Predator-prey relationships (that is, neither competitive nor mutualistic relationships) have been seen as providing the necessary stability for almost infinite numbers of species to exist in ecosystems. Such relationships do so by keeping the size of species populations in check at supportable levels.
Stefano Allesina and Si Tang, researchers at the University of Chicago, have studied such relationships. Their recent investigations have noted that, "When prey are high, predators increase and reduce the number of prey by predation. When predators are low, prey decrease and thus reduce the number of predators by starvation. These predator/prey relationships thereby promote stability in ecosystems and enable them to maintain large numbers of species.
By contrast, mutualistic relationships may reinforce the growth of large populations and competitive relationships may depress population numbers to the point of ecological instability."
The term carnivore is used in a variety of ways. The general ecological definition of a carnivore is an organism that feeds on animals, as opposed to feeding...
Spinner dolphinLast Updated on 2014-04-17 17:28:05The Spinner dolphin (Stenella longirostris), a marine mammal in the family of oceanic dolphins, gets its name from the spinning behavior it shows when it leaps out of the water. This cetacean species lives in schools showing a dominance hierarchy and displays complex interactions among individuals. S. longirostris also engages in intricate echolocation underwater acoustics. Spinner dolphins attract tourists for dolphin watching. The species is of special interest for scientific investigation because of its remarkable capacity to learn.
Species:--------Stenella longirostris... More »
OrcaLast Updated on 2014-04-16 15:11:43Orcinus orca, or simply orca, is in fact the largest of the dolphins within the order of cetaceans. This species of marine mammal, also commonly known as the killer whale, is easily identified by its black and white coloration; the underside is white with white patches behind the eyes and a greyish white area called a saddle-patch behind the dorsal fin. The shape of the saddle is unique in each animal, and can help to identify individuals. The dorsal fin is also used to recognize individuals. Male orcas have the tallest dorsal fin known in the animal kingdom, measuring up to six feet high in mature males. Females have shorter, more curved dorsal fins.
Kingdom: Anamalia (Animals)
Class:------ Mammalia... More »
Kalahari xeric savannaLast Updated on 2014-04-15 13:18:17The Kalahari xeric savanna is an ecoregion in southern Africa characterized by a harsh climate, where temperatures may increase by 45°C from night to day, and rainfall is infrequent. Rain falls only during the summer on the reddish-brown Kalahari sands , pelting the savanna with violent, localized storms. Although this area is semi-arid, there is an impressive diversity of migratory birds and large mammals, both herbivorous and carnivorous. A considerable amount (approximately 18 percent) of this ecoregion is protected. Where it is not protected, heavy grazing has degraded the habitat. Fences are a serious problem because they obstruct the migratory routes of ungulates, and they pose significant threats to biodiversity in unprotected areas.
The Kalahari xeric savanna ecoregion stretches across northwestern South Africa, southern Botswana and southeastern Namibia. Most of it... More »
Talamancan montane forestsLast Updated on 2014-03-13 12:44:36
The Talamancan montane forests is an ecoregion situated along the mountainous spine of the Cordillera Talamanca within Costa Rica and Panama. These forests represent one of Central America’s most intactThe condition of an ecological habitat being an undisturbed or natural environment habitats.
The steep slopes, remoteness and relatively cool temperatures have limited the impact of agriculture and human development in most of this area.
This region provides habitat for considerable floral and faunal species diversity, many of which taxa are endemic. Over 30 percent of the ecoregion's flora, including over 10,000 vascular and 4000 non-vascular plant species, are endemic to this area, as are a number of fauna species. Nearly 75 percent of original forest cover remains intact, with forty percent protected by national and international parks.
However, the clearing of... More »
HerbivoreLast Updated on 2014-02-13 16:58:29A herbivore is an animal that obtains its energy and nutrients by feeding on plants. Different types of herbivores eat different plant parts. For example, folivores feed on leaves, frugivores feed on fruits, granivores feed on seeds, pollinivores feed on pollen, and nectarivores feed on nectar. Herbivores can vary greatly in size, ranging from the largest terrestrial animals (elephants) and large marine mammals such as manatees and dugongs to small insects, nematodes and thrips. Herbivores are primary consumers (they receive their energy by consuming primary producers), so they play an important trophic role in ecological communities and food webs.
Because mature leaves are low in nutrients, and difficult to digest because of their high cellulose content, animals use many different strategies to eat leaves. Animals that feed on grass leaves are generally... More »
Drag and drop the content to change the order of featured content. The top nine will be displayed.