Bubbles turn on chemical catalysts

Scientists have figured out a new way to strong-arm some catalysts, tying the chemical compounds down and then, as needed, unleashing them with brute force. The research, published online April 6 in Nature Chemistry, could lead to coatings that heal when scratched or new fluids for making moldings or microchips. The work also offers a way to monitor stress in materials found in products such as bike helmets.
A catalyst’s job is to speed up or slow down a reaction in everything from car engines to cells. But to do so, an area known as the active site has to be exposed. In materials science, catalysts are often spurred into action with heat, UV light or a change in pH. In the new study scientists used the ultrasonic force released by bursting bubbles to unleash two catalysts that had been bound in chains of polymers.
“This has a lot of materials applications,” comments chemist Alshakim Nelson of the IBM Almaden Research Center in San Jose, Calif. “It offers a lot of control.”
A team of researchers led by Rint Sijbesma of the Eindhoven University of Technology in the Netherlands began by experimenting with known catalysts, including one based on the versatile ruthenium. This platinum-related metal’s catalytic properties were explored by Robert Grubbs, who shared the Nobel Prize in chemistry in 2005 for his work.
The scientists started with catalysts that included a metal — either ruthenium or silver — sandwiched between molecules known as carbenes. Carbene-metal combinations are often used because they are stable but can be activated as necessary.
To each carbene, the scientists attached a long polymer chain, so the latent catalysts sat at the center like a watch face with two extended straps. The chained catalysts were mixed in flasks with a particular set of chemicals. Then the researchers stuck an ultrasound probe into each flask.
The force generated by the ultrasound stressed the polymer chains, which extended.
“It’s just like in a game of tug-of-war,” Sijbesma says. “There is drag on every piece of the chain, and at the center of the chain the force is the highest.”
As the chains extended, a break eventually occurred at the weakest point, between the polymer chain and the carbene. This exposed the active site of the catalysts — in one instance the ruthenium and in the other the carbene. Thus, the reactions proceeded at a time precisely dictated by the ultrasound.
After one hour with the ultrasound probe in a flask containing benzyl alcohol, vinyl acetate and the silver-based chained catalyst, 65 percent of the reactants converted to the desired product, benzyl acetate. Only 3 percent did so in control flasks that received no sonification, the researchers report. The yield was lower in the flask with the ruthenium-based chained catalyst.
The yield will have to improve for the reactions to be less wasteful, Nelson says. Chemists typically strive for a 99 percent conversion rate, which costs less time and money. But fine-tuning the setup may result in better yields, he says.
While the team used ultrasound in the current study, Sijbesma envisions the chained catalysts being embedded in materials such as a coating on a car or a building, where the actual force of a scratch would release the catalyst and the material would automatically heal.
The findings could also be applied to large- and small-scale fluid operations where the force of sending a fluid through a jet spurs the liquid to solidify. Dyes could be incorporated into materials so they change color where the catalyst has been active, alerting a biker to weak spots on a helmet, for example.
Discovering that force applied to polymer chains could be used to control a catalyst was particularly exciting, says Sijbesma. “I had had this in my mind for quite a few years.”

Viruses could power devices

A computer virus won’t help your laptop work — but a biological virus could. Tweaking their genes just so could engineer viruses for making the rechargeable lithium ion batteries that power devices such as laptops, iPods and cell phones, researchers report online April 2 in Science.
In previous research, the same team used viruses to construct the negative electrode, or anode, of the battery. In the new work, the researchers engineered viruses for the positive electrode, or cathode. When the two are put together, the virus batteries should perform better than traditional lithium ion batteries and also be environmentally friendly, the team reports.
“Because the viruses are living organisms, we had to use only water-based solvents, no high pressures and no high temperatures,” says Angela Belcher, a materials scientist at the Massachusetts Institute of Technology in Cambridge and a study coauthor.
Lithium ion batteries store up and release electrical energy when lithium ions and electrons move between the anode and cathode. The cathode is often made of iron phosphate, a stable material that, when it reacts with lithium, has a high capacity to store energy. But it’s not a very good conductor. The movement of ions and electrons through the cathode is relatively slow, making the battery less efficient at releasing energy.
Ions and electrons can move through smaller particles more quickly. But fabricating nano-sized particles of iron phosphate is a difficult and expensive process, the researchers say.
So Belcher’s team let the virus do the work. By manipulating a gene of the M13 virus to make the viruses coat themselves in iron phosphate, the researchers created very small iron phosphate particles.
“We’re using a biological template that’s already on the nanoscale,” Belcher says.
Tweaking a second gene made one end of the virus bind to carbon nanotubes, which conduct energy well. The resulting network of iron phosphate-coated viruses and carbon nanotubes formed a highly conductive cathode, one that ions and electrons could move through quickly.
“This work is an exciting breakthrough,” comments battery chemist Kang Xu of the U.S. Army Research Laboratory in Adelphi, Md. “Belcher is the first to use viruses as a nano-template to assemble materials.”
Using different cathode materials could make the future batteries even better, Belcher says. “This paper proved that the concept works.”

zeedonk zebra-donkey hybrid

Endangered Animals The first meaning is the result of interbreeding between two animals or plants of different taxa.
Hybrids between different species within the same genus are sometimes known as interspecific hybrids or crosses.
Hybrids between different sub-species within a species are known as intra-specific hybrids.
Hybrids between different genera are sometimes known as intergeneric hybrids.
Extremely rare interfamilial hybrids have been known to occur (such as the guineafowl hybrids).
The second meaning of "hybrid" is crosses between populations, breeds or cultivars of a single species.
This second meaning is often used in plant and animal breeding. An example of an intraspecific hybrid is a hybrid between a Bengal tiger and an Amur (Siberian) tiger.
Interspecific hybrids are bred by mating two species, normally from within the same genus.
The offspring display traits and characteristics of both parents.
The offspring of an interspecific cross very often are sterile, this hybrid sterility prevents the movement of genes from one species to the other, keeping both species distinct.
Sterility is often attributed to the different number of chromosomes the two species have, for example donkeys have 62 chromosomes, while horses have 64 chromosomes, and mules and hinnies have 63 chromosomes.
Mules, hinnies, and other normally sterile interspecific hybrids cannot produce viable gametes because the extra chromosome cannot make a homologous pair at meiosis, meiosis is disrupted, and viable sperm and eggs are not formed.
However, fertility in female mules has been reported with a donkey as the father.
Most often other mechanisms are used by plants and animals to keep gametic isolation and species distinction.
Species often have different mating or courtship patterns or behavours, the breeding seasons maybe distinct and even if mating does occur antigenic reactions to the sperm of other species prevent fertilization or embryo development.
The Lonicera fly is the first known animal species that resulted from natural hybridization.
Until the discovery of the Lonicera fly, this process was known to occur in nature only among plants..
For more information about the topic Hybrid, read the full article at Wikipedia.org, or see the following related articles:
Zeedonk (zebra - donkey hybrid) — A zeedonk (also spelled zedonk) (also known a zebrass, zebronkey, zonkey, zebadonk, zenkey or deebra) is an interspecies cross between a zebra and a ... > read moreCanine hybrids — Canid hybrids are the result of interbreeding between two different members of the canine (dog) family (Canidae). The wolf (including the dingo), ... > read moreHinny — A hinny is the offspring of a male horse and a female donkey (jennet or jenny). They are rarer than mules, which are the offspring of a male donkey ... > read moreTransgenic plants — Transgenic plants are plants that have been genetically engineered, a breeding approach that uses recombinant DNA techniques to create plants with ... > read more

The arachnids, Arachnida, are a class of joint-legged invertebrate animals in the subphylum Chelicerata. Arachnids are named for the mythological figure Arachne. They are chiefly terrestrial arthropods, some 65,000 to 73,000 species including the spiders, scorpions, harvestmen, ticks, and mites. The arachnids are easily distinguished from the insects by the fact that they have eight legs instead of six. The pedipalpi (leg-like mouthparts) of some species has instead been adapted for sensory, prey capture or reproductive functions. In solifugae the palpi are quite leg-like and make solifugae appear to have ten legs. Larval mites have only six legs: they grow their fourth pair when they molt into nymphs.

Arachnids are further distinguished by the fact they have no antennae and no wings. They have a two-segment body, made up merely of the thorax and abdomen.

Arachnids are mostly carnivorous, feeding on the pre-digested bodies of insects and other small animals. Many are venomous - they secrete poison from specialized glands to kill prey or enemies. Others are parasites, some of which are carriers of disease. Arachnids usually lay eggs, which hatch into immature adults.


Physical characteristics
The scorpion body is divided into 2 main segments: the cephalothorax (also called the prosoma) and the abdomen/opisthosoma. The abdomen consists of the mesosoma and the metasoma.

Cephalothorax/prosoma: the “head” of the scorpion comprising the carapace, eyes, chelicerae (mouth parts), pedipalps ( claw) and the 4 pairs of walking legs.

Mesosoma: The first half of the abdomen and is made up of six segments. The first segment contains the sexual organs as well as a pair of vestigial and modified appendages forming a structure called the genital operculum. The second segment bears a pair of featherlike sensory organs known as the pectines. And the final four segments each contains a pair of book lungs. The mesosoma is armoured with chitinous plates, on the upper surface by the tergites and on the lower surface by the sternites.

Metasoma: The tail of the scorpion comprising 6 segments (the first tail segment looks like a last mesosoman segment), the last containing the anus of the scorpion and bearing the telson (the sting). The telson, in turn, consists of the vesicle, which holds a pair of venom (poison) glands, and the hypodermic aculeus, the barb used to inject the venom.

Cuticle: The cuticle makes a tough armour around the body. In some places it covered with hairs that acts like balance organs. An outer layer that makes them fluoresce in green under ultraviolet light is called the hyaline layer. Newly molted scorpions do not glow before after their cuticle has hardened. The hyaline layer is said to still be intact in hundreds of millions of years old fossil rocks, and it is still able to fluoresce.

Main scorpion physical features:

Pedipalps: The claws. Some believe these were originally modified legs that evolved into claws. The claws are used primarily for prey capture, but also play an important part in the scorpion mating dance. The pedipalps are made of up of 6 segments. The claw itself consists of the upper fixed finger ( tibia) and the lower movable finger ( tarsus). The size of the pedipalps is highly dependent on the species; however a general trend is that the more venomous the scorpion, the narrower the pedipalps, as scorpions with less potent venom use their larger pincers to subdue prey.

Pectines: These are a pair of feather-like sensory organs, consisting of a row of pegs, and are unique in scorpions. The pectines are located beneath the scorpion, attached to the sternum. They constantly touch the ground and play an important role in the scorpion's sensory equipment. The pectines are covered in thousands of chemosensors that allow the scorpion to detect minute chemical signals in their environment; they probably play an important role in social interaction, mating and hunting.

Eyes: Fossil scorpions had compund eyes, present scorpions in general have three sets of eyes. One pair located in the top centre of the carapace are called the median eyes. There are two more sets of lateral eyes on either side of the front of prosoma, the number varies between species. In total there are usually from three and up to six pairs of eyes present. Some species of cave- and litter-dwelling scorpions, however, have no eyes, relying purely on their other senses. Scorpions' eyes are primitive organs, only able to detect regions of strongly contrasting light intensity, such as horizons. The eyes are however very sensitive: some have theorised that they even allow the scorpion to navigate by star light, and they are important in regulating the scorpion's circadian rhythm. It is doubtful as to whether they are used in prey capture.

Sound: Scorpions make a characteristic sound similar to the rasping or chirping of cockroaches, but a bit higher pitched.


Scorpion venom
All species of scorpion possess venom. In general scorpion venom is described as neurotoxic in nature. It consists of a variety of small proteins as well as sodium and potassium cations, which serve to interfere with neurotransmission in the victim. Scorpions use their venom to kill or paralyze their prey so that it can be eaten; in general it is fast acting, allowing for effective prey capture.

Scorpion venoms are geared towards activity in other arthropods and therefore most scorpions are relatively harmless to humans; stings produce only local effects (such as pain, numbness or swelling). However a few scorpions, mostly in the family Buthidae, can be dangerous to humans. Among the most dangerous are Leiurus quinquestriatus, which has the most potent venom in the family, and members of genus Parabuthus, Tityus and Androctonus whose venom is also strong. These scorpions and others in the family Buthidae have been responsible for many deaths, although scorpions are generally unable to deliver enough venom to kill healthy adults; deaths normally occur in the young, elderly or infirm. Unless molested, scorpions are generally harmless and timid, and only make use of the sting for the purpose of killing prey. Generally, they will run from danger, or remain very still. It is unknown whether scorpions are venom conservers, however often the venom is not used unless the prey cannot be subdued with the claws. Many species of scorpions such as Pandinus and Hadogenes rarely, if ever, use their venom, instead relying on their strong bulky pedipalps in prey capture.


Reproduction
Scorpions generally reproduce sexually and all species have male and female individuals. Reproduction is accomplished by the transfer of a spermatophore from the male to the female; scorpions have evolved a complex courtship and mating ritual to effect this transfer.

Mating starts by the male and female locating and identifying each other using a mixture of pheromones and vibronic communication, once they have satisfied each other that they are of opposite sex and of the correct species mating can commence.

The courtship starts with the male grasping the female’s pedipalps with his own; the pair then performs a “dance” called the “promenade à deux”. In reality this is the male leading the female around searching for a suitable place to deposit his spermatophore. The courtship ritual can involve several other behaviours such as juddering and a cheliceral kiss, probably as a meanings of pacifying the female.

When he has identified a suitable location he guides the female over the spermatophore allowing it to enter her genital opercula, this triggers release of the sperm; fertilising the female. The mating process can take from 1 to 25+ hours and depends on the ability of the male to find a suitable place to deposit his spermatophore, if mating goes on for too long females may eventually break off the process.

Once the mating is complete the male and female quickly separate: the male will generally retreat quickly to avoid being cannibalised by the female, although sexual cannibalism is infrequent with scorpions.


Birth and development

Compsobutus werneri female with youngUnlike the majority of Arachnida, scorpions are viviparous. The young are born one by one, and the brood is carried about on its mother's back until the young have under gone at least one moult. Before the first moult scorplings cannot survive naturally without the mother, depending on her for protection and to regulate their moisture levels. In some species the young/mother association can continue for an extended period of time especially in species which display more advanced sociability (e.g Pandinus spp.). The size of the litter depends on the species and can range from 3 to 100+ scorplings .

The young in a general way resemble their parents. Growth is accomplished by periodical shedding of the exoskeleton ( ecdysis). A scorpion's developmental progress is measured in instars (how many moults it has undergone). Generally scorpions require between 5-7 moults to reach maturity. Moulting is effected by means of a split in the old exoskeleton which takes place just below the edge of the carapace (at the front of the prosoma). The scorpion then emerges from this split, the pedipalps and legs are first removed from the old exoskeleton, followed eventually by the metasoma. When it emerges the scorpion’s new exoskeleton is soft, making the scorpion highly vulnerable to attack. The scorpion must constantly stretch while the new exoskeleton hardens to ensure that it can move when the hardening is complete. The process of hardening is called sclerotization. The new exoskeleton does not fluoresce, however as sclerotization occurs the fluorescence gradually returns.

Scorpions have very variable life spans and the actual life span of most species is not known, however the range is approximately 4-25 years (25 years being the maximum reported life span of the species H. arizonensis)


Origins
Scorpion remains are often found in coal deposits that are believed to be of the Carboniferous Period, and no essential structural difference has been discovered between these fossils and existing forms—suggesting that the group has existed without material structural modification for millions of years. These scorpions were believed to be preceded by others, now occurring in marine Silurian deposits, which apparently lived in the sea and exhibit some anatomical differences marking them off as a group distinct from their Carboniferous and recent descendants and attesting affinity with the still earlier marine Arachnida referred to the group Gigantostraca. Their legs were thought to be short, thick, tapering, and ended in a single strong claw, and were well adapted, it seems, like the legs of shore-crabs, for maintaining a secure hold upon rocks or seaweed against the wash of waves. The method of breathing of these ancient types is not certainly known; but probably respiration was effected by means of book gills attached to the ventral plates of the body. At all events no trace of respiratory stigmata has been detected even in well-preserved material. These Silurian scorpions, of which the best-known genus is Palaeophonus, were of small size, only two to five centimeters in length.

Myrmeleontidae

Antlions are a family of insects, classified as Myrmeleontidae, from the Greek "myrmex", meaning "ant", and "leon", meaning "lion". Antlions are small, fully developed larvae being 1.5 cm, and adults being 4 cm. Antlions are omnivorous. The antlion larvae eat ants and other insects, while the adult antlion eats pollen and nectar.

The antlion is most often called a " doodlebug". One theory is that it gets this name from the odd winding, spiralling trails it leaves in the sand while looking for a good location to build its trap. These trails look like someone has doodled in the sand.

The adult antlion has two pairs of long, narrow, multi-veined wings in which the apical veins enclose regular oblong spaces, and a long, slender abdomen. Although they greatly resemble dragonflies or damselflies, they belong to an entirely different order of insects. Antlions are easily distinguished from damselflies by their longer, prominent, apically clubbed antennae and different type of wing pattern. They also are very feeble fliers and are normally found fluttering about in the night, in search of a mate. The adult is rarely seen in the wild because it is active only in the evening. During the day it rests, motionless, well- camouflaged by its transparent wings and brownish body.

The best-known species, Myrmeleon formicarius, which may be found adult in the late summer, occurs in many countries on the European continent, though like the rest of this group it is not indigenous in England. Strictly speaking, however, the term antlion applies to the larval form, which has been known scientifically for over two hundred years, on account of its peculiar and forbidding appearance and its skilful and unique manner of entrapping prey by means of a pitfall.

The life cycle of the antlion begins with egg-laying or "oviposition". The female antlion repeatedly taps the sand surface with the tip of her abdomen. She then inserts the abdomen into the sand and lays an egg. The antlion larva is a ferocious-appearing creature with a robust, fusiform body bearing three pairs of walking legs and a prothorax forming a slender mobile neck for the large square head, which bears an enormous pair of sicklelike jaws (mandibles) with several sharp, hollow projections. Depending on species and where it lives, the larvae will either hide under leaves or pieces of wood, or dig pits in sandy areas.


Closeup of an antlion larvaHaving marked out the chosen site by a circular groove, it starts to crawl backwards, using its abdomen as a plough to shovel up the soil. By the aid of one front leg it places consecutive heaps of loosened particles upon its head, then with a smart jerk throws each little pile clear of the scene of operations. Proceeding thus it gradually works its way from the circumference towards the centre. As it slowly moves round and round, the pit gradually gets deeper and deeper. When the pit is completed, the larva settles down at the bottom, buried in the soil with only the jaws projecting above the surface, often in a wide-opened position on either side of the very tip of the cone.


Sand pit trap of the antlionSince the sides of the pit consist of loose sand they afford an insecure foothold to any small insects that inadvertently venture over the edge, such as ants. Slipping to the bottom the prey is immediately seized by the lurking ant-lion; or if it attempt to scramble again up the treacherous walls of the pit, is speedily checked in its efforts and brought down by showers of loose sand which are jerked at it from below by the larva. Antlion larvae are capable of capturing and killing a variety of insects, and can even subdue small spiders. The projections in the jaws of the insect are hollow and through this the larva will suck the fluids out of its victim. After consuming all the contents, the lifeless, dry carcass is flicked out of the pit, and the pit is readied once again. A full-grown larva digs a pit about 2 inches deep and 3 inches wide at the edge.


Adult AntlionAntlions are especially abundant in soft sand beneath trees or under overhanging rocks. Apparently the larvae prefer dry places that are protected from the rain. Eventually the larva attains its maximum size and undergoes metamorphosis. The entire length of time from egg-laying to adulthood may take two or three years due to the uncertainty and irregular nature of its food supply. When it first hatches, the tiny larva specializes in very small insects, but as it grows larger, it constructs larger pits and thus catches larger prey.

Although antlion larva have a ferocious appearance, they are completely harmless to humans. In fact, there are those who keep them as pets.

The pupa stage of the ant-lion is quiescent. The larva makes a globular cocoon of sand stuck together with fine silk spun, it is said, from a slender spinneret at the posterior end of the body. These cocoons may be buried several centimeters deep in the sand. It remains there for one month, until the completion of the transformation into the sexually mature insect, which then emerges from the case, leaving the pupal integument behind, and climbs to the surface. After about 20 minutes the adult's wings are fully opened and it will fly off in search of a mate.

In certain species of Myrmeleonidae, such as Dendroleon pantheormis, the larva, although resembling that of Myrmeleon structurally, makes no pitfall, but seizes passing prey from any nook or crevice in which it shelters.

The exact meaning of the name ant-lion (French fourmilion) is uncertain. It has been thought that it refers to the fact that ants form a large percentage of the prey of the insect, the suffix "lion" merely suggesting destroyer or eater. Perhaps, however, the name may only signify a large terrestrial biting apterous insect, surpassing the ant in size and predatory habits.

angel sharks

The angel sharks are an unusual group of sharks, with their flattened bodies and broad pectoral fins that give them a strong resemblance to skates and rays. The 16-odd known species are all classified in a single genus Squatina belonging to its own family Squatinidae and order Squatiniformes. They occur worldwide in temperate and tropical seas.

While the forward part of the body is broad and flattened, the rear part retains a muscular appearance more typical of other sharks. The eyes and spiracles are on top, and the five gill slits are on bottom. Both the pectorals and the pelvic fins are large and held horizontally. There are two dorsal fins, no anal fin, and unusually for sharks, the lower lobe of the caudal fin is longer than the upper lobe. Most types grow to a length of 1.5 meters (5 ft), with the Japanese angel shark Squatina japonica known to reach 2 meters.

Angel sharks are bottom-dwellers, burying themselves in sand or mud, then lunging to snap up prey, which includes fish, crustaceans, and various types of mollusks. The Pacific angel shark Squatina californica is also known to leave the bottom at night to forage. Although they are not normally aggressive, they do bite when stepped on or handled.

Angel sharks are ovoviviparous, with litters known up to 13 pups.

The sharks were long considered of no commercial interest, but in 1978, Michael Wagner, a fish processor in Santa Barbara, California began to promote angel sharks, and 310 metric tons were taken off California in 1984. The fishery devastated the population, and is now regulated

The molluscs or mollusks are the large and diverse phylum Mollusca, which includes a variety of familiar creatures well-known for their decorative shells or as seafood. These range from tiny snails, clams, and abalone to the octopus and squid (which are considered the most intelligent invertebrates). There are some 70,000 described species within this phylum [1].

The giant squid, which until recently had not been observed alive in its adult form is the largest invertebrate although it is likely that the Colossal Squid is even larger. The scientific study of molluscs is called malacology.



Anatomy
Molluscs are triploblastic protostomes. The principal body cavity is a blood-filled hemocoel. It is unknown whether they have a true coelom (eucoelom); any coelomic cavities have been reduced to vestiges around the hearts, gonads, and metanephridia ( kidney-like organs). The body is often divided into a head, with eyes or tentacles, a muscular foot and a visceral mass housing the organs.

Molluscs have a mantle, which is a fold of the outer skin lining the shell, and a muscular foot that is used for motion. Many molluscs have their mantle produce a calcium carbonate external shell and their gill extracts oxygen from the water and disposes waste. All species of the phylum Mollusca have a complete digestive tract that starts from the mouth to the anus. Many have a feeding structure, the radula, mostly composed of chitin. Radulae are diverse within the Mollusca, ranging from structures used to scrape algae off rocks, to the harpoon-like structures of cone snails. Cephalopods (squid, octopuses, cuttlefish) also possess a chitinous beak. Unlike the closely related annelids, molluscs lack body segmentation.

Development passes through one or two trochophore stages, one of which (the veliger) is unique to the group. These suggest a close relationship between the molluscs and various other protostomes, notably the Annelids.

Mollusc fossils are some of the best known and are found from the Cambrian onwards.

The octopus is a cephalopod of the order Octopoda that inhabits many diverse regions of the ocean, especially coral reefs. The term may also refer to only those creatures in the genus Octopus. In the larger sense, there are 289 different octopus species, which is over one-third the total number of cephalopod species.

Octopuses are characterized by their eight arms (not tentacles), usually bearing suction cups. These arms are a type of muscular hydrostat. Unlike most other cephalopods, the majority of octopuses — those in the suborder most commonly known, Incirrata — have almost entirely soft bodies with no internal skeleton. They have neither a protective outer shell like the nautilus, nor any vestige of an internal shell or bones, like cuttlefish or squids. A beak, similar in shape to a parrot's beak, is their only hard part. This enables them to squeeze through very narrow slits between underwater rocks, which is very helpful when they are fleeing from morays or other predatory fish. The octopuses in the less familiar Cirrata suborder have two fins and an internal shell, generally lessening their ability to squeeze into small spaces.

Three defensive mechanisms are typical of octopuses: ink sacs, camouflage, and autotomising limbs. Most octopuses can eject a thick blackish ink in a large cloud to aid in escaping from predators. They also have specialized skin cells both for colour changing ( chromatophores) and light reflection and refraction ( iridophores and leucophores). They use this ability to blend into the environment to hide, communicate with other octopuses, or warn. The very poisonous Blue-ringed Octopus becomes bright yellow with blue rings when it is provoked. When under attack, some octopuses can autotomise their limbs, in a similar manner to skinks and other lizards. The crawling arm serves as a distraction to would-be predators; this ability is also used in mating. A few species, such as the Mimic Octopus have a fourth defense mechanism. They can combine their highly flexible bodies with their colour changing ability to accurately mimic other, more dangerous animals such as lionfish and eels.

When octopuses reproduce, they use a specialized arm called a hectocotylus to insert spermatophores (packets of sperm) into the female's mantle cavity. The hectocotylus is usually the third right arm. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female lays roughly 200,000 eggs (this figure dramatically varies between species). The female hangs these eggs in strings from the ceiling of her lair. After the eggs hatch, the young larval octopuses must spend a period of time drifting in clouds of plankton, where they feed on copepods, larval crabs and larval seastars until they are ready to sink down to the bottom of the ocean, where the cycle repeats itself. In some deeper dwelling species, the young don't go through this period. This is a dangerous time for the larval octopuses; as they become part of the plankton cloud they are vulnerable to many plankton eaters.

Octopuses have a relatively short life span, and some species live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch, for they neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs.

Octopuses have three hearts. Two pump blood through each of the two gills, while the third pumps blood through the body. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Less efficient than the iron-rich hemoglobin of vertebrates, the hemocyanin is dissolved in the plasma instead of being bound in red blood cells and gives the blood a blue colour.



Intelligence
Octopuses are highly intelligent, probably the most intelligent of any of the invertebrates, with their intelligence supposedly comparable to that of the average housecat. Maze and problem-solving experiments show that they have both short- and long-term memory, although their short lifespans limit the amount they can ultimately learn.

An octopus has a highly complex nervous system, only part of which is localized in its brain. Two-thirds of an octopus's neurons are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. Some octopuses, such as the mimic octopus, will move their arms in ways that emulate the movements of other sea creatures.

In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They are able to open jars after learning from observation. Octopuses have also been observed in what may be described as play; repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing ships and opened holds to eat crabs.

In many countries, including the United States and the United Kingdom, octopuses are on the list of experimental animals on which surgery may not be performed without anesthesia.


Sensation
Octopuses have keen eyesight. Although their slit-shaped pupils might be expected to afflict them with astigmatism, it appears that this is not a problem in the light levels in which an octopus typically hunts. Surprisingly, they do not appear to have colour vision, although they can distinguish the polarization of light. Attached to the brain are two special organs, called statocysts, that allow the octopus to sense the orientation of its body relative to horizontal. An autonomic response keeps the octopus's eyes oriented so that the pupil slit is always horizontal.

Octopuses also have an excellent sense of touch. The octopus's suckers are equipped with chemoreceptors so that the octopus can taste what it is touching. The arms contain tension sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus's body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus's arms is much greater than that of the limbs of vertebrates, which devote large areas of cerebral cortex to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.

The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.


Locomotion
Octopuses move about by crawling or swimming. Their main means of slow travel is crawling, with some swimming. Their only means of fast travel is swimming.

They crawl by walking on their arms, usually on many at once, on solid surfaces, while supported in water. In 2005 it was reported that some octopuses can walk on two arms on a solid surface, while at the same time imitating a coconut or a clump of seaweed.

They swim by expelling a jet of water from a contractile mantle, and aiming it via a muscular siphon.

Introduction
The Alpaca (Vicugna pacos) is one of two domesticated breeds of South American camel-like ungulates, derived from the wild guanaco. It resembles a sheep in appearance, but is larger in size, and has a long erect neck with a handsome head.

Alpacas are kept in large flocks that graze on the level heights of the Andes of southern Peru, northern Bolivia, and northern Chile at an altitude of between 3500 and 5000 meters above sea-level, throughout the year. They are not used as beasts of burden like llamas, but are valued only for their fiber, of which Indian blankets and ponchos are made. The alpaca comes in 22 natural colours. In stature, the alpaca is considerably inferior to the llama, but has the same unpleasant habit of spitting.

In the textile industry, "alpaca" is a name given to two distinct things. It is primarily a term applied to the wool, or rather hair, obtained from the Peruvian alpaca. It is, however, more broadly applied to a style of fabric originally made from alpaca fiber but now frequently made from a similar type of fiber, such as mohair, Icelandic sheep wool, or even some high-quality English wool. In trade, distinctions are made between alpacas and the several styles of mohairs and lustres. However, as far as the general purchaser is concerned, little or no distinction is made.


Background

Alpacas have been domesticated for thousands of years, and originate from Peru, Chile and Bolivia. There are no wild alpacas; it is believed that they are descended from the vicuna, which is also native to South America. They are closely related to llamas, which are descended from the guanaco. These four species of animals are collectively called camelids.

Of the four, the alpaca and the vicuña are the most valuable wool-bearing animals: the alpaca because of the quality and quantity of its wool, and the vicuña because of the softness, fineness and quality of its coat.

Alpacas and llamas can (and do) successfully cross breed, the resulting offspring are called huarizo.

There are two types of alpaca – huacaya (with crimpy sheep-like “wool”) and suri (with silky dreadlocks). Suris are much rarer than huacaya, estimated to make up between 6 and 10% of the alpaca population. The suri is probably rarer because it is less hardy in the harsh South American mountain climates, as the style of its fleece offers less insulation against the cold (the suri fleece parts along the spine, exposing the animal to the cold unlike the huacaya fleece which provides excellent cover over the backbone).

Alpaca fleece is a luxurious fibre, similar to sheep’s wool in some respects, although it is lighter in weight, silkier to the touch, warmer and not as prickly. A big trade of alpace fleece exists in the countries where alpacas live, from very simple and not so expensive garments made by the aboriginal communities, to sophisticated products industrially made, that can have significantly high prices.

White is the predominant colour of alpacas, both suri and huacaya. This is because selective breeding has favoured white – bulk white fleece is easier to market and can be dyed any colour. However, alpacas come in 22 natural colours, from a true blue black through browns and fawns to white, and there are silver greys and rose greys as well.

Traditionally, alpaca meat has been eaten fresh, fried or in stews, by Andean inhabitants. There is a resurgent interest in alpaca meat in countries like Peru, where it is relatively easy to find it at upscale restaurants.


Alpaca behaviour

Alpacas are social herd animals and should always be kept with others of their kind. They are gentle and elegant, inquisitive and observant. As they are a prey animal, rather than a predator, they are cautious and will understandably be nervous if they feel threatened. They like their own space and don’t appreciate another alpaca (or human) getting too close, especially from behind. They will warn the intruder away by threatening to spit, or by spitting, or by kicking. Some alpacas kick, some don’t – but yes, they all spit.

Spitting is reserved for other alpacas, not for humans, but sometimes the human can get in the line of fire, or the alpaca aims badly and misses the intended target. The spit is not pleasant: it is the contents of the stomach – green (regurgitated grass) – and smells foul.

Alpacas don’t like their heads being touched. Once they know their owners, and feel confident around them, they will probably allow their backs and necks to be touched, but they won’t appreciate being grabbed, especially by boisterous children. If an owner need to catch an alpaca, the neck offers a good handle – and holding the neck firmly between the arms is the best way to restrain the animal.

To help alpacas control their internal parasites they have a communal dung pile, which they do not graze. Generally, males have much tidier dung piles than females who tend to stand in a line and all go at once!

Sheep baa, cows moo and alpacas hum. Different animals have different voices, but basically it is a "mmm" sound. However, they make other sounds as well as humming. When danger is present they sound the alarm call, a high pitched shriek, for instance. Some breeds are known to make a sound similar to a "Wark" noise when excited, and they stand proud with their tails sticking out and their ears in a very alert position. Strange dogs – and even cats – can trigger this reaction. (They recognise domestic cats for what they are – a relation of the puma, a natural predator of the alpaca in South America.)

When males fight they also scream, a warbling bird-like cry, presumably intended to terrify the other combatant. Fighting is to determine dominance, and therefore the right to mate the females in the herd, and it is triggered by testosterone. This is why males are often kept in separate paddocks – when two dominant males get together war breaks out!

A male in the act of mating, or hoping for a chance to mate, will “orgle.” This orgling will help to put the female in the mood, and it is believed that it also helps her to ovulate after the act of mating – very necessary for a pregnancy to take place!

Pregnancies last eleven and a half months and the young are called crias. Soon after the cria is born the female will be ready to mate again, babies are therefore an annual event. A female is usually ready to mate for the first time at a year of age, but a male can often not work until he is two or even three years old.

Alpacas generally live for more than 20 years – we think! Conditions and nutrition are better in the USA, Australia, New Zealand and Europe than in South America, so animals live longer and are healthier. One of the oldest alpacas in New Zealand (fondly known as Vomiting Violet) died at the end of 2005 at the ripe old age of 29.


History of the Scientific Name
In 1758 the four South American camelid species were assigned scientific names. At that time, the alpaca was assumed to be descended from the llama, ignoring similarities in size, fleece and dentition between the alpaca and the vicuña. Classification was complicated by the fact that all four species of South American camelid can interbreed and produce fertile offspring. It was not until the advent of DNA technology that a more accurate classification was possible.

Miss Great Aunt Edds started the first out of continent farm. She established the first Canadian Alpaca farm outside of Kingston Ontario. Originally started with only 4 alpacas, the farm grew to no less than 24 alpacas by 2005. The alpacas, originally raised for their fleece, now also serve the local restaurant industry, providing them with delicious alpaca steaks.

In 2001 the alpaca genus classification changed from Lama pacos to Vicugna pacos following the presentation of a paper Genetic analysis reveals the wild ancestors of the llama and the alpaca on work by Dr Jane Wheeler et al on alpaca DNA to the Royal Society showing that the alpaca is descended from the vicuña, not the guanaco.

The relationship between alpacas and vicuñas was disputed for many years, but Wheeler's DNA work proved it. However many academic sites have not caught up with this, so it is something well known to alpaca breeders who have read Dr Hoffman's book, and to Royal Society members who have access to the current classification data, but not more widely known.


Fiber
Alpaca fiber is warmer than sheeps' wool and lighter in weight. It is soft and luxurious and lacks the "prickle" factor. However, as with all fleece producing animals, quality varies from animal to animal, and some alpaca produce fibre which is less than ideal.

Alpaca have been bred in South America for hundreds of years (mainly Peru, but also Chile and Bolivia), but in recent years have been exported to other countries. In countries such as the USA, Australia and New Zealand breeders shear their animals annually, weigh the fleeces and test them for fineness. With the resulting knowledge they are able to breed heavier fleeced animals with finer fibre. Fleece weights vary, with the top stud males reaching annual shear weights up to 6kg.

Two types of fleece are produced: huacaya and suri. It has been proposed that in fact these are two different breeds of animal, and that camelids come in five types - guanaco, vicuna, llama, huacaya (alpaca) and suri. This view is not commonly accepted however.

In physical structure, alpaca is somewhat akin to (human?) hair, being very glossy, but its softness and fineness enable the spinner to produce satisfactory yarn with comparative ease.