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...
Desert birdsLast Updated on 2013-10-29 21:52:31Deserts are challenging environments. Any organism that makes the desert its home must be able to cope with extreme temperatures and a scarce supply of water. Birds have the obvious advantage of flight which allows many of them to be only temporary visitors stopping off along their migrations, or seasonal inhabitants sticking around to breed during the more favorable seasons and leaving when things get too rough. There are a limited number of bird species that can truly call themselves desert dwellers, living primarily or only in such arid environments and not migrating. These birds possess some fascinating adaptations for dealing with life in the desert. (see: Adaptations of desert birds and mammals)
Organisms living in desert environments face several challenges including (1) obtaining and retaining water, (2) regulating their body temperature, and (3) obtaining and conserving... More »
HerbivoreLast Updated on 2013-10-24 16:24:24A 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 »
Bornean Clouded LeopardLast Updated on 2013-09-30 23:00:04The Bornean clouded leopard (Neofelis diardi), or Sundaland clouded leopard, is a medium-sized wildcat found on Borneo, Sumatra and the Batu Islands in the Malay Archipelago Its coat is marked with irregularly-shaped, dark-edged ovals which are said to be shaped like clouds, hence its common name. Though scientists have known of its existence since the early 19th century, it was positively identified as being a distinct species in its own right in 2006, having long been believed to be a subspecies of the mainland Clouded Leopard (Neofelis nebulosa). WWF quoted Dr. Stephen O'Brien of the U.S. National Cancer Institute as saying, "Genetic research results clearly indicate that the clouded leopard of Borneo should be considered a separate species".
Conservation... More »
Coexistence of mesopredators in an intact polar ocean ecosystem: The basis for defining a Ross Sea Marine Protected AreaLast Updated on 2012-09-18 00:00:00
Designation of an effective Marine Protected Area (MPA) requires substantial knowledge of how key wildlife species use the area. Within the Ross Sea, Antarctica, the least altered high seas marine ecosystem on Earth, incredibly large populations of several marine bird and marine mammal species coexist. Understanding how that is possible is a key to maintaining the ecological integrity of the system, the major goal in designating the Ross Sea as an MPA.
Main points of the research
G.Ballard et al documented the environmental niches of nine of the 13 mesopredator species in the Ross Sea. Chief features of the research protocols, findings and applications are:
Species had high environmental niche overlap, but low overlap in horizontal space.
Every five kilometer grid cell in the region was ranked in terms of conservation priority.
Results show that a... More »
Reef crustacean named after Bob MarleyLast Updated on 2012-07-10 00:00:00
President Obama, Stephen Colbert, Elvis Presley, Beyoncé and Bill Gates—each has one. Each of these luminaries has a biological species that has been named after them.
New Coral Reef Crustacean Described and Named
After Late Reggae Performer Bob Marley
Study of new parasitic coral reef species advances understanding of factors influencing disease transmission in oceans.
President Barack Obama has one. Comedian Stephen Colbert has one. Elvis Presley has one. Even computer software magnate Bill Gates has one. And now, Bob Marley--the late popular Jamaican singer and guitarist--also has one. So what is it that each of these luminaries has? The answer: they each have a biological species that has been named after them.
Paul Sikkel, an assistant professor of marine ecology and a field marine biologist at Arkansas State University, discovered and just named... More »
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