Crustacea.

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

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

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

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
1.	Bacillariophyta	a, c	β-carotene ± -carotene rarely fucoxanthin,.		Chrysolaminarin oils	1 apical flagellum in male gametes: cell in two halves with elaborate markings.
2.	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.
3.	Chrysophycophyta (golden algae)	a, c ,	β-carotene, fucoxanthin		Chrysolaminarin oils	1 or 2 unequal, apical flagella, in some, cell surface covered by characteristic scales.
4.	Cyanobacteria (blue green algae)	a,c	β-carotene, phycobilins
5.	Phaeco phycophyta (brown algae)	a,c	β-carotene, ± fucoxanthin, violaxanthin		Laminarin, soluble carbohydrates, oils	2 lateral flagella
6.	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.
7.	Rhodo phycophyta (red algae )	a, rarely d	β-carotene, zeaxanthin ± β carotene	Phyco erythrin phyco cyanin	Floridean starch oils	Flagella absent

corals

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

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

the solar system

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.