Arthropoda

Biome on lobster The lobster lives in the aquatic biome and more specifically the marine intertidal zone, which is Laos to the shore line. This is where many rocks are located, which would explain why lobsters live their. Th aquatic biome is basically anywhere with a body of water, this includes ponds, lakes, and oceans Some of the abiotic factors of this biome that could effect the organisms living there would be light, temperature, and water current. Light is important for plant organisms, because light allows for photosynthesis and that is important for plants to grow and be food sources for other aquatic living animals,like lobsters. Temperature is important for two reasons, oxygen levels and difference in tropical and arctic animals. Oxygen levels would change, and this effects the metabolism rates of aquatic living species. Temperature change would effect living conditions for animals if there environment becomes colder or warmer than it should be and could lead to mass death of species. This could be specific to animals that are cold blooded and need to be in warm water area; if the temperature fell in this area this cold blooded species could die out. Water current could effect what types of plants are living in near a river that is running faster than another. A plant with week roots or a stem may not be able to survive next to a rushing river while others would be more adapt to survive there. This could also effect what kind of fish would live in the river. Crustaceans, fish, and plants are the biotic animals that live there. Jake and Shimon (The document above includes all the pictures that we could not add to the Wiki because it wouldn't work) Hello, the specific Arthropoda that we will be focusing are research on will be the crustaceans, and more specifically the lobster.

Arthropoda

body plan

1. bilateral symmetry- you can cut the organism vertically and both sides will be symmetrical 2. specialized tissue- different tissues serve different purposes i.e. brain, liver, heart 3. many pairs of legs- many appendages in order to move 4. segmented body- outer shell is broken up into different segments (lobsters specifically have 14 segments) 5. hard exoskeleton- hard body providing for protection- calcium carbonated shell 6. jointed legs- legs have joints in order to move cephalothorax- has a head and thorax compound eyes-A compound eye has a mesh-like appearance because it consists of hundreds or thousands of tiny lens-capped optical units called ommatidia coelomates- have body cavities open circulatory system cartilaginous body structure

http://evolution.berkeley.edu/evolibrary/article/0_0_0/arthropods_04

Ectoderm- epidermis+epidermic tissue- i.e. hair, nails, etc. mesoderm- between ectoderm and endoderm, connective tissue like bone and muscle Endoderm- inner organs, respiratory tract, circulatory tract, and digestive tract About a billion billion (1,000,000,000,000,000,000) insects are alive at any time. That's about 160 million insects for each person on Earth!

At any moment, there are about 1,000,000,000,000,000 ants alive on the planet. If each ant were half a centimeter long, they would form a chain long enough to circle the Earth 125,000 times!

Almost any way you look at them, arthropods are successful: They have been around for more than 500 million years and are still evolving. They live on Earth in overwhelming numbers. They have come in all shapes and sizes. They have evolved to fill a variety of ecological niches — from tiny internal parasite to giant bird-eating predator.

life processes of chosen class

sexually reproducing- opposite of asexual, they have sex

A female lobster can mate only just after she sheds her shell. Lobsters have developed a system where the female lobster will approach the male’s den right when she is ready to molt, and release a sex perfume called pheromone, to avoid vulnerability. Unlike a female moth, whose sex pheromone may attract dozens of random predators, the female lobster at a certain time and place. She usually seeks out the largest male in the neighborhood and stands outside his den, releasing her scent in a stream of urine from openings just below her antennae. He responds by churning the water with his swimmerets, filling the den with the perfume. He emerges from his den with his claws raised. She responds to him with a brief boxing match or by turning her back to him. Both actions seem to work. The female then raises her claws, just as the male did, and she gently places them on the males’ head. They both then enter into the den and when the female molts the mating begins. At this point the male could mate with her or eat her, but he usually does the first of the two. He gently turn over her soft body with his legs and mouthparts. The male then inserts his first pair of swimmerets and passes his sperm into a receptacle in the female's body. She stay in his den until her new shell hardens, then the attraction is gone and she leaves

male lobsters will deposit sperm on the underside of the female. The female will later use the sperm to fertilize her eggs after they are laid. The female can store the sperm for several months as she waits for the egg-laying season, which typically occurs during July and August. Females breed every two years.

a female lobster carry their eggs, also known as berries beneath her abdomen, attached to structures called spinnerets. the amount of eggs has a direct correlation to the size of the female, and is typically about 5,000 eggs for a 10 inch long female, and 40,000 for a 14 inch long female.

external egg fertilization external egg development

Method of acquiring nutrition

digestive organs pyloric gland: the muscular passage at the bottom of the stomach that lead into the duodenum, secretes pepsin gastric mill: muscular pouch used to grind up food lobsters don’t have oral teeth the food is ground up in the gastric mill with teeth like structures

cardiac gland: secretes mucus into the stomach fundic gland: secretes digestive acid mouth: for food intake tomalley: fulfills the purpose of both liver and pancreas- secretes digestive enzymes, it’s the green stuff you see when you eat lobster intestine: further absorption occurs in the intestine anus: releases material too large to be absorbed pincer claw and crusher claw: used for defense against predators, but also used for offense to catch their prey

the segmented body of a lobster makes the lobster which in turn results in increase agility

lobster navigation -internal magnetic compass that enables them to determine the four cardinal directions: north, south, east, and west. -antenna provides for sensory reception- the lobster can detect animals within a certain distance

predators and prey The biggest predator of the lobster is humans. After man, their next biggest predators are ground fish such as flounder and cod, sculpins, eels, rock gunnels, crabs, and seals.

The records that show that 52 Million Lobsters were harvested.

Lobsters will eat basically anything that they can get their claws on, even if it’s dead. The main diet of a lobster is crab, mussels, clams, starfish, sea urchins and various marine worms. They are also known to catch fast moving animals like shrimp, amphipods (also known as “sand fleas”) and even small fish. Lobsters eat mostly animals, but if these resources are scarce, a lobster might eat plants, or sponges too.

After lobsters molt they need to eat a lot and will even eat their newly vacated shell, which is rich in calcium and will quicken the process of growing a new shell

digestive system The digestive system lobsters consists of three main parts, the foregut, midgut, and the hindgut, two of which are stomachs. The first stomach, the foregut, contains a gastric mill, a muscular pouch used to grind up food into fine particles. The pyloric, fundic, and cardiac glands all secrete different digestive enzymes into the stomach and breaking down molecules like proteins. The remaining food particles then pass into the second stomach where the midgut glands further digest the food particles. The midgut glands are actually the tomalley. Material that is too large to be absorbed is eventually passed into the hindgut and then through to the enlarged rectum and out the anus at the tip of the lobster’s tail.

Lobster evolutionary advantages- lobsters have the developed the ability to use autotonony, which is the self-amputation. This can be used to escape when being caught by a predator. Lobsters will re-grow the limb after molting, but it will usually be smaller. Environment- they live on the ocean floor under rocks. When they are larvae they live under pebbles to protect themselves from predators. Eventually after molting many times they are able to hide in dug out holes in the ground (Crevices). Predators include flounder, cod, sculpins, eels, and rock gunnels. Lobsters were believed to be cannibal animals because scientists found partially digested lobster shells in their stomach, however this was actually just their own shell they molted out of and ate to gain the calcium. Lobsters act as a food source to many animals in the ocean and to humans as well. They also play a key role by filter feeding in it planktonic stage, which means during one of their larva stages, lobsters use the process of taking in water to obtain parts of prey. Essential they open there mouth and eat whatever they catch. This helps clarify the water for other animals. This process is used in other crustaceans too like krill.

Red groupers dig holes that lobsters are able to use for habitat. Spiny lobsters in the Florida bay area are able to hide in the dug out excavations.

As far as Evolution goes the Arthropod population has two theories, one were scientists believe that the main traits were ancestral and one were they think that Arthropods evolved up to four times. Arthropods are considered the most successful phylum on the planet because of the amount of them that exist in the world, up to 6 million. The jointed legs help with mobility, the segmented body allows for much more specialization for different activities, an example is the pill bug that rolls up when it senses danger and a lobster that uses the segmented body for the tail that is used for fast swimming to escape from predators, lastly the exoskeleton is used to prevent water loss from the arthropod body. Th exoskeleton helps with muscle use because it allows better use for muscle so that they can walk and not just flop around. A disadvantage is frequent molting.

Excretory system is located near the antennae. This organ removes toxic products of protein metabolism and tissue breakdown. Was products can also be removed through gills, digestive glands, or they can be lost during molting. Twenty pairs of gills are located on the Cephalothorax making up the respiratory system. They are many feathery like filaments. Water passes through the opening of the lobsters leg and flows into its gills, every few minutes the current changes and this flushes out debris from the gills. This is called the gill current and is used to project urine towards the head, this is because it is believed that urine is used to identify the sex of a lobster. This would be helpful in mating because it would help lobsters find mates. Lobsters do not have brains, really, they lack a cerebral cortex which is used to register pain. Ventral ganglion is located under the stomach of the lobster and is segmented throughout the entire body. Lobsters circulatory system is an open one meaning, it is only a single chamber with muscles and openings called Ostia. The heart is located above the stomach and it beats 50-136 beats per minute.

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