Zoology Final Exam

Juvenile Trichinella worms live in the intestine. This is because Trichinella is a parasitic worm that primarily infects the intestines of humans and animals. Once ingested, the larvae of the worm mature and reproduce in the small intestine. From there, they penetrate the intestinal wall and enter the bloodstream, eventually migrating to various tissues in the body, including the skeletal muscle. However, their initial habitat is the intestine where they establish their presence and cause infection.

Male nematodes bear a pair of posterior spicules which aid in inseminating a female nematode. These spicules are used during copulation to penetrate the female's reproductive tract and transfer sperm. This process is essential for fertilization and reproduction in nematodes. The spicules play a crucial role in ensuring successful reproduction by facilitating the transfer of sperm to the female nematode.

The correct answer is Trochophore because it is the first larval stage that is typical of mollusks. Trochophore larvae have a ciliated band around their bodies that helps them swim and feed. They are usually planktonic and undergo metamorphosis to develop into the adult form of the mollusk. This larval stage is common among many different groups of mollusks, including gastropods, bivalves, and cephalopods.

The polychaetes differ from the other annelids by having a well-developed head that often bears the eyes, antennae, and sensory palps, and is often called a prostomium or first segment.

If you are discovered to have an infection of Ascaris worms, your most likely danger is blockage of the intestines. Ascaris worms are large intestinal parasites that can grow up to 35 cm in length. When a large number of worms accumulate in the intestines, they can cause a physical blockage, preventing the normal flow of food and waste through the digestive system. This blockage can lead to severe abdominal pain, vomiting, and constipation. If left untreated, it can cause serious complications such as intestinal perforation or obstruction, which may require surgical intervention.

The correct answer is that cilia drive fluids through the tubules for excretion. Flame cells are specialized cells found in flatworms and other simple organisms that help with excretion. These cells have cilia, which are tiny hair-like structures that move in a coordinated manner to create currents in the fluid-filled tubules. These currents help to drive waste fluids and other excretory products out of the organism's body.

The jet propulsion method of swimming in squid is accomplished by forcing water from the mantle cavity through the funnel. The funnel acts as a muscular tube that contracts and expels water, propelling the squid forward. This mechanism allows the squid to move quickly and efficiently through the water. The siphuncle is a structure found in certain mollusks, but it is not involved in jet propulsion swimming. The radula is a feeding structure, the excurrent siphon is a part of the respiratory system, and the blow hole is found in marine mammals, none of which are relevant to the squid's method of swimming.

Metanephridia is the correct answer because it is a type of kidney found in mollusks that serves both excretion of waste and removal of excess water. This type of kidney is composed of a network of tubules that filter waste products from the blood and transport them to the outside of the body.

Cnidarians have a radial body plan, not a tube-within-a-tube body plan. They have a central mouth surrounded by tentacles, but they do not have a separate anus.

An anemone is a type of cnidarian that uses its mouth to take in food. The food then passes through a specialized structure called the syphonoglyph, which helps direct the food towards the pharynx. From the pharynx, the food moves into the gastrovascular cavity, where digestion takes place. Therefore, the correct path for food to move into the body of an anemone is Mouth-syphonoglyph-pharynx-gastrovascular cavity.

The correct answer is Ostia - spongocoel - osculum. In a simple sponge, water enters through small pores called ostia, then flows into a central cavity called the spongocoel, and finally exits through a larger opening called the osculum. This unidirectional flow of water allows the sponge to filter out tiny food particles and oxygenate its cells.

The gelatinous matrix found in sponges is called mesohyl. Mesohyl is a gel-like substance that fills the space between the outer and inner layers of cells in a sponge. It provides structural support to the sponge and contains various cells, fibers, and other components. Mesohyl also acts as a medium for transporting nutrients and waste throughout the sponge's body.

The pericardial cavity is the space around the heart. In a mollusk such as a clam, the pericardial cavity would be located in the area surrounding the heart.

The correct answer is Miracidium. The miracidium is the free-swimming, ciliated stage that hatches from a trematode egg. It is an intermediate stage in the life cycle of a trematode parasite. Once hatched, the miracidium seeks out a suitable host, typically a snail, in order to continue its development and complete its life cycle.

Sponges are sessile filter feeders, meaning they remain attached to a surface and filter food particles from the water. Their body wall typically consists of two cell layers. Flagellated collar cells, also known as choanocytes, help in moving water through the sponge's body. However, water does not enter through the osculum, which is the opening through which water exits the sponge. Instead, water enters the sponge through small pores called ostia. The statement that water enters through the osculum is incorrect.

Elephantiasis is a condition characterized by the enlargement of body parts, such as legs, arms, and scrotum. This enlargement is caused by a microscopic nematode, which reproduces and clogs the lymph glands. The nematode enters the human body, typically through mosquito bites, and affects the lymphatic system, leading to the accumulation of fluid and swelling in the affected areas. This condition is not caused by an infection of the human coelom by Ascaris, a large number of Trichinella worms encysting in the muscles, contracting a disease that usually occurs in elephants, or a protozoan that lives in tropical roundworms.

Leeches feed from the body fluids of prey by attaching themselves with their posterior sucker and secreting an anticoagulant to prevent the blood from clotting. They also secrete an anesthetic to numb the area they are feeding on. However, leeches do not attach themselves with segmental setae. Setae are bristle-like structures found in many invertebrates that help with locomotion, but leeches do not use them to attach to their prey.

Ascaris and trichina are two roundworm parasites that have life cycles involving being coughed up and swallowed. Ascaris is a parasite that infects the intestines and can cause symptoms such as coughing and difficulty breathing. The eggs of Ascaris are passed in the feces and can be ingested by another host when contaminated food or water is consumed. Trichina is a parasite that infects muscle tissue and can cause symptoms such as muscle pain and swelling. The larvae of Trichina can be ingested by another host when undercooked meat containing the larvae is consumed. In both cases, the worms are coughed up or released from the host's body and then swallowed by another host to complete their life cycle.

Choragogen tissue is the correct answer because it is the type of tissue found around the intestine in annelids that can synthesize glycogen and break free to distribute nutrients in the coelom. This tissue plays an important role in the digestion and distribution of nutrients in annelids. Pancreatic tissue is not found in annelids, and archeoblastic tissue, nephridial tissue, and excretory tissue do not have the same functions as choragogen tissue in annelids.

The correct answer is Dextral. The term "dextral" refers to the shells of gastropods twisting to the right. This is a common characteristic among gastropods, where the shell spirals in a clockwise direction when viewed from the apex.

Humans become infected with blood flukes by wading in infected waters. Blood flukes are parasites that live in freshwater snails. The parasites release their larvae into the water, and when humans come into contact with the infected water, the larvae can penetrate their skin and enter their bloodstream. Once inside the body, the blood flukes can cause various health problems, including schistosomiasis. Eating infected fish, crabs, or crayfish, drinking contaminated water, and eating undercooked pork can also lead to different types of infections, but in this case, wading in infected waters is the specific mode of transmission for blood flukes.

Protandrous refers to organisms that start their reproductive life as one sex and then change to the opposite sex later on. In the case of hermaphroditic sea anemones, they first produce sperm and then later produce eggs to prevent self-fertilization. This strategy helps to increase genetic diversity and avoid inbreeding. Therefore, the term protandrous accurately describes the reproductive behavior of these sea anemones.

The adaption of bivalves to a sedentary, filter feeding lifestyle that exploits the sand of a beach as a habitat has led to the loss of the head and the radula. Bivalves, such as clams and mussels, have evolved to have a streamlined body shape that allows them to bury themselves in the sand and filter feed. As a result, they no longer require a distinct head region or a radula, which is a feeding organ found in many other mollusks. The loss of the head and radula is an adaptation that allows bivalves to efficiently carry out their filter feeding lifestyle.

The correct answer is "Beating the flagella of collar cells to form a current; food is absorbed by collar cells." This explanation suggests that sponges feed by creating a current through the beating of their flagella. This current allows food particles to be swept into the sponge, where they are absorbed by the collar cells. This process is how sponges obtain their food.

Archaeocytes are cells that are found in the mesohyl of sponges. They are capable of moving around and have the ability to digest particles. In addition to their role in digestion, archaeocytes can also specialize for other functions within the sponge, such as producing reproductive cells or forming skeletal elements. Therefore, archaeocytes are the cells that fit the description given in the question.

A fringing reef is close to the land and typically has either no lagoon or a very shallow lagoon. It directly borders the shoreline and is formed by coral growth that extends from the coast. This type of reef is commonly found in areas with a steep drop-off from the land into the ocean, allowing the coral to grow close to the shore. Fringing reefs are important for coastal protection as they act as a barrier against wave action and erosion.

Larvae burrow into your feet is the correct answer because Nectar americanus hookworms are known to enter the human body through the skin, particularly through the feet. The larvae can penetrate the skin when a person comes into contact with contaminated soil or sand. Once inside the body, the larvae migrate through the bloodstream and eventually reach the intestines, where they mature into adult hookworms. This method of infection is known as cutaneous larva migrans.

Collagen is the correct answer because it is a structural protein that is found in all sponges. Collagen provides strength and support to the sponge's body structure, allowing it to maintain its shape and withstand external pressures. Spongin is another structural protein found in some sponges, but it is not present in all sponges. Spiculin is a type of skeletal element found in some sponges, while mesohyl is the gelatinous matrix that fills the sponge's body. Gorgonin is a protein found in certain species of corals, not sponges.

Animals with three well-defined germ layers and that have one solid mass of tissue rather than tissues and organs nestled inside a body cavity are referred to as acoelomates. Acoelomates lack a coelom, which is a fluid-filled body cavity found in other animals. Instead, their organs are directly embedded in the solid mass of tissue. This structural characteristic distinguishes acoelomates from pseudocoelomates, which have a body cavity that is not completely lined with mesoderm, and coelomates, which have a true coelom. Quasicoelomates do not exist in the classification of animal body plans.

Dogs commonly suffer from heartworm caused by filarial worms. Filarial worms are a type of parasitic worm that are transmitted to dogs through mosquito bites. The worms then migrate to the heart and lungs, causing damage and leading to heartworm disease. This is a well-known and documented cause of heartworm in dogs, and preventive measures such as regular heartworm medication are commonly recommended to protect dogs from this infection.

The body of a typical mollusk can be divided into two main sections: the head-foot and the mantle. The head-foot is responsible for locomotion and sensory functions, while the mantle is a thin layer of tissue that covers the body and secretes the shell in many mollusk species. This division of the body into head-foot and mantle is a characteristic feature of mollusks and helps to differentiate them from other animal groups.

The correct answer is "Incurrent siphon, gills, suprabranchial chamber, excurrent siphon." Mollusks, such as clams, breathe by passing water through their incurrent siphon, which leads to the gills. The gills are responsible for extracting oxygen from the water and releasing carbon dioxide. From the gills, the water then flows into the suprabranchial chamber, where gas exchange occurs between the respiratory surface and the blood vessels. Finally, the water is expelled through the excurrent siphon.

The correct answer is "Eating infected undercooked or uncooked fish". This is because the liver fluke is a parasite that infects fish and its larvae can be present in undercooked or uncooked fish. When a person consumes this infected fish, the larvae can enter their body and cause an infection. This mode of transmission is common in regions where the liver fluke is prevalent and people consume raw or undercooked fish as part of their diet.

Schistosoma is not a nematode. Nematodes are a type of roundworm, while Schistosoma is a type of flatworm. Ascaris, Trichinella, Wuchereria, and Hookworm are all examples of nematodes.

The name "hookworm" is due to the fact they have an anterior end that curves dorsally like a hook.

The correct answer is "Periostracum, prismatic layer, nacreous layer." The periostracum is the outermost layer of a mollusk's shell, followed by the prismatic layer in the middle, and the nacreous layer on the inside.

Annelids are a group of segmented worms that respire through various structures. They can respire through their skin, gills, and parapodia, which are fleshy appendages. However, setae are bristle-like structures found on the body of annelids that help in locomotion and sensation, but they do not play a role in respiration. Therefore, the correct answer is setae.

The visceral mass is not used by mollusks for respiration. The visceral mass is a part of the body that contains the internal organs of the mollusk, such as the digestive and reproductive organs. Respiration in mollusks is primarily carried out through gills, mantle, and ctendia, which are specialized structures that allow for the exchange of gases with the surrounding environment. Lungs are also used for respiration in some mollusk species, but the visceral mass itself does not play a direct role in respiration.

Sclerocytes are specialized archaeocytes that secrete spicules. Spicules are skeletal structures found in sponges that provide support and protection. Sclerocytes are responsible for the production of these spicules, which are made of various materials such as calcium carbonate or silica. Other cell types listed, such as collencytes, choanocytes, and spongocytes, have different functions within the sponge but do not secrete spicules. Spiculocytes, on the other hand, are not a recognized cell type in sponges, making sclerocytes the correct answer.

The epidermis of most cnidarians does not contain nutritive muscular cells. Nutritive muscular cells are found in the gastrodermis, which is the inner layer of cells in cnidarians. These cells are responsible for both digestion and movement of food particles within the body. The epidermis, on the other hand, primarily consists of epitheliomuscular cells, gland cells, interstitial cells, and sensory cells. Epitheliomuscular cells provide structural support and help in contraction and expansion of the body. Gland cells secrete mucus or toxins. Interstitial cells are responsible for reproduction and regeneration. Sensory cells detect stimuli from the environment.

The statement that the rudimentary circulatory system has a small central heart is true. Planaria have a simple circulatory system that consists of a small central heart and a network of vessels that transport nutrients and oxygen throughout their body. This circulatory system helps in the distribution of necessary substances to different parts of the planaria's body.

The male capulatory organ of turbellarians is called a cirrus. A cirrus is a specialized structure that is used for sperm transfer during mating. It is typically a long, slender, and flexible organ that is located near the anterior end of the body. The cirrus is capable of extending and retracting, allowing it to reach and insert into the female reproductive opening for sperm transfer. This organ plays a crucial role in the reproductive process of turbellarians.

Filiarial worms do not enter the mouth of their human host and leave as eggs with the human feces. Filiarial worms are transmitted to humans through the bite of infected mosquitoes. The larvae of these worms enter the bloodstream and migrate to various tissues in the body, where they develop into adult worms. The adult worms do not lay eggs that are passed through the feces; instead, they release microscopic larvae called microfilariae into the bloodstream, which can be taken up by mosquitoes when they bite an infected person.

Hookworm is the most likely nematode parasite when the main disease symptom is anemia. Hookworms are blood-feeding parasites that attach themselves to the intestinal wall and feed on the host's blood, which can lead to iron deficiency anemia. Trichinella is a parasite that causes trichinosis, a disease characterized by muscle pain and swelling. Ascaris is a common intestinal parasite but does not typically cause anemia. Pinworms are also common intestinal parasites but do not cause anemia. Planaria is not a nematode parasite but a type of flatworm.

The correct answer is "Tearing and sucking food particles via a mid-ventral proboscis." Planarians are flatworms that have a mid-ventral proboscis, which they use to tear and suck food particles. This proboscis is located on the ventral side of the worm and is used to grasp and tear apart prey, allowing the planarian to consume it. The planarian then uses its muscular pharynx to suck in the food particles for digestion. This method of feeding is characteristic of planarians and is essential for their survival and nutrition.

The statement that the nervous system consists of a single nerve cord running dorsally down the body is incorrect. Nematodes actually have a nerve ring around the pharynx from which several longitudinal nerve cords extend. These nerve cords run along the length of the body and are connected by transverse nerves, forming a ladder-like nervous system.

Trematodes have a body covering known as a tegument. The tegument is a specialized outer layer that helps protect the trematode's body and aids in its survival. Unlike an exoskeleton or shell, which are hard and rigid coverings, the tegument is a flexible and dynamic layer that allows the trematode to adapt to its environment. The tegument also plays a role in nutrient absorption, waste excretion, and defense against the host's immune system. Overall, the tegument is an essential feature of trematodes that enables their survival and successful parasitic lifestyle.

The correct answer is "Nephrostome, nephridiopore". The nephridium is a structure in segmented worms that functions as an excretory organ. It is composed of a ciliated funnel called a nephrostome, which collects waste products and fluids from the coelom. The waste is then transported through the nephridium and expelled through an opening called a nephridiopore.

Myocytes are the correct answer because they are modified cells in sponges that form circular bands and are responsible for providing a little constriction to control flow. These cells are specialized for muscle contraction and play a role in regulating water flow through the sponge's body.

The nervous system of leeches is described as having two small brains with a double ventral nerve cord. This means that leeches have two separate brain ganglia, or clusters of nerve cells, and a nerve cord that runs along the ventral side of their body. The double ventral nerve cord allows for more efficient communication and coordination of sensory and motor information throughout the leech's body.

Polychaetes are a type of marine annelid worms that possess various sensory organs to perceive their environment. Simple eyes, statocysts, nuchal organs, and chemoreceptors are sensory organs commonly found in polychaetes. However, neurosecretory cells are not considered sensory organs. Instead, they are specialized cells found in the nervous system that release hormones and other signaling molecules. These cells play a role in regulating various physiological processes in polychaetes, but they are not directly involved in sensory perception.

The given answer states that "We have superior drugs and surgeons" is not a factor that protects North America from many parasitic worm infections. This implies that the presence of superior drugs and surgeons does not contribute to the prevention or control of parasitic worm infections in North America. It suggests that other factors listed in the options, such as bitter cold winters, wearing shoes, cooking meat, and not using human excreta to fertilize crops, play a more significant role in protecting against parasitic worm infections in the region.