Name Date Period Crustaceans- Chapter 10 Guided notes 10.1 Introduction to Crustaceans The Lobster Arthropods phylum Arthropoda, meaning Characteristic Outer skeleton is its Made of, type of carbohydrate Varies in flexible to hard in different arthropod species Functions as protective as well as a place for muscles to attach Diverse in appearance, some scientist want to divide them in different classes, subphya, or separate phyla Crustacean Features Crustaceans animals with hard outer covering, divided into two main segments Cephalothorax tail (if present) Carapace exoskeleton that covers the head Lobster, crabs, and shrimp have 5 pairs of legs Referred to as Claws that are used in are 1 st pair and the 4 other pair are for Head has Some crustaceans can glide along the sea floor by using a small paddlelike appendages located under the abdomen Crustacean
The Lobster Two common lobster species Homarus americanus has 2 lg. claws Live in Found from Labrador to Virginia Panulirus argus No lg. claws Found in waters of Lobsters are aggressive, often fight amongst themselves Lobsters can Structures and Life Activities of Lobsters Lobsters are Feed on other invertebrates Food digested in a Mouth Esophagus Stomach Intestines Breathe through, under carapace Each gill attached to the upper end of walking legs Oxygen & nutrients transport around lobster s body in its blood Blood is in color due to pigment hemocyanine contains copper which binds oxygen Blood pumps through the body by a one-chamber heart, aided by body muscular contraction
The Crab No capillaries connecting arteries and veins, blood just passes through tissue space Nervous system enable a variety of responses Eyes on movable stalks Two pairs antennae actively feel out environment Impulses from receptors carried by sensory nerves to brain, or cerebral ganglia Responses carried out when brain send impulses back via ventral nerve cord to muscles Lobster reproduce Fertilization internal, development external Sperm deposited in females abdomen Eggs are released and carried by female on swimmerets for almost a year before hatching Embryo go through larval phase, float as part of plankton population, molting as they grow into adult form The Crab fiddler crab (Uca) digs tunnels in the sand along shore Retreat into tunnel and plug up entrances Gets its name for its Male has one lg. and one sm. claws Female has two sm. claws Mole crab Emertia lives in turbulent surf zone along sandy beaches Has that diminishes impact of waves, allows crab to burrow and move efficiently through swirling mixtures of sand and water Has featherlike antennae, used to capture microscopic organisms Hermit crab Pagurus longicarpus born with For protection hermit crab finds
Inhabit shallow coastal waters Scavenge on particles of food As it increases in size it - Spider crab Libinia emarginata slow moving, has no paddle appendages used for crawling along ocean bottom have time to attach and grow on their backs Inhabits Atlantic and Pacific waters Biggest crab in the ocean is the giant spider crab Macrocheira kaempferi Found in deep waters off Japan Leg tip to leg tip 4 meters in width Crabs body is divided into segments covered by carapace are the Cephalothorax - Abdomen small flat, between walking legs on ventral side Shape of abdomen tells the Female has a Male has a Crabs eat mainly dead plants and animal matter, graze on algae and some are predatory Claws are One-way digestive tract Mouth, esophagus, stomach, & intestines Breath through gills Two eyes and antennae Well-developed nervous system Female carries a, male fertilizes eggs internally Embryos develop Diversity Among Crustaceans: The Shrimp and Others The Shrimp sm. Version of the lobster Gulf shrimp Penaeus duorarum grow up to 17 cm long, seafood industry
Smaller common shore shrimp Palaemonetes vulgaris lives among the grasses and seaweeds in salt marshes Smallest shrimp Periclimenes survives by eating parasites and are found on the skin of reef fish a symbiotic relationship Mantis shrimp Squilla empusa largest of all shrimp grows to 25 cm long Burrow in the sand or mud, spear its prey Copepods and Krill Copepod is the Over 1000 species ½ cm long Eats mainly diatoms Important part Reproduce sexually Krill is a Grows to 5 cm long Most live in Planktonic animal, eats diatoms, and floats on ocean surface in lg. masses Principal Amphipods and Isopods These crustaceans are found near the edge of the sea- under in the Scud Gammarus are bottom dwellers Live in wet sand East and West coast Beach flea Talorchestia Use seaweed for cover and food Sea roach Ligua resemble a Swim, crawl in coastal waters Feed on algae
Active at Flattened bodies and Can live attached to gills and skin of fish such as cod and halibut The Barnacle Often mistaken for a mollusk Acorn or rock barnacle Balanus lives in the upper intertidal zone, attached to rocks and hard surfaces Overlapping Attach to almost A type of encrusting organism Structures and Life Activities of Barnacles Barnacle s body id actually folded up within its shell so that its appendages can protrude from the opening When tide comes in barnacle opens Cirri whip about catching phytoplankton and other food particles and brings it to its mouth Filter feeders Food digested in a one-way tract Mouth, stomach, and intestine O2 and CO2 are exchanged across barnacle s skin membrane At low tide when barnacle is exposed to air its overlapping plates Barnacle contains both ovaries and testes, does not occur Mating occurs when penis of one barnacle is inserted into a neighboring barnacle Fertilization occurs inside the barnacle, and fertilized eggs develop into swimming larvae that is shed into the water
When larvae come into contact with suitable substrate they attach to it by secreting glue from a special gland and develop into an adult 10.4 Diversity Among the Arthropods The Horseshoe Crab Limulus polyphemus arthropod Has More closely Placed in its own class, Inhabits waters along Atlantic and Gulf coast and Asian Pacific coast Searched for food in the mud, preying on sm. Mollusks and crustaceans Has 4 eyes, two simple and two compound eyes, on top of carapace Compound eyes contains many visual units which are grouped together for better vision Structures and Life Activities of Horseshoe Crabs Legs are on the underside of horseshoe crab First pair is set with pinching claws cheliceras Other five are walking legs In male Body and legs are covered by carapace Behind the legs are numerous overlapping membranes, these are the used for breathing and locomotion Spiked tail or is not used as a weapon It is used for locomotion and when tossed on its back by a wave it uses it as a lever to flip itself over Life Cycle of the Horseshoe Crab In late spring at high tide, thousands of horseshoe crabs invade the sandy beaches and marshes Females carrying the smaller male clutched to their backs at the high-tide mark dig holes in sand and lay hundreds of tiny pale green eggs
Males still attached to female externally fertilize the eggs and then cover the eggs with sand After two weeks eggs hatch and tiny juveniles carried out to sea by the tide swim away. Within months they develop spiked tails and other characteristics of adults Horseshoe crab reaches sexual maturity in about eight yrs. During its period of growth it undergoes many molts, shedding its outer shell and growing another These old shells are often found on the beach and mistaken for dead crabs Fossils of the horseshoe crab show that this animal in 400-millionyears For this reason the horseshoe crab is often called a Marine Insects Some inhabit the high salinity water and others are found in the salt marsh Biting insects live in the salt marsh and inland bays All possess chitinous exoskeleton & jointed appendages Only have, head, thorax and abdomen Have just - Placed in the class Insecta Most familiar is the marsh mosquito Greenhead fly Sad fly or no-see-um These insects often inhabit inland estuaries Eggs can develop into larvae which then develop and hatch into adults