Exam 3
Urochordata
1,300 species, fr. Greek oura = tail, Latin chorda = cord - tunicates • Sessile marine organisms as adults • Covered with a cellulose cloak or tunic
Which of the following statements about deuterostomes is false? All deuterostomes have a coelom. All deuterostomes are triploblastic and have three tissue layers. All deuterostomes have a similar pattern of early embryonic development. All deuterostomes exhibit radial symmetry in their bodies.
All deuterostomes exhibit radial symmetry in their bodies. This statement is false; in the deuterostome lineage, only adult echinoderms exhibit radial symmetry.
Which phylum is characterized by animals that have a segmented body? Cnidaria Mollusca Platyhelminthes Arthropoda
Arthropoda
Chelicerates (sea spiders, horseshoe crabs, scorpions, ticks, mites, and spiders)
Chelicerates have six pairs of cephalothoracic appendages - including chelicerae, pedipalps, and four pair of legs • Lack mandibles and antennae • Most suck liquid food from prey
Phylum Echinodermata
Exclusively marine; 7,000 species • Pentaradial symmetry (5-part symmetry) • Have an endoskeleton • Sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers Sea stars and most other echinoderms are slow-moving or sessile marine animals • A thin epidermis covers an endoskeleton of hard calcareous plates • Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion and feeding • Males and females are usually separate, and sexual reproduction is external
Which structure is not an innovation that occurred during vertebrate diversification? Jaws Amniotic egg Bone Exoskeleton
Exoskeleton Exoskeletons are present in groups other than the vertebrates, including some in the protostome lineage.
True or false? An organism that is radially symmetric has many well-developed head regions.
False An organism that is radially symmetric does not have a well-developed head region.
You find what you believe is a new species of animal. Which of the following characteristics would enable you to argue that it is more closely related to a nematode than it is to an annelid? It has a hemocoel. It is a suspension feeder. It is shaped like a worm. It has a mouth and an anus.
It has a hemocoel.
For the common ancestor of all the Bilateria, what was the fate of the blastopore? deuterostomy (D) protostomy (P) neither (N) It is impossible to tell from the data provided.
It is impossible to tell from the data provided. Based on the phylogeny, the ancestral condition in bilaterians may have been similar to that in Acoela, where the blastopore closes and the mouth forms elsewhere (N); however, it is also possible that blastopore fate in Acoela is a derived trait and hence is not informative about the ancestral condition.
How many times has blastopore fate changed over the course of evolution? 0 times 1 time 2 times Multiple times, though the exact number is uncertain.
Multiple times, though the exact number is uncertain. The phylogeny indicates that blastopore fate has changed multiple times over the course of evolution. However, a precise determination cannot be made. For example, if we assume that the ancestral condition was similar to that in Acoela and that the common ancestor of all non-Acoela bilaterians (marked with a 1 on the tree) exhibited protostomy, then blastopore fate has changed at least five times: once in common ancestor 1, once in Deuterostomia, at least once in Mollusca, at least once in Annelida, and at least once in Arthropoda. Other assumptions would lead to different estimates.
Which of the following characteristics in an organism would indicate that lacks a coelom? Muscular activity of its digestive system distorts the body wall. It is triploblastic. It has bilateral symmetry. It possesses sensory structures at its anterior end.
Muscular activity of its digestive system distorts the body wall.
Myriapods (centipedes and millipedes)
Myriapods includes millipedes (Diplopoda) and centipedes (Chilopoda) • All are terrestrial • They have a pair of antennae and three pairs of appendages modified as mouthparts • Millipedes eat decaying leaves and plant matter • Millipedes have many legs, with two pairs per trunk segment
Which structure can be used for feeding and gas exchange? Pharyngeal gill slit Endoskeleton Notochord Dorsal nerve cord
Pharyngeal gill slit A pharyngeal gill slit is an opening into the throat that can be used for feeding and gas exchange.
Which of the following combinations of phylum and description is correct? Nematoda−−roundworms, internal skeleton Platyhelminthes−−flatworms, gastrovascular cavity, no body cavity Echinodermata−−radial symmetry as a larva, coelom Porifera−−gastrovascular cavity, coelom
Platyhelminthes−−flatworms, gastrovascular cavity, no body cavity
Pancrustaceans (lobsters and other crustaceans, as well as insects and their relatives)
Recent evidence indicates that terrestrial insects are more closely related to crustaceans than myriapods • Together, insects and crustaceans form the clade Pancrustacea
Blood Flukes
Schistosoma - blood flukes - Schistosomiasis - Infects 200 million people in the tropics - Causes anemia, diarrhea, tissue damage, and brain damage
Cephalochordata
Segmented musculature (mesoderm) - Independent evolution of segmentation - That is, it was not inherited from a protostome ancestor • Segmentation in chordates is probably an adaptation for burrowing (as in annelid worms)
Placing sponges as the basal metazoans on the basis of lack of tissues implies which of the following? Sponge ancestors never had tissues. Modern-day sponges have lost the ability to form tissues. Multicellular, modern-day choanoflagellates can form tissues. Sponges do not have nerve cells.
Sponge ancestors never had tissues.
Which of the following statements about vertebrates is true? The development of more efficient surfaces for gas exchange in reptiles stimulated expansion into terrestrial habitats. The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water. Birds are more related to mammals than to dinosaurs. All vertebrates have jaws with which to catch their prey.
The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water. Reptiles and their descendants reproduce on land via an amniotic egg, which prevents the embryo from drying out.
Which of the following is a feature of the digestive tube in most animal phyla? The outer tube consists of a hard exoskeleton. The two "tubes" are separated by tissue that comes from embryonic endoderm. The outer tube consists of digestive organs. The mouth and anus form the ends of the inner tube.
The mouth and anus form the ends of the inner tube.
Which characteristics define a chordate? The ability to live on land The development of an anus from the blastopore The presence of four specific morphological traits The presence of a well-developed circulatory system
The presence of four specific morphological traits Chordates are defined by the presence of four morphological traits: a notochord, a dorsal nerve cord, pharyngeal gill slits, and a tail behind the anus.
To what extent has the presence of a coelom in animals changed over the course of evolution? The presence or absence of a coelom appears to have changed exactly once during the course of evolution. The presence or absence of a coelom appears not to have changed during the course of evolution. The presence or absence of a coelom appears to have changed multiple times during the course of evolution. It is impossible to tell whether the presence or absence of a coelom has changed during the course of evolution.
The presence or absence of a coelom appears to have changed multiple times during the course of evolution. Depending on whether or not the last common ancestor of the Bilateria had a true coelom, the presence of a true coelom has either been lost or gained multiple times during the evolutionary history of bilaterians.
Which characteristic distinguishes echinoderms from the other two deuterostome lineages? Their body plan Their habitat The presence of an endoskeleton Their ability to move
Their body plan Echinoderms exhibit a unique body plan characterized by an endoskeleton and a water vascular system.
Which of the following statements correctly describes a characteristic of the phylum Platyhelminthes? They typically reproduce asexually. They are all parasitic. They are diploblastic. They are radially symmetrical. They are dorsoventrally flattened.
They are dorsoventrally flattened. This is why they are also known as flatworms. When an animal or plant / its organ is compressed along its dorsal ( upper ) and ventral ( lower ) side , it is called Dorsiventrally flattened . ( Also called Dorsoventrally flattened ) Such an animal ( plant organ like leaf ) shows good length as well as breadth but has not much of ' thickness '
Which of the following is NOT a characteristic of all animals? They are eukaryotes. They are all multicellular. They ingest their food. They are heterotrophic. They have tissues, organs, and organ systems.
They have tissues, organs, and organ systems. Sponges are considered animals, and they lack these levels of organization.
Which of the following statements is true of annelids? They perform gas exchange across their skin. They have an open circulatory system. They have a nerve net. They have a gastrovascular cavity. They have pseudocoeloms.
They perform gas exchange across their skin. Cutaneous respiration occurs across their skins. Some annelids, such as the errantians, have lateral extensions (parapodia) which provide additional surface area for cutaneous respiration.
Some invertebrates combine morphological simplicity with features of great structural or biochemical complexity. Select all correct examples of this statement. Trematodes are acoelomates that have effective defenses against attack by their hosts' immune system. Cnidarians are diploblasts that produce complex, capsule-like organelles. Sponges lack true tissues but have more variation in cell type than animals in any other phylum.
Trematodes are acoelomates that have effective defenses against attack by their hosts' immune system. Cnidarians are diploblasts that produce complex, capsule-like organelles.
Subphylum Vertebrata
Vertebrates are chordates with a spinal column • Distinguished from nonvertebrates by - Vertebral column - Encloses and protects the dorsal nerve cord - Head - Distinct and well-differentiated possessing sensory organs
Which of the following is radially symmetrical? a doughnut an automobile a spoon a submarine sandwich a dog
a doughnut A doughnut has no front, no back, no left, and no right.
A land snail, a clam, and an octopus all share distinct cephalization. a radula. a mantle. gills.
a mantle
Which structure do sea slugs use to feed on their prey? nematocysts an incurrent siphon a radula a mantle cavity
a radula
Sponges
are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues[10] and organs
Members of the phylum Mollusca __________. have tentacles surrounding a central mouth/anus are filter feeders are soft-bodied and often covered by a shell have segmented bodies and paired, jointed appendages have closed circulatory systems
are soft-bodied and often covered by a shell Members of the phylum Mollusca are soft-bodied and are often covered by a shell.
Which of the following statements correctly describes one difference between nematodes and arthropods? nematodes have an open circulatory system and arthropods have a closed circulatory system arthropods have an open circulatory system while nematodes do not have a circulatory system nematodes shed their cuticle when they grow but arthropods do not arthropods shed their cuticle when they grow but nematodes do not
arthropods have an open circulatory system while nematodes do not have a circulatory system
Which of the following animals does NOT have a body cavity? mouse earthworm nematode flatworm clam
flatworm Flatworms are acoelomates, even those that are not classified as acoels.
Which of the following animals does NOT have a body cavity? nematode earthworm mouse clam flatworm
flatworm Flatworms are acoelomates, even those that are not classified as acoels.
Which of the following is a characteristic of cnidarians? bilateral symmetry gastrovascular cavity radula mesoderm anus
gastrovascular cavity The gastrovascular cavity, characterized by a single opening, is the digestive compartment of cnidarians.
One of the characteristics unique to animals is sexual reproduction. gastrulation. flagellated sperm. multicellularity.
gastrulation.
Gastrulation is the process that directly forms the __________. germ layers blastulacentral nervous system muscles organs
germ layers Gastrulation gives rise to either two or three germ layers.
Which of the following statements applies to both nematodes and arthropods? are parasites grow in conjunction with shedding of their exoskeleton have ciliated larvae develop an anus from the blastopore (pore) formed in the gastrula stage
grow in conjunction with shedding of their exoskeleton
Our understanding of many of the evolutionary relationships among animals changed after those phylogenies were based on morphological and molecular data (as opposed to only using morphological data).What do these changes indicate? molecular studies are extremely time consuming and expensive and really don't add additional information to our understanding of evolutionary history molecular studies are less reliable than morphological studies molecular studies add additional information to morphological studies and improve our understanding of evolutionary history molecular and morphological studies rarely agree
molecular studies add additional information to morphological studies and improve our understanding of evolutionary history
Both animals and fungi are heterotrophic. Which of the following distinguishes animal heterotrophy from fungal heterotrophy? most animals derive their nutrition by ingesting materials most animals derive their nutrition by consuming living, rather than dead, prey most animals derive their nutrition by using enzymes to digest their food most animals derive their nutrition by preying on other animals
most animals derive their nutrition by ingesting materials
If you brush your fingers along the tentacles of a sea anemone, which of the following are you most likely to find upon microscopic examination of your fingers? nematocysts spicules spines teeth marks
nematocysts a specialized cell in the tentacles of a jellyfish or other coelenterate, containing a barbed or venomous coiled thread that can be projected in self-defense or to capture prey.
Which of the following characteristics is unique to animals? heterotrophy nervous system signal conduction flagellated gametes the structural carbohydrate, chitin
nervous system signal conduction
Which of the following statements best explains how planarians can survive and thrive without respiratory or circulatory systems? their body cavity, a pseudocoelom, carries out these functions their flame bulbs can carry out respiratory and circulatory functions none of their cells are far removed from the gastrovascular cavity or from the external environment they lack mesoderm as embryos and, therefore, lack the adult tissues derived from mesoderm
none of their cells are far removed from the gastrovascular cavity or from the external environment
You find a multi-legged animal in your garden and want to determine if it is a centipede or a millipede. Which of the following characteristics would allow you to make this distinction? egg-laying poisonous claws molting presence of body segments
poisonous claws
What would be the most effective method of reducing the incidence of blood flukes in a human population? carefully wash all raw fruits and vegetables reduce the mosquito population reduce the population of the intermediate snail host avoid contact with rodent droppings
reduce the population of the intermediate snail host
Which of the following statements describes sponges? they have feeding cells called dinoflagellates they have a nerve net but not a central nervous system they have larvae that are motile and move via the motion of flagella they are the simplest diploblastic animals
they have larvae that are motile and move via the motion of flagella
Why did the researchers use naive bats in this study? to avoid a situation when bats have the same level of experience at capturing moths to estimate the ability of bats to act in new conditions to estimate the ability of bats to learn to avoid a situation when bats become tamed to avoid a situation when experienced bats know how to capture moths
to estimate the ability of bats to learn to avoid a situation when experienced bats know how to capture moths
The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of a complete digestive tract. a circulatory system. true tissues. a body cavity. mesoderm.
true tissues.
Why do large animals need specialized organs for gas exchange? surface area increases more rapidly than volume as size increases they require more oxygen per unit of volume volume increases more rapidly than surface area as size increases they collect more energy and therefore have more energy to allocate to specialized tissues
volume increases more rapidly than surface area as size increases
Phylum Chordata
• Chordates are deuterostome coelomates • Nearest relatives are echinoderms (the only other deuterostomes) • Fishes, amphibians, reptiles, birds, and mammals . Nerve cord 2. Notochord 3. Pharyngeal slits/clefts 4. Postanal tail