The Giant Redwoods

Have you ever seen a redwood? They are tall! They are also called Sequoias which is a common name for a group of big, majestic evergreen trees of the cypress family. They can grow up to 100 feet tall or more! The sequoias are so big, that they are even bigger than the whale! If you saw a picture of a full grown Sequoia with a person standing next to it, that person would only be a large dot! Even if you saw the person well enough to identify him, the Sequoia would be like a big, huge background and you wouldn't know that it was a tree! It would take about ten people to all hold hands around a Sequoia because the circumfrence is so big!

The Giant Sequoia is found on the western slopes of the Sierra Nevada . A Sequoia is estimated to weigh as much as 2500 metric tons! If you wanted to know how old a tree was after it had been cut down, you could look at the stump, and count the number of rings it has. Once you figure that out, you'll know how old the tree is (was). Some trees have been 2300 years of age. However, some other trees have lived up to 4000 years!
The leaves on a Giant Sequoia are scale like and lie close to the branches. The bark is spongy in texture. The wood is light, and highly resistant to insects and fire.

At one time, the most popular Sequoia was the dawn redwood. Its height is just about 100 feet and its diameter is about 6 feet.
Do you see that picture next to this. That little red dot is actually a person standing next to the Giant Sequoia! Can you believe it?
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Starfish / Sea Star

Sea stars, also known as starfish, are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" are sometimes differentiated,with "starfish" used in a broader sense to include the closely related brittle stars, which make up the class Ophiuroidea, as well as excluding sea stars which do not have five arms, such as the sun stars and cushion stars.

Sea stars exhibit a superficially radial symmetry. They typically have five "arms" which radiate from a central disk (pentaradial symmetry). However, the evolutionary ancestors of echinoderms are believed to have had bilateral symmetry. Sea stars do exhibit some superficial remnant of this body structure, evident in their larval pluteus forms.

Sea stars do not rely on a jointed, movable skeleton for support and locomotion (although they are protected by their skeleton), but instead possess a hydraulic water vascular system that aids in locomotion. The water vascular system has many projections called tube feet on the ventral face of the sea star's arms which function in locomotion and aid with feeding. Sea stars usually hunt for shelled animals such as oysters and clams. They have two stomachs. One stomach is used for digestion, and the other stomach can be extended outward to engulf and digest prey. This feature allows the sea star to hunt prey that is much larger than its mouth would otherwise allow. Sea stars are able to regenerate lost arms. A new sea star may be regenerated from a single arm attached to a portion of the central disk.

Diet

Most species are generalist predators, eating clams, oysters or any animal too slow to evade the attack (e.g. dying fish). Some species are detritivores, eating decomposed animal and plant material or organic films attached to substrate. Others may consume coral polyps (the best-known example for this is the infamous Acanthaster planci), sponges or even suspended particles and plankton (sea star from the Order Brisingida).The processes of feeding and capture may be aided by special parts; Pisaster brevispinus or short-spined pisaster from the West Coast of America may use a set of specialized tube feet to extend itself deep into the soft substrata to extract prey (usually clams). Grasping the shellfish, the sea star slowly pries open the shell by wearing out the adductor muscle and then inserts (also called evisceration) its stomach into an opening to devour the organism. Sea stars have also been known to attack animals such as marine snails. Protoreaster Nodotus, or horned sea stars, eat snails in an aquarium setting if the detritus in the tank is not sufficient to satisfy the sea star's hunger.

Reproduction

Sea stars are capable of both sexual and asexual reproduction. Individual sea stars are male or female. Fertilization takes place externally, both male and female releasing their gametes into the environment. Resulting fertilized embryos form part of the zooplankton.

Sea stars are developmentally (embryologically) known as deuterostomes. Their embryo initially develops bilateral symmetry, indicating that sea stars probably share a common ancestor with the chordates, which includes the fish. Later development takes a very different path however as the developing star fish settles out of the zooplankton and develops the characteristic radial symmetry. Some species reproduce cooperatively, using environmental signals to coordinate the timing of gamete release; in other species, one to one pairing is the norm.

Sea stars commonly reproduce by free-spawning: releasing their gametes into the water where they hopefully are fertilized by gametes from the opposite sex. To increase their chances of fertilization, sea stars probably gather in groups when they are ready to spawn, use environmental signals to coordinate timing (day length to indicate the correct time of the year, dawn or dusk to indicate the correct time of day), and may use chemical signals to indicate their readiness to each other.

Fertilized eggs grow into bipinnaria and later into brachiolaria larvae, which either grow using a yolk or by catching and eating other plankton. In either case, they live as plankton, suspended in the water and swimming by using beating cilia. The larvae are bilaterally symmetric — unlike adults, they have a distinct left and right side. Eventually, they undergo a complete metamorphosis, settle to the bottom, and grow into adults.Some species of sea star brood their young: the males spawn gametes which fertilize eggs held by the females. The females may hold the eggs on their surface, in the pyloric stomach (as in Leptasterias tenera), or even attach them to the ground (as in Asterina gibbosa). Brooding is especially common in polar and deep-sea species, environments less favourable for larvae.

Male and female sea stars are not distinguishable from the outside; one needs to see the gonads or be lucky enough to catch them spawning. The gonads are located in each arm, and release gametes through gonoducts located on the central body between the arms.

Some species of sea star also reproduce asexually by fragmentation, often with part of an arm becoming detached and eventually developing into an independent individual sea stars. This has led to some notoriety. Sea stars can be pests to fishermen who make their living on the capture of clams and other mollusks at sea as sea stars prey on these. The fishermen would presumably kill the sea stars by chopping them up and disposing of them at sea, ultimately leading to their increased numbers until the issue was better understood. A sea-star arm can only regenerate into a whole new organism if some of the central ring of the sea star is part of the chopped off arm.

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Jellyfish

Jellyfish (also known as jellies or sea jellies) are free-swimming members of the phylum Cnidaria. They have several different morphologies that represent several different cnidarian classes including the Scyphozoa (about 200 species), Staurozoa (about 50 species), Cubozoa (about 20 species), and Hydrozoa (about 1000-1500 species that make jellyfish and many more that do not). The jellyfish in these groups are also called, respectively, scyphomedusae, stauromedusae, cubomedusae, and hydromedusae; "medusa" (plural "medusae") is another word for jellyfish. Jellyfish are found in every ocean, from the surface to the deep sea. Some hydrozoan jellyfish, or hydromedusae, are also found in fresh water. Most of the information about jellyfish that follows in this article is about scyphozoan jellyfish, or scyphomedusae. These are the big, often colorful, jellyfish that are common in coastal zones worldwide.

In its broadest sense, the term jellyfish is sometimes used also to refer to members of the phylum Ctenophora. Although not closely related to cnidarian jellyfish, ctenophores are also free-swimming planktonic carnivores, are also generally transparent or translucent, and occur in shallow to deep portions of all the world's oceans. Ctenophores move using eight rows of fused cilia that beat in metachronal waves that diffract light, so that they sparkle with all of the colors of the rainbow. The rest of this article deals only with jellyfish in the phylum Cnidaria.

Jellyfish don't have specialized digestive, osmoregulatory, central nervous, respiratory, or circulatory systems. They digest using the gastrodermal lining of the gastrovascular cavity, where nutrients are absorbed. They do not need a respiratory system since their skin is thin enough that the body is oxygenated by diffusion. They have limited control over movement, but can use their hydrostatic skeleton to accomplish movement through contraction-pulsations of the bell-like body; some species actively swim most of the time, while others are passive much of the time. Jellyfish are composed of more than 90% water; most of their umbrella mass is a gelatinous material - the jelly - called mesoglea which is surrounded by two layers of epithelial cells which form the exumbrella (top surface) and subumbrella (bottom surface) of the bell, or body.

Jellyfish do not have a brain or central nervous system, but rather have a loose network of nerves, located in the epidermis, which is called a "nerve net." A jellyfish detects various stimuli including the touch of other animals via this nerve net, which then transmits impulses both throughout the nerve net and around a circular nerve ring, through the rhopalial lappet, located at the rim of the jellyfish body, to other nerve cells. Some jellyfish also have ocelli: light-sensitive organs that do not form images but which can detect light, and are used to determine up from down, responding to sunlight shining on the water's surface.

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The Amazing Banana

Doctors - Home Remedy: If you want a quick fix for flagging energy levels there's no better snack than a banana. Containing three natural sugars - sucrose, fructose and glucose - combined with fiber a banana gives an instant, sustained and substantial boost of energy.

Research has proven that just two bananas provide enough energy for a strenuous 90 minute workout.

No wonder the banana is the number one fruit with the world's leading athletes. But energy isn't the only way a banana can help us keep fit. It can also help overcome or prevent a substantial number of illnesses and conditions making it a must to add to our daily diet.

Depression: According to a recent survey undertaken by MIND amongst people suffering from depression, many felt much better after eating a banana. This is because bananas contain tryptophan, a type of protein that the body converts into serotonin known to make you relax, improve your mood and generally make you feel happier.

PMS: Forget the pills - eat a banana. The vitamin B6 it contains regulates blood glucose levels, which can affect your mood.

Anemia: High in iron, bananas can stimulate the production of hemoglobin in the blood and so helps in cases of anemia.

Blood Pressure: This unique tropical fruit is extremely high in potassium yet low in salt making it the perfect to beat blood pressure. So much so, the US Food and Drug Administration has just allowed the banana industry to make official claims for the fruit's ability to reduce the risk of blood pressure and stroke.

Brain Power: 200 students at a Twickenham (Middlesex) school were helped through their exams this year by eating bananas at breakfast, break and lunch in a bid to boost their brain power. Research has shown that the potassium packed fruit can assist learning by making pupils more alert.

Constipation: High in fiber, including bananas in the diet can help restore normal bowel action, helping to overcome the problem without resorting to laxatives.

Hangovers: One of the quickest ways of curing a hangover is to make a banana milk shake, sweetened with honey. The banana calms the stomach and, with the help of the honey, builds up depleted blood sugar levels, while the milk soothes and re-hydrates your system.

Heart burn: Bananas have a natural antacid effect in the body so if you suffer from heart burn, try eating a banana for soothing relief.

Morning Sickness: Snacking on bananas between meals helps to keep blood sugar levels up and avoid morning sickness.

Mosquito bites: Before reaching for the insect bite cream, try rubbing the affected area with the inside of a banana skin. Many people find it amazingly successful at reducing swelling and irritation.

Nerves: Bananas are high in B vitamins that help calm the nervous system.

Overweight and at work? Studies at the Institute of Psychology in Austria found pressure at work leads to gorging on comfort food like chocolate and crisps. Looking at 5,000 hospital patients, researchers found the most obese were more likely to be in high-pressure jobs. The report concluded that, to avoid panic induced food cravings, we need to control our blood sugar levels by snacking on high carbohydrate foods every two hours to keep levels steady.

Ulcers: The banana is used as the dietary food against intestinal disorders because of its soft texture and smoothness. It is the only raw fruit that can be eaten without distress in over chronicler cases. It also neutralizes over acidity and reduces irritation by coating the lining of the stomach.

Temperature control: Many other cultures see bananas as a 'cooling' fruit that can lower both the physical and emotional temperature of expectant mothers. In Thailand, for example, pregnant women eat bananas to ensure their baby is born with a cool temperature.

Seasonal Affective Disorder (SAD): Bananas can help SAD sufferers because they contain the natural mood enhancer, tryptophan.

Smoking: Bananas can also help people trying to give up smoking. The B6, B12 they contain, as well as the potassium and magnesium found in them, help the body recover from the effects of nicotine withdrawal.

Stress: Potassium is a vital mineral, which helps normalize the heartbeat, sends oxygen to the brain and regulates your body's water balance. When we are stressed, our metabolic rate rises, there by reducing our potassium levels. These can be re-balanced with the help of a high potassium banana snack.

Strokes: According to research in 'The New England Journal of Medicine' eating bananas as part of a regular diet can cut the risk of death by strokes by as much as 40%!

Warts: Those keen on natural alternatives swear that, if you want to kill off a wart, take a piece of banana skin and place it on the wart,with the yellow side out. Carefully hold the skin in place with a plaster or surgical tape!

So you see a banana really is a natural remedy for many ills. When you compare it to an apple, it has four times the protein, twice the carbohydrate, three times the phosphorus, five times the vitamin A and iron, and twice the other vitamins and minerals. It is also rich in potassium and is one of the best value foods around.

So maybe its time to change that well known phrase so that we say, "A Banana a day keeps the doctor away."

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Great White Bear

The polar bear rules the north. To the hardy native people who settled the harsh lands of the Arctic, the powerful hunter with the ghostly white coat is known as the “lonely roamer.” But most of us know the huge mammal as the polar bear. And the story of how the world’s largest land predator prospers in one of Earth’s harshest environments is the subject of the NATURE program Great White Bear.

In extraordinary scenes collected across the top of the world, Great White Bear shows that polar bears are prodigious roamers indeed. Single bears have been known to trek and swim as far as 3,000 miles across icy seas and mossy, treeless tundra in search of food. Typically, however, studies suggest the bears stay within a home range that is just a few hundred square miles. Still, polar bears, by far, range over the largest territories of any bear.

The reason for the huge territories, scientists believe, is the unpredictable availability of their favorite food: ringed seals. As Great White Bear shows, populations of this common, four-foot long arctic seal can build up and melt away mysteriously, much like the ice sheets the sleek swimmers often inhabit. In good years, the bears may not have to travel far to find a seal meal. But in bad years the dark, cream-spotted animals are few and far between.

Though polar bears are excellent swimmers — their scientific name, Ursus maritimus, means “sea bear” — they usually aren’t fast enough to catch a seal in open water. Instead, in winter, the bears creep within striking distance of one of the breathing holes the seals have made in the ice. When a seal pops its head out of the hole to catch a breath, as it must do every ten minutes or so, the bear leaps and yanks the unsuspecting bather out of the water.

Sometimes, however, bears take a more direct route: as Great White Bear shows, they will crash through the top layer of the ice itself in an effort to trap the seals that may be resting in the hollow space below.

Ringed seals are a staple of the polar bear diet. In early summer, when the seals like to bask in the warming sun, hunting bears must use a different strategy. They wait until the seals are asleep and then creep close, freezing in place when the snoozers periodically open an eye to check for danger. Eventually, if the seals don’t spot the stalker, the bear gets close enough to make a powerful pounce.

More often than not, however, the seals escape: some studies have shown that bears outwit their prey less than five percent of the time.

But when the hunting is good, bears can be finicky eaters. They will easily polish off a 100-pound meal consisting of the seal’s energy-packed skin and blubber, or fat layer. But they commonly will leave much of the less nutritious muscle behind. Young bears will sometimes devour the leftovers, but it is often another Arctic inhabitant — an Arctic fox or gull — that rushes in to claim a free meal.

It can take a lot of seals to satisfy a polar bear. Males can be ten feet tall and weigh 1,500 pounds, while females are smaller, topping the scales at about 550 pounds. Remarkably, however, the huge animals can withstand lengthy periods without food. Male bears, for instance, are routinely forced to go without a major meal for three or four months each summer, when melting ice prevents them from hunting seals. And pregnant females apparently go without food for eight months — a record among mammals. Mothers even keep fasting for some weeks after their one-pound cubs, usually twins, are born between late November and January. By the time the cubs have left her care one to three years later, however, the mother has rebuilt her energy stores and is ready for another litter.

To survive their forced diets, polar bears burn a thick layer of reserve fat. In some cases, this layer can be up to five inches thick. But the blubber doesn’t just store energy: in winter, it also provides an excellent insulating blanket in temperatures that can plunge to 40 degrees below zero. Other adaptations, such as a small tail and ears and two layers of specialized heat-trapping fur, also help the bears conserve heat. In addition, each hair of a polar bear’s coat is hollow and transparent, helping to draw the sun’s rays toward the bear’s black skin. But when things get too cold, even polar bears must seek shelter, digging out snow caves in which they curl up like giant furry balls.

In summer, however, that same fat can present a problem. Polar bears can easily overheat when they run — which probably explains why they spend much of their time loping across the landscape at such a leisurely pace. In the southern part of their range, where summer temperatures can rise to levels downright blistering for bears, they may even take to the water simply to stay cool. Such strategies have allowed polar bears, which can live for 30 years, to prosper for at least 200,000 years in a challenging Arctic landscape that is by winter enveloped in icy darkness and by summer bathed by a never-setting sun.

But hunting and environmental changes, such as signs that a warming climate could be melting pack ice, may be taking their toll on the bears. And concern is growing about pollutants, such as mercury and other toxic chemicals, that are making their way into the once pristine Arctic food chain. As a result, scientists are keeping an increasingly close eye on the up to 40,000 bears that live in Canada, Russia, Alaska, Greenland, and Norway. “If a polar bear population is healthy, then one can probably safely assume that the rest of the components of that food chain are doing well,” explains a spokesman for the Canadian Wildlife Service, which has sponsored extensive monitoring studies. “However, if problems develop with polar bear populations, it may indicate problems elsewhere in the ecosystem.”

The goal, scientists involved in such studies say, is to make sure that the Arctic’s great white bear continues to roam across the top of the world.

http://www.pbs.org/

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The remarkable bee

Bees can be used to detect landmines. Tiny radio plates the size of a rice grain will be attached to honey bees to detect antipersonnel landmines, of which there are about 100 million in 70 war-torn countries.

The tiny radio plates are engraved with serial numbers to keep track of the bees, which are being conditioned to develop a preference in addition to nectar, in this case TNT, or any other material that releases metamphenamine. Special spectrometers that can "smell" TNT are placed in movable beehives to indicate landmines in specific areas. Bees that "smell" of explosives can then be tracked to the landmine. The bees won't detonate the landmines.

This is just one of many reasons why bees are important to us. Without bees, there will be no flowers or crops. Although birds, other insects and the wind also pollinate plants, bees do most of it.
Busy bees

Bee pic by PO GustafssonBetween 20 000 and 60 000 bees live in a single hive. The queen bee lays 1 500 eggs a day and lives for up to 2 years. The drone, whose only job it is to mate with the queen bee, has a lifespan of around 24 days - they have no stinger. Worker bees - all sterile females - usually work themselves to death within 40 days in summer, collecting pollen and nectar. Worker bees fly up to 14km (9 miles) to find pollen and nectar, flying at 24km/h (15 mph).

Pollen is the main supply of protein and vitamins for bees, with the 10 amino acids they require. Nectar is up to 80% sugar but less than 0.2% in protein, so nectar is the carbohydrate supply for the hive. Bees place the nectar in honeycomb cells and then evaporate the water from the nectar by rapid wing movement. When the amount of water is less than 18%, the mixture is called honey and the bees cap off the cells. Thus honey is 80% sugars and 20% water. A mixture of honey and pollen is called "bee bread" and is the food for larvae and bees.

A worker bee communicates her floral findings by performing a dance on the honeycomb. The orientation of her movements and the frequency of her vibrations indicate the direction and distance of the flowers.
The sting

Bee pic by PO GustafssonThe worker bees defend the hive. The muscular barbed stinger quickly saw into the skin of the invader and the venom pouch begins to contract rhythmically to pump venom into the intruder.

But the bee species themselves are under severe attack: in recent years thousands of colonies were destroyed by two parasitic mites, acarapis woodi and varroa jacobsoni. Scientist have not discovered a remedy yet, but have noticed a disturbing trend: the highest numbers of infested bees and the highest infestation rates were seen at high stress sites, ie. polluted areas. In addition, as the human population rapidly increases and take down woods and forests the ideal breeding space for bees are destroyed. However, we can make a difference. The challenge to individuals like us is to protect these amazing animals by making our gardens bee-friendly.

Bee pic by PO GustafssonThe bee is a remarkable animal - flowers are pollinated mostly by bees; up to one third of all plant pollination on earth are by bees. In short, this means that one in every three spoons of food you put in your mouth was a direct result of the work done by bees. And they do it for free.

Bees do not have ears, but they have an excellent sense of smell with chemoreceptors in their antennae. Bees see colors differently than we do. They are insensitive to red but detects ultraviolet light which is invisible to us.

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