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    Zoology Final Pt2 Flashcards

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    Zoology Final Pt2

    What evidence suggests that vertebrates are more closely related to echinoderms than are any other invertebrate phyla?

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    Shared DNA sequences

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    A land snail, a clam, and an octopus all share

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    What evidence suggests that vertebrates are more closely related to echinoderms than are any other invertebrate phyla?

    Shared DNA sequences

    A land snail, a clam, and an octopus all share


    Which of the following is a characteristic of all chordates at some point during their life cycle?

    post-anal tail

    Sexual reproduction leads to increased genetic variation, but male bdelloid rotifers have never been observed. Which of the following are correct statements with regard to evolution in bdelloid rotifers?

    Bdelloid rotifers gain genetic variation by absorbing DNA from the external environment

    Which of the following characteristics do all insects exhibit?

    they have an exoskeleton or cuticle

    What structure is responsible for gas exchange in most spiders?

    book lungs

    Which of the following statements best explains how planarians can survive and thrive without respiratory or circulatory systems

    none of their cells are far removed from the gastrovascular cavity or from the external environment

    Which of the following statements about bryozoans (ectoprocts) is correct?

    Bryozoans build reefs and have lophophores that extend through a hard exoskeleton

    Which phylum is characterized by animals that have a segmented body?


    The phylum Cycliophora includes 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 saclike and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans have a coelom, do not molt (though their host does), and their embryos undergo spiral cleavage.Based on the information provided, to which clades should cycliophorans belong?

    Eumetazoa and Lophotrochozoa

    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.

    Which of the following chordates is most likely to look the least like other chordates?

    adult tunicate

    You work for the Iowa Department of Natural Resources and are inventorying mussels in the Cedar River. You find similar results to those in this research. Which of the following is true?

    Mussel populations are declining.

    In order to restore mussel populations in U.S. rivers, which of the following would likely be best?

    Restore rivers to their former natural state

    If trends in mussel populations continue, which of the following is most impacted in fresh waters?

    water filtration

    Your environmental science class visits a local stream to look for mussels. Where are you most likely to find some?

    Sitting on the bottom of a stream

    Your friend is studying a mass die-off of warblers in Canada. Which of the following is most likely to lead your friend to believe a pathogen is the cause?

    only warblers were affected

    In early chordates, the primitive pharyngeal slits carried out which of the following functions?

    suspension-feeding devices

    Adult urochordates (tunicates) lack notochords, even though larval urochordates have them. What is the function of notochords in larval urochordates?

    they aid in swimming

    Which of the following adaptations led to an explosion in insect evolution


    Which of the following statements is correct regarding lancelets?

    Recent work in molecular systematics supports the hypothesis that lancelets are the basal clade of chordates.

    Echinoderms show enormous diversity in which of the following traits?

    body shape and food habits

    The presences of which of the following anatomicals would best distinguish a gastropod from a chiton?

    dorsal plates

    The antennae of insects have a function most similar to that of ________.


    Against which of the following do the circular and longitudinal muscles of annelids work?

    Hydrostatic skeleton

    Which of the following characteristics of parasites explains how parasitism has become so widespread among living organisms?

    Parasites do not generally kill their hosts; thus they can feed on the same host throughout the host's normal life span and do not have competition from decomposers.

    The water vascular system of echinoderms

    functions in locomotion and feeding

    Which of the following statements applies to both nematodes and arthropods

    grow in conjunction with shedding of their exoskeleton

    Which of the following statements is true of annelids

    They perform gas exchange across their skin.

    Which one of these mollusc groups is classified as suspension feeders?


    Which of the following statements correctly describes a characteristic of the phylum Platyhelminthes?

    Source : quizlet.com

    Which of the following is not an advantage of the exoskeleton in arthropods and mollusca?

    Click here👆to get an answer to your question ✍️ Which of the following is not an advantage of the exoskeleton in arthropods and mollusca?


    Which of the following is not an advantage of the exoskeleton in arthropods and mollusca?


    Provides protection from predators


    Provides a rigid place for muscles to insert against which they can do work


    Enhances sensory perception


    Permits greater range of movement than body plan without a rigid skeletal structures

    Medium Open in App

    Source : www.toppr.com



    From Wikipedia, the free encyclopedia

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    "Robot exoskeleton" redirects here. For the type of machine, see powered exoskeleton.

    The discarded exoskeleton (exuviae) of dragonfly nymph

    Exoskeleton of cicada attached to a

    An exoskeleton (from Greek έξω, "outer" and σκελετός, "skeleton"[1]) is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton (endoskeleton) of, for example, a human. In usage, some of the larger kinds of exoskeletons are known as "shells". Examples of animals with exoskeletons include insects such as grasshoppers and cockroaches, and crustaceans such as crabs and lobsters, as well as the shells of certain sponges and the various groups of shelled molluscs, including those of snails, clams, tusk shells, chitons and nautilus. Some animals, such as the tortoise and turtle (shell page), have both an endoskeleton and an exoskeleton.


    1 Role 2 Growth

    3 Paleontological significance

    4 Evolution 5 See also 6 References 7 External links


    Exoskeletons contain rigid and resistant components that fulfill a set of functional roles in many animals including protection, excretion, sensing, support, feeding and acting as a barrier against desiccation in terrestrial organisms. Exoskeletons have a role in defense from pests and predators, support and in providing an attachment framework for musculature.[2]

    Arthropod exoskeletons contain chitin; the addition of calcium carbonate makes them harder and stronger, at the price of increased weight.[3] Ingrowths of the arthropod exoskeleton known as apodemes serve as attachment sites for muscles. These structures are composed of chitin and are approximately six times stronger and twice the stiffness of vertebrate tendons. Similar to tendons, apodemes can stretch to store elastic energy for jumping, notably in locusts.[4] Calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. Silica forms the exoskeleton in the microscopic diatoms and radiolaria. One species of mollusc, the scaly-foot gastropod, even makes use of the iron sulfides greigite and pyrite.

    Some organisms, such as some foraminifera, agglutinate exoskeletons by sticking grains of sand and shell to their exterior. Contrary to a common misconception, echinoderms do not possess an exoskeleton, as their test is always contained within a layer of living tissue.

    Exoskeletons have evolved independently many times; 18 lineages evolved calcified exoskeletons alone.[5] Further, other lineages have produced tough outer coatings analogous to an exoskeleton, such as some mammals. This coating is constructed from bone in the armadillo, and hair in the pangolin. The armor of reptiles like turtles and dinosaurs like Ankylosaurs is constructed of bone; crocodiles have bony scutes and horny scales.


    Main article: Ecdysis

    Since exoskeletons are rigid, they present some limits to growth. Organisms with open shells can grow by adding new material to the aperture of their shell, as is the case in snails, bivalves and other molluscans. A true exoskeleton, like that found in arthropods, must be shed (moulted) when it is outgrown.[6] A new exoskeleton is produced beneath the old one. As the old one is shed, the new skeleton is soft and pliable. The animal will typically stay in a den or burrow for this time,[] as it is quite vulnerable during this period. Once at least partially set, the organism will plump itself up to try to expand the exoskeleton.[] The new exoskeleton is still capable of growing to some degree, however.[] Animals of the order arthropoda, like lizards, amphibians, and many other animals that shed their skin, are indeterminate growers.[1] Animals that are indeterminate growers grow in size continually throughout their life because, in this case, their exoskeleton is always being replaced. Failure to shed the exoskeleton once outgrown can result in the animal being suffocated within its own shell, and will stop subadults from reaching maturity, thus preventing them from reproducing. This is the mechanism behind some insect pesticides, such as Azadirachtin.[7]

    Paleontological significance[edit]

    Borings in exoskeletons can provide evidence of animal behavior. In this case, boring sponges attacked this hard clam shell after the death of the clam, producing the trace fossil .

    Exoskeletons, as hard parts of organisms, are greatly useful in assisting preservation of organisms, whose soft parts usually rot before they can be fossilized. Mineralized exoskeletons can be preserved "as is", as shell fragments, for example. The possession of an exoskeleton permits a couple of other routes to fossilization. For instance, the tough layer can resist compaction, allowing a mold of the organism to be formed underneath the skeleton, which may later decay.[8] Alternatively, exceptional preservation may result in chitin being mineralized, as in the Burgess Shale,[9] or transformed to the resistant polymer keratin, which can resist decay and be recovered.

    Source : en.wikipedia.org

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