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Name and Section: Organismal – Prof Goffe Invertebrates Lab – Week 9 1. What characteristics do all animals have in common? 2. What is an invertebrate? 3. Which animal phyla are considered invertebrates? 4. What is a coelom? 5. Label the diagram with the following terms: dorsal, ventral, anterior, posterior. ______________________________________________________________________ Major points/terms from this lab Terms: invertebrate, vertebrate, asymmetrical, radial symmetry, bilateral symmetry, coelom, acoelomate, pseudocoelomate, hydroskeleton, endoskeleton, exoskeleton, dorsal, ventral, anterior, posterior Classification for organisms studied through phylum Major characteristics of each phylum studied in this lab Characteristics that all animals share Chart for organisms studied in this lab Identify major structures for each organism studied (see lab for list) in a diagram and the in the organism/slide Laboratory 9 – Animal Diversity I Introduction: Today we will be studying representative samples of the Kingdom Animalia. Remember that the classification of all living organisms fits into the taxonomic scheme of: Domain Kingdom Phyla Class Order Family Genus species The general characteristics of animals include: heterotrophic, locomotion, multicellular, life cycle where adult is diploid, and undergoes sexual reproduction to produce an embryo. One of the major distinctions between animals within Kingdom Animalia is whether or not they have an endoskeleton. The two classifications within this characteristic (and a representative way to classify all animals) are invertebrate and vertebrate. Invertebrates lack an endoskeleton of bone or cartilage, whereas vertebrates have an endoskeleton of bone or cartilage. Invertebrates are the most abundant creatures on earth. It is nearly impossible to go a day without encountering one of the million species of arthropods. Most of them are insects, and many others are spiders, yet most of us rarely notice them unless they're in our gardens or on our dinner plates. Invertebrates—animals without backbones—are nature's unsung heroes, quietly playing vital roles in earth's ecosystems. Invertebrates defy nearly every generality. Of some 30 phyla representing 95 to 99 percent of the planet's animal species, the only thing they have in common is what they lack: a backbone. Otherwise, you would be hard pressed to find similarities among species as distinct as enormous moths, ethereal medusas, skittering scorpions, or stationary sponges. They may be spineless, but don't disregard these wildly diverse creatures. Vertebrates—such as fish, amphibians, reptiles, birds, and mammals—make up a tiny fraction of life on earth. These animals will possess a backbone mad of cartilage or bone. Out of the 30 main animal phyla, only 9 are commonly represented in textbooks. These nine phyla will have representative members in today’s lab. The major invertebrate phyla are: Phylum Porifera Members the Phylum Porifera, ("pore-bearer") are commonly known as sponges, and approximately 5,000 have been described by scientists. Until the 18th century, scientists mistook them for plants. Found worldwide in marine and fresh water environments, the sponges are notable for their unique feeding system. Specialized collar cells pump a current of water through pores into the sponge, which then filters out nutrients (classifying it as a filter feeder). Though simple in design, sponges have strikingly bold colors and elaborate shapes. For instance, the aptly named orange puffball sponge, Tethya aurantia, is mostly spherical and orange to yellow in color. The delicately latticed Venus' flower basket sponge, Euplectella aspergillum, often shelters pairs of shrimp and as a result was once a symbol of marital fidelity in Japanese weddings. Phylum Cnidaria Cnidarians, whose best-known representatives include jellyfish, corals, and sea anemones are characterized by one thrilling trait: they possess stinging cells called cnidocytes (Greek for stinging nettle), from which the phylum takes its name. Its 9,500 members may appear serene and waif-like, but these carnivorous creatures can swiftly sting or entangle prey and defend themselves ably when threatened. For example, the Australian sea wasp, Tripedalia cystophora, has enough venom to kill 60 people. The joined exoskeletons of tiny cnidarians (called polyps) form coral reefs. Coral reefs provide habitat to more than one fourth of marine animal species including fish, anemones, cephalopods, anemones, crustaceans, and sponges. Coral reefs also benefit humans by protecting seashore communities from strong waves and storms. Silt runoff from farming, roads, and ocean-side construction smothers the polyps and destroys delicate reef ecosystems. Most members of this phylum are marine species. Many species have two stages to their life cycle. During the first stage, they are free-swimming, umbrella-like form, and a cylindrical attached/stationary form. When stationary, many of the same species will congregate together. Phylum Platyhelminthes The Platyhelminthes ("flat worms") includes some of nature's biggest freeloaders. Two-thirds of the 13,000 species in this taxon are parasitic, including the ultimate moocher, the tapeworm. With no mouth or digestive system to speak of, tapeworms (Class Cestoda) simply absorb their host's nutrients. A specialized epidermis allows these parasitic worms to survive in the gastrointestinal tracts of vertebrates without being digested. If not treated, tapeworms can be deadly to their hosts. They have been known to reach lengths of up to 50 feet!! Phylum Nematoda Nematodes (the round worms) contain parasites common to humans and domestic animals, including the species that causes heartworm in dogs. The vast majority of species is free-living (not parasitic) and harmless to humans. Nematodes can be found in abundance in all terrestrial and aquatic environments and at climatic extremes from arctic waters to arid deserts. A small amount of dirt or a piece of rotting fruit can contain hundreds to thousands of nematodes. The phylum contains an estimated 10,000 to 500,000 species. Phylum Annelida The most familiar worm to gardeners—and anyone who likes to play in the dirt—are earthworms, members of phylum Annelida, as are thousands of species of marine worms and leeches. Commonly known as segmented worms, a series of repeated ring-like structures form the annelid body. The body of the Giant Gippsland earthworm (Megascolides australis) is composed of 500 to 600 segments, and individuals can grow up to ten feet in length. Earthworms enrich the soil by eating dirt, literally. To burrow, earthworms may simply wiggle through the ground, but compact earth requires them to swallow the soil. This is also how these animals obtain nutrients. Along with dirt, they swallow (by means of a sucking action performed by the pharynx) decaying plants, seeds, animal larva, and other organic material. As they digest, they grind and sift this material and eventually excrete it back into the soil as castings, tiny piles of digested dirt that dot the surface of the ground. The castings are full of nutrients that are released into the soil and absorbed by plants. Phylum Mollusca Phylum Mollusca contains an estimated 100,000 species. This phylum includes animals such as the octopus and nautilus. There are three well known Classes of Molluscs; the cephalopods, gastropods, and bivalves. Cephalopods, squid and octopus in particular, are some of the most intelligent invertebrates, capable of learning quickly and retaining information. The Class Gastropoda, represented by familiar creatures like slugs and snails, is the largest Class. Enjoyed by many people for chowder and pearls, members of Class Bivalvia secrete shells divided into two parts that are held closed by powerful muscles. Molluscs have variously modified shells, ranging from the large, whorled shell of the whelk to the thin vestigial plate embedded in the body of a slug. Phylum Arthropoda More than three-quarters of the world's known animal species are arthropods, inhabiting air, land, and water. The major classes are the insects, representing 90 percent of arthropods, the arachnids, which include spiders and scorpions, and the crustaceans, containing crabs, barnacles, and lobsters. Arthropods have protective, jointed exoskeletons, which they occasionally molt to allow for growth and repair. Their exoskeleton is made of chitin. The exoskeleton is periodically molted as the animal increases in size. Arthropods are segmented organisms with jointed appendages. As the animal kingdom's largest phylum, arthropods constitute an abundant food source. Members of the mammalian order Insectivora, such as shrews, hedgehogs, and moles, feed primarily on insects and other invertebrates. Baleen whales gulp down swarms of krill, a shrimp-like crustacean and major component of the whales' diet. Birds commonly feed on spiders, but the world's largest spider, the Goliath bird-eating tarantula (Therophosa leblondi), turns the tables on avian predators. The tarantula will eat young birds on occasion, although its usual diet consists of frogs, beetles, or small snakes. Phylum Echinodermata Represented by sea stars, sea urchins, and their relatives, phylum Echinodermata ("spiny-skinned") exclusively inhabits marine environments and consists of about 6,500 species. If you have ever seen the underside of a sea star, you may have noticed rows of projections radiating from its center. These tentacle-like structures, called tube feet, are common to echinoderms and are used for food-gathering, locomotion, and sensation. All echinoderms possess a five-point radial organization, with five sets of organs, five major arteries, five-point symmetry, and in some cases, five sets of appendages. The fleshy, oblong sea cucumber is radially symmetrical at the organ level only. They are some of the gutsiest echinoderms, spewing out their organs when disturbed and regenerating them over several weeks in a process called evisceration. Body Organization Let’s define some of the important ways to characterize the various Phyla within the Kingdom Animalia. Animals are commonly placed into groups depending on certain anatomical aspects that they may have (or lack). Orientation: During this lab and the following labs, you will be asked to identify parts of an organism using specific terms. Dorsal refers to the “top” side of the organism, or the side facing up. For a dog, the dorsal side would be its back. For a fish or a whale, the dorsal side is the side facing the surface of the water or sky (i.e. dorsal fin). Ventral refers to the underside of the organism. For instance, the area commonly referred to as the stomach in a cat would be its ventral side. Anterior (cranial) refers to the end of the organism that leads when an organism is moving; towards the front of an animal. Posterior (caudal) refers to the end of the organism that trails behind the anterior end; towards the back of an animal. Body Cavity As we move from more simplistic organisms to more complex organisms, you will notices changes in body structures and differentiation of systems. A major factor to look at is the