Crabs.Crabs are found all over the world, both on land and in water. In fact, scientists have counted more than 4400 species of crabs! Crabs are crustaceans (crus TAY shuns), like lobsters and shrimp. Most crustaceans have a soft body covered by a hard shell, or carapace carapace (kâr`əpās), shield, or shell covering, found over all or part of the anterior dorsal portion of an animal. In lobsters, shrimps, crayfish, and crabs, the carapace is the part of the exoskeleton that covers the head and thorax (CARE uh pace). Crustaceans breathe through gills, just like fish. Crabs smell through their antennas. Characteristics Crabs come in many sizes. The smallest is the pea crab Noun 1. pea crab - tiny soft-bodied crab living commensally in the mantles of certain bivalve mollusks crab - decapod having eyes on short stalks and a broad flattened carapace with a small abdomen folded under the thorax and pincers , which is only 1/2 inch wide. The largest is the Japanese spider crab The Japanese spider crab, Macrocheira kaempferi, is the largest living arthropod; fully grown it can reach a leg span of almost 4 m (13 feet), a body size of up to 37 cm (15 inches) and a weight of up to 20 kg (44 pounds). , which can grow up to 12 feet across. That is twice as long as your bed! Crabs have 10 jointed legs on the sides of their bodies. They usually walk sideways. Some crabs have paddles on their back legs and can swim in all directions. Crabs are scavengers, which means they eat dead plants and animals Plants and Animals are a Canadian indie-rock band from Montreal, comprised of guitarist-vocalists Warren Spicer and Nic Basque, and drummer-vocalist Matthew Woodley.[1] They are signed to Secret City Records. . They use their claws to grab food. Some of their favorite foods are fish (dead or alive), clams, plankton plankton: see marine biology. plankton Marine and freshwater organisms that, because they are unable to move or are too small or too weak to swim against water currents, exist in a drifting, floating state. , and seaweed seaweed, name commonly used for the multicellular marine algae. Simpler forms, consisting of one cell (e.g., the diatom) or of a few cells, are not generally called seaweeds; these tiny plants help to make up plankton. . Land crabs land crab n. A terrestrial crab of the tropical family Gecarinidae, having a large square body. like to eat leaves and rotting fruit. Crabs have excellent eyesight eye·sight n. 1. The faculty of sight; vision. 2. Range of vision; view. . Their eyes are on stalks, which they can raise or lower. Survivors Crabs have been around for millions of years, changing little from their original forms. Birds, fish, and octopuses like to eat crabs. So do people! Crabs, though, are great survivors. To protect themselves, they hide in mud or sand with just their eyestalks sticking out Adj. 1. sticking out - extending out above or beyond a surface or boundary; "the jutting limb of a tree"; "massive projected buttresses"; "his protruding ribs"; "a pile of boards sticking over the end of his truck" . Sometimes they put shells or bits of seaweed or sponge on Verb 1. sponge on - apply with a sponge; "The painter sponged on his washes" apply, put on - apply to a surface; "She applied paint to the back of the house"; "Put on make-up!" their shells for camouflage. Crabs are also protected by their shells and powerful, pinching claws. If an enemy grabs its leg, a crab can break it off and speed away! Later, the leg will grow back! This is called regeneration. A Crab's Life Crabs hatch from eggs. A female blue crab blue crab, common name for a crustacean, Callinectes sapidus, found on the S Atlantic and Gulf coasts of North America. The blue crab is a member of the family of swimming crabs known as the Portunidae and is characterized by a broad, semitriangular carapace may lay up to 2 million eggs at once! However, most of these will not make it to adulthood. After hatching, crabs' bodies go through many changes before they become adults. Crabs grow bigger, but their shells don't. They shed their old shells and grow brand-new, bigger ones. When the new shell is ready, the crab leaves its old shell. This is called molting molting, periodical shedding and renewal of the outer skin, exoskeleton, fur, or feathers of an animal. In most animals the process is triggered by secretions of the thyroid and pituitary glands. . Are crabs "crabby crab·by adj. crab·bi·er, crab·bi·est Informal Grouchy; ill-tempered. crab  bi·ly adv. ," like grouchy grouch·y adj. grouch·i·er, grouch·i·est Tending to complain or grumble; peevish or grumpy. grouch i·ly adv. people? Experts disagree about whether
crabs are bad-tempered, but many crabs do fight when crowded together.
Background Many of us are familiar with crabs because we've seen them on our dinner plate or perhaps in a tasty soup or as a crab cake A crab cake is an American dish comprised of a crab meat patty and various other ingredients such as breadcrumbs, milk, eggs, onions, and seasonings. Occasionally other ingredients such as red or green peppers are added, at which point the cake is then sautéed, baked, or grilled, . However, the well-known species of edible crabs (Zool.) any species of crab used as food, esp. the American blue crab (Callinectes hastatus). See Crab. See also: Edible are just a tiny fraction of all the various kinds of crabs in the world. Crabs are fascinating, diverse creatures found almost everywhere on Earth. There are more than 4400 different species of crab. Crabs are a much-loved food throughout the world. The annual harvest of crabs is a multimillion dollar industry in the U.S. For many people, crabbing is a fiercely independent way of life, passed down from generation to generation. One of the most important food crabs is the blue crab, found along the Atlantic coastline. Another is the Dungeness, caught along the Pacific coast of the U.S. King crabs king crab: see crab; horseshoe crab. king crab or Alaskan king crab or Japanese crab Marine decapod (Paralithodes camtschatica), an edible crab. , prized for their large, tasty legs, live in the north Pacific and Bering Sea Bering Sea, c.878,000 sq mi (2,274,020 sq km), northward extension of the Pacific Ocean between Siberia and Alaska. It is screened from the Pacific proper by the Aleutian Islands. The Bering Strait connects it with the Arctic Ocean. . For stone crabs, caught in the coastal waters of Florida and Louisiana, only the claws are eaten. Most crabs live in the sea, but some live in fresh or brackish brack·ish adj. 1. Having a somewhat salty taste, especially from containing a mixture of seawater and fresh water: "You could cut the brackish winds with a knife/Here in Nantucket" (partly salty salt·y adj. salt·i·er, salt·i·est 1. Of, containing, or seasoned with salt. 2. Suggestive of the sea or sailing life. 3. Witty; pungent; earthy: salty humor. ) water, and some on land. Still others divide their time between the land and water. Crabs are crustaceans, like lobsters and shrimp. Scientists have found fossils that show crab ancestors were on Earth almost 200 million years ago and have changed little from their original form. What Makes It a Crab? Crabs have 10 jointed legs, 4 antennas, and a hard outer shell, or carapace (CARE uh pace) covering a soft body. They usually walk sideways, because their legs are attached to the sides of their bodies. Swimming crabs generally have paddles on their back legs and can swim in all directions. All crabs have claws on their 2 front legs. They use them to grab and hold food, to crack open the hard shells of their prey, and to fight and defend themselves. Their antennas help them smell, taste, and sense vibrations. Crabs' eyes are on stalks, which they can raise or lower into their sockets. They can also rotate their eyes to see almost directly behind them. Crabs' eyes are compound, made of many lenses, and their eyesight is excellent. Sometimes crabs bury themselves in sand, with just their eyes poking up, hiding from predators or waiting for a meal to pass by. Burrowing crabs have a special mouth structure which allows them to breathe while buried. Crabs breathe like fish, taking oxygen from the water through their gills, which are located under their shells. Land crabs can breathe air, but must return to the water to wet their gills. You can tell the sex of most crabs by looking at the abdomen, or "apron." The size of crabs varies tremendously. Pea crabs may be just 1/2 inch wide. Meanwhile, the enormous Japanese spider crab may measure up to 12 feet from claw to claw! With a varied diet and voracious voracious said of appetite. See polyphagia. appetites, crabs are scavengers, eating dead plants and animals. Among their favorite foods are fish (dead or alive), clams, plankton, and seaweed. Land crabs also enjoy dining on leaves and rotting fruit. False Crabs Some "crabs," like hermit hermit [Gr.,=desert], one who lives in solitude, especially from ascetic motives. Hermits are known in many cultures. Permanent solitude was common in ancient Christian asceticism; St. Anthony of Egypt and St. Simeon Stylites were noted hermits. and horseshoe crabs horseshoe crab, large, primitive marine arthropod related to the spider, sometimes called a king crab (a name also used for the largest of the edible true crabs). The heavy dark brown exoskeleton, or carapace, is domed and shaped like a horseshoe. , aren't true crabs at all. Hermit crabs hermit crab, a crustacean distinguished from true crabs by its long, soft, spirally coiled abdomen terminating in an asymmetrically hooked tail. Most hermit crabs protect this vulnerable portion of their bodies by occupying the empty shells of periwinkles, whelks, are not true crabs because they borrow their shells from dead marine animals such as periwinkles and whelks. Every so often, the hermit crab has to move to a "bigger house" when it outgrows its borrowed shell. Unlike true crabs, horseshoe crabs have more than one pair of claws and lack jaws and antennas. Horseshoe crabs today are very similar to those living millions of years ago. For that reason, horseshoe crabs are sometimes called "living fossils living fossil n. An organism, such as a coelacanth or the ginkgo, that is the sole surviving member of an otherwise extinct taxonomic group. ." Scientists have been able to learn a lot about human eyesight from studying horseshoe crab eyes. Life Cycle Visual and auditory signals are especially important in the mating rituals Mating rituals: see
A female blue crab may lay up to 2 million eggs at a time! Only a few of these will survive to adulthood, however. When crab eggs hatch, tiny larvae Larvae, in Roman religion Larvae: see lemures. called zoea zo·e·a n. pl. zo·e·ae or zo·e·as A larval form of crabs and other decapod crustaceans, characterized by one or more spines on the carapace and rudimentary limbs on the abdomen and thorax. emerge. Most zoea are just 1/100 inch wide. They do not look very much like adult crabs. The zoea feed on plankton (while larger plankton and fish feed on them!) They molt repeatedly and eventually become megalops, with very large eyes, a large abdomen, and long tails. Finally, the megalops become adult crabs. In order to grow, crabs must molt. A new, larger shell has already grown underneath the old shell, but it is soft at first. Crabs are vulnerable and will hide during their soft shell stage, which lasts several days. Blue crab males will protect the female during this time. Right after the molt, the crab gulps water to make its body expand before the new shell hardens. Crabs have some amazing a·maze v. a·mazed, a·maz·ing, a·maz·es v.tr. 1. To affect with great wonder; astonish. See Synonyms at surprise. 2. Obsolete To bewilder; perplex. v.intr. abilities. One is called autotomy au·tot·o·my n. The spontaneous casting off of a body part, especially of an invertebrate, when injured or under attack. . If a predator grabs a crab's leg, or if it is injured in·jure tr.v. in·jured, in·jur·ing, in·jures 1. To cause physical harm to; hurt. 2. To cause damage to; impair. 3. or trapped, the crab can cast off its own claw or leg and escape. The leg or claw is broken off along a built-in weak spot, or breaking plane. To complete the process, the crab also has the ability to grow a new limb to replace the lost one! This is called regeneration. It takes many molts for a lost leg or claw to be completely regenerated. Crab Products When people eat blue crabs, they only consume about 10 to 15% of the crab. Rather than waste the remainder, researchers have found many uses for crab products. Crab parts are made into fish bait. The shells of crabs contain chitin (KITE in), a protein material similar to fingernails. Chitin is broken down into fibers and made into bandages. These bandages help skin grow better and speed the healing of wounds. They are often used on burn victims. Chitin is also spun into thread for sutures. It is often added to animal feed and used to enrich soil. Chitin has recently been marketed as a weight loss product, but its effectiveness has not been proven. Future of Crabs Crabs are remarkable survivors, having been on Earth for almost 200 million years. They protect themselves with their hard shells, powerful claws, and the ability to regenerate re·gen·er·ate v. re·gen·er·at·ed, re·gen·er·at·ing, re·gen·er·ates v.tr. 1. To reform spiritually or morally. 2. To form, construct, or create anew, especially in an improved state. lost limbs. Many crabs also camouflage themselves, putting seashells, bits of sponge, or seaweed on their shells. Some crabs bury themselves in sand or mud, or hide among rocks and seaweed. Despite these defenses - and the fact that females produce vast numbers of eggs - scientists worry that crab populations may be declining, in some cases due to overfishing Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans. More precise biological and bioeconomic terms define 'acceptable level'. . For example, some experts predict that the Japanese spider crab may be extinct within a few decades. People are eating too many of them, including the egg-laying females. Some fluctuations are seasonal. The number of crabs can greatly increase or decrease from year to year. Excessive rain can lower the salinity (salt) level of the water and kill crab larvae. Extremely cold temperatures in winter can kill dormant crabs. Unusually large numbers of predators can also affect crab populations. Pollution harms crabs in many ways. Fertilizers used on lawns and farms run off into waterways The list of waterways is a link page for any river, canal, estuary or firth. International waterways
Rapid growth in the sales of a mutual fund's shares to the extent that the fund has difficulty finding promising new investments or it must take such large positions in individual investments that its trading flexibility is reduced. of algae algae (ăl`jē) [plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that . Too much algae depletes the oxygen in the water. It also keeps sunlight from reaching the aquatic grasses which crabs eat and use for shelter. Run-off of manure from chicken farms has been blamed for recent outbreaks of disease in East Coast waters. These diseases kill large numbers of fish, which crabs, in turn, rely on as a food source. Scientists are now studying the adverse effects of ozone depletion Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earth's stratosphere since around 1980; and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions on phytoplankton phytoplankton Flora of freely floating, often minute organisms that drift with water currents. Like land vegetation, phytoplankton uses carbon dioxide, releases oxygen, and converts minerals to a form animals can use. , the basis of the food chain in all rivers, bays, and oceans. So far, results show that phytoplankton in some areas, including the Chesapeake Bay Chesapeake Bay, inlet of the Atlantic Ocean, c.200 mi (320 km) long, from 3 to 30 mi (4.8–48 km) wide, and 3,237 sq mi (8,384 sq km), separating the Delmarva Peninsula from mainland Maryland. and Virginia. (home to large numbers of blue crabs), are doing better than others. National science Education Standards The National Science Education Standards (NSES) are a set of guidelines for the science education in primary and secondary schools in the United States, as established by the National Research Council in 1996. Unifying Concepts and Processes (K-8) * Systems, order, and organization * Evidence, models, and explanation * Constancy con·stan·cy n. 1. Steadfastness, as in purpose or affection; faithfulness. 2. The condition or quality of being constant; changelessness. Noun 1. , change, and measurement * Evolution and equilibrium * Form and function Standard A: Science as Inquiry (K-8) * Abilities necessary to do scientific inquiry * Understanding about scientific inquiry Standard B: Physical Science (K-4) * Properties of objects and materials * Position and motion of objects (5-8) * Properties and changes of properties in matter * Motions and forces Standard C: Life Science (K-4) * The characteristics of organisms * Life cycle of organisms * Organisms and environments (5-8) * Structure and function in living systems * Reproduction and heredity heredity, transmission from generation to generation through the process of reproduction in plants and animals of factors which cause the offspring to resemble their parents. That like begets like has been a maxim since ancient times. * Regulation and behavior * Populations and ecosystems * Diversity and adaptations of organisms Standard D: Earth and Space Science (K-4) * Properties of earth materials Earth materials is a general term that includes rocks and materials that are not by definition rocks but are commonly regarded as rocks. Examples of the latter are coal and volcanic glass, which are not composed of minerals. (5-8) * Structure of the earth system Standard G: History and Nature of Science (5-8) * Science as a human endeavor Meet Some Amazing Crabs Japanese spider crabs - The largest of all crabs, they can grow to be 12 feet from claw to claw. A single claw may be 6 feet long! Their bodies are small relative to the size of their legs. These crabs use the hairlike hooks on their bodies to attach bits of shell and seaweed as camouflage. Blue crabs - They are one of the most important food crabs for humans and are sometimes eaten in their soft shell state. Many people think they are the tastiest crabs. The greatest concentration of blue crabs is in the Chesapeake Bay. They live up to 3 years. Pea crabs - One of the smallest crabs, they may be just 1/2 inch wide. Female pea crabs sometimes live inside the shells of mussels, clams, and oysters, feeding on whatever their host eats. Stone crabs - The claws of these crabs are prized for eating. Crabbers in Florida catch them, remove one claw, and throw the crab back to grow another claw. Robber or coconut crabs coconut crab n. A large terrestrial hermit crab (Birgus latro) that can climb trees and that feeds on carrion and vegetation. - They climb trees "Climb Trees" is a 12" vinyl by rapper Sage Francis, released by the anticon. label in 2002. Track listing
Fiddler crabs - Fiddler crabs live on land, burrowing in mud or sand or among mangrove mangrove, large tropical evergreen tree, genus Rhizophora, that grows on muddy tidal flats and along protected ocean shorelines. Mangroves are most abundant in tropical Asia, Africa, and the islands of the SW Pacific. tree roots. Males have one large claw, which they use to signal other fiddler crabs. Crabs from different beaches may not understand each other's "sign language." Ghost crabs ghost crab n. Any of several light-colored burrowing crabs of the genus Ocypoda frequenting the tide line along sandy shores from the northeast United States to Brazil. Also called white crab. - These fast land crabs dig large burrows in sand. They can run 7 feet in 1 second! Dungeness crabs Dungeness crab Edible crab (Cancer magister) found along the Pacific coast from Alaska to lower California, one of the coast's largest and most important commercial crabs. The male is 7–9 in. (18–23 cm) wide and 4–5 in. (10–13 cm) long. - These crabs are found on the Pacific coast, from Alaska to San Francisco San Francisco (săn frănsĭs`kō), city (1990 pop. 723,959), coextensive with San Francisco co., W Calif., on the tip of a peninsula between the Pacific Ocean and San Francisco Bay, which are connected by the strait known as the Golden . They are large, weighing up to 3 pounds and measuring 10 inches across their shell. They have a long life span for a crab (up to 8 years.) Arrow crabs The arrow crab (Stenorhynchus seticornis) is a saltwater invertebrate that resembles a harvestman (daddy long-legs) that may grow up to a length of about 6 inches (15 cm). - A type of spider crab spider crab Any species of sluggish marine crab in the widely distributed family Majidae (or Maiidae). Spider crabs have a beak-shaped head; thick, rounded body; and long, spindly legs. , these crabs spread out their long legs in the ocean. They then eat the bits of dead animal and plant matter that stick to their legs. Striped shore crabs shore crab n. Any of numerous crabs, such as the spider crab of the United States or the common edible crab Carcinus maenas, usually found along seashores. - These crabs live on beaches in Oregon and California and hunt for food in and out of the water. Their bodies are about 2 inches across. DID YOU KNOW?? A crab's legs are made up of rigid parts with flexible joints, so they can bend. DID YOU KNOW?? The fast ghost crab runs on its tip-toes! DID YOU KNOW?? Female blue crabs are said to "paint their fingernails" because their claw tips are red. DID YOU KNOW?? Callinectus sapidus is the scientific name for the blue crab. It means "beautiful swimmer." DID YOU KNOW? Most crabs can't swim. DID YOU KNOW?? A crab's legs are made up of rigid parts with flexible joints, so they can bend. DID YOU KNOW?? Some male ghost crabs build sand pyramids to attract a mate. DID YOU KNOW?? Callinecticus sapidus is the scientific name for the blue crab. It means "beautiful swimmer." We suggest bringing a real crab or crab shell to class, if possible, so your students can examine it first-hand. Vocabulary Circle the things crabs like to eat. The words can go across, backwards, up, down, or diagonally. S D Z B A I T V A H N V B L F H S R F S E A W E E D Z H E P R M N V R N O T K N A L P A S I A E A A U K I I E P S S V Q M L L B I F I S H E S D G E U P C S S C L G T F L A Q G S I D S M R O W S L A S Q A E V D seaweed plankton eggs bait snails clams fish leaves worms fruit shrimp eels squid Weeky Lab Make your own bread roll crab! You need: a kaiser (or other hard) roll, 5 large pipe cleaners pipe cleaner, n a small, brushlike device used to clean the spaces between the teeth (used also for other purposes). It should not be inserted all the way between the teeth, but rather just far enough to massage the tissue and remove any plaque. (cut in half), 5 plastic straws (each cut in 8 pieces), 2 toothpicks, 2 raisins, 2 small binder or bulldog bulldog, breed of thick-set nonsporting dog developed in the British Isles many centuries ago. It stands from 13 to 15 in. (33–38.1 cm) high at the shoulder and weighs from 40 to 50 lb (18.1–22.7 kg). clips Step 1: Slide 4 straw pieces onto a pipe cleaner. Bend 1 end of the pipe cleaner down to keep the straws from coming off. Push the other end of the pipe cleaner into the side of your roll. (See picture.) This is one of your crab's legs. Step 2: Make 7 more legs and stick them into the roll. Put 4 legs on each side. Step 3: Put 3 straw pieces on each of the last 2 pipe cleaners. Attach a binder clip A binder clip, or a banker's clip, is a simple device for binding a few to many sheets of paper. It leaves the paper intact and can be removed quickly and easily unlike the staple. to the end of each one. Stick the other ends of the pipe cleaners in the front of your roll. These are your crab's claws. (Bend all of your pipe cleaners.) Step 4: Push a raisin raisin, in botany and cooking raisin, dried fruit of certain varieties of grapevines bearing grapes with a high content of sugar and solid flesh. Although the fruit is sometimes artificially dehydrated, it is usually sun-dried. onto the end of each toothpick toothpick, n a wood sliver used to cleanse the interdental space. toothpick, balsa wood, n a triangular wedge of balsa wood used to clean the teeth interproximally and stimulate the interdental gingival tissues. . Stick the toothpicks in the top of your roll, near the front. These are your crab's eyes masses of calcareous matter found, at certain seasons of the year, on either side of the stomach of the European crawfishes, and formerly used in medicine for absorbent and antacid purposes; the gastroliths. See also: Crab and eyestalks. DID YOU KNOW?? The word crustacean crustacean (krŭstā`shən), primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. comes from the Latin words "crusta" meaning shell and "acea" meaning group. DID YOU KNOW?? Some "decorator" crabs trick their enemies by decorating themselves with shells and plants. Bonus: Glue bits of tissue paper, sponges, and sequins on your roll to help disguise and protect your crab from enemies, just like decorator crabs. Weekly Problem Solve the problems to find out these crab facts. Ghost crabs can run -- feet in one second. (387 + 420) - 800 = Dungeness crabs can live up to -- years. (501 - 497) x 2 = Crabs may molt more than -- times in their lives. (27 x 7) - 169 = A Blue crab can weigh -- pound. 2/10 + 3/10 = (reduce) DID YOU KNOW?? Horseshoe crabs and hermit crabs are NOT really crabs. DID YOU KNOW?? Crabs have eyes on long eyestalks. This lets them peep over things to check that everything is safe. Writing for Science The old science editor at 4KIDS-TV has just been fired for doing an awful job of researching their upcoming program on crabs. Congratulations! You have been hired as the new, improved science editor. Your first job is to fix the mistakes in this story. Circle all the mistakes. Then write up your corrected crab report. CRABS There are less than 100 different species of crabs! All crabs have soft shells over their hard bodies. They have excellent eyesight. Some of their favorite foods are fish, clams, and plankton, but they will not eat anything that is dead. Crabs come in many sizes. The smallest crab is the tiny Japanese spider crab, no bigger than a nickel. Crabs have been on Earth for millions of years, and they have changed a lot from their original form. Crabs hatch from eggs. If a crab loses a leg, it can grow a new one? This is called molting. DID YOU KNOW?? When a blue crab molts, it "backs out" of its old shell. DID YOU KNOW?? The arrow crab has such long legs, it looks like it is walking on stilts This article is about the poles. For the type of bird, see stilt. For other uses, see Stilts (disambiguation). Stilts are poles, posts or pillars used to allow a person or structure to stand at a certain distance above the ground. . DID YOU KNOW?? Coconut crabs climb palm trees to get coconuts to eat. Challenge Male fiddler crabs have one very large claw. They wave this claw to signal messages to nearby fiddler crabs. They also use it to fight other males and to attract females. Play Fiddler Crab Charades! Divide up into. teams. Quietly, decide on the crab words you want to use. Write them on slips of paper and put them in a bag. The words must have something to do with crabs, like a crab part, something crabs eat, or the name of a type of crab. Now you are ready to play! Take turns picking words from another team's bag. You can use your body to give clues to your teammates, but no talking is allowed! Bonus: Try giving clues using just one arm (your "claw") like fiddler crabs do! DID YOU KNOW?? Crab shells contain chitin, which is used to make bandages. DID YOU KNOW?? If a male fiddler crab's large front claw breaks off, it grows a small new one. Then its other front claw turns into the big one. DID YOU KNOW?? Some ancient Egyptian coins had pictures of crabs on them. Puzzle Some female pea crabs live inside these. 1) Cross out all the consonants This is a list of all consonants, ordered by place and manner of articulation. Ordered by place of articulation Labial consonants Bilabial consonants
2) Cross out all the letters in Row B that come before the letter M in the alphabet. 3) Cross out all the vowels in Columns 1, 3, and 5. 4) Cross out all the letters h, f, and w. 5) To find the answer, circle the remaining letters. Write them, in order, in the spaces below. DID YOU KNOW?? The pine crab lives in water that collects at the bottom of bromeliad bromeliad, common name for plants of the family Bromeliaceae (pineapple family). bromeliad Any of the flowering plants of the order Bromeliales, containing a single family, Bromeliaceae, with almost 2,600 species. plants that grow on tropical trees. Level Pre-A Main Concepts: Crabs have hard shells and 10 legs. They are many kinds of crabs. Picture Activity Ask your students what they see on the front page. WHY-FLY is looking at some crabs on the beach - (from left to right) a fiddler crab, a ghost crab, and a blue crab. Explain that there are many kinds of crabs. They have hard shells and 10 legs. Their hard shells protect them. Read what WHY-FLY is saying. Explain that some crabs swim and others walk. The ghost crab can run very fast. The fiddler crab has one very large claw for signaling to other fiddler crabs. The blue crab is a water crab and swims very well. Have them point out each crab. Ask if they have ever seen a crab. Vocabulary Go over the "sh" sound together. Have everyone put a finger to their lips and say "Shhh!" Read the sentences to them. Then have them trace over all the letters "sh." Have them say the "sh" words out loud. Weekly Problem Answers: The fiddler crab has the most legs - 10 (circle in red). The girl has the fewest legs - 2 (circle in purple). (The dog has 4 legs and the ant has 6.) Explain that all crabs have 10 legs. First go over the directions together and then have them color in Verb 1. color in - add color to; "The child colored the drawings"; "Fall colored the trees"; "colorize black and white film" color, colorise, colorize, colour in, colourise, colourize, colour the mini-crayons. Next have them count the legs on each one and circle the ones with the most legs and the fewest legs. Storytelling Storytelling Aesop semi-legendary fabulist of ancient Greece. [Gk. Lit.: Harvey, 10] Münchäusen Baron traveler grossly embellishes his experiences. [Ger. Lit. Crabs' eyes are on stalks. The stalks can go up, down, and all around. Explain that sometimes crabs will hide in mud or sand with just their eyes sticking out. This helps protect the crabs from their enemies. The buried crabs can easily see when an enemy or something to eat comes by. Crabs see very well, which helps them find food. Challenge Crabs' legs are on the sides of their bodies. This is why they walk sideways, but can swim in all directions. Have them try walking like a crab on their hands and knees. They can try crawling forwards and then sideways. Which was harder for them? (It is harder for us to crawl sideways, because our legs are not on the sides of our bodies.) If space permits indoors, or the weather is nice outdoors, plan a class crab relay race relay race Race between teams in which each team member successively covers a specified portion of the course. In track events, such as the 4 × 100-m and 4 × 400-m relays, the runner finishing one leg passes a baton to the next runner while both are running within . Have them alternate crawling forwards and sideways or have teams try one method and then the other. Weekly Lab You need: scissors scissors Cutting instrument or tool consisting of a pair of opposed metal blades that meet and cut when the handles at their ends are brought together. Modern scissors are of two types: the more usual pivoted blades have a rivet or screw connection between the cutting ends , paper plates, staplers or tape, pipe cleaners, mini-marshmallows, paper fasteners fasteners In construction, connectors between structural members. Bolted connections are used when it is necessary to fasten two elements tightly together, especially to resist shear and bending, as in column and beam connections. , crayons (optional - a hole punch
A hole punch (known also as a hole puncher, paper puncher or perforator ). This lab will help reinforce the parts of a crab's body - shell, legs, and claws. Explain that a crab's legs are jointed, so they can bend. Ask them if their legs can bend. Have your students fold their plates in half. Then have them cut out the side legs, the front legs, and the claws. They can tape or staple the side legs to the sides of their plates. Then have them tape the rest of the plate together, leaving an open space in front. Have them insert paper fasteners in the red dots on the 2 front legs and the claws, and attach them together. (You can use a hole punch, if needed, to make the holes.) Next have them attach the 2 front legs to the front of the paper plate with paper fasteners - at the blue dots. Finally, have them put their mini-marshmallows (or gum drops may also be used) on the ends of the pipe cleaners. They will stick the pipe cleaners into the front of their plates. They may need to use more tape or staples to secure them. These will be their crab's eyes and eyestalks. Have them color in their crab's shell. Encourage them to be creative - most often, crabs are green, blue, or gray, but some are purple, red, pink, yellow, orange, or spotted. DID YOU KNOW?? The fast ghost crab runs on its tip-toes! Level A Main Concepts: Crabs have hard shells and 10 legs. There are many kinds of crabs. They may live on land or in water. Picture Activity See TN Level Pre-A - PICTURE ACTIVITY. Vocabulary Go over the "sh" sound together. Have everyone put a finger to their lips and say "Shhh!" Have them write "sh" in the blank spaces Noun 1. blank space - a blank area; "write your name in the space provided" space, place surface area, expanse, area - the extent of a 2-dimensional surface enclosed within a boundary; "the area of a rectangle"; "it was about 500 square feet in area" . Read the sentences and have them say the "sh" words out loud. Can they think of any more words that begin with the "sh" sound? Weekly Problem Answers: dog - 4, fiddler crab - 10, girl - 2, ant - 6. The fiddler crab has the most legs (circle in red). The girl has the fewest legs (circle in purple), Explain that all crabs have 10 legs. First read the directions and then have them color in the mini-crayons. Next have them count the legs on each one, fill-in the boxes, and circle the ones with the most and the fewest legs. Writing for Science Explain that crabs' eyes are on stalks that can go up, down, and around. Crabs sometimes hide in mud or sand with just their eyes peeking out. This protects them from their enemies. The buried crabs can easily see when an enemy or something to eat comes by. Crabs see very well, which helps them find food. Encourage them to use their imaginations when creating their stories. Challenge Crabs' legs are on the sides of their bodies. This is why they walk sideways, but can swim in all directions. Have them try walking like a crab on their hands and knees. They can try crawling forwards and sideways. Which was harder for them? (It is harder for us to crawl sideways, because our legs are not on the sides of our bodies.) If space permits indoors, or the weather is nice outdoors, plan a class crab relay race. Have them alternate crawling forwards and sideways or have teams try one method and then the other. Weekly Lab See TN Level Pre-A-WEEKLY LAB. In addition, at this level, they will be making 2-part claws that open and close. Have them use paper fasteners to attach each of the claw pieces to each other (at the yellow dots). DID YOU KNOW?? The word crustacean comes from the Latin words "crusta" meaning shell and "acea" meaning group. DID YOU KNOW?? Some ancient Egyptian coins had pictures of crabs on them. Level B Main Concepts: There are many kinds of crabs. Some live in water and some on land. Crabs have hard shells and 10 legs. Some crabs have paddles for swimming. The Japanese spider crab on the front page is twice as long as a bed. The pea crab is as tiny as a pea pea, hardy, annual, climbing leguminous plant (Pisum sativum) of the family Leguminosae (pulse family), grown for food by humans at least since the early Bronze Age; no longer known in the wild form. . Vocabulary Answers: fish, shells, shore, shirt. Go over the pictures together first. Have them think of other words with the "sh" sound. Weekly Problem Answers: 1) 7, 14 2) 12. Writing for Science Explain that crabs' eyes are on stalks. The stalks can move up, down, and all around. Sometimes crabs hide in mud or sand with just their eyes sticking out. This helps protect them from their enemies. The buried crabs can easily see when an enemy or something to eat comes by. Crabs see very well, which helps them find food. Encourage your students to think of different situations at home, school, and play where they could benefit from having their eyes on stalks. Challenge Crabs' legs are on the sides of their bodies. This is why they walk sideways, but can swim in all directions. Have them try walking like a crab on their hands and knees. They can try crawling forwards and then sideways. Which was harder for them? (It is harder for us to crawl sideways, because our legs are not on the sides of our bodies.) If space permits indoors, or the weather is nice outdoors, plan a class crab relay race. Have them alternate crawling forwards and sideways or have teams try one method and then the other. Have them switch, and try again. Which way did they prefer? Weekly Lab This lab will help reinforce the parts of a crab's body - shell, legs, and claws. Explain that a crab's legs are jointed, so they can bend. You may use gum drops instead of marshmallows for the crab's eyes. You may need to use tape or staples to securely hold the pipe cleaner eyestalks in place. Encourage your students to be creative when coloring their crabs' shells - most often, crabs are green, blue, or gray, but some are purple, red, pink, yellow, orange, or spotted. Some crabs put small shells and bits of seaweed on their shells to help camouflage themselves. Level C Main Concepts: There are thousands of kinds of crabs. They can protect themselves from enemies in many ways. Crabs molt when they get too big for their shells. Vocabulary Answers: The 2 missing consonants are "s" and "I." 1) shell 2) stalks 3) claws 4) paddles. Weekly Lab For this lab, you can use any type of hard roll - round or oval shapes work well (e.g., Kaiser rolls or small baguettes.) Mini-marshmallows or gum drops can be used instead of raisins for eyes. The binder or bulldog clips are a nice feature to add, because they illustrate the strong gripping power of a crab's claws. You can also have them construct 2 part claws, made out of cardboard. Put the parts together with paper fasteners, so they can open and close, and attach them to the ends of the 2 front pipe cleaners. They can also use large, open paper clips to represent the claws. Weekly Problem Answers: Crabby ate 17 pieces of food, Gabby gab·by adj. gab·bi·er, gab·bi·est Slang Tending to talk excessively; garrulous. gab bi·ness n. ate 27 pieces, Tabby
ate 15 pieces, and Abby ate 30 pieces. Abby ate the most.
Writing for Science Discuss the different ways crabs protect themselves. They have hard shells and claws for pinching. They can hide in mud or sand with just their eyes sticking out. Some crabs camouflage themselves with bits of sponge, shells, and seaweed. The male fiddler crab even has one huge front claw that it can use to fight with other males. Have your students imagine some special ways a "Supercrab" could protect itself. Then have them write their stories. Challenge See TN Level B - CHALLENGE. In addition, have them name some other animals that have legs on the sides of their bodies (e.g., spiders, lobsters, lizards, etc.). Puzzle Answers: ACROSS - bait, seaweed, fish BACKWARDS - plankton, worms UP - clams, eggs DOWN - shrimp, eels, leaves, squid. Crabs are scavengers - they eat dead plants and animals. (They also eat live plants and fish.) Ask if your students have ever gone crabbing. What did they use for bait? DID YOU KNOW?? Soldier crabs (Zool.) The hermit crab. The fiddler crab. See also: Soldier Soldier walk forwards, not sideways, like other crabs. Level D Main Concepts: There are thousands of kinds of crabs. Crabs are crustaceans. They protect themselves from predators in many ways. Crabs molt when they get too big for their shells. Vocabulary Answers: ACROSS - bait, seaweed, fish BACKWARDS - plankton, worms UP - clams, eggs DOWN - shrimp, eels, leaves, squid. Crabs are scavengers - they eat dead plants and animals. (They also eat live plants and fish.) Ask if your students have ever gone crabbing. What did they use for bait? Weekly Lab See TN Level C - WEEKLY LAB. In addition, for the bonus, have your students glue bits of sponges, tissue paper, sequins, or small shells on their crabs. This is similar to how decorator crabs "disguise" themselves from their enemies. Weekly Problem Answers: 1) 7 2) 8 3) 20. Writing for Science See TN Level C - WRITING FOR SCIENCE. Challenge Fiddler crabs have one very large claw that they use to signal to other fiddler crabs. Scientists have found that fiddler crabs living on one beach may not be able to understand the signals of those on another beach. Play this game like regular Charades, but use only crab-related words. You might want to review Charades signals such as "sounds like," "short word," etc. Puzzle Answer: oysters. (The o will be left in Row A. The y, s, and t will be in Row B, the e in Row D, the r in Row F, and the s in Row G.) Female pea crabs are no more than 1/2 inch wide, and sometimes live inside the shells of live oysters. These tiny crabs feed on whatever the oyster eats. Level E Main Concepts: There are more than 4400 species of crabs. They are crustaceans and have many ways of protecting themselves. Crabs molt when they get too big for their shells. They can regenerate lost limbs. Vocabulary Answers: ACROSS - bait, seaweed, fish BACKWARD - plankton, worms UP - clams, eggs DOWN - shrimp, eels, leaves, squid DIAGONALLY - snails, fruit. Crabs are scavengers - they eat dead animals and plants (as well as live food). Have your students ever gone crabbing? What did they use for bait? Weekly Lab For this lab, you can use any type of hard roll. Round or oval shapes work well (e.g., a Kaiser roll or a small baguette.) Mini-marshmallows or gum drops can be used instead of raisins. The binder or bulldog clips are a nice feature to add, because they illustrate the strong gripping power of a crab's claws. As an alternative, they can construct 2 part claws, made out of cardboard. Put the parts together with paper fasteners, so they can open and close, and attach them to the ends of the 2 front pipe cleaners. They can also use large, open paper clips to represent the claws. In addition, for the bonus, have your students glue bits of sponges, tissue paper, sequins, or small shells on their crabs. This is similar to how decorator crabs "disguise" or camouflage themselves to hide from their enemies. Weekly Problem Answers: 1) 7 2) 8 3) 20 4) 1/2. Writing for Science Answers: The mistakes are: There are less than 100 species of crabs, crabs have soft shells over hard bodies, they will not eat anything dead, the smallest crab is the Japanese spider crab, they have changed a lot from their original form, and growing a new leg is called molting. The correct information is: there are more than 4400 species of crabs, crabs have hard shells over soft bodies, they do eat dead things "Dead Things" is the 13th episode of season 6 of the television series Buffy the Vampire Slayer. Plot synopsis Summary Warren, Andrew and Jonathan try to make Warren's ex-girlfriend Katrina their willing sex slave by magical means, but when she fights , the Pea crab is the smallest crab, crabs have not changed much, and growing a new leg is called regeneration. Challenge See TN Level D - CHALLENGE. As a bonus, let your students try giving clues with just one "claw"! Puzzle Answer: oysters. (The o will be left in Row A. The y, s, and t will be in Row B, the e in Row D, the r in Row F, and the s in Row G.) Female pea crabs are no more than 1/2 inch wide, and sometimes live inside the shells of live oysters. These tiny crabs feed on whatever the oyster eats. DID YOU KNOW?? The pine crab lives in water that collects at the bottom of bromeliad plants that grow on tropical trees. Level F Main Concepts: There are more than 4400 species of crabs, living throughout the world, on land and in water. Crabs are crustaceans. They have many methods of self-protection. Crabs molt when they get too big for their shells. They can regenerate lost limbs. Weekly Lab Lab A: See TN Level E - WEEKLY LAB. Lab B: Explain that the populations of water crabs often vary greatly from year to year. One reason for this is that, after hatching, crabs are very sensitive to the water's salinity levels (the amount of salt in the water). Salinity levels vary depending on how much rainfall there is. In this lab, your students will find that the pen cap rises in the water as more salt is added. Fresh water is less dense than salt water. As the salt content increases, the water gets denser and has greater buoyancy buoyancy (boi`ənsē, b  `yən–), upward force exerted by a fluid on any body immersed in it. Buoyant force can be explained in terms of Archimedes' principle. , which lifts
the cap higher in the water. A scientist studying the health of crabs
would use a hydrometer hydrometer (hīdrŏm`ətər), device used to determine directly the specific gravity of a liquid. It usually consists of a thin glass tube closed at both ends, with one end enlarged into a bulb that contains fine lead shot or mercury to to measure the water's salinity.
Weekly Problem Answers: 1) 7 2) 8 3) 20 4) 1/2. Writing for Science See TN Level E - WRITING FOR SCIENCE. Challenge Answers: ACROSS - bait, seaweed, fish DOWN - shrimp, eels, leaves, squid BACKWARDS - plankton, worms UP - clams, eggs DIAGONALLY - snails, fruit. Crabs are scavengers - they eat dead animals and plants. (They also eat live food) Ask if your students have ever gone crabbing. What did they use for bait? Puzzle Answer: oysters. (The o will be left in Row A, The y, s, and t will be in Row B, the e in Row D, the r in Row F, and the s in Row G.) Female pea crabs are no more than 1/2 inch wide, and sometimes live inside the shells of live oysters. These tiny crabs feed on whatever the oyster eats. DID YOU KNOW?? Female blue crabs are said to "paint their fingernails" because their claw tips are red. DID YOU KNOW?? When a blue crab molts, it "backs out" of its old shell. We wish to thank Prof. Fred Wheaton, Chairman, Dept. of Biological Resources Engineering, at University of Maryland, College Park The University of Maryland, College Park (also known as UM, UMD, or UMCP) is a public university located in the city of College Park, in Prince George's County, Maryland, just outside Washington, D.C., in the United States. , for his kind assistance. Helpful Sources for Planning Your Science Weekly Classroom Activities Recommended Resources * Bailey, Jill. The Life Cycle of a Crab. New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : The Bookwright Press, 1990 * Cooper, Jason. Crabs. Vero Beach Vero Beach (vēr`o), city (1990 pop. 17,350), seat of Indian River co., E Fla., on Indian River (a lagoon and part of the Intracoastal Waterway); founded c.1888, inc. 1919. , FL: Rourke Publications, 1996 * Day, Nancy. The Horseshoe Crab. New York: Dillon Press, 1992 * Hollenbeck, Kathleen M. Dancing on the Sand - A Story of an Atlantic Blue Crab. Washington, DC: Smithsonian Institution Smithsonian Institution, research and education center, at Washington, D.C.; founded 1846 under terms of the will of James Smithson of London, who in 1829 bequeathed his fortune to the United States to create an establishment for the "increase and diffusion of , 1999 * Johnson, Sylvia. Hermit Crabs. Minneapolis: Lerner Publications Company, 1989 * Kite, Patricia. Down In the Sea: The Crab. Morton Grove Morton Grove, village (1990 pop. 22,408), Cook co., N of Chicago, NE Ill.; inc. 1895. It has research laboratories and plants that manufacture goods such as pumps, electrical equipment, and cosmetics. , IL: Albert Whitman and Company, 1994 * Stefoff, Rebecca. Crab, New York: Benchmark Books, 1998 Internet Resources Blue crabs - http://www.blue-crab.net http://www.dnr.state.md.us/fisheries/fishingreport/blucrbft.htm http://www.vims.edu/adv/ed/crab/anatomy.html Pea crabs - http://brandon.ittralee.ie/research/Mary.htm Japanese spider crabs - http://www.vt360.com/aquarium/tour3.htm True crabs, false crabs, and hermit crabs - http://www.mov.vic.gov.au/crust/hermbiol.html Lots of crab pics - http://www.tropicabelize.com/Restaurant/Crabs/Crabs%20&%20Lobsters.htm Materials Needed for Issue 3 - Secret Codes Pre-A - white crayons, water-soluble markers, white paper, mirrors (optional - lemon juice, Q-tips, lamps) A - red and yellow construction paper, clear tape, scissors, paper towel rolls, paper clips (optional - white crayons, water-soluble markers, white paper) B - red and yellow construction paper, clear tape, scissors, paper towel rolls, paper clips, mirrors C - scissors, paper fasteners, paper clips D - scissors, paper fasteners, paper clips (optional - construction paper, white paper) E, F - scissors, paper fasteners, paper clips We wish to thank Prof. Fred Wheaton, Chairman, Dept. of Biological Resources Engineering, at University of Maryland, College Park, for his kind assistance. |
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