1.
Sponges are most accurately described as
Correct Answer
D. Aquatic filter feeders
Explanation
Sponges are most accurately described as aquatic filter feeders because they are stationary animals that live in water and obtain their food by filtering small particles from the water. They have specialized cells called choanocytes that create water currents and trap food particles, allowing them to feed on microscopic organisms and organic matter suspended in the water. This feeding method is characteristic of filter feeders, which rely on filtering mechanisms to extract nutrients from their environment.
2.
How many of the following are characteristics of at least some members of the phylum Cnidaria?
1. a gastrovascular cavity
2. a polyp stage
3. a medusa stage
4. cnidocytes
5. a pseudocoelom
Correct Answer
D. Four of these
Explanation
Four of the characteristics listed are found in at least some members of the phylum Cnidaria. These characteristics are: a gastrovascular cavity, a polyp stage, a medusa stage, and cnidocytes. A gastrovascular cavity is a central digestive cavity found in Cnidarians. Cnidarians also exhibit both polyp and medusa stages in their life cycle. Cnidocytes are specialized cells that contain stinging structures called cnidocysts, which are used for defense and capturing prey. However, a pseudocoelom is not a characteristic of the phylum Cnidaria.
3.
The heartworms that can accumulate within the hearts of dogs and other mammals have a psuedocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?
Correct Answer
C. Nematoda
Explanation
Heartworms belong to the phylum Nematoda because they possess a pseudocoelom (a fluid-filled body cavity), an alimentary canal (digestive system), and an outer covering that is occasionally shed. Nematoda is a phylum that includes roundworms, which have these characteristic features. Platyhelminthes, Arthropoda, Acoela, and Annelida do not possess all of these characteristics, making Nematoda the correct phylum for heartworms.
4.
Among the invertebrate phyla, phylum Arthopoda is unique in possessing members that have
Correct Answer
D. Wings
Explanation
Phylum Arthropoda is unique among invertebrate phyla because it possesses members that have wings. Wings are a characteristic feature of certain arthropods, such as insects and some crustaceans, that enable them to fly or glide through the air. This adaptation has allowed arthropods with wings to occupy different ecological niches and explore new habitats. Wings provide arthropods with the ability to escape predators, find food, and disperse to new locations. This unique feature sets arthropods apart from other invertebrate phyla.
5.
The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars, contain a potent toxin. If it were discovered that crown-of-thorns sea stars do not make this toxin themselves, then the most likely alternative would be that this toxin is
Correct Answer
A. Derived from the nematocysts of its prey.
Explanation
If crown-of-thorns sea stars do not produce the toxin themselves, the most likely explanation is that the toxin is derived from the nematocysts of its prey. Nematocysts are stinging cells found in the tentacles of certain marine organisms, such as jellyfish and anemones. It is possible that the sea star feeds on prey with nematocysts, and somehow incorporates or utilizes these nematocysts to produce its own toxic spines. This would explain why the sea star's spines contain a potent toxin, unlike most other sea stars.
6.
The water vascular system of echinoderms
Correct Answer
B. Functions in locomotion and feeding
Explanation
The water vascular system of echinoderms functions in locomotion and feeding. This system consists of a network of canals and tube feet that allow echinoderms to move and capture food. The water vascular system helps in the movement of the tube feet by regulating the water pressure within them. It also aids in feeding by allowing the echinoderm to extend its tube feet to capture and manipulate food particles. Therefore, the correct answer is that the water vascular system functions in locomotion and feeding.
7.
Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition by
Correct Answer
B. Ingesting it
Explanation
Animals and fungi are both heterotrophic, meaning they obtain their nutrition from organic sources. However, what distinguishes animal heterotrophy from fungal heterotrophy is that animals obtain their nutrition by ingesting their food. This means that they take in solid or liquid food through their mouth or specialized feeding structures. In contrast, fungi obtain their nutrition by absorbing nutrients from their surroundings, usually by breaking down organic matter externally and then absorbing the dissolved nutrients.
8.
Which of the following is (are) unique to animals?
Correct Answer
C. Nervous conduction and muscular movement
Explanation
Nervous conduction and muscular movement are unique to animals. While cells that have mitochondria, the structural carbohydrate chitin, and heterotrophy are also features of animals, they are not exclusive to animals. Nervous conduction allows animals to transmit electrical signals through their nervous system, enabling them to respond to stimuli and coordinate movement. Muscular movement, powered by the contraction of muscle cells, allows animals to move and perform various activities. These characteristics are not found in other organisms such as plants or fungi.
9.
What is the probable sequence in which the following clades of animals originated, from earliest to most recent?
1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians
Correct Answer
B. 5 → 3 → 2 → 1 → 4
Explanation
Bilaterians are the most recent clade to have originated, followed by deuterostomes, vertebrates, tetrapods, and finally amniotes. This sequence is based on the evolutionary history of these clades, with bilaterians being the most diverse and complex group of animals. Deuterostomes include vertebrates, which in turn include tetrapods. Amniotes, a group of tetrapods, evolved later in the timeline. Therefore, the correct sequence is 5 → 3 → 2 → 1 → 4.
10.
If a multicellular animal lacks true tissues, then it can properly be included among the
Correct Answer
B. Parazoa
Explanation
If a multicellular animal lacks true tissues, it can be properly included among the parazoa. Parazoa is a subkingdom of animals that includes organisms without true tissues, such as sponges. These animals are characterized by a lack of specialized cells and organs.
11.
The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not molt (though their host does), and their mouth develops from the blastopore.
Basing your inferences on information in the previous paragraph, to which clade(s) should cycliophorans belong?
1. Eumetazoa
2. Deuterostomia
3. Bilateria
4. Ecdysozoa
5. Lophotrochozoa
Correct Answer
C. 1, 3, and 5
Explanation
The passage states that cycliophorans are eucoelomate, do not molt, and their mouth develops from the blastopore. Based on this information, we can infer that cycliophorans belong to clades 1, 3, and 5. Clade 1 (Eumetazoa) includes animals with true tissues, clade 3 (Bilateria) includes animals with bilateral symmetry, and clade 5 (Lophotrochozoa) includes animals with a lophophore or trochophore larval stage.
12.
Among the characteristics unique to animals is
Correct Answer
A. Gastrulation
Explanation
Gastrulation is a process that occurs during early embryonic development in animals, where the blastula (a hollow ball of cells) undergoes significant rearrangements to form a gastrula with distinct germ layers. This process is unique to animals and plays a crucial role in the formation of tissues and organs. Multicellularity, sexual reproduction, flagellated sperm, and heterotrophic nutrition are also characteristics of animals, but they are not unique to animals as they can be found in other organisms as well.
13.
When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the
Correct Answer
C. Fungicide might also kill mycorrhizae
Explanation
The correct answer is that the fungicide might also kill mycorrhizae. Mycorrhizae are beneficial fungi that form a symbiotic relationship with the roots of grape vines, aiding in nutrient uptake. If the fungicide kills these mycorrhizae, it can disrupt the vine's ability to absorb essential nutrients, leading to decreased growth and productivity. Therefore, grape farmers should be concerned about the potential harm to mycorrhizae when using the fungicide.
14.
Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants'
Correct Answer
A. Leaf mesopHyll
Explanation
The given answer, "leaf mesophyll," is the correct answer because mycorrhizae are symbiotic associations between fungi and plant roots, specifically the root system. Similarly, endophytes are symbiotic associations between fungi or bacteria and the internal tissues of plants, including the leaf mesophyll. Therefore, just as mycorrhizae are associated with the roots of vascular plants, endophytes are associated with the leaf mesophyll of vascular plants.
15.
Choose the option that best describes the relationship between the cell wall thickness of parenchyma cells versus sclerenchyma cells.
Correct Answer
A. The cell walls of parenchyma cells are thinner than those of sclerenchyma cells
Explanation
Parenchyma cells and sclerenchyma cells are two types of plant cells that have different functions. Parenchyma cells are responsible for various metabolic activities and are found in various parts of the plant, while sclerenchyma cells provide structural support and are found in the stems, roots, and leaves. The cell walls of parenchyma cells are thinner than those of sclerenchyma cells because parenchyma cells do not require as much structural support as sclerenchyma cells.
16.
________ is to xylem as ________ is to phloem.
Correct Answer
C. Vessel element; sieve-tube member
Explanation
The correct answer is vessel element; sieve-tube member. Xylem and phloem are the two types of vascular tissues in plants. Xylem is responsible for transporting water and minerals from the roots to the rest of the plant, while phloem is responsible for transporting sugars and other organic compounds. Within the xylem, vessel elements are the main conducting cells that form long, interconnected tubes for efficient water transport. Similarly, within the phloem, sieve-tube members are the main conducting cells that form sieve tubes for efficient sugar transport. Therefore, vessel element is to xylem as sieve-tube member is to phloem.
17.
Which of the following root tissues gives rise to lateral roots?
Correct Answer
E. Pericycle
Explanation
The pericycle is the correct answer because it is a tissue located just inside the endodermis in the root of a plant. It is responsible for giving rise to lateral roots, which are the roots that grow out from the main root. The pericycle contains cells that have the ability to divide and differentiate into new root tissue, allowing for the formation of lateral roots.
18.
All of the following cell types are correctly matched with their functions except A) mesophyll–photosynthesis.
B) guard cell–regulation of transpiration.
C) sieve-tube member–translocation.
D) vessel element–water transport.
E) companion cell–formation of secondary xylem and phloem.
Correct Answer
E. Companion cell–formation of secondary xylem and pHloem
Explanation
The correct answer is companion cell–formation of secondary xylem and phloem. Companion cells are specialized cells found in the phloem tissue of plants and are responsible for supporting the function of sieve-tube members, which are involved in translocation. They provide energy and nutrients to the sieve-tube members, but they do not play a role in the formation of secondary xylem and phloem.
19.
Which of the following cells or tissues arise from lateral meristem activity?
Correct Answer
A. Secondary xylem
Explanation
Secondary xylem arises from lateral meristem activity. Lateral meristems, specifically the vascular cambium, are responsible for the secondary growth in plants, which leads to the formation of secondary xylem. This tissue is important for water transport and support in the plant. Therefore, secondary xylem is the correct answer as it is directly derived from lateral meristem activity.
20.
The innermost layer of the root cortex is the
Correct Answer
C. Endodermis
Explanation
The endodermis is the innermost layer of the root cortex. It is a single layer of cells that surrounds the vascular tissue in the root. The endodermis is responsible for controlling the movement of water and nutrients into the vascular tissue. It contains a specialized structure called the Casparian strip, which acts as a barrier and forces all water and solutes to pass through the endodermal cells before entering the vascular tissue. This helps in regulating the uptake and transport of water and nutrients in the plant.
21.
A plant developed a mineral deficiency after being treated with a fungicide. What is the most probable cause of the deficiency?
Correct Answer
B. Mycorrhizal fungi were killed
Explanation
The most probable cause of the mineral deficiency in the plant is that the mycorrhizal fungi, which are responsible for assisting the plant in absorbing minerals from the soil, were killed.
22.
The value for Ψ in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ψ = -0.23 MPa), the net water flow would
Correct Answer
A. Be from the tissue into the sucrose solution
Explanation
When comparing the values of Ψ for the root tissue (-0.15 MPa) and the sucrose solution (-0.23 MPa), it can be observed that the sucrose solution has a lower water potential. Water flows from an area of higher water potential to an area of lower water potential, so the net water flow would be from the tissue into the sucrose solution.
23.
In plant roots, the Casparian strip is correctly described by which of the following?
Correct Answer
D. It ensures that all water and dissolved substances must pass through a cell membrane before entering the stele
Explanation
The Casparian strip is a specialized structure found in plant roots. It is made up of a band of waterproof material called suberin, which blocks the movement of water and dissolved substances between cells in the root cortex. This forces all water and dissolved substances to pass through a cell membrane before entering the stele, which is the central region of the root where water and nutrients are transported. This helps regulate the movement of substances into the stele and ensures that all water and dissolved substances are properly regulated and controlled before entering the plant's vascular system.
24.
What drives the flow of water through the xylem?
Correct Answer
C. The evaporation of water from the leaves
Explanation
The evaporation of water from the leaves, also known as transpiration, creates a negative pressure or tension in the xylem. This negative pressure pulls water up from the roots through the xylem vessels and tracheids, resulting in the flow of water through the xylem.
25.
What is the main cause of guttation in plants?
Correct Answer
A. Root pressure
Explanation
Root pressure is the main cause of guttation in plants. Guttation is the process by which water is exuded from the tips or edges of leaves, typically in the form of droplets. Root pressure occurs when water is pushed up from the roots to the stems and leaves of a plant. This pressure is created by the active transport of mineral ions into the roots, which causes water to enter the roots by osmosis. The excess water is then forced out through specialized structures called hydathodes, resulting in guttation.
26.
Which of these are amniotes?
Correct Answer
E. More than one of these is correct
Explanation
Amniotes are a group of animals that possess an amniotic egg, which is an adaptation for reproduction on land. This allows the embryo to develop in a protected fluid-filled sac. Both egg-laying mammals (such as platypus and echidna) and placental mammals (such as humans and dogs) are amniotes. Therefore, the correct answer is "More than one of these is correct."
27.
Which of the following are the only extant animals that descended directly from dinosaurs?
Correct Answer
D. Birds
Explanation
Birds are the only extant animals that descended directly from dinosaurs. This is supported by scientific evidence, including fossil records and genetic studies, which show a clear evolutionary link between dinosaurs and birds. Birds share many anatomical and physiological characteristics with dinosaurs, such as hollow bones, feathers, and a similar reproductive system. Additionally, birds are the only living descendants of the group of dinosaurs known as theropods, which includes famous species like Tyrannosaurus rex. Therefore, birds are considered the modern-day representatives of dinosaurs.
28.
Which shark structure is most analogous to a swim bladder full of gas?
Correct Answer
C. Its liver
Explanation
The liver of a shark is most analogous to a swim bladder full of gas. The swim bladder is an organ found in bony fish that helps them control their buoyancy. It is filled with gas and allows the fish to adjust its position in the water column. Similarly, the liver of a shark helps with buoyancy control by storing oil. The oil in the liver is less dense than water, allowing the shark to stay buoyant and control its depth in the water.
29.
Vertebrates and tunicates share
Correct Answer
E. A notochord and a dorsal, hollow nerve cord
Explanation
Vertebrates and tunicates share a notochord and a dorsal, hollow nerve cord. This means that both vertebrates and tunicates have a flexible rod-like structure called a notochord that runs along their back, providing support. They also have a nerve cord that runs along their back, which is hollow and located on the dorsal side. This nerve cord is responsible for transmitting signals between the brain and the rest of the body. These shared characteristics suggest a common ancestor and evolutionary relationship between vertebrates and tunicates.
30.
The body's automatic tendency to maintain a constant and optimal internal environment is termed
Correct Answer
C. Homeostasis
Explanation
Homeostasis refers to the body's ability to maintain a stable and optimal internal environment despite external changes. It involves various physiological processes that help regulate temperature, pH levels, blood pressure, and other factors within a narrow range. This balance is crucial for the proper functioning of cells, tissues, and organs. Homeostasis is achieved through feedback mechanisms that detect any deviations from the set point and initiate appropriate responses to restore equilibrium.
31.
The panting responses that are observed in overheated birds and mammals dissipates excess heat by
Correct Answer
E. Evaporation
Explanation
The panting responses observed in overheated birds and mammals are a mechanism to dissipate excess heat. When these animals pant, they increase their respiratory rate and release moisture through their breath. This moisture evaporates from their respiratory surfaces, taking away heat from their bodies and cooling them down. Therefore, evaporation is the correct answer as it explains how the excess heat is dissipated in overheated birds and mammals.
32.
Among these choices, the least reliable indicator of a terrestrial animal's metabolic rate is the amount of
Correct Answer
E. Water consumed in one day
Explanation
The amount of water consumed in one day is the least reliable indicator of a terrestrial animal's metabolic rate because water consumption can vary depending on factors such as temperature, humidity, and availability of water sources. It is not directly related to the metabolic processes that determine an animal's energy expenditure. In contrast, the other options - food eaten, heat generated, oxygen used in mitochondria, and carbon dioxide produced - are all directly linked to metabolic rate and energy production.
33.
Examine the figure above. Near a goose's abdomen, the countercurrent arrangement of the arterial and venous blood vessels causes
Correct Answer
A. He temperature difference between the contents of the two sets of vessels to be minimized
Explanation
The countercurrent arrangement of the arterial and venous blood vessels near a goose's abdomen allows for the temperature difference between the contents of the two sets of vessels to be minimized. This is because the warm arterial blood flowing towards the feet is in close contact with the colder venous blood flowing back towards the body, allowing for heat exchange to occur. This minimizes the loss of heat to the environment and helps to maintain a relatively stable body temperature for the goose.
34.
Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?
Correct Answer
D. A desert bird
Explanation
A desert bird uses the largest percentage of its energy budget for homeostatic regulation. Homeostatic regulation refers to the processes that maintain a stable internal environment within an organism. In a desert environment, where temperatures can be extreme, the bird needs to expend a significant amount of energy to regulate its body temperature and prevent dehydration. This includes activities such as panting, evaporative cooling, and regulating blood flow to the skin. Therefore, the desert bird requires a large percentage of its energy budget for these homeostatic processes.
35.
What do all craniates have that earlier chordates did not have?
Correct Answer
D. Partial or complete skull
Explanation
Craniates, which include all vertebrates, have a partial or complete skull, which earlier chordates did not have. This skull provides protection and support for the brain and sensory organs. It is a significant evolutionary development that distinguishes craniates from earlier chordates.