Biology 1402 Exam 2 (Part 3)

Sea stars are not the only echinoderms that are fully sessile. Other echinoderms, such as sea cucumbers and sea urchins, can also be sessile.

Sea squirts are not examples of echinoderms. Echinoderms are a group of marine animals that include sea cucumbers, brittle stars, sand dollars, and sea daisies. Sea squirts, on the other hand, belong to a different group called tunicates. They are filter-feeding organisms that attach themselves to surfaces and have a sac-like body structure. While sea squirts may share some similarities with echinoderms, they are not classified as echinoderms.

The correct answer is madreporite --> stone canal --> ring canal --> radial canal --> tube foot. This is the correct sequence of the movement of water through the water vascular system of a sea star. The madreporite is the entrance to the system, followed by the stone canal which connects to the ring canal. From the ring canal, water moves into the radial canals, which extend into the arms of the sea star. Finally, the water reaches the tube feet, which are used for locomotion and other functions.

The ctenidia is actually responsible for respiration in mollusks, not secretion of the shell. The shell is typically secreted by the mantle.

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Brachiopods are often misidentified as bivalves, brachiopods were much more diverse in the past, most brachiopods are sessile (attached), and the lophophore resides within the brachiopod's shells. However, the statement that the valves in brachiopods are lateral (left and right) to the body axis is false. In brachiopods, the valves are dorsal (top) and ventral (bottom) to the body axis, unlike in bivalves where the valves are lateral.

The chitinous exoskeleton found in arthropods offers some protection, reduces water loss, allows for muscle attachment sites inside the skeleton, and provides a strong, flexible framework. However, it does impose limitations on body size because the exoskeleton cannot grow, and the arthropod must molt in order to increase in size.

Book lungs are not found in larval insects. Book lungs are respiratory organs found in spiders and some other arachnids. Larval insects typically have tracheal systems or gills for respiration. Therefore, the association between book lungs and larval insects is incorrect.

The correct answer is tunicate. Tunicates are filter-feeding marine animals that have a pharynx with an endostyle. The endostyle produces a mucous sheet that helps in trapping microscopic food particles in the water. This allows tunicates to feed on suspended particles and plankton.

Lancelets are small, fishlike marine chordates that are pointed at both ends and lack a distinguishable head. They have a notochord that runs the entire length of the nerve cord. This distinguishes them from other options such as arrow worms, tunicates, acorn worms, and lampreys, which have different anatomical characteristics.

The operculum is a hard plate that covers the gills on each side of the head in most bony fishes. It acts as a protective covering for the delicate gills, allowing water to flow over them while preventing debris or predators from entering. The operculum also helps regulate the flow of water and aids in respiration by allowing the fish to control the opening and closing of the gill slits. Therefore, the operculum is the correct answer in this case.

The correct answer is the amniotic egg. Reptiles have evolved this adaptation to enable them to reproduce on land. The amniotic egg is enclosed in a protective shell and contains a specialized membrane that provides a suitable environment for the developing embryo, including protection from desiccation. This adaptation allows reptiles to lay their eggs on land and reduces their dependence on water for reproduction, making them well-suited to terrestrial environments.

Birds and mammals are called endothermic because they can regulate their body temperatures within close limits. Unlike ectothermic animals, such as reptiles, which rely on external sources of heat to regulate their body temperature, endothermic animals are able to generate and maintain their own body heat through metabolic processes. This allows birds and mammals to thrive in a wide range of environments and climates, as they are not dependent on external temperatures for their survival.

The key innovation that started chordates along the evolutionary path that led to vertebrates is the development of a flexible rod to which muscles are attached, allowing for lateral movement of their backs. This innovation allowed for greater mobility and flexibility in movement, which likely provided an advantage in survival and resource acquisition. This eventually led to the development of a more complex skeletal system and the emergence of vertebrates.

Chordates are a phylum of animals that possess a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail at some stage in their life cycle. Amphioxus, mammals, birds, and amphibians are all examples of chordates. Echinoderms, on the other hand, are a separate phylum that includes animals such as starfish and sea urchins. They do not possess the characteristic features of chordates, making them the only option that is not included in the chordate group.

Chordates are characterized by having a nerve cord, notochord, pharyngeal slits, and a postanal tail at some point in their lives. However, an endostyle is not a characteristic of chordates. An endostyle is a structure found in some invertebrate chordates, such as tunicates, that functions in filter feeding. Therefore, the correct answer is an endostyle.

Tunicates are marine animals that belong to the phylum Chordata. They have a larval stage and an adult stage. The given statement "Larval forms feed actively" is not true about tunicates. In their larval stage, tunicates do not actively feed. Instead, they rely on their yolk sac for nutrition. Once they undergo metamorphosis and become adults, tunicates become filter feeders, using their siphons to draw in water and filter out small particles of food. Therefore, the correct answer is that larval forms of tunicates do not feed actively.

All vertebrates have a distinctive head or skull because it is a characteristic feature of their anatomy. The head or skull houses important sensory organs such as the brain, eyes, ears, and nose, which are essential for their survival. It also provides protection to these delicate organs and supports the overall structure of the body. Therefore, the presence of a distinctive head or skull is a defining trait of vertebrates.

During the early Devonian period, sharks and bony fish were the vertebrates that evolved. This is supported by fossil evidence that shows the presence of early shark and bony fish species during this time. The evolution of these two groups of vertebrates during the Devonian period played a significant role in shaping the future diversity and ecology of marine ecosystems.

Amphibians are thought to have evolved from lobe-finned fish. This is because lobe-finned fish, such as the coelacanth and lungfish, share several anatomical features with early amphibians. These features include the presence of lungs, limb-like fins, and a bony skeleton, which allowed them to move and breathe in shallow water or on land. The transition from water to land was a crucial step in the evolution of amphibians, and lobe-finned fish provided the necessary adaptations for this transition.

Bony fishes have evolved various adaptations that contribute to their remarkable success. These adaptations include swim bladders, which help them control their buoyancy, lateral line systems that detect vibrations and movements in the water, and gill covers that protect their gills. They also have a counter-current exchange system in their gills, which enhances their ability to extract oxygen from the water. However, bony fishes do not have a three-chambered heart with a pulmonary circuit. Instead, they have a two-chambered heart with a single circulation system, where blood flows from the heart to the gills for oxygenation and then to the rest of the body.

Amphibians share several characteristics, such as legs, coetaneous respiration and lungs, a partially divided heart, and pulmonary veins. However, they do not have keratinized skin. Keratinized skin is a characteristic of reptiles, birds, and mammals, but not amphibians. Amphibians have moist and permeable skin that allows them to breathe through their skin. This is why they are often found in moist environments and require water for reproduction.

Amphibians are not completely free to live on dry land because their reproduction depends on water. Unlike other animals, amphibians lay eggs in water, and their young hatch as aquatic larvae. These larvae then undergo metamorphosis and develop into adults that can live both on land and in water. Therefore, water is crucial for the reproductive cycle of amphibians, making them dependent on it for their survival.

Amniotic eggs were not a feature that directly contributed to the successful invasion of land by amphibians. While amniotic eggs are a key adaptation for reptiles, birds, and mammals, they did not evolve until much later in evolutionary history. Amphibians, on the other hand, have moist, jelly-like eggs that require water for development. Therefore, the presence of amniotic eggs cannot be considered a contributing factor to the successful invasion of land by amphibians.

Reptiles have retained several features from the time they replaced amphibians as the dominant terrestrial vertebrates. These include the amniotic egg, which allows them to reproduce on land, dry skin to prevent water loss, thoracic breathing for efficient respiration, and reoriented appendages for better movement on land. However, endothermy, or the ability to regulate body temperature internally, is not a feature retained by reptiles. Unlike mammals and birds, reptiles are ectothermic, meaning their body temperature is determined by the environment.

The ectoderm is not one of the membranes of the reptilian amniotic egg. The amniotic egg consists of several membranes that protect and nourish the developing embryo. These membranes include the chorion, amnion, yolk sac, and allantois. The ectoderm, on the other hand, is one of the three primary germ layers in the developing embryo, which gives rise to the outer layer of the skin, nervous system, and other structures. It is not a specific membrane within the amniotic egg.

Reptiles can maintain their internal body temperature through behavioral mechanisms such as basking in the sun or seeking shade. They regulate their body temperature by adjusting their behavior and moving to different environments to either warm up or cool down. This allows them to adapt to their surroundings and maintain a stable internal body temperature without relying on external factors such as warm or cool water, increased food consumption, an insulating covering, or rerouting blood flow.

The correct answer is "ectothermic" because reptiles are known for their inability to regulate their own body temperature internally. Instead, they rely on external sources of heat to warm up their bodies. This characteristic is what makes them ectothermic.

The ability of reptiles to survive on dry land is attributed to various features. The amniotic egg provides protection and allows reproduction away from water. Dry skin covered with scales helps prevent dehydration. An efficient circulatory system ensures oxygen and nutrients are delivered throughout the body. Efficient lungs enable reptiles to extract oxygen from the air. However, endothermy, or the ability to regulate body temperature internally, is not a feature that contributes to their survival on dry land. Reptiles are ectothermic, meaning their body temperature is influenced by the environment.

Crocodiles care for their young and have a four-chambered heart, just like birds do. This means that they exhibit parental care and provide protection and assistance to their offspring. Additionally, the presence of a four-chambered heart indicates that crocodiles have a more efficient circulatory system, allowing for better oxygenation of their tissues.

Birds are the most successful terrestrial vertebrates that invaded the air because they have adapted to fly efficiently and have a diverse range of species. They possess lightweight bodies, strong wings, and feathers that enable them to soar through the air. Birds have evolved various flight adaptations, such as hollow bones, a keeled breastbone for muscle attachment, and a unique respiratory system, allowing them to achieve sustained flight. Their ability to fly has allowed birds to inhabit diverse ecosystems, exploit different food sources, and migrate over long distances, making them highly successful in the aerial environment.

Birds are different from reptiles in their lack of teeth, the presence of feathers, and the presence of a flight skeleton. Bipedalism refers to the ability to walk on two legs, which is a characteristic shared by both birds and some reptiles. Therefore, bipedalism is not a feature that distinguishes birds from reptiles.

Birds have a four-chambered heart, which allows for efficient circulation of oxygenated and deoxygenated blood. This is necessary to meet the high energy demands of flight. Efficient respiration, efficient circulation, endothermy, and the presence of auxiliary air sacs and hollow bones are all adaptations that help birds cope with their energy demands. However, a three-chambered heart would not be sufficient for the demands of flight, as it would not provide efficient separation of oxygenated and deoxygenated blood.

Modern birds are characterized by feathers, thin hollow skeletons and auxiliary air sacs, a four-chambered heart, and the amniotic egg. However, they are not characterized by ectothermy, which refers to the ability to regulate body temperature through external sources such as the sun. Birds are endothermic, meaning they can generate and maintain their own body heat internally.

Therapsids are a group of reptile-like mammals that lived during the Permian and Triassic periods. They are considered to be the ancestors of modern mammals because they share many characteristics with mammals, such as a specialized jaw joint and a more efficient way of chewing food. Thecodonts, dinosaurs, and archosaurs are reptiles that are not directly related to mammals, while marsupials are a group of mammals that evolved later than therapsids. Therefore, therapsids are the most likely ancestors of mammals.

Hair is a characteristic of all mammals and not of any other living vertebrates. While some mammals may have minimal or no hair, it is still present in some form. Hair is a unique feature that distinguishes mammals from other vertebrates, as no other group of animals possess this specific trait.

Bats are the only mammals that fly at night to obtain insect food or fruit to eat and navigate by sonar. They have the ability to emit high-frequency sounds and listen to the echoes that bounce back, allowing them to navigate and locate their prey in the dark. This unique adaptation is known as echolocation. Marsupials, monotremes, moles, and birds do not possess this ability, making bats the correct answer.

Monotremes, such as platypuses and echidnas, are unique among mammals because they lay shelled eggs. This is different from other mammals, which give birth to live young. Monotremes have a reproductive system that resembles that of reptiles and birds, as they have cloacas and lay eggs. This adaptation sets them apart from other mammals and is a defining characteristic of monotremes.

The correct answer is opossum. The opossum is the only marsupial mammal that is native to North America. It is known for its unique adaptation of carrying and nursing its young in a pouch. While other animals listed, such as the raccoon and weasel, are also found in North America, they are not marsupials. The ring-tailed cat and wombat are not native to North America at all. Therefore, the opossum is the only correct answer.

The question is asking for the order of placental mammals that is not included in the given options. The options include primates, rodentia, cetacea, carnivora, and marsupialia. Primates, rodentia, cetacea, and carnivora are all orders of placental mammals. Marsupialia, on the other hand, is not a placental mammal order. Marsupials are a distinct group of mammals that give birth to relatively undeveloped young, which then continue to develop in a pouch. Therefore, the correct answer is marsupialia.

The key specializations that occurred in the evolution of mammals include warm-bloodedness, the presence of a placenta in most, different teeth suited to their diet, and digestive tract specialization. However, reduction in brain size is not a specialization that occurred in the evolution of mammals.

The correct answer is Eustachian tube. In humans, one pair of pharyngeal pouches develop into the Eustachian tube. The Eustachian tube connects the middle ear to the back of the throat and helps to equalize pressure between the middle ear and the outside environment. It plays a crucial role in maintaining proper hearing and preventing ear infections. The esophagus is the tube that connects the throat to the stomach, the trachea is the windpipe, the bronchial tube is a branch of the trachea that leads to the lungs, and the pharynx is the throat.

Tunicate larvae can reproduce. This statement is incorrect because tunicate larvae are not capable of reproduction. Tunicates have a complex life cycle where the larvae, also known as tadpole larvae, are free-swimming and possess all the basic chordate characteristics. However, once they reach adulthood, tunicates become sessile and lose their ability to reproduce. Instead, they rely on sexual reproduction as adults to produce new larvae.

The mismatched pair in the given options is "Placodermi—lobe-finned fish." Placodermi is an extinct class of armored fish that existed during the Devonian period, while lobe-finned fish belong to the class Sarcopterygii. Lobe-finned fish are not a subclass or superclass of Placodermi, making this pair mismatched.

Bony fishes possess swim bladders, a lateral line system, and gill covers called opercula. These three features are unique to bony fishes and are not found in other types of fish. The swim bladder is an internal gas-filled organ that helps the fish control its buoyancy. The lateral line system is a series of sensory organs that detect changes in water pressure and vibrations, allowing the fish to navigate and detect prey. The gill covers, or opercula, protect the delicate gills and help regulate water flow over them for efficient respiration.

Archaeopteryx actually had teeth, unlike modern birds. This is one of the unique characteristics of Archaeopteryx that distinguishes it from modern birds.

Homo habilis was called "handy man" because of its association with tools. This species of early humans was known for its ability to create and use tools, which demonstrated their advanced cognitive abilities and problem-solving skills. The name "Homo habilis" reflects their dexterity and resourcefulness in utilizing tools for various purposes, making them the "handy man" of early human evolution.

Homo sapiens is the correct answer because it is the only species mentioned that is commonly known as modern humans. Homo habilis and Homo erectus are both earlier hominin species that lived before Homo sapiens. Homo hominis and Homo australopithecus are not valid species names. Therefore, Homo sapiens is the most likely species to have evolved in Africa less than 200,000 years ago.

Cro-Magnons is the correct answer because they were the first early modern humans to inhabit Europe around 34,000 years ago. They were anatomically similar to modern humans and had advanced tools and weapons, allowing them to outcompete and replace the Neanderthals. Homo habilis and Homo erectus are both earlier hominid species that existed in Africa, while Homo sapiens refers to modern humans, who coexisted with Cro-Magnons. Neanderthals were a distinct species that lived in Europe before being replaced by Cro-Magnons.

Primates are mammals with grasping fingers and toes, they belong to the order containing lemurs, monkeys, and apes, they have binocular vision, and they have increased brain size. However, primates do not have prehensile tails, which are tails that are capable of grasping or holding objects.