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94 GLOSSARY                                                                                                                                                                                          REPTILES AND DINOSAURS  95


















                                                                                                                                                                   groups. This biological concept should be
          Mammals                             Omnivore                            Pheromones                                   Reabsorption                        distinguished from the concept of a species as a  Vertebrates
          Vertebrate animals whose females have  Animal that feeds on animal and plant species  Chemical substances secreted by the  Process in which substances that are filtered  category and as a taxon.  Animals with a spinal column that provides a
          mammary glands, which secrete substances                                reproductive glands of certain animals in order  or secreted by the kidneys and which are                           structural axis and develops around the
          that serve as food for their young.  Opisthoglyph                       to attract individuals of the opposite sex.  necessary for maintaining the organism's  Sperm Cell                   notochord, completely replacing it in most
                                                                                                                               internal equilibrium are reincorporated into                           species.
          Mass Extinction                     Group of snakes with fangs located in the back  Photoperiod                      the plasma.                         Mature male sex cell, which is typically mobile
                                              of the upper jaw and smaller teeth in front. The                                                                     and smaller than the female sex cell.  Viviparous
          Brief geological interval in which the extinction  fangs can be smooth or have a groove on the  Relative length of night and day that enables  Reflex
          rate is greatly increased, affecting a large  surface that enables secretions to flow into the  organisms to measure the change of seasons and           Spinal Cord                        Animal species whose females do not lay eggs
          number of species and causing a considerable  wound they produced.      that influences their behavior and physiology.  Simple action of the nervous system that                            and whose young are born live.
          reduction of biodiversity.                                                                                           involves a sensory neuron, often one or more  Part of the central nervous system of
                                              Order                               Phylogeny                                    interneurons, and one or more motor neurons.  vertebrates, surrounded by the spinal column.  Warm-blooded
          Metabolism
                                              Taxonomic category below class and above  Evolutionary history of any taxonomic group.  Sensory Receptors            Striated Muscle                    Organism whose main heat source is internal
          The sum of all the physical and chemical  suborder and family. For example, snakes and  Usually represented as a branching tree.                                                            and is produced largely through oxidative
          transformations that occur within a cell or  saurian reptiles belong to the order Squamata.                          Cells, tissues, or organs that detect internal or  Muscle tissue with a striped appearance that  metabolism.
          organism.                                                               Piscivore                                    external stimuli.                   shows the arrangement of the contracting
                                              Ovary                                                                                                                elements. Includes the voluntary skeletal muscle  Zoonosis
          Mimicry                             Organ that produces eggs (female sex cells).  Animal that eats only fish.        Sexual Reproduction                 and the cardiac muscle.            Illness transmitted by animals to humans.
          A superficial similarity in shape, color, or                            Plastron                                     Reproduction based on the fertilization of a  Thalamus
          behavior on the part of certain organisms  Oviparous                                                                 female sex cell by a male sex cell, resulting in
          (mimetics) to others (models) or to objects in                          Lower part of the shell of a turtle or tortoise.  the production of descendants different from  Part of the prosencephalon of vertebrates
          the environment for the purpose of hiding,  Animal that reproduces by laying eggs.                                   either parent.                      located behind and below the cerebrum. It is
          seeking protection, or some other benefit.                              Predator                                                                         the main connection center between the brain
                                              Ovoviviparous                                                                    Shedding                            stem and the upper cerebral regions.
          Mitosis                             Animal that reproduces by forming eggs that  Animal that captures and eats other animals  Sloughing off or change of skin, a process that  Thermoregulation
                                                                                  as prey.
          Nuclear cell division, in which two daughter  are carried, with soft shells, inside the female                       happens naturally in many reptiles.
          nuclei are formed that are identical to the  until they hatch. They may hatch inside the  Protein                                                        Ability of reptiles to change their body
                                              mother and come out as if they had been born
          parent nucleus.                                                                                                      Smooth Muscle                       temperature by moving from a warm place to
                                              live or be expelled from the egg pouch, breaking  Macromolecule composed of one or more                              a cooler one or vice versa.
                                              its membrane in order to hatch.     chains of amino acids. They define the physical  Non-striated muscle that covers the walls of the
          Molars                                                                  characteristics of an organism and, when     hollow organs and arteries and is controlled  Tissue
          Group of teeth that crush food within the  Ovum                         acting as enzymes, regulate chemical reactions.  involuntarily.
          mouth.                                                                                                                                                   Group of identical cells that carry out a common
                                              A female haploid reproductive cell. It contains  Proteroglyph                                                        function.
                                              half as many chromosomes as the parent cell.                                     Solenoglyph
          Molecular Clock                                                         System of fangs in cobras, mambas, coral     System of long, hollow fangs in some snakes or  Trophic Level
          Marker used to estimate the evolutionary  Parasite                      snakes, and sea snakes; or the name referring  the name of the group that refers to snakes
          distance between two species. It is evaluated  Organism that lives at the expense of another  to the group that contains these types of  possessing this characteristic. The fangs are the  The position of a species in the food web or
          by comparing the gradual accumulation of  and typically obtains nutrients that have already  snakes. The fangs are located in the front of  only teeth in the upper jaw, and they pivot so  food chain.
          amino acids between the proteins of those  been processed by the host.  the upper jaw and are hollow or have a surface  that they lie flat along the roof of the mouth
          species.                                                                groove for carrying venom. They are relatively  when the mouth is closed. They inject venom  Uric Acid
                                                                                  short and are fixed in an extended position.  deep into the tissues of prey.
          Nucleic Acid                        Parthenogenesis                     Protractile                                                                      Water-insoluble nitrogenated waste product;
                                                                                                                                                                   the main component of the excrement of
                                              Form of asexual reproduction in certain species,                                 Species
          Molecule carrying the genetic information   such as the gecko, in which the females produce  Describes a type of reptilian tongue that can be            reptiles and insects.
          of a cell.                                                                                                           Biological concept of a group of organisms that
                                              young (all or mostly females) without the  voluntarily hurled outward in an extremely  can or do interbreed in the wild and are
                                              intervention of a male.             rapid, precise movement.                     reproductively isolated from other similar
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