Biophysics is the application of physics and physical chemistry to biological systems. The field is often confined within the molecular biology realm, but it is equally valid at macroscopic scales when considering aspects of organism transport on land, in the atmosphere and in water.
Molecular biophysics addresses cellular physical chemistry such as interactions between DNA, RNA and protein biosynthesis, including regulation of these functions. Moreover, within this province are organism tissue studies including osmotic motion at the root/ soil interface;stomatal gas exchange in plants; alveoli gas exchange in animals; and electromagnetic aspects of neuron. Technology used in molecular biophysics includes electron microscopy, x-ray crystallography, nuclear magnetic resonance and polarized light spectroscopy.
At a macroscopic level, biophysics is concerned with quantification of organism morphology and fitness. Thus, measurement of animal movement (velocity and acceleration) and body mass are fundamental in assessing fitness. Seed dispersal is concerned with the ability of seeds to achieve significant airborne buoyancy and range. The entire subject of animal flight is a valid subject of biophysics; moreover, the subjects of organism fluid buoyancy and swimming fitness are central in analyzing aquatic organism fitness.
A virus is a microscopic organism that can replicate only inside the cells of a host organism. Most viruses are so tiny they are only observable with at least a conventional...
Successional Soils: How edaphic conditions change within aggrading forests in a case study of the North Carolina PiedmontLast Updated on 2014-06-30 15:03:45
Soil composition—its abiotic physical and chemical properties—changes under an aggrading forest. Through "space for time studies" in the Piedmont of North Carolina, researchers have examined changes in soil composition and processes among three successional stages of old fields. Differences in nitrification rates, nutrient concentration, and acidity indicate that soil nutrient availability decreases during the course of forest succession.
The characteristics of forest change are highly interconnected with changes in soil conditions through time. A positive relationship exists between species richness and soil nutrient availability. Organisms can change the chemical composition of the soil, which in turn influences the forest composition. For example, some species of trees and other plants decrease soil pH while others increase nitrogen availability. Much... More »
Top-down controlLast Updated on 2014-06-23 17:39:31
All organisms require energy and nutrients in some form to survive and grow. Thus, the existence and total biomass of ecosystems are ultimately regulated from the "bottom up", that is, by availability of resources such as sunlight, inorganic nutrients, water and other abiotic factors. Nevertheless, on more localized scales, the abundances of organisms at lower trophic levels can be strongly affected by their own predation, that is, by top-down control. Ecosystems often have been assumed to be controlled from the bottom-up, wherein nutrients and light stimulate primary production by plants, and the greater primary production in turn supports more animal production at higher trophic levels. But this is not the whole story. A simple way to envision top-down control is as follows: because the predator eats prey, the prey population is reduced, so when predators are removed,... More »
Counter current exchangeLast Updated on 2014-06-19 15:47:30Counter current exchange is the mechanism by which some property of a fluid, such as heat or a chemical substance, is transferred from one fluid across a semi-permeable membrane or thermally conductive material to another fluid flowing in the opposite direction. The general requirements for counter current exchange are (1) that two fluids flow in close proximity to each other and (2) that the fluids flow in opposite directions. The purpose of counter current exchange is to maintain a concentration gradient between the two fluids in order to maximize movement from one fluid to the other. The opposite of counter current exchange occurs in concurrent exchange when two fluids flow in the same direction.
The principle of counter current exchange can be illustrated using fish gills. In the gills, oxygen diffuses from an area of high concentration, the water, into an area of lower... More »
Coral bleachingLast Updated on 2014-05-12 12:51:51Coral bleaching is the reduction of intracellular endosymbionts in living coral reefs either via loss or expulsion of algal pigmentation. The symbiotic relationship between coral and zooxanthellae is directly related to coral bleaching. When this relationship fails, and the zooxanthellae do not receive required inputs from the coral or vice-versa, the zooxanthellae will pale and turn white or be expelled into the water.
The resultant decline in coral health from bleaching is deleterious to the coral ecosystem. Chief drivers for coral bleaching are freshwater dilution, change in pH, marine water pollution, increase in sunlight or alteration of seawater temperature. Particularly widespread water pollution is in the form of marine sedimentation from excessive runoff and discharge of untreated sewage. In addition to these abiotic causes of coral bleaching, the phenomenon of overfishing... More »
Esperance malleeLast Updated on 2014-05-05 17:54:45
WWF Terrestrial Ecoregions Collection
The Esperance mallee is an ecoregion in southwestern Australia amounting to approximately 44,600 squares miles in terrestrial extent. It is classified within the Mediterranean Forests, Woodlands and Shrub biome. About one half of the land area of this ecoregion is currently being used for agriculture, with most of the damage from agricultural clearance having been carried out in government sponsored public works programs.
There are a total of 382 recorded macro-fauna in the Esperance Mallee, including numerous special status birds and reptiles. The semi-arid ecoregion boasts a plethora of snakes, including two endemic squamata; there is also one endemic amphibian species, Neobatrachus albipes, in the Esperance Mallee.
Esperance mallee is an aggregation of the Esperance Plains and Mallee regions of the... More »
Drag and drop the content to change the order of featured content. The top nine will be displayed.