Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Arthropods & Echinoderms Phylum Arthropoda Well-Known Subdivisions of Phylum Arthropoda Class Arachnida Order Scorpiones (scorpions) Order Opiliones (daddy-longlegs) Order Acari (mites & ticks) Order Araneae (spiders) Class Chilopoda (centipedes) Class Diplopoda (millipedes) Class Insecta (insects) Evolution Precambrian seas over 600 million years ago well established by 500 million years ago Constantly evolving very diverse phylum Symmetry Bilaterally symmetrical Advantages: Specialization of body organs Cephalization Efficient movement Defined direction of movement Less resistance to water and substances Finding food, mating, avoiding predators Body Cavity Coelomate mesoderm lines body cavity and surrounds and supports the endodermic gut mesoderm forms tissues of attachment for organs located in coelom (liver, lungs, etc.) Structural Support Exoskeleton 3 Layers: Waxy outer layer made up of proteins and lipids; repels water; helps prevent drying out Middle layer provides primary protection; made of protein and chitin; sometimes calcium carbonate Inner layer contains protein and chitin; flexible at jointsallows arthropod to move freely; Muscles attached to inner layer at joints move body segments QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Parts of a Crayfish QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Sensory- antennules, antennae Defense- chelipeds Feeding- mandible, mouth, maxillipeds, maxilla Walking- walking legs Swimming- swimmerets, uropods Appendage Antennule Antenna Mandible Maxilla Function Touch, taste, equilibriium Touch, taste Chew food Manipulate food, draw water currents over gills Maxilliped Touch, taste, manipulate food Cheliped Walking leg Capture food, defense Swimmeret Create water currents, transfer sperm (males), carry eggs and young (females) Uropod Propulsion during tailflips Locomotion over solid surfaces Nutrition & Digestion Crayfish (crustacean): DIET: omnivores; they eat plants, animals, and decaying organisms Ex: shrimp, fish, water plants, plankton, insects food passes through esophagus to stomach teeth made of chitin and calcium carbonate grind food into fine paste enzymes secreted by digestive gland mix paste Paste enters intestine and digestive gland for further digestion and absorption indigestible material leaves through anus Nutrition and Digestion (cont.) Scorpions: Spiders: DIET: mainly insects and spiders DIET: mainly insects; some can eat fish, frogs, or birds; consume body fluids of prey Similar digestive system to crustaceans (like crayfish) Parasitic mites: suck fluids from leaves of fruit trees; feed on blood, dead skin, hair, and feathers of vertebrates, like humans, cattle, and dogs Parasitic ticks: feed on blood of host Millipedes: use mandibles and maxillae to chew on plants and decaying plant matter Centipedes: use poisonous claws to kill prey (earthworms, insects, etc.) and use mandibles and maxillae to tear apart food Transportation Some are sessile as adults Ex: Barnacles Isopods: “equal legs” Have 7 pairs of identical legs Ex: sow bugs, pill bugs Decapods: “ten feet” 5 pairs of legs Ex: crayfish, lobsters, shrimps, crabs Transportation (cont.) Tailflip: muscles of a crustacean (such as a crayfish) can bend the abdomen and propel it backwards very rapidly Uropods on the abdomen of a crayfish help propel crayfish during tailflips Arachnids: have 4 pairs of walking legs Ex: spiders, scorpions, mites, ticks Mites and ticks can also be parasitic Myriapods: Millipedes have 2 pairs of legs on each body segment except the last two; move slowly Centipedes have anywhere from 15 to 175 pairs of legs; can move quickly Circulation All have open circulatory systems Crustaeans: Dorsal heart pumps hemolymph into blood vessels Vessels carry it to different parts of body Hemolymph leaves vessels, enters hemocoel and surrounds tissues Passes through the gills, where it exchanges CO2 and O2 with H20 Hemolymph returns from gills to dorsal heart Spider’s and scorpion’s circulatory systems are similar to crustaceans Respiration/Gas Exchange Crustaceans: All except smallest crustaceans use gills Gills extend from base of each walking leg into a chamber under carapace Legs circulate water across gills as the crustacean walks Small crustaceans- CO2 and O2 diffuse through thin parts of the exoskeleton Feathery branches on maxillae also help direct water over gills A thin extension of the exoskeleton covers each gill and permits gases to diffuse across gill surface Respiration/Gas Exchange (cont.) Spiders: Book lungs- paired sacs in abdomen with several parallel folds Like pages in a book Allow for large surface area for efficient gas exchange Tracheae- tubes that carry air from openings in the exoskeleton to tissues in the body Openings- spiracles Some spiders have either book lungs or tracheae, and some have both Water Balance/Excretion Crayfish: Hypertonic to environment Excess water eliminated by green glands- excretory organs Water and other fluids leave crayfish through a pore at the base of the antennae Spiders: Malphighian tubules- hollow projections of the digestive tract that carry body fluids and wastes to the intestine Help spiders conserve water Some spiders have coxal glands Remove wastes through openings at the base of the spider’s legs Reproduction/Development Crustaceans: Mate in fall Male transfers sperm to female using first and second swimmerets Sperm fertilize eggs and are released in spring; eggs stay on the female’s swimmerets Eggs hatch after 6 weeks Have several larval stages Naupilus- free-swimming larva; has one eye and three pairs of appendages Emerge from larval stages as a smaller version of adult firm Molt 7 times first year; molte 2 times in their remaining life Reproduction/Development (cont.) Spiders: Mature male transfers sperm to pedipalp sacs Male places sperm in female’s seminal receptacle Male must leave as soon as mating is finished- female might eat him otherwise Female fertilizes eggs and passes them into a cocoon which she spins herself She will either carry the case around or attach it to a plant or web Spiders undergo their first molt within two weeks of entering the cocoon; they leave the cocoon after those two weeks Can grow to as large as 9 cm long Unique Characteristics & Interesting Facts QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Arthropods make up 75% of all animals! Centipedes can have anywhere from 15 to 175 pairs of legs! Arthropods go through a process called molting Their exoskeleton cannot grow, so they have to periodically shred it in order to get larger Copepods, crustaceans that are less than a centimeter long, are the most abundant animals in the ocean. There are so many of them that they outweigh all the whales on Earth! QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Unique Characteristics & Interesting Facts QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Only arthropods have all five characteristics! Subphylum Crustacea Procambarus fallax Pond crayfish QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Class Arachnida Nephila clavipes Golden Silk Banana Spider QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Pandinus imperator QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Black Emperor Scorpion Class Diplopoda Deseret Millipede Orthoporus ornatus QuickTime™ and a TIFF (Uncomp resse d) d eco mpres sor are nee ded to s ee this picture . Class Chilopoda QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Desert Millipede Scolopendra Subphylum Insecta Symmetry/Body Cavity/ Structural Support All insects have bilateral symmetry Insects are coelomate arthopods hard exoskeleton of insects allows for structural support of muscles thorax provides structural support for the legs and, if present, wings. Nutrition/Digestion Insects obtain nutrients from the food they eat three regions in the digestive system foregut (stomodeum) midgut (mesenteron) hindgut (proctodeum) All insects have a complete digestive system food processing occurs within the alimentary canal, a tube-like enclosure, which runs lengthwise through the body Ingested food travels in only one direction Nutrition/Digestion (cont.) An Insect’s mouth is specialized Grasshopper’s mouths are used for cutting and chewing leaves and blades of grass Labrum & Labium: mouth parts that function and upper and lower lips Mosquitoes have long, thin mouth parts used for piercing flesh and sucking blood Flies have soft, sponge-like mouths used for soaking up liquids, such as fruit juices Digestion/Excretion food enters the mouth and passes through the esophagus to the crop Food then travels to the gizzard where it is shredded Shredded food moves to the midgut where nutrients are absorbed through the wall and into the coelom Moistened by saliva from salivary glands Gastric ceca: pockets that branch from the digestive track which secrete enzymes Any undigested material travels to the hindgut and exits the body through the anus Stomodaeum Mesenteron Proctodeum Circulation All insects have an open circulatory system responsible for movement of nutrients, salts, hormones, and metabolic wastes Large dorsal vessel (aorta) carries hemolymph through the insect’s body The heart, located in the abdomen and thorax, pumps hemolymph to the “head” of the insect The hemolymph then moves back through the coelom and reenters the heart through small pores Transportation Insects have three pairs of jointed legs Most have one or two pairs of wings Grasshopper: Two pairs of walking legs One pair of hind legs Used Two for jumping pairs of wings Gas Exchange/Respiration All insects are aerobic organisms respiratory system transports carbon dioxide and oxygen separate from the circulatory system Insects use a tracheal system, complex network of tubes that brings oxygen-containing air all around the body Gas Exchange/Respiration (cont.) Air enters the body through spiracles, valve-like openings in the exoskeleton located along the thorax and abdomen of most insects Air travels through the tracheae which have ends filled with fluid Oxygen diffuses through the fluid and into the cells Carbon dioxide diffuses the opposite way Water Balance The exoskeleton contains a waxy covering which helps to keep moisture in Insects can lose water in 3 ways by evaporation general surface of the body wall spiracular system both Some insects keep their spiracles closed to conserve water only opening them to receive enough oxygen Malphighian Tubes: collect water and cellular wastes from the hemolymph as well as return water to the hemolymph Reproduction All insects have separate sexes Male places sperm in female’s seminal receptacle, and they are stored there until eggs are released by the ovaries Eggs are fertilized internally In grasshoppers, the female has an ovipositor on the last segment of her abdomen Ovipositor: organ which the female grasshopper uses to dig a hole in the ground to lay the fertilized eggs Development After hatching, a young insect must molt several times before becoming fully mature Most insects go through metamorphosis, a developmental change in form Two main kinds: incomplete and complete Development (cont.) incomplete A nymph, an immature version of the adult, is hatched from the egg, gradually develops into an adult Grasshoppers, mayflies, dragonflies, and termites undergo incomplete metamorphosis Complete Worm-like larvae hatches from the egg Exoskeleton falls off and larvae develops into a pupa, stage of development where the larvae becomes an adult After metamorphosis is complete, the pupa molts into a mature adult Butterflies, moths, and bees undergo complete metamorphosis Unique Characteristics & Interesting Facts 95% of all the animal species on the earth are insects one out of every four animals on earth is a beetle Scientists estimate that 10% of the animal biomass of the world is ants, and another 10% is termites About 1,000,000,000,000,000,000 (a billion billion) insects are alive at any time. This is about 160 million insects for each person on Earth! Monarch Butterfly Order: Lepidoptera Scientific Name: Danaus plexippus Honey Bee Order: Hymenoptera Scientific Name: Apis mellifera Common House Mosquito Order: diptera Scientific Name: Culex pipiens pallens