also known as necrotroph.


*In contrast, Biotrophic parasites cannot survive in a dead host and therefore keep their hosts alive. Many viruses, for example, are biotrophic because they use the host%26#039;s genetic and cellular processes to multiply





7)Amensalism : is a biological interaction between two species in which one impedes or restricts the success of the other without being affected positively or negatively by the presence of the other.


e.g -


*penicillium secrete penicillin, a chemical that kills bacteria. *black walnut tree (Juglans nigra), which secrete juglone, a chemical that harms or kills some species of neighboring plants, from its roots.


*Antibiosis or allelopathy also explain similar interactions.


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