The Arachnid Arthropods

The Arachnid Arthropods Arachnids (Arachnida) are a group of arthropods that include spiders, ticks, mites, scorpions and harvestmen. Scientists estimate that there are more than 100,000 species of arachnids alive today. Arachnids have two main body segments (the cephalothorax and the abdomen) and four pairs of jointed legs. By contrast, insects have three main body segments and three pairs of legs- making them easily distinguishable from arachnids. Arachnids also differ from insects in that they lack wings and antennae. It should be noted that in some groups of arachnids such as mites and hooded tickspiders, the larval stages have only three pairs of legs and fourth leg pair appears after they develop into nymphs. Arachnids have an exoskeleton that must be shed periodically for the animal to grow. Arachnids also have an internal structure called an endosternite that is composed of a cartilage-like material and provides a structure for muscle attachment. In addition to their four pairs of legs, arachnids also have two additional pairs of appendages that they use for a variety of purposes such as feeding, defense, locomotion, reproduction or sensory perception. These pairs of appendages include the chelicerae and the pedipalps. Most species of arachnids are terrestrial although some groups (especially ticks and mites) live in aquatic freshwater or marine environments. Arachnids have numerous adaptations for a terrestrial lifestyle. Their respiratory system is advanced although it varies among the different arachnid groups. Generally, it consists of tracheae, book lung and vascular lamellae that enable efficient gas exchange. Arachnids reproduce via internal fertilization (another adaptation to life on land) and have very efficient excretory systems that enable them to conserve water. Arachnids have various types of blood depending on their particular method of respiration. Some arachnids have blood that contains hemocyanin (similar in function to the hemoglobin molecule of vertebrates, but copper-based instead of iron-based). Arachnids have a stomach and numerous diverticula that enable them to absorb nutrients from their food. A nitrogenous waste (called guanine) is excreted from the anus at the back of the abdomen. Most arachnids feed on insects and other small invertebrates. Arachnids kill their prey using their chelicerae and pedipalps (some species of arachnids are venomous as well, and subdue their prey by injecting them with venom). Since arachnids have small mouths, the saturate their prey in digestive enzymes, and when the prey liquifies, the arachnid drinks its prey. Classification: Animals Invertebrates Arthropods Chelicerates Arachnids Arachnids are classified into about a dozen subgroups, some of which are not widely known. Some of the better-known arachnid groups include: True spiders (Araneae): There are about 40,000 species of true spiders alive today, making the Araneae the most species-rich of all arachnid groups. Spiders are known for their ability to produce silk from spinneret glands located at the base of their abdomen.Harvestmen or daddy-long-legs (Opiliones): There are about 6,300 species of harvestmen (also known as daddy-long-legs) alive today. Members of this group have very long legs, and their abdomen and cephalothorax are almost completely fused.Ticks and mites  (Acarina): There are about 30,000 species of ticks and mites alive today. Most members of this group are very small, although a few species can grow to as much as 20mm in length.Scorpions (Scorpiones): There are about 2000 species of scorpions alive today. Members of this group are easily recognized by their segmented tail that bears a venom-filled telson (sting) at the end.

U.S.-Japanese Foreign Policies Before World War II

U.S.-Japanese Foreign Policies Before World War II On December 7, 1941, nearly 90 years of American-Japanese diplomatic relations spiraled into World War II in the Pacific. That diplomatic collapse is the story of how the foreign policies of the two nations forced each other into war. History U.S. Commodore Matthew Perry opened American trade relations with Japan in 1854. President Theodore Roosevelt brokered a 1905 peace treaty in the Russo-Japanese War that was favorable to Japan, and the two had signed a Commerce and Navigation Treaty in 1911. Japan had also sided with the U.S., Great Britain, and France during World War I. During that time, Japan also embarked on an empire that it modeled greatly after the British Empire. Japan made no secret that it wanted economic control of the Asia-Pacific region. By 1931, however, U.S.-Japanese relations had soured. Japans civilian government, unable to cope with the strains of the global Great Depression, had given way to a militarist government. The new regime was prepared to strengthen Japan by forcibly annexing areas in the Asia-Pacific, and it started with China. Japan Attacks China Also in 1931, the Japanese army launched attacks on Manchuria, quickly subduing it. Japan announced that it had annexed Manchuria and renamed it Manchukuo. The U.S. refused to diplomatically acknowledge the addition of Manchuria to Japan, and Secretary of State Henry Stimson said as much in the so-called Stimson Doctrine. That response, however, was only diplomatic. The U.S. threatened no military or economic retaliation. In truth, the United States did not want to disrupt its lucrative trade with Japan. In addition to a variety of consumer goods, the U.S. supplied resource-poor Japan with most of its scrap iron and steel. Most importantly, it sold Japan 80% of its oil. In a series of naval treaties in the 1920s, the United States and Great Britain had endeavored to limit the size of Japans naval fleet. However, they had made no attempt to cut off Japans supply of oil. When Japan renewed aggression against China, it did so with American oil. In 1937, Japan began a full-blown war with China, attacking near Peking (now Beijing) and Nanking. Japanese troops killed not only Chinese soldiers, but women and children as well. The so-called Rape of Nanking shocked Americans with its disregard for human rights. American Responses In 1935 and 1936, the United States Congress had passed Neutrality Acts to prohibit the U.S. from selling goods to countries at war. The acts were ostensibly to protect the U.S. from falling into another war like World War I. President Franklin D. Roosevelt signed the acts, although he did not like them because they prohibited the U.S. from helping allies in need. Still, the acts were not active unless Roosevelt invoked them, which he did not do in the case of Japan and China. He favored China in the crisis, and by not invoking the 1936 act he could still shuttle aid to the Chinese. Not until 1939, however, did the United States begin to directly challenge continued Japanese aggression in China. That year the U.S. announced it was pulling out of the 1911 Treaty of Commerce and Navigation with Japan, signaling a coming end to trade with the empire. Japan continued its campaign through China, and in 1940 Roosevelt declared a partial embargo of U.S. shipments of oil, gasoline, and metals to Japan. That move forced Japan to consider drastic options. It had no intention of ceasing its imperial conquests, and it was poised to move into French Indochina. With a total American resource embargo likely, Japanese militarists began looking at the oil fields of the Dutch East Indies as possible replacements for American oil. That presented a military challenge, though, because the American-controlled Philippines and the American Pacific Fleet based at Pearl Harbor, Hawaii, were between Japan and the Dutch possessions. In July 1941, the United States completely embargoed resources to Japan, and it froze all Japanese assets in American entities. The American policies forced Japan to the wall. With the approval of Japanese Emperor Hirohito, the Japanese Navy began planning to attack Pearl Harbor, the Philippines, and other bases in the Pacific in early December to open the route to the Dutch East Indies. Ultimatum: The Hull Note The Japanese kept diplomatic lines open with the United States on the off-chance they could negotiate an end to the embargo. Any hope of that vanished on November 26, 1941, when U.S. Secretary of State Cordell Hull handed Japanese ambassadors in Washington D.C. what has come to be known as the Hull Note. The note said that the only way for the U.S. to remove the resource embargo was for Japan to: Remove all troops from China.Remove all troops from Indochina.End the alliance it had signed with Germany and Italy the previous year. Japan could not accept the conditions. By the time Hull delivered his note to the Japanese diplomats, imperial armadas were already sailing for Hawaii and the Philippines. World War II in the Pacific was only days away.