Invertebrate Animals

Invertebrate Animals By: Anthony March

Animals Characteristics • Eukaryotic • Multicellular • Have no cell walls • cell membranes made of fatty acids • Reproduce either sexually or asexually

Symmetry • Symmetry - the quality of being made up of exactly similar parts facing each other • Asymmetrical - having parts that fail to correspond to one another in shape, size, or arrangement; lacking symmetry (Ex: Fiddler crab) • 2 types of symmetry – • Bilateral symmetry (Ex: Humans) • Radial symmetry (Ex: Sea urchins)

Invertebrates • An animal lacking a backbone

Sponges • Definition – a primitive sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibers or calcareous or glassy spicules. Sponges draw in a current of water to extract nutrients and oxygen • 5,000 species of sponges • Filter feeders - are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. (Ex: sponges) • Sponges live in sea water and freshwater • Sponges are important to their ecosystem because they serve as protection to fish, and they provide the animals that live inside of them with a rich food supply that they get from the water circulating through them.

Sponges body Forms • Sponges are supported by different things including calcareous laminae, organic filaments, and siliceous and calcareous spicules. • Spongin - the horny or fibrous substance found in the skeleton of many sponges. • Sponges are made up of cells, spicules, and spongin. • Sponges body parts: • Spicule - Small pointed structure serving as a skeletal element in various marine and freshwater invertebrates e.g. sponges and corals • Ostium - One of the small openings in a sponge's body through which water enters • Filter Chamber - Specialized structure that allows fluid feeders to obtain more nutrients; increases absorption area • Osculum- A large opening on a sponge through which filtered water is expelled • Collar Cell - Any of the flagellated cells in sponges having a collar of cytoplasm around the flagellum • Tubular -Having hollow tubes (as for the passage of fluids)

Cnidarians • Definition - an aquatic invertebrate animal of the phylum Cnidaria • Hydra – They live in unpolluted fresh-water ponds, lakes, and streams in the temperate and tropical regions. They mainly feed on small aquatic invertebrates such as Daphnia and Cyclops. They capture their prey by extending their tentacles, injecting their prey with nematocysts, wrapping the tentacles around their prey and pulling it into their mouth. • Jellyfish – They live in oceans. Since jellyfish are carnivorous, they mainly feed on plankton, crustaceans, fish eggs, small fish and other jellyfish. They deliver an electric shock to their prey, wrap their tentacles around it and pull it into their mouth. • Corals – They live in shallow tropical water. They stay alive by receiving nutrients from algae, capturing particles such as plankton, and taking up dissolved substances from the water. The tentacles of the coral kill or immobilize the prey and pull it in to be eater. • Anemones – They live at the bottom of the oceans. They feed on smaller organism by killing/immobilizing them and pulling them into their mouth with their tentacles

Cnidarians Body Forms • Polyp Stage – cylindrical in shape and elongated at the axis of the vase-shaped body. Body could be roughly compared to a sac. Body parts/anatomy include tentacles, a mouth/anus, gastrovascular cavity, mesoglea, ectoderm/endoderm. • Medusa Stage – Symmetrical body and looks like an umbrella. Body parts/anatomy include tentacles, a mouth/anus, gastrovascular cavity, mesoglea, ectoderm/endoderm.

Flatworms • Definition - a worm of a phylum that includes the planarians together with the parasitic flukes and tapeworms. They are distinguished by having a simple flattened body that lacks blood vessels, and a digestive tract that, if present, has a single opening • Planarians (Turbellaria) – Mostly feed on small organisms or dead bodies of organisms. Most live in freshwater under rocks, and on plant materials. • Flukes (Trematoda) – Flukes are parasitic so they live off the host that they are attached toon the inside of their host or on the outside. • Tapeworms (Cestoda) – Tapeworms are parasitic. Their head attaches to the intestinal walls of Humans and animals. This way they live and feed off their host.

Tapeworms • Definition - a parasitic flatworm, the adult of which lives in the intestine of humans and other vertebrates. It has a long ribbon-like body with many segments that can become independent, and a small head bearing hooks and suckers. Tapeworms grow and survive by taking nutrients directly from their hosts. They do this because they are parasitic. • Parasitism – Parasitism is a non-mutual (one benefits while other is harmed) symbiotic relationship between two organisms where one organism (Parasite) benefits at the expense of the other (host) • Tapeworms live on the intestinal walls of its host (humans, dogs, cats, etc..) and they feed off their hosts to stay alive.

Roundworms • Definition - a nematode, esp. a parasitic one found in the intestines of mammals. • have a thick cuticle that covers their bodies and is shed in order to allow for growth • They have muscles located between the cuticle and the pseudocoel that push on both the cuticle and the pseudocoel and create a kind of hydrostatic skeleton • muscle cells branch toward the nerve cells • mouth usually has 16 protruding sensory organs and sometimes displays piercing structures called “stylets.” They survive by alternating between hosts and regions in their hosts' bodies. This is non-mutual symbiotic relationship that they have where they benefit from their host. A hookworm is a type of roundworm. Hookworms live in the small intestines of its host and it feeds of its host.

Mollusk • Definition - an invertebrate of a large phylum that includes snails, slugs, mussels, and octopuses. They have a soft, unsegmented body and live in aquatic or damp habitats, and most kinds have an external calcareous shell • Mantle – excrete calcium carbonate to create the shell of the animal. • Gills – to breath • Characteristics - contain a soft body containing a visceral mass, a foot and a mantle, bilateral symmetry, have a mantle cavity that functions to excrete gases and waste • Anatomy/Body Structure – Some of the organisms have hard shell as protection. Anatomy includes gills, complete digestive systems, 3-5 cell layers, nerve system, and for some a shell.

Type of Mollusks • Snail – Has a single spiral shell into which the whole body can be withdrawn. They live in diverse climates such as deserts and mountain areas and even in marshes. What they eat depends on the type of snail they are and where they are and what’s in their environment • Slug – Atough-skinned terrestrial mollusk that typically lacks a shell and secretes a film of mucus for protection. They live in damp areas, soil litter, under foliage of plants. Ripe strawberries are a favorite meal for slugs. In addition to the strawberries, they like many kinds of plants, including corn, lettuce, beans, and flowers of all kinds. • Squid - An elongated, fast-swimming cephalopod mollusk with ten arms (technically, eight arms and two long tentacles), typically able to change color. They live in all of the oceans of the world. A squid's diet consists of shrimp, plankton, crabs, and small plants. Squid also eat small fish. Larger squid will sometimes feed on smaller squid, as well

Segmented Worms (Annelids) • Earthworm –They live in the soil, trees, under rocks and on banks of streams. They form burrows in wet soil and may go up to six feet deep into the soil. They eat dirt. Their nutrition comes from things in the dirt such as decaying roots and leaves. • Marine sand worm – They live in mud or sand in coastal areas. Different types of marine worms eat different things. The filter feeding worms eat bacteria and phytoplankton while the burrowing one eat pieces of plants and animals in the sand. The predatory worms eat shrimp, sea urchins, and fish. • Leeches – They live in freshwater surroundings, but some species can survive in marine and terrestrial environments. They feed on tubificid worms and on the flesh or fluids of other animals They are made up of ring-like segments called annuli. These segments are covered in small bristles. There body is a long slippery structure. Their anatomy includes a complete digestion system, a mouth/anus, anterior connection of nerves, single ventral nerve cord with ganglia, setae for locomotion with muscular contractions, non skeleton, seminal vesicles/receptacles.

Arthropods • Definition - an invertebrate animal of the large phylum Arthropoda, such as an insect, spider, or crustacean. • Appendages - an external body part that protrudes from an organisms body • Exoskeleton - a rigid external covering for the body in some invertebrate animals, esp. arthropods, providing both support and protection. • Their anatomy includes a complete digestive system with side-to-side jaws, Developed brain, ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton. • An example of arthropods would be insects. Insects mainly live in the soil, caves and on the mountains. Some of them eat other insects. Some of them eat blood (like mosquitoes). Nectar from plants is also a popular food. And many insects (like cockroaches or ants) will eat food that falls on the floor like a cookie.

Insects • 3 regions of insects include the head, the thorax, and the abdomen • Open circulatory system - The open circulatory system is common to molluscs and arthropods. Open circulatory systems (evolved in crustaceans, insects, mollusks and other invertebrates) pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells. Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood. • Fly – They are commonly found in homes, restaurants and other facilities where food is processed since they live off bacteria ad germs. • Ant – They live on the ground or on the soil surface. They live in colonies; where you spot a small mound of dirt on the ground. Ants like sweets and they more often than not swarm around sweets or sugar but rarely crowd around salty food. • Ladybug - They reside where insect pest populations are high. Such as in crop fields, gardens, and in the canopies of trees. They eat aphids which are insects that suck the sap out of plants. • An insects anatomy includes - a complete digestive system with side-to-side jaws, Developed brain, ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton, and wings

Metamorphosis • Complete Metamorphosis - insect development in which egg, larval, pupal, and adult stages occur Incomplete Metamorphosis - A life style of certain insects characterized by the absence of a pupal stage between the immature and adult stages.

Crustaceans • Defined - an arthropod of the large, mainly aquatic group Crustacea, such as a crab, lobster, shrimp, or barnacle. • Lobster – They live in all of the oceans. The lobsters live and eat at the bottom of the oceans floor. They eat small fish, worms, invertebrates, protozoa, sea plants, and even other crustaceans • Crabs – They live in the ocean or on river banks, lakes, rocks, and in deep holes in the sand. Crabs are small sea creatures with eight legs and two claws that they use to crack open the shells of marine snails and eat them. • Spiders – They live in almost every habitat on earth,but in oceans and Antarctica.mostly common in gardens. The majority of spiders feed on insects but the larger species will also eat other small animals such as millipedes and wood lice (slaters), small lizards and frogs, and even small birds in the case of tarantulas and the largest of the golden orb weavers. • Harvestman – The live in fields and forests. They feed on insects and other small creatures. Anatomy- includes a complete digestive system with side-to-side jaws, Developed brain, ventral nerve cord, many specialized sensory organs, jointed legs, exoskeleton.

Echinoderms • - a marine invertebrate of the phylum Echinodermata, such as a starfish, sea urchin, or sea cucumber. • Star fish – Starfish occur in all of the Earth's oceans. Almost anything that moves slower than they do – which is a lot of sea creatures. Sea stars are successful scavengers and predators. Some attack mollusks, like mussels and oysters, which don't move, and some feed on dead fish or other carrion • Sea urchin – They live on the floor of the oceans or bays. They can also be found in the rocks of the shallows. They can also attach themselves to coral. Their diet includes things such as mussels, small fish, algae, and sponges • Brittle stars – They live under rocks on the floor of the oceans or bays. Different species of brittle stars have any one of 3 different feeding habits. Some are suspension feeders who capture particles of algae etc. from the water floating by them. Some are bottom feeders collecting from the ocean bottom. Then there are some that are predatory using their arms to capture small sea animals and mollusks. • Anatomy includes stomach, radial nerves, tube feet, digestive glands, gills, and a spine

Water-Vascular system • Definition: a network of water vessels in the body, the tube feet being operated by hydraulic pressure within the vessels

Invertebrate Animals