The Banded butterflyfish (Chaetodon striatus) is a member of the butterflyfish family (Family Chaetodontidae) that lives on coral reefs in the Western Atlantic Ocean and...
CactusLast Updated on 2015-04-08 23:49:44Cactus is a family of plants that are specially adapted to survive arid conditions, most often having leaves reduced to spines, and succulent characteristics. The scientific family name Cactaceae is applied to this group comprising 121 different genera. This plant family is concentrated in the Americas and has a surprisingly broad latitude range in both the Northern and Southern Hemispheres.
A considerable number of cacti species are threatened, chiefly due to habitat loss to agriculture, trampling by illegal human immigration into the southwestern USA, large-scale desert solar power projects, as well as overcollecting.
The cactus family is generally considered native to the Americas. A notable exception is Mistletoe cactus, Rhipsalis baccifera, which is thought to have spread, fairly recently, from the American tropics to the subtropics and the deserts of the... More »
BiogeographyLast Updated on 2014-11-30 22:10:52Biogeography is the study of the spatial distribution of biological organisms. The scale of analysis ranges from very small micro-topography regimes to continental dimensions. Fundamental concepts in this field of study are the nature of barrier formation and response of species in their patterns of travel and migration; in particular, the presence of rivers, mountain ranges, deserts and other natural boundaries are examples of large scale barriers. Besides such major landform barriers, there are soil, topographic and meteorological factors that influence the distribution of each species. In the case of smaller scale regimes that are applicable for some bacteria or limited range plant species, there are often very restricted niches; for example, certain bacteria extremophiles may be limited to such localized features as small geyser pools, and some rare plants may have a single extant... More »
Species range limitsLast Updated on 2014-11-09 18:49:44Species range limits (SRLs) are defined as the spatial boundaries beyond which no living individuals of a given species occur. Populations occurring near or at SRLs are often referred to as “marginal,” “peripheral,” “edge,” or “border” populations. SRLs may represent areas beyond which individuals cannot physiologically tolerate ecological conditions or areas where they have not yet dispersed. SRLs may be stable (i.e., at equilibrium) or may represent areas where range expansion through migration or population growth is in the process of occurring. SRLs are significant to ecology, evolution, and conservation for several reasons. They provide opportunities to understand the conditions under which populations expand or contract, and the conditions under which populations may evolve new forms. Additionally, SRLs... More »
Umbrella speciesLast Updated on 2014-11-09 18:40:24
The concept of an umbrella species has been used by conservation practitioners to provide protection for other species using the same habitat as the umbrella species. As the term implies, a species casts an “umbrella” over the other species by being more or equally sensitive to habitat changes. Thus monitoring this one species and managing for its continued success results in the maintenance of high quality habitat for the other species in the area. Animals identified as umbrella species typically have large home ranges that cover multiple habitat types. Therefore, protecting the umbrella species effectively protects many habitat types and the many species that depend on those habitats. Although the effectiveness of this conservation approach is debated, it is often used by practitioners to select a minimum size for protected... More »
PlantLast Updated on 2014-10-28 12:04:37
A plant is any one of the vast number of organisms within the biological kingdom Plantae; in general, these species are considered of limited motility and generally manufacture their own food. They include a host of familiar organisms including trees, forbs, shrubs, grasses, vines, ferns, and mosses. Conventionally the term plant implies a taxon with characteristics of multicellularity, cell structure with walls containing cellulose, and organisms capable of photosynthesis. Modern classification schemes are driven by somewhat rigid categorizations inherent in DNA and common ancestry.
Throughout most of the history of science from Aristotle to Linnaeus and into the 20th century, species were divided into two kingdoms: animals and plants. Driven by DNA characterizations and other modern analysis, fungi and bacteria have now been removed to separate kingdoms; in particular,... More »
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