zoology

Crustacea.

2010-09-16T04:07:00.000-07:00

Crabs, Prawns, Shrimps and Lobsters, but also Woodlice and Barnacles are but a few of the wonderfully diverse members of the group of organisms known as the Crustacea.

The Crustaceans are only the third largest of the great Arthropod subphylla, containing a lower number of species than either the insects or the arachnids. However in terms of diversity of form they exceed both these groups together.

This great flexibility of structure, along with the general successfulness of the Arthropod plan (exoskeleton and jointed limbs) has enabled them to be extremely successful as a group of animals. However it has also made it almost impossible to describe a typical Crustacean.

sea anemones

2010-05-17T12:36:00.000-07:00

Phylum: Cnidaria
Class: Anthozoa
Order: Actiniaria

A sea anemone usually attaches itself to rocks or coral. They have a central mouth which is surrounded by tentacles with nematocysts, stinging cells that paralyze and entangle small marine animals. Sea anemones primarily reproduce sexually: most often, their eggs are fertilized in the gastric cavity, and then their young are released through the mouth temporarily as free-swimming larvae--they soon find somewhere to attach themselves to. A few sea anemones have symbiotic relationships with some hermit crabs; they attach themselves on the shell of the hermit crab (or they are attached by the hermit crab). There are theories that this is beneficial to the hermit crab for protection since the stinging cells on certain sea anemones can be quite potent, and the sea anemone may benefit from scraps of the hermit crab's food that it did not eat. They are the relatives of and sea fans. They exist only in the polyp stage and obtain their food by filter feeding.

sea snake

2010-05-17T12:29:00.000-07:00

Sea snakes are air breathers probably descended from a family of Australian land snakes. They inhabit the tropical waters of the Indo-Pacific and are highly venomous. Thirty-two species have been identified in the waters about the Barrier Reef in Australia. They seem to congregate in certain areas in the region about the swain Reefs and the Keppel Islands, where the olive sea snake (Aipysurus laevis) is a familiar sight.

Sea snakes have specialized flattened tails for swimming and have valves over their nostrils which are closed underwater. They differ from eels in that they don't have gill slits and have scales. Due to their need to breathe air, they are usually found in shallow water where they swim about the bottom feeding on fish, fish eggs and eels.

The yellow-bellied sea snake ( Pelamis platurus ) is pelagic, and is seen on occasions floating in massive groups. Fish that come up to shelter under these slicks provide food for the snakes. Occasionally these yellow-bellies get washed up on beaches after storms and pose a hazard to children.

Aggressive only during the mating season in the winter, the sea snake is very curious, and they become fascinated by elongated objects such as high pressure hoses. Advice here is to inflate your BC so as to lift away from the bottom and the snake. Provoked snakes can become very aggressive and persistent --requiring repeated kicks from the fins to ward them off.

Persistent myths about sea snakes include the mistaken idea that they can't bite very effectively. The truth is that their short fangs (2.5-4.5mm) are adequate to penetrate the skin, and they can open their small mouths wide enough to bite a table top. It is said that even a small snake can bite a man's thigh. Sea snakes can swallow a fish that is more than twice the diameter of their neck.

Most sea snake bites occur on trawlers, when the snakes are sometimes hauled in with the catch. Only a small proportion of bites are fatal to man, as the snake can control the amount of envenomation, a fact probably accounting for the large number of folk cures said to be 95% effective.

algae

2010-05-15T23:17:00.000-07:00

The classification of algae into taxonomic groups is based upon the same rules that are used for the classification of land plants, but the organization of groups of algae above the order level has changed substantially since 1960. using electron microscopes has demonstrated differences in features, such as the flagellar apparatus, cell division process, and organelle structure and function, that are important in the classification of Similarities and differences among algal, fungal, and protozoan groups have led scientists to propose major taxonomic changes, and these changes are continuing.

Division-level classification, as with kingdom-level classification, is tenuous for algae. For example, some phycologists place the classes Bacillariophyceae, Phaeophyceae, and Xanthophyceae in the division Chromophyta, whereas others place each class in separate divisions: Bacillariophyta, Phaeophyta, and Xanthophyta. Yet, almost all phycologists agree on the definition of the respective classes Bacillariophyceae, Phaeophyceae, and Xanthophyceae.

The classes are distinguished by the structure of flagellate cells (e.g., scales, angle of flagellar insertion, microtubular roots, and striated roots), the nuclear division process (mitosis), the cytoplasmic division process (cytokinesis), and the cell covering. Many scientists combine the Micromonadophyceae with the Pleurastrophyceae, naming the combined group the Prasinophyceae. “Phylum” and “division” represent the same level of organization; the former is the zoological term, the latter is the botanical term

Properties of Major Algal Taxonomic Groups

S.No

Taxonomic Group

Chlorophyll

Carotenoids

Bilo

proteins

Storage products

Flagellation &Cell structure

Bacillariophyta

a, c

β-carotene

± -carotene rarely fucoxanthin,.

Chrysolaminarin

oils

1 apical flagellum in male gametes:

cell in two halves with elaborate

markings.

Chloro

phycophyta

(green algae)

a, b

β-carotene,

± -carotene

rarely carotene

and lycopene,

lutein.

Starch, oils

1,2,4 to many,

equal, apical or

subapical flagella.

Chrysophycophyta

(golden algae)

a, c ,

β-carotene,

fucoxanthin

Chrysolaminarin

oils

1 or 2 unequal, apical flagella, in some, cell surface covered by characteristic scales.

Cyanobacteria

(blue green algae)

a,c

β-carotene,

phycobilins

Phaeco

phycophyta

(brown algae)

a,c

β-carotene, ±

fucoxanthin,

violaxanthin

Laminarin, soluble

carbohydrates, oils

2 lateral flagella

Dinophyta

(dinpflagellates)

a,c

β-carotene,

peridinin,

neoperididnin

dinoxanthin,

neodinoxanthin.

Starch, oils

2 lateral, 1 trailing,1 girdling flagellum, in most, there

is a longitudinal

and transverse

furrow and angular plates.

Rhodo

phycophyta

(red algae )

a, rarely d

β-carotene, zeaxanthin

± β carotene

Phyco

erythrin

phyco

cyanin

Floridean starch

oils

Flagella absent

corals

2010-05-15T23:16:00.001-07:00

Coral reefs aren't just beautiful and rich in species. They also have long served as an evolutionary wellspring for countless types of marine life, even groups such as clams and snails that researchers thought had originated in shallow coastal waters. That's the conclusion of a new examination of the fossil record, and the findings reinforce the idea that evolutionary potential is linked to the environment.

Coral reefs are well-known hot spots for biodiversity, but scientists have assumed that many types of reef-dwelling animals had migrated from other ecosystems, such as shallow coastal waters. Paleontologist and lead author Wolfgang Kiessling of the Museum für Naturkunde in Berlin initially shared that assumption. But spurred by older studies of reefs and hints from the genetics of fishes, he took a closer look.

In 2000, Kiessling and two colleagues began to study fossils of sea-bottom-dwelling animals. Poring over the scientific literature and contributing field results of their own, they compiled records of organisms from around the world and dating back 540 million years--most of the history of multicellular life. "We thought that only an all-embracing study would answer our question [of whether] reefs are general cradles of evolution," he says.

The trio determined the environment where 6615 genera of marine species originated, based on where the fossils first appeared. In tomorrow's issue of Science, the researchers reveales that 1426 of the genera originated in reef environments, nearly 50% more than in shallow-water environments. In addition, Kiessling says, reefs were found to contribute diversity to other habitats, because members of genera that originated in reef systems migrated away. "We were surprised to see how large the cradle effect really is."

"It's an intriguing and important paper," says paleontologist Richard Aronson of the Florida Institute of Technology in Melbourne. "The implication," he says, "is if modern reefs continue to degrade, that could have long-term evolutionary consequences for other ecosystems by cutting off the supply of new biodiversity."

flora in egypt

2010-05-15T23:10:00.000-07:00

The plant life in the Sinai is as diverse and as adapted as the fauna - both on land and under the sea. Often the land plants exhibit 'anti-social' characteristics - bad smell, sticky substances, prickly, spikey and often misleading [looking good but bad news when eaten].As with the animals they possess well adapted water management mechanisms and though they can survive for long periods without ground water, eventually they will die off with prolonged periods of drought. But, in this case, with the first decent rains, they sprout and restart the cycle. Others however are ephemeral and last long enough to set seed before drying out for another season.
The most fascinating aspect of all is the great wealth of herbal medicine based on the shrubs and herbs of the Sinai. Samwa, a foul smelling plant that not even the camels eat is a proven treatment for diabetes. Baatharan, is a universal panacea for upset stomachs, while the Hammad is good for salads and the fruit of the Nabq looks like an apple but has a tangy taste.
Common names both in Arabic and other languages may differ from place to place.

Acacia Thorn Tree »Genus = Acacia »Species = radianna »Common Name = Sayyal	Mangrove »Genus = Avicennia »Species = marina »Common Name = Shoora
Tamarix »Genus = Tamarix »Species = aphylla »Common Name = Tarfa	Sodom's Apple »Genus = Calotropis »Species = procera »Common Name = Oshar
Date Palm »Genus = Phoenix »Species = dactylifera »Common Name = Nakhl	Boaitheran »Genus = Artemisia »Species = judaica »Common Name = Baatharan
Desert Lettuce »Genus = Rumex »Species = sp. »Common Name = Hammad	Meswaak »Genus = Salvadora »Species = persica »Common Name = Arak
Desert Mellon »Genus = Citrullus »Species = colocynthis »Common Name = Handal	Gharqad »Genus = Nitraria »Species = retusa »Common Name = Gharqad
zafra »Genus = Iphiona »Species = scabra »Common Name = Zafra	Lasaf »Genus = Capparis »Species = sinaica »Common Name = Lasaf

Acacia Thorn Tree
»Genus = Acacia
»Species = radianna
»Common Name = Sayyal

Mangrove
»Genus = Avicennia
»Species = marina
»Common Name = Shoora

Tamarix
»Genus = Tamarix
»Species = aphylla
»Common Name = Tarfa

Sodom's Apple
»Genus = Calotropis
»Species = procera
»Common Name = Oshar

Date Palm
»Genus = Phoenix
»Species = dactylifera
»Common Name = Nakhl

Boaitheran
»Genus = Artemisia
»Species = judaica
»Common Name = Baatharan

Desert Lettuce
»Genus = Rumex
»Species = sp.
»Common Name =
Hammad

Meswaak
»Genus = Salvadora
»Species = persica
»Common Name = Arak

Desert Mellon
»Genus = Citrullus
»Species = colocynthis
»Common Name = Handal

Gharqad
»Genus = Nitraria
»Species = retusa
»Common Name =
Gharqad

zafra
»Genus = Iphiona
»Species = scabra
»Common Name = Zafra

Lasaf
»Genus = Capparis
»Species = sinaica
»Common Name = Lasaf

the solar system

2010-05-15T23:05:00.001-07:00

From our small world we have gazed upon the cosmic ocean for thousands of years. Ancient astronomers observed points of light that appeared to move among the stars. They called these objects "planets," meaning wanderers, and named them after Roman deities—Jupiter, king of the gods; Mars, the god of war; Mercury, messenger of the gods; Venus, the goddes of love and beauty, and Saturn, father of Jupiter and god of agriculture. The stargazers also observed comets with sparkling tails, and meteors or shooting stars apparently falling from the sky.

Since the invention of the telescope, three more planets have been discovered in our solar system: Uranus (1781), Neptune (1846), and, now downgraded to a dwarf planet, Pluto (1930). In addition, there are thousands of small bodies such as asteroids and comets. Most of the asteroids orbit in a region between the orbits of Mars and Jupiter, while the home of comets lies far beyond the orbit of Pluto, in the Oort Cloud.

The four planets closest to the sun—Mercury, Venus, Earth, and Mars—are called the terrestrial planets because they have solid rocky surfaces. The four large planets beyond the orbit of Mars—Jupiter, Saturn, Uranus, and Neptune—are called gas giants. Tiny, distant, Pluto has a solid but icier surface than the terrestrial planets.

Nearly every planet—and some of the moons—has an atmosphere. Earth's atmosphere is primarily nitrogen and oxygen. Venus has a thick atmosphere of carbon dioxide, with traces of poisonous gases such as sulfur dioxide. Mars's carbon dioxide atmosphere is extremely thin. Jupiter, Saturn, Uranus, and Neptune are primarily hydrogen and helium. When Pluto is near the sun, it has a thin atmosphere, but when Pluto travels to the outer regions of its orbit, the atmosphere freezes and collapses to the planet's surface. In that way, Pluto acts like a comet.

Moons, Rings, and Magnetospheres

There are 140 known natural satellites, also called moons, in orbit around the various planets in our solar system, ranging from bodies larger than our own moon to small pieces of debris.

From 1610 to 1977, Saturn was thought to be the only planet with rings. We now know that Jupiter, Uranus, and Neptune also have ring systems, although Saturn's is by far the largest. Particles in these ring systems range in size from dust to boulders to house-size, and may be rocky and/or icy.

Most of the planets also have magnetic fields, which extend into space and form a magnetosphere around each planet. These magnetospheres rotate with the planet, sweeping charged particles with them. The sun has a magnetic field, the heliosphere, which envelops our entire solar system.

Ancient astronomers believed that the Earth was the center of the universe, and that the sun and all the other stars revolved around the Earth. Copernicus proved that Earth and the other planets in our solar system orbit our sun. Little by little, we are charting the universe, and an obvious question arises: Are there other planets where life might exist? Only recently have astronomers had the tools to indirectly detect large planets around other stars in nearby solar systems.

the desert

2010-05-15T22:51:00.000-07:00

The desert biome

Sand dunes in Death Valley National Monument, California.

Deserts cover about one fifth of the Earth's surface and occur where rainfall is less than 50 cm/year. Although most deserts, such as the Sahara of North Africa and the deserts of the southwestern U.S., Mexico, and Australia, occur at low latitudes, another kind of desert, cold deserts, occur in the basin and range area of Utah and Nevada and in parts of western Asia. Most deserts have a considerable amount of specialized vegetation, as well as specialized vertebrate and invertebrate animals. Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter. Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.

There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for large animals. The dominant animals of warm deserts are nonmammalian vertebrates, such as reptiles. Mammals are usually small, like the kangaroo mice of North American deserts.

krebs cycle

2009-09-26T11:39:00.001-07:00

AKA the Tricarboxylic Acid (TCA) Cycle or the. Krebs CycleThe Citric Acid Cycle is one of 3 stages of cellular respiration. The others are glycolysis and electron transport/oxidative phosphorylation. The big picture: Glycolysis breaks 1 glucose into 2 pyruvate, producing 6 ATP. Pyruvate is used to make acetyl-CoA, the starting product for the citric acid cycle. Each turn of the cycle oxidizes 1 pyruvate, so it takes 2 turns to completely oxidize 1 glucose. Two turns produce 8 NADH, 2 FADH2, and 2 ATP. NADH and FADH2 are then oxidatively phosphorylated, resulting in 28 more ATP. The 3 stages together produce 30 to 38 ATP. The net reaction for the 8 proper steps of the cycle:Acetyl-CoA + 3 NAD+ + FAD + GDP + Pi + 2H20 <==> CoASH + 3 NADH + FADH2 + GTP + 2CO2 + 3H+ DG؛' = -49 kJ/mol DG ~ -115 kJ/mol

soil pollution

2009-09-26T03:27:00.000-07:00

Soil pollution comprises the pollution of soils with materials, mostly chemicals, that are out of place or are present at concentrations higher than normal which may have adverse effects on humans or other organisms. It is difficult to define soil pollution exactly because different opinions exist on how to characterize a pollutant; while some consider the use of pesticides acceptable if their effect does not exceed the intended result, others do not consider any use of pesticides or even chemical fertilizers acceptable. However, soil pollution is also caused by means other than the direct addition of xenobiotic (man-made) chemicals such as agricultural runoff waters, industrial waste materials, acidic precipitates, and radioactive fallout.
Both organic (those that contain carbon) and inorganic (those that don't) contaminants are important in soil. The most prominent chemical groups of organic contaminants are fuel hydrocarbons, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated aromatic compounds, detergents, and pesticides. Inorganic species include nitrates, phosphates, and heavy metals such as cadmium, chromium and lead; inorganic acids; and radionuclides (radioactive substances). Among the sources of these contaminants are agricultural runoffs, acidic precipitates, industrial waste materials, and radioactive fallout.

An area of Karabache, Russia, where soil has been poisoned by high concentrations of lead, arsenic, nickel, cobalt, and cadmium. (
©Gyori Antoine/Corbis Sygma. Reproduced by permission.)
Soil pollution can lead to water pollution if toxic chemicals leach into groundwater, or if contaminated runoff reaches streams, lakes, or oceans. Soil also naturally contributes to air pollution by releasing volatile compounds into the atmosphere. Nitrogen escapes through ammonia volatilization and denitrification. The decomposition of organic materials in soil can release sulfur dioxide and other sulfur compounds, causing acid rain. Heavy metals and other potentially toxic elements are the most serious soil pollutants in sewage. Sewage sludge contains heavy metals and, if applied repeatedly or in large amounts, the treated soil may accumulate heavy metals and consequently become unable to even support plant life.
In addition, chemicals that are not water soluble contaminate plants that grow on polluted soils, and they also tend to accumulate increasingly toward the top of the food chain. The banning of the pesticide DDT in the United States resulted from its tendency to become more and more concentrated as it moved from soil to worms or fish, and then to birds and their eggs. This occurred as creatures higher on the food chain ingested animals that were already contaminated with the pesticide from eating plants and other lower animals. Lake Michigan, as an example, has 2 parts per trillion (ppt) of DDT in the water, 14 parts per billion (ppb) in the bottom mud, 410 ppb in amphipods (tiny water fleas and similar creatures), 3 to 6 parts per million (ppm) in fish such as coho salmon and lake trout, and as much as 99 ppm in herring gulls at the top of the food chain.
The ever-increasing pollution of the environment has been one of the greatest concerns for science and the general public in the last fifty years. The rapid industrialization of agriculture, expansion of the chemical industry, and the need to generate cheap forms of energy has caused the continuous release of man-made organic chemicals into natural ecosystems. Consequently, the atmosphere, bodies of water, and many soil environments have become polluted by a large variety of toxic compounds. Many of these compounds at high concentrations or following prolonged exposure have the potential to produce adverse effects in humans and other organisms: These include the danger of acute toxicity, mutagenesis (genetic changes), carcinogenesis, and teratogenesis (birth defects) for humans and other organisms. Some of these man-made toxic compounds are also resistant to physical, chemical, or biological degradation and thus represent an environmental burden of considerable magnitude.
Numerous attempts are being made to decontaminate polluted soils, including an array of both in situ (on-site, in the soil) and off-site (removal of contaminated soil for treatment) techniques. None of these is ideal for remediating contaminated soils, and often, more than one of the techniques may be necessary to optimize the cleanup effort.
The most common decontamination method for polluted soils is to remove the soil and deposit it in landfills or to incinerate it. These methods, however, often exchange one problem for another: landfilling merely confines the polluted soil while doing little to decontaminate it, and incineration removes toxic organic chemicals from the soil, but subsequently releases them into the air, in the process causing air pollution.
For the removal and recovery of heavy metals various soil washing techniques have been developed including physical methods, such as attrition scrubbing and wet-screening, and chemical methods consisting of treatments with organic and inorganic acids, bases, salts and chelating agents. For example, chemicals used to extract radionuclides and toxic metals include hydrochloric, nitric, phosphoric and citric acids, sodium carbonate and sodium hydroxide and the chelating agents EDTA and DTPA. The problem with these methods, however, is again that they generate secondary waste products that may require additional hazardous waste treatments.
In contrast to the previously described methods, in situ methods are used directly at the contamination site. In this case, soil does not need to be excavated, and therefore the chance of causing further environmental harm is minimized. In situ biodegradation involves the enhancement of naturally occurring microorganisms by artificially stimulating their numbers and activity. The microorganisms then assist in degrading the soil contaminants. A number of environmental, chemical, and management factors affect the biodegradation of soil pollutants, including moisture content, pH, temperature, the microbial community that is present, and the availability of nutrients. Biodegradation is facilitated by aerobic soil conditions and soil pH in the neutral range (between pH 5.5 to 8.0), with an optimum reading occurring at approximately pH 7, and a temperature in the range of 20 to 30°C. These physical parameters can be influenced, thereby promoting the microorganisms' ability to degrade chemical contaminants. Of all the decontamination methods bioremediation appears to be the least damaging and most environmentally acceptable technique.
.

water pollution

2009-09-25T06:42:00.000-07:00

CAUSES OF POLLUTION

Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. Pollution is also caused when silt and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respirationbecomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain.
Polluted River in the United Kingdom
The pollution of rivers and streams with chemical contaminants has become one of the most crutial environmental problems within the 20th century. Waterborne chemical pollution entering rivers and streams cause tramendous amounts of destruction.

Pathogens are another type of pollution that prove very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness.
ADDITIONAL FORMS OF WATER POLLUTION
Three last forms of water pollution exist in the forms of petroleum, radioactive substances, and heat. Petroleum often pollutes waterbodies in the form of oil, resulting from oil spills. The previously mentioned Exxon Valdez is an example of this type of water pollution. These large-scale accidental discharges of petroleum are an important cause of pollution along shore lines. Besides the supertankers, off-shore drilling operations contribute a large share of pollution. One estimate is that one ton of oil is spilled for every million tons of oil transported. This is equal to about 0.0001 percent. Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials. Specific forms of waste are uranium and thorium mining and refining. The last form of water pollution is heat. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs.
Demonstrators Protest Drilling
Oil pollution is a growing problem, particularly devestating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating.

Oil Spill Clean-up
Workers use special nets to clean up a California beach after an oil tanker spill. Tanker spills are an increasing environmental problem because once oil has spilled, it is virtually impossible to completely remove or contain it. Even small amounts spread rapidly across large areas of water. Because oil and water do not mix, the oil floats on the water and then washes up on broad expanses of shoreline. Attempts to chemically treat or sink the oil may further disrupt marine and beach ecosystems.

CLASSIFYING WATER POLLUTION

The major sources of water pollution can be classified as municipal, industrial, and agricultural. Municipal water pollution consists of waste water from homes and commercial establishments. For many years, the main goal of treating municipal wastewater was simply to reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria. In recent years, however, more stress has been placed on improving means of disposal of the solid residues from the municipal treatment processes. The basic methods of treating municipal wastewater fall into three stages: primary treatment, including grit removal, screening, grinding, and sedimentation; secondary treatment, which entails oxidation of dissolved organic matter by means of using biologically active sludge, which is then filtered off; and tertiary treatment, in which advanced biological methods of nitrogen removal and chemical and physical methods such as granular filtration and activated carbon absorption are employed. The handling and disposal of solid residues can account for 25 to 50 percent of the capital and operational costs of a treatment plant. The characteristics of industrial waste waters can differ considerably both within and among industries. The impact of industrial discharges depends not only on their collective characteristics, such as biochemical oxygen demand and the amount of suspended solids, but also on their content of specific inorganic and organic substances. Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; wastewater can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters.
Wastewater Treatment
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible.

Agriculture, including commercial livestock and poultry farming, is the source of many organic and inorganic pollutants in surface waters and groundwater. These contaminants include both sediment from erosion cropland and compounds of phosphorus and nitrogen that partly originate in animal wastes and commercial fertilizers. Animal wastes are high in oxygen demanding material, nitrogen and phosphorus, and they often harbor pathogenic organisms. Wastes from commercial feeders are contained and disposed of on land; their main threat to natural waters, therefore, is from runoff and leaching. Control may involve settling basins for liquids, limited biological treatment in aerobic or anaerobic lagoons, and a variety of other methods.

air pollution

2009-09-23T07:50:00.000-07:00

Air pollution comes from many different sources such as factories, power plants, dry cleaners, cars, buses, trucks and even windblown dust and wildfires. Air pollution can threaten the health of human beings, trees, lakes, crops, and animals, as well as damage the ozone layer and buildings. Air pollution also can cause haze, reducing visibility in national parks and wilderness areas. EPA protects human health and the environment through the regulatory process and voluntary programs such as Energy Star and Commuter Choice. Under the Clean Air Act, EPA sets limits on how much of a pollutant is a llowed in the air anywhere in the United States. Although national air quality has improved over the last 20 years, many challenges remain in protecting public health and the environment. EPA's goal is to have clean air to breathe for this generation and those to follow.

Folic acid

2009-09-18T06:17:00.001-07:00

Folic acid is a conjugated molecule consisting of a pteridine ring structure linked to para-aminobenzoic acid (PABA) that forms pteroic acid. Folic acid itself is then generated through the conjugation of glutamic acid residues to pteroic acid. Folic acid is obtained primarily from yeasts and leafy vegetables as well as animal liver. Animal cannot synthesize PABA nor attach glutamate residues to pteroic acid, thus, requiring folate intake in the diet.
When stored in the liver or ingested folic acid exists in a polyglutamate form. Intestinal mucosal cells remove some of the glutamate residues through the action of the lysosomal enzyme, conjugase. The removal of glutamate residues makes folate less negatively charged (from the polyglutamic acids) and therefore more capable of passing through the basal lamenal membrane of the epithelial cells of the intestine and into the bloodstream. Folic acid is reduced within cells (principally the liver where it is stored) to tetrahydrofolate (THF also H4folate) through the action of dihydrofolate reductase (DHFR), an NADPH-requiring enzyme.
The function of THF derivatives is to carry and transfer various forms of one carbon units during biosynthetic reactions. The one carbon units are either methyl, methylene, methenyl, formyl or formimino groups.
Note that the N5 position is the site of attachment of methyl groups, the N10 the site for attachment of formyl and formimino groups and that both N5 and N10 bridge the methylene and methenyl groups

vitamin E

2009-09-18T06:08:00.000-07:00

Vitamin E
α-Tocopherol
Vitamin E is a mixture of several related compounds known as tocopherols. The α-tocopherol molecule is the most potent of the tocopherols. Vitamin E is absorbed from the intestines packaged in chylomicrons. It is delivered to the tissues via chylomicron transport and then to the liver through chylomicron remnant uptake. The liver can export vitamin E in VLDLs. Due to its lipophilic nature, vitamin E accumulates in cellular membranes, fat deposits and other circulating lipoproteins. The major site of vitamin E storage is in adipose tissue.
The major function of vitamin E is to act as a natural antioxidant by scavenging free radicals and molecular oxygen. In particular vitamin E is important for preventing peroxidation of polyunsaturated membrane fatty acids. The vitamins E and C are interrelated in their antioxidant capabilities. Active α-tocopherol can be regenerated by interaction with vitamin C following scavenge of a peroxy free radical. Alternatively, α-tocopherol can scavenge two peroxy free radicals and then be conjugated to glucuronate for excretion in the bile.
Clinical Significances of Vitamin E Deficiency
No major disease states have been found to be associated with vitamin E deficiency due to adequate levels in the average American diet. The major symptom of vitamin E deficiency in humans is an increase in red blood cell fragility. Since vitamin E is absorbed from the intestines in chylomicrons, any fat malabsorption diseases can lead to deficiencies in vitamin E intake. Neurological disorders have been associated with vitamin E deficiencies associated with fat malabsorptive disorders. Increased intake of vitamin E is recommended in premature infants fed formulas that are low in the vitamin as well as in persons consuming a diet high in polyunsaturated fatty acids. Polyunsaturated fatty acids tend to form free radicals upon exposure to oxygen and this may lead to an increased risk of certain cancers.

biochemistry the structure of vitamin A

2009-09-18T05:58:00.000-07:00

Vitamin A
Vitamin A consists of three biologically active molecules, retinol, retinal (retinaldehyde) and retinoic acid.
All-trans-retinal
11-cis-retinal

Retinol
Retinoic Acid
Each of these compounds are derived from the plant precursor molecule, β-carotene (a member of a family of molecules known as carotenoids). Beta-carotene, which consists of two molecules of retinal linked at their aldehyde ends, is also referred to as the provitamin form of vitamin A.
Ingested β-carotene is cleaved in the lumen of the intestine by β-carotene dioxygenase to yield retinal. Retinal is reduced to retinol by retinaldehyde reductase, an NADPH requiring enzyme within the intestines. Retinol is esterified to palmitic acid and delivered to the blood via chylomicrons. The uptake of chylomicron remnants by the liver results in delivery of retinol to this organ for storage as a lipid ester within lipocytes. Transport of retinol from the liver to extrahepatic tissues occurs by binding of hydrolyzed retinol to aporetinol binding protein (RBP). the retinol-RBP complex is then transported to the cell surface within the Golgi and secreted. Within extrahepatic tissues retinol is bound to cellular retinol binding protein (CRBP). Plasma transport of retinoic acid is accomplished by binding to albumin

Pure Science and Applied Science

2009-08-10T14:16:00.000-07:00

Pure and Applied Science is a two-year pre-university profile that prepares students for entry to university in the physical and engineering sciences. The profile will introduce students to the basics of chemistry and biology while allowing them to obtain an in-depth knowledge of mathematics and physics. From Pure and Applied Science, students can pursue a Bachelor’s degree in such fields as computer science, mathematics, geology, and physics and in professional programs such as engineering and architecture.
Among the skills you will develop are:
approaching problem-solving in a systematic way
applying the experimental method
using data-processing technology and electronic forms of communication
using computerized data-acquisition systems
identifying the context in which scientific ideas originated and evolved
using the basic vocabulary of the sciences in French
Career Opportunities
Depending on the profile you choose, you may pursue university studies in a variety of fields, including:
Architecture
Astronomy
Biology
Biotechnologies
Chemistry
Computer Science
Dentistry
Education
Engineering
Environmental Science
Geology
Mathematics
Medicine
Nursing Science
Occupational Therapy
Pharmacy
Physics
Physiotherapy
Veterinary Science

CO2 sponge

2009-08-05T14:02:00.000-07:00

CO2 sponge macromolecule that was accidentally discovered when scientists left stuff sitting on a lab bench seems to soak up atmospheric carbon dioxide, a study now suggests.
The original find was made by a research team led by chemists at the University of Southampton in England. They were trying to design and create molecules that could capture negatively charged ions, such as chlorides and phosphates, on the surfaces of bioengineered cells. In one experiment, the researchers set aside an alkaline solution of various organic substances to evaporate, says geochemist John A. Tossell, author of the new study. When analyzing the crystals that formed, the team found that the organic macromolecule that made up the crystal unexpectedly contained carbonates, which form in solutions containing carbon dioxide.
The carbon dioxide in those carbonates probably came from the air in the lab and was converted to carbonate in the solution, says Tossell, of George Washington University in Washington, D.C. He describes, in the Aug. 3 Inorganic Chemistry, the macromolecule’s ability to absorb carbonate.
Though the carbonate isn’t chemically bonded to the macromolecule, spontaneous absorption of carbon dioxide from the air suggests that the combination is very stable, Tossell says. Theoretical analyses show the macromolecule is a giant ring composed mostly of ring-shaped subcomponents and that the negatively-charged carbonate ion nestles within the positively-charged center of that macromolecule, he notes.
Scientists are evaluating many chemical means to absorb and store carbon dioxide to help diminish its atmospheric buildup and slow climate change (SN: 5/10/08, p. 18). To use this macromolecule to soak carbon dioxide from the air or from industrial emissions on a large scale, engineers would need to separate the carbonate from the macromolecule. This could be done one of several ways, Tossell suggests. Heating the combination would drive out the carbonate, but might require large amounts of energy — and producing that energy using fossil fuels would create carbon dioxide. Alternatively, making the alkaline solution more acidic would cause the carbonate ion to latch on to protons, which would make the combination less stable and therefore more easily broken apart.
Though the macromolecule may be too expensive to be used in large-scale CO2 scrubbers, Tossell says, studying the macromolecule and how it’s made may help future efforts to make similar materials more cheaply.
“This work is careful and thorough”, says Omar Yaghi, a chemist at UCLA. However, he notes, the new material may not have the capacity to absorb large amounts of carbon dioxide and might absorb other gases as well, which could reduce the material’s effectiveness.

fishes

2009-07-31T07:07:00.000-07:00

Fish are members of the Animalia Kingdom (animals) and are also classified into the Phylum Chordata. In order to be a chordate an animal must have a notochord (a slim and flexible rod that supports the body) at some point in their lives; have a tubular nerve chord along their back (dorsal surface) with the brain developing from a swelling found at the anterior end (front) of this tube; paired gill slits at some stage of their life history; segmentation of at least part of their body; a post-anal tail at some stage in their life history; a ventral heart; and an endoskeleton (Arms & Camp, 1979).
Fish are further classified into the Vertebrata Subphylum. In order to be a vertebrate, an animal must have a vertebral column, or backbone. This backbone encloses, supports and protects the spinal cord. Fish are vertebrates that live in water and breathe with gills. Fish are ectotherms, or cold-blooded. Fish have either backbones of cartilage or bone. Most fish are adapted to live in salt or fresh water. Most fish have fins and scales, which cover and protect the body. The body systems of the fish, such as the digestive, circulatory, etc. are well developed. The fish are further classified into three classes. These classes are the Agnatha, jawless fish such as the hagfish and lampreys; the Chrondrichthyes, fish whose skeleton is made of cartilage such as sharks, rays and skates; and the Osteichthyes, fish whose skeleton is composed mostly of bone such as bass, perch, catfish, and flounder. There are approximately 50 species of jawless fish, 600 species of cartilaginous fish and more than 30,000 species of bony fish. The bony fish, Osteichthyes, are then further classified into two main groups called the ray-finned group (e.g., perch, and catfish) and the lobe-finned group (e.g., lungfish). Most bony fish belong to the “ray-finned” group. There are approximately 70 fish orders known to biologists.

Some of the main groups of fish used by scientists are the sharks and rays; sturgeon and gars; herring-like fishes; trout and salmon; eels, minnows, suckers, and catfish; flyingfish and relatives; cod-like fish; flatfish; seahorses and relatives; mullets, silversides, and barracuda; and mackerels and tunas (Zim and Shoemaker, 1956).
In Charles S. Manooch’s, III (1984) Fisherman’s Guide, Fishes of the Southeastern United States, he classifies fish according to the water temperature and type of water (fresh or salt) in which they live. He further subdivides the fish into groups by the ocean habitat in which they live. For example, he uses categories such as: Cold Freshwater Fish - such as the Rainbow Trout and Brown Trout; Cool Freshwater Fish – such as the Smallmouth bass and Walleye; Warm Freshwater Fish – such as the American Eel and Yellow Bullhead; Anadromous (migrate from saltwater to freshwater to spawn) Upper Estuarine Fish – such as the Atlantic Sturgeon and Blueback Herring; Coastal Ground Fish – Scalloped Hammerhead and Florida Pompano; Coastal Pelagic Fish (open ocean fish) – Tarpon and Cobia; Offshore Reef Fish – such as Black Sea Bass and Greater Barracuda; and Oceanic Pelagic Fish – such as Wahoo and Sailfish.
In the SCDNR field guide for South Carolina marine fish, Moore (1996) groups marine fish into the following categories: sturgeons, eels, tarpons, herrings, temperate basses, sea basses, tilefishes, bluefishes, cobias, jacks, snappers, porgies, drums, wrasses, mackerels, swordfishes, billfishes, lefteyed flounders, and leatherjackets. It should be obvious to the reader that there are a variety of ways to classify fish. Many of the classification systems used depend on the way the biologist looks at and works with the fish. You are advised to look at recent high school and college biology and zoology texts and various excellent fish field guides for further information about fish classification. There are many good ones available for the fish enthusiast

Class Mammalia

2009-07-30T05:26:00.000-07:00

Class Mammalia
Class Mammalia is a relatively small group of animals that are very well known. There are approx. 4500 species of mammals, with very few left to be discovered. Some discoveries are still possible, as is the case of the cloudrunner, a squirrel-sized mammal discovered in the late 1990's. All mammals have similar characteristics. First off, they all, just like other vertebrates, have a backbone and spinal column. They also have a notochord at some stage of development. All mammals are warm-blooded, meaning they can control their body temperature. They can keep it at a steady 36-38°C. Mammals lack feathers but rather are covered with fur or hairy skin. They all have specialized teeth, with the exception of the Edentates (armadillos), who lack teeth entirely. Mammal bones are solid and filled with either marrow (as in humans) or spongy bone (as in elephants). No mammals are completely cartilaginous. Mammals lack wings, with the exception of Chiroptera (bats), which numbers to 900 species. All female mammals have mammary glands which produce milk for the young. Mammary glands are the best way of defining mammals and is where the term Mammalia came from.
Mammals are divided into 3 sub-classes based on their mode of reproduction:
Subclass Prototheria
Prototheria is composed of egg-laying mammals. There are only 6 species of these and they belong to one order:
Monotremata (platypus and echidna)
Subclass Metatheria
Metatheria numbers to 250 species and is composed of seven orders (previously 1 - Marsupialia). Their young are born tiny and immature and must climb into the mother's pouch, where they grab hold of a teat and do not leave until they are mature.
Didelphimorphia (New World opossums) Paucituberculata (South American rat opossums) Microbiotheria (colocolo) Dasyuromorphia (dasyurids, thylacines) Peramelemorphia (bandicoots) Notoryctemorphia (marsupial moles) Diprotodontia (kangaroos, koalas, wombats, possums)
Subclass Eutheria
The sub-class Eutheria is composed of all the placental mammals, whose young form as embryos in the mother's stomach. Humans are an example of the sub-class Eutheria. Below is a list of all 19 orders in this sub-class:
Insectivora (moles, shrews) Dermoptera (flying lemurs) Chiroptera (bats) Cetacea (whales) Carnivora (cats, bears, dogs, otters, seals, sea lions) Tubulidentata (aardvarks) Proboscidea (elephants) Hyracoidea (hyraxes) Primates (monkeys, lemurs, bushbabies, aye-ayes) Xenarthra or Edentata (armadillos, anteaters, sloths) Pholidota (pangolins) Lagomorpha (rabbits, hares, pikas) Rodentia (mice, rats, squirrels, porcupines, beavers, voles, hamsters) Sirenia (manatees, dugongs) Perissodactyla (horses, donkeys, zebras, rhinoceroses,tapirs) Artiodactyla (pronghorns, deer, camels, gnus, goats, giraffes, hippopotami, pigs, peccaries, chevrotains, musk-deer, cows) Scandentia (tree shrews) Macroscelidea (Elephant Shrews

Human Genome

2009-07-29T09:16:00.000-07:00

1,000 Genomes Project: Expanding the Map of Human Geneticsmore than 1,000 as part of a new international research consortium's effort to trace the potential genetic origins of disease. But first the mother, father and adult child of a European-ancestry family from Utah and a Yoruba-ancestry family from Nigeria will join an anonymous individual as well as famous g these six will also each have their genetic codes examined at least 20 times, providing 10 times the accuracy of existing genetic sequences as well as paving the way for the ambitious effort dubbed the 1,000 Genomes Project, which will comprehensively map humanity's genetic variation.
"The reference sequence that we obtained in 2003 [from the anonymous individual] is just a human genome sequence, but there are six billion humans and it is the sequence of all of us that is important," says project co-chair Richard Durbin of the Wellcome Trust Sanger Institute in Cambridge, England. "We can't get that, but the output of the 1,000 Genomes Project will be a lot closer."
The project will proceed in three steps, according to the consortium. The first, currently underway and expected to be completed by year's end, is the detailed scanning of the six individuals. This will be followed by less detailed genome scans of 180 anonymous people from around the world and then partial scans of an additional 1,000 people. "If we look at about 1,000 individuals, we'll get genetic variants in those samples that are somewhere around 1 percent or lower frequency" in the human population, says geneticist Lisa Brooks, director of the Bethesda, Md.–based National Human Genome Research Institute's Genetic Variation Program.
The researchers plan to use common genetic sequences from the initial six individuals to allow less rigorous scanning as the project accelerates. For example, a shared stretch of DNA from one of the detailed individual scans could fill in the blanks for a less rigorously scanned later individual. "This all needs to be tested," Brooks says. "Is doing these scans 2x [twice] sufficient?"
Blood samples for the final project have already been collected from the first six candidates as well as randomly selected populations from throughout the world: Japanese from Tokyo, Chinese from Beijing, Luhya and Masai from Kenya, Toscani from Italy, Gujarati Asian Indians from Houston, Chinese from Denver, Mexican-Americans from Los Angeles and African-Americans from the southwestern U.S. "We wanted to look at a couple of populations, two or three from each of the major Old World continents. That gives you the variety of people but no one population is needed," Brooks notes. "We don't know exactly who these people are."
The researchers collected no identifying individual information, such as medical histories or basic height and weight data, because the study is not looking for specific diseases but rather the range of human genetic variation. "How many individuals with autism would be in 100 samples from a community?" Brooks says. "It's not a very good disease study but this is going to support a zillion disease studies that are properly designed."
For example, once complete, the 1,000-genome resource will allow researchers to pinpoint genes, structural variants in chromosomes and other individual genomic variations that are associated with diseases ranging from autism tocanser. Researchers using the incomplete genetic information presently available have already identified at least 100 by comparing the DNA variation between healthy and ill subjects. "This project is talking about a hundred times as much data" as existing genetic resources, Durbin says.eneticists Craig Venter and James Watson as part of the handful of humans to have on record

CLASS MALACOSTRACA

2009-07-25T09:57:00.000-07:00

TheMalacostraca is also a large and diverse group of Crustaceans , and contains the most familiar forms, especially on dinner tables. This group is treated further in the section on Malacostraca . The subclasses of Malacostracans are:
Subclass Phyllocarida (leptostracans)
Subclass Eumalacostraca (shrimps, crabs, lobsters, amphipods, isopods, mysids, euphausids, and others

CLASS MAXILLOPODA

2009-07-25T09:55:00.000-07:00

Maxillopoda is a large and diverse group of Crustaceans , and contains many familiar forms, as well as many other less familiar but ecologically important groups. The subclasses of this large group are:
Subclass Ostracoda (seed or mussell shrimps)
Subclass Mystacocarida (Mystacocarids)
Subclass Copepoda (Copepods)
Subclass Branchiura (fish lice)
Subclass Cirrepedia (barnacles and relatives)
Subclass Tantulocarida (tantulocarids) Although its difficult to generalize about such a diverse group, most Maxillopods are relatively small organisms, with the barnacles having the largest individuals. Most are marine, although there are many freshwater species of copepods and ostracods . There are about 18,000 described species, most of these in the subclasses Ostracoda and Copepoda .

CLASSBRANCHIOPODA

2009-07-25T09:51:00.000-07:00

The Branchiopods consists primarily of freshwater forms, although there are a few genera of marine Cladocera found in the plankton . The brine shrimp , closely related to the freshwater fairy shrimp , has reinvaded high salinity habitats in inland areas, but does not normally inhabit marine waters (except in some isolated areas where fish predators are absent).

CLASS CEPHALOCARIDA

2009-07-25T09:47:00.000-07:00

Only about nine species of living Cephalocarids have been described. They are small benthic marine animals, less than 4 mm long, that retain many primitive features. Cephalocarids feed on organic detritus in mud or sand sediments. They range from the intertidal zone to waters as much as 1500 meters deep.

CLASS REMIPEDIA remipedes

2009-07-25T09:44:00.000-07:00

Remipedia is a small group of crustaceans that were recently discovered in a cavern on Grand Bahama Island in the Caribbean . These unusual organisms, which superficially resemble centipedes possess an interesting combination of primitive and advanced characteristics. Not much is yet known about their biology.