Mastering Biology Chapter 33

Chapter 33 Question 1 Part A - Identifying body symmetry Which type of symmetry does each of the following animals display? Drag each picture to the appropriate bin.

Chapter 33 Question 1 Part B - Germ layers, tissues, and body cavities Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). Select the three statements that are true. To review the germ layers and the terminology associated with body cavities, see the Hints. A diploblast has no mesoderm. A pseudocoelom has the same functions as a true coelom. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity. The digestive tract of a coelomate functions as a coelom. An acoelomate triploblast has no endoderm. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the lining of the digestive tract. In a pseudocoelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the muscles.

Chapter 33 Question 1 Part C - Differences in development between protostomes and deuterostomes Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither. Drag each item to the appropriate bin. To review protostome and deuterostome characteristics, see the Hints.

Chapter 32 Question 35 Ecdysozoans Protostomes are categorized into two clades: Lophotrochozoa and Ecdysozoa. Ecdysozoa includes about eight phyla, including the phyla Arthropoda and Nematoda. Arthropods and nematodes (roundworms) are among the most abundant of all animal groups. The simplified evolutionary tree below shows the relationship between arthropods, nematodes, and lophotrochozoans. (There are more ecdysozoan phyla than shown on this tree.) Part A - Comparing nematodes and arthropods Nematodes and arthropods are the largest ecdysozoan phyla. Which of the following statements are true? Select all that apply. The cuticle in nematodes lengthens as the animal grows. Arthropods are named for their jointed appendages. Nematodes are acoelomate, whereas arthropods are coelomate. Both nematodes and arthropods possess an external covering, or cuticle. Some nematodes are parasitic on humans. Arthropods possess an open circulatory system. Both nematodes and arthropods must molt in order to increase in size. Both nematodes and arthropods have segmented body plans. Nematodes possess a closed circulatory system.

Chapter 32 Question 35 Part B - Differentiating between arthropods The phylum Arthropoda includes four major lineages: cheliceriforms (also called chelicerates); myriapods; insects and their relatives (together called hexapods); and crustaceans. Drag each word or phrase to the appropriate bin.

Chapter 32 Question 35 Part C - Insect diversity Insects are the most diverse group of organisms, in terms of numbers of species, dominating terrestrial habitats. More than 30 orders of insects have been described, with the order Coleoptera being the largest. Classification is based on traits such as wings and mouthparts. All insects have a three-part body plan consisting of a head, thorax, and abdomen; three pairs of walking legs; and one or two pairs of wings. The chart below indicates defining characteristics for eight of the more than 30 orders of insects. Complete the chart by following these steps: Drag blue labels onto blue targets only to identify wing characteristics. Drag white labels onto white targets only to identify the type of development. Drag pink labels onto pink targets only to identify examples of insects in each order. Labels can be used once or not at all.

Chapter 33 Question 42 Part A Use the following information when to answer the question(s) below. Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings (called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spiracles are opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time (represented by VCO2) by several species of centipedes. The figure below presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. (C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods. Journal of Experimental Biology 205:1019-29.) Copyright 2002 The Company of Biologists and the Journal of Experimental Biology. Look at the graph for Cormocephalus morsitans in the figure above. What is the best interpretation of these results? A. The centipede had its spiracles open the entire time. B. The centipede had its spiracles closed the entire time. C. The centipede had its spiracles open when carbon dioxide (CO2) emission peaked and closed when CO2 emission was low. D. The centipede had its spiracles closed when carbon dioxide (CO2) emission peaked and open when CO2 emission was low.

Chapter 33 Question 43 Part A Use the following information when to answer the question(s) below. Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings (called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spiracles are opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time (represented by VCO2) by several species of centipedes. The figure below presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. (C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods. Journal of Experimental Biology 205:1019-29.) Copyright 2002 The Company of Biologists and the Journal of Experimental Biology. Look at the graph for Scutigerina weberi (note the scale of the y-axis) in the figure above. What is the best interpretation of these results? A. The centipede had its spiracles open when carbon dioxide (CO2) emission peaked and closed when CO2 emission was low. B. The centipede had its spiracles open the entire time. C. The centipede had its spiracles closed when carbon dioxide (CO2) emission peaked and open when CO2 emission was low. D. The centipede had its spiracles closed the entire time.

Chapter 33 Question 44 Part A Use the following information when to answer the question(s) below. Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings (called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spiracles are opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time (represented by VCO2) by several species of centipedes. The figure below presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. (C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods. Journal of Experimental Biology 205:1019-29.) Copyright 2002 The Company of Biologists and the Journal of Experimental Biology. How would a terrestrial centipede most likely benefit from the ability to close its spiracles? Closing spiracles would _____. A. allow the centipede to move more quickly B. allow the centipede to stay warmer C. allow more oxygen from the environment to reach the centipede's tissues D. allow the centipede to retain more moisture in its tissues