Friday, 29 February 2008

Lantern Fishes


Lantern Fishes

Kingdom:

Animalia

Phylum:
Chordata

Class:
Actinopterygii

Order:
Myctophiformes

Family:
Myctophidae

Lanternfishes are small, deep sea fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, having a circumglobal distribution. They are aptly named after their conspicuous use of bioluminescence. Their sister family, the Neoscopelidae, is much fewer in number but superficially very similar; at least one neoscopelid shares the common name 'lanternfish': The large-scaled lantern fish, Neoscopelus macrolepidotus.
Sampling via deep trawling indicates that, together with the bristlemouths (Gonostomatidae) and lightfishes (Phosichthyidae), lanternfish account for as much as 90% of all deep sea fish biomass. Indeed, lanternfish are among the most widely distributed, populous, and diverse of all vertebrates, playing an important ecological role as prey for larger organisms. With an estimated global biomass of 550 - 660 million metric tonnes, several times the entire world fisheries catch, lanternfish also account for much of the biomass responsible for the deep scattering layer of the world's oceans. In the Southern Ocean, Myctophids provide an alternative food resource to krill for predators such as squid and the King Penguin. Although plentiful and prolific, currently only a few commercial lanternfish fisheries exist: These include limited operations off South Africa, in the sub-Antarctic, and in the Gulf of Oman.
Myctophid morphology is typified by a slender, compressed body covered in small, silvery deciduous cycloid scales (ctenoid in four species), a large bluntly rounded head, large elliptical to round lateral eyes (dorsolateral in Protomyctophum species), and a large terminal mouth with jaws closely set with rows of small teeth. The fins are generally small, with a single high dorsal fin, an adipose fin, and an anal fin—supported by a cartilaginous plate at its base—originating under or slightly behind the posterior end of the dorsal fin; the caudal fin is forked. The pectoral fins, usually with eight rays, may be large and well-developed to small and degenerate, or completely absent in a few species; the pectorals are greatly elongated in others, such as Lampanyctus species. The gas bladder is present in most lanternfish, but it degenerates or fills with lipids during the maturation of a few species. The lateral line is uninterrupted.
Lanternfish are well-known for their diel vertical migrations: during daylight hours most species remain within the gloomy bathypelagic zone, between 300 – 1,200 m depth; but towards sundown the fish begin to rise into the epipelagic zone, between 10 and 100 m depth. The lanternfish are thought to do this in order to avoid predation, and because they are following the diel vertical migrations of zooplankton upon which the lanternfish feed. After a night spent feeding in the surface layers of the water column, the lanternfish begin to descend back into the lightless depths and are gone by daybreak. Most species remain near to the coast, schooling over the continental slope. Different species are known to segregate themselves by depth, forming dense, discrete conspecific layers — this is believed to be a means of avoiding interspecies competition. Due to the lanternfishes' gas bladders, these layers are visible on sonar scans and give the impression of a "false bottom": this is the so-called deep-scattering layer that so perplexed early oceanographers.
It should be noted that there is great variability in migration patterns within the family. Some deeper-living species may not migrate at all, while others may do so only sporadically. Migration patterns may also be dependent on life history stage, sex, latitude, and season.
The arrangements of lanternfish photophores are different for each species, so it is assumed that their bioluminescence plays a role in intraspecies communication, specifically in shoaling and courtship behaviour. The concentration of the photophores on the flanks of the fish also indicate the light's use as camouflage: in a strategy termed counterillumination, the lanternfish regulate the brightness of the bluish light emitted by their photophores to match the ambient light level above, effectively masking the lanternfishes' silhouette when viewed from below.
A major source of food for many marine animals, lanternfish are an important link in the food chain of many local ecosystems, being heavily preyed upon by cetaceans, including whales and dolphins; large pelagic fish such as tuna and sharks; grenadiers and other deep-sea fish (including other lanternfish); pinnipeds; sea birds, notably penguins; and large squid such as the jumbo squid, Dosidicus gigas.

Saturday, 23 February 2008

Endangered Species

Asian Arowana ->
Loggerhead Sea Turtle ->
Endangered Species



An endangered species is a population of an organism which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters. An endangered species is usually a taxonomic species, but may be another evolutionary significant unit. The World Conservation Union (IUCN) has calculated the percentage of endangered species as 40 percent of all organisms based on the sample of species that have been evaluated through 2006. (Note: the IUCN groups all threatened species for their summary purposes.) Many nations have laws offering protection to these species: for example, forbidding hunting, restricting land development or creating preserves. Only a few of the many species at risk of extinction actually make it to the lists and obtain legal protection. Many more species become extinct, or potentially will become extinct, without gaining public notice.
The conservation status of a species is an indicator of the likelihood of that endangered species not living. Many factors are taken into account when assessing the conservation status of a species; not simply the number remaining, but the overall increase or decrease in the population over time, breeding success rates, known threats, and so on. The IUCN Red List is the best known conservation status listing.
Internationally, 189 countries have signed an accord agreeing to create Biodiversity Action Plans to protect endangered and other threatened species. In the United States this plan is usually called a species Recovery Plan.
IUCN Red List of Threatened Species uses the term endangered species as a specific category of imperilment, rather than as a general term. Under the IUCN Categories and Criteria, endangered species is between critically endangered and vulnerable. Also critically endangered species may also be counted as endangered species and fill all the criteria
The more general term used by the IUCN for species at risk of extinction is threatened species, which also includes the less-at-risk category of vulnerable species together with endangered and critically endangered.
Some endangered species laws are controversial. Typical areas of controversy include: criteria for placing a species on the endangered species list, and criteria for removing a species from the list once its population has recovered; whether restrictions on land development constitute a "taking" of land by the government; the related question of whether private landowners should be compensated for the loss of use of their land; and obtaining reasonable exceptions to protection laws.
Being listed as an endangered species can have negative effect since it could make a species more desirable for collectors and poachers. This effect is potentially reduce-able, such as in China where commercially farmed turtles may be reducing some of the pressure to poach endangered species.
Another problem with listing species is its effect of inciting the use of the "shoot, shovel, and shut-up" method of clearing endangered species from an area of land. Some landowners currently may perceive a diminution in value for their land after finding an endangered animal on it. They have allegedly opted to silently kill and bury the animals or destroy habitat, thus removing the problem from their land, but at the same time further reducing the population of an endangered species. The effectiveness of the Endangered Species Act, which coined the term "endangered species", has been questioned by business advocacy groups and their publications, but is nevertheless widely recognized as an effective recovery tool by wildlife scientists who work with the species. Nineteen species have been delisted and recovered and 93% of listed species have a recovering or stable population.

Some endangered animals:
- Island Fox
- Sea Otter
- American Bison
- California Condor
- Loggerhead Sea Turtle
- Santa-Cruz Long-Toed Salamander
- Asian Arowana

Friday, 22 February 2008

Devil Frog



Devil Frog


Beelzebufo ampinga was a particularly large species of prehistoric frog first identified in 2007. Common names assigned by the media include "Devil Frog", "Devil Toad", and "the Frog from Hell". Fossils of Beelzebufo have been recovered from strata dating to the late Cretaceous Period, some 70 million years ago.

The generic name Beelzebufo is a portmanteau of Beelzebub (a Semitic deity sometimes identified as one of the chief lieutenants, or persona of the Judeo-Christian Devil) and bufo (Latin for "toad"). The specific name ampinga means "shield" in Malagasy, the national language of Madagascar.

The species may have grown to over 40 cm (16 in.) and four kg (10 lb.) — larger than any living frogs, including the largest known species, the goliath frog, which can be up to 32 cm (12.5 in.).

Although Beelzebufo appears to have lived in what is now Madagascar, it superficially resembled its closest living relatives, the horned toads of South America, marketed as pacman frogs in the United States pet trade. Modern pacman frogs grow to 15 cm (6 in.) long.
Richard Lane, program director in NSF's Division of Earth Sciences, said "The occurrence of this frog in Madagascar and its relatives' existence in South America provides strong evidence that the supercontinent Gondwana 'disassembled' during the latest part of the Cretaceous."

In comparison with the living horned frogs, Beelzebufo was a rapacious predator that would have attacked any animal that could fit into its capacious mouth, and would have been capable of eating relatively large prey, perhaps even juvenile dinosaurs. Beelzebufo was probably a dry-land frog, living in arid environments and ambushing prey.
The first fossil fragments were found in 1993 by David W. Krause of New York's Stony Brook University, but it took 14 years for scientists Susan E. Evans, Marc E. H. Jones, and Krause to assemble enough data for publication in the Proceedings of the National Academy of Sciences, the journal of the United States National Academy of Sciences. Some 75 fossil fragments have been found. Researchers have been able to reconstruct parts of the frog's skeleton, including nearly the entire skull.

Sunday, 17 February 2008

The Bug's Life (Sparing Times Edition)




Sparing Times




See from your nearest sight, then their lifes will look beautiful. Spare a little of times to see, and maybe they will give something useful. It's a truth that there are only few peoples that look at the insect that share life space with us. But, in fact, they make the gardens and parks as living places for themselves.

Global Warming


Global Warming

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation.

The global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 100 years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" via the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by at least 30 scientific societies and academies of science,
including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.

Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century.
The range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.

Increasing global temperature will cause sea level to rise, and is expected to increase the intensity of extreme weather events and to change the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors.


Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.

Cell


Cell


The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is sometimes called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg. In 1837 before the final cell theory was developed, a Czech Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.


All cells have several different abilities:
-Reproduction by cell division: (binary fission/mitosis or meiosis).
-Use of enzymes and other proteins coded for by DNA genes and made via messenger RNA intermediates and ribosomes.
-Metabolism, including taking in raw materials, building cell components, converting energy, molecules and releasing by-products. The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy is released and then used in metabolic pathways.
-Response to external and internal stimuli such as changes in temperature, pH or levels of nutrients.
-Cell contents are contained within a cell surface membrane that is made from a lipid bilayer with proteins embedded in it.


There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually independent, while eukaryotic cells are often found in multicellular organisms.

Saturday, 16 February 2008

Mushroom



Mushroom


A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus, hence the word mushroom is most often applied to fungi (Basidiomycota, Agaricomycetes) that have a stem (stipe), a cap (pileus), and gills (lamellae, sing. lamella) on the underside of the cap just as do store-bought white mushrooms.

However, "mushroom" can also refer to a wide variety of gilled fungi, with or without stems, and the term is used even more generally to describe both the fleshy fruiting bodies of some Ascomycota and the woody or leathery fruiting bodies of some Basidiomycota, depending upon the context of the word. Forms deviating from the standard form usually have more specific names, such as "puffball", "stinkhorn", and "morel", and gilled mushrooms themselves are often called "agarics" in reference to their similarity to Agaricus or their placement in the order Agaricales. By extension, "mushroom" can also designate the entire fungus when in culture or the thallus (called a mycelium) of species forming the fruiting bodies called mushrooms.

Identifying mushrooms requires a basic understanding of their macroscopic structure. Most are Basidiomycetes and gilled. Their spores, called basidiospores, are produced on the gills and fall in a fine rain of powder from under the caps as a result. At the microscopic level the basidiospores are shot off of basidia and then fall between the gills in the dead air space. As a result, for most mushrooms, if the cap is cut off and placed gill-side-down overnight, a powdery impression reflecting the shape of the gills (or pores, or spines, etc.) is formed (when the fruitbody is sporulating). The color of the powdery print, called a spore print, is used to help classify mushrooms and can help to identify them. Spore print colors include white (most common), brown, black, purple-brown, pink, yellow, and cream, but almost never blue, green, or red.

While modern identification of mushrooms is quickly becoming molecular, the standard methods for identification are still used by most and have developed into a fine art harking back to medieval times and the Victorian era, combined with microscopic examination. The presence of juices upon breaking, bruising reactions, odors, tastes, shades of color, habitat, habit, and season are all considered by mycologists, amateur and professional alike. Tasting and smelling mushrooms carries its own hazards because of poisons and allergens. Chemical spot tests are also used for some genera.

In general, identification to genus can often be accomplished in the field using a local mushroom guide. Identification to species, however, requires more effort; one must remember that a mushroom develops from a button stage into a mature structure, and only the latter can provide certain characteristics needed for the identification of the species. However, over-mature specimens lose features and cease producing spores. Many novices have mistaken humid water marks on paper for white spore prints, or discolored paper from oozing liquids on lamella edges for colored spored prints.

Though mushrooms are thought to be short-lived, the fungus that forms the mushroom fruitbodies can itself be long-lived and massive. A colony of Armillaria ostoyae in Malheur National Forest in the United States is estimated to be 2,400 years old, possibly older, and spans an estimated 2,200 acres. Most of the fungus is underground and in decaying wood or dying tree roots in the form of white mycelia combined with black shoelace-like rhizomorphs that bridge colonized separated woody substrates.