Exam 3 BIO

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Colorado State University, Fort Collins *

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110

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Biology

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Dec 6, 2023

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docx

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CHAPTER 12 Which of the following are defining characteristics of phylum Annelida? metameric body ventral nerve cord The annelid clade Sedentaria now includes which of the following? Some polychaetes Leeches Earthworms In annelids, the segmentation of their bodies into repeated units is called ______. Metamerism In annelids, each segment has its own excretory, nervous , and circulatory structures. Recent molecular phylogenetic studies have shown Blank______ to be synonymous with Annelida. Polychaeta One advantage of a coelom is to serve as a hydrostatic skeleton. What is the habitat for most polychaetes? Marine The annelid clade Sedentaria now includes which of the following? Leeches Some polychaetes Earthworms Annelids possess lateral extensions called parapodia as shown in the figure. Parapodia are reduced or absent in which group of annelids? Sedentarians Oligochaetes and leeches mainly are found in these habitats. Soil Freshwater External bristles on the body of an annelid are called setae. Sensory organs Parapodia Setae In polychaetes, these ciliated pits serve as chemosensory organs.

Nuchal organs Select the two parts of the annelid head. Prostomium Peristomium Chapter 13 Nematodes, and other animals in the clade Ecdysozoa, periodically molt an outer, nonliving structure called the cuticle. Select all of the following that are characteristics of the phylum Nematoda. They inhabit saltwater and freshwater. They live in topsoil. They parasitize plants and animals. Eutely is when _______. somatic cell number is constant for all individuals Which of the following are distinguishing characteristics of all Nematodes? Cylindrical shape Collagenous cuticle Longitudinal muscles The cuticle of nematodes functions to contain the high hydrostatic pressure exerted by internal fluids and as protection against hostile environmental conditions. The process of molting a cuticle is called ecdysis and occurs in nematodes. The consistency in somatic cell number is termed eutely , and is found in the nematode C. elegans . Which of the following are functions of the cuticle in nematodes? To maintain a high internal hydrostatic pressure To provide mechanical protection In parasitic species, to resist digestion by the host Chapter 11 Which of the following general statements concerning molluscs are true? Some members of the mollusc taxa are excellent predators. Cephalopods have rapid locomotion, complex sensory structures, and tearing mouthparts. Molluscs and annelids are both animal groups that are classified in the lophotrochozoan group.

Which accurately describes a typical mollusc? Bilaterally symmetrical, reduced coelom, presence of a radula Of the two main body regions found in a mollusc, the head-foot contains the sensory structures and the means of locomotion and attachment. The nacreous layer is the innermost layer of the shell that is continuously secreted by the mantle. The body of a mollusc has two general parts, the head-foot and the visceral mass. Which statements below are accurate? The head-foot contains the means of attachment and locomotion The head-foot contains the mouth and sensory structures The visceral mass contains the organs of reproduction, digestion, and excretion, among others The mantle cavity is located between the mantle and the foot. Which of the following descriptions of the radula is correct? Muscle moves the radula back and forth over the odontophore and scraped food moves posteriorly to the digestive tract Most molluscs have a(n) open circulatory system with a pumping heart, blood vessels, and blood sinuses. With over 65,000 species, the class Gastropoda is the largest class of molluscs.. In molluscs the space between the mantle and the foot, called the mantle cavity, functions in gas exchange, excretion, elimination of digestive wastes, and what other function? Release of reproductive products The radula sits above a fleshy tonguelike structure that is supported by what cartilage? Odontophore Torsion is a process where the visceral mass, mantle, and mantle cavity rotate 180 degrees counterclockwise relative to the head. The ancestral form of gastropod shells involved coiling in how many planes? one

Which statements concerning gastropod locomotion are accurate? Large gastropods use muscular contractions for movement The gastropod foot can be modified in some groups for clinging or swimming The foot of a gastropod is often ciliated Digestion in gastropods involves the movement of a mucoid mass called the protostyle into the stomach where it is rotated by cilia. Most modern snail shells are asymmetrically coiled into a more compact form. Terrestrial gastropods do not have gills, or have greatly reduced gills, and rely on a vascular mantle to allow for gas exchange between the blood and air. Gastropod feeding strategies can be described as which of the following? Can be herbivores Can be carnivores Can be scavengers The radula is a rasping structure that is found in almost all molluscs. Which statement best describes the use of a hydraulic skeleton in the gastropod? To extend sensory tentacles from the head, a gastropod can squeeze blood into the tentacle from nearby areas A digestive gland in the gastropod visceral mass secretes enzymes and acid to the stomach to facilitate digestion. True The pneumostome is an external opening of the _lung_____ in pulmonate gastropods. In a hydraulic skeleton, fluid is under pressure that allows it to provide support to the animal. If marine snails are dioecious then the gametes are released to the water for external fertilization. Bivalves are the second most abundant gastropod group and include clams, oysters, mussels, and scallops. The pulmonates include land and most freshwater snails and slugs.

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