. Behavior of the lower organisms. Animal behavior; Invertebrates. CHAPTER II THE BEHAVIOR OF BACTERIA i. Structure and Movements Bacteria are perhaps the lowest organisms having a definite form and special organs for locomotion. In these characteristics they are less simple than Amoeba and resemble higher animals, though in other ways the bacteria are among the simplest of organisms. Whether they are more nearly related to animals or to plants is a question of little impor- tance for our purposes; they are usually considered as nearer to plants. Bacteria are minute organisms living in immense
. Behavior of the lower organisms. Animal behavior; Invertebrates. CHAPTER II THE BEHAVIOR OF BACTERIA i. Structure and Movements Bacteria are perhaps the lowest organisms having a definite form and special organs for locomotion. In these characteristics they are less simple than Amoeba and resemble higher animals, though in other ways the bacteria are among the simplest of organisms. Whether they are more nearly related to animals or to plants is a question of little impor- tance for our purposes; they are usually considered as nearer to plants. Bacteria are minute organisms living in immense numbers in decay- ing organic matter, and found in smaller numbers almost everywhere. They have characteristic definite forms (Fig. 23); some are straight cylindrical rods; some are curved rods; some are spiral in form; others are spherical, oval, or of other shapes. The individuals are often united together in chains. While some bacteria are quiet, others move about rapidly. The movements are produced by the swinging of whiplike protoplasmic - Difterent species of bacteria, processes, the flagella or cilia. The flagella may be borne singly or in numbers at one end of the body, or may be scattered over the entire surface. Figure 23 shows the dis- tribution of flagella in a number of species. In most bacteria we can distinguish a permanent longitudinal axis, and along this axis movement takes place. Thus both the form, and in correspondence with it, the movement, are more definite than in Amceba. If the bacterium is quiet, we can predict that when it moves it will move in the direction of this axis; for Amceba such a prediction cannot be 26. Fig. showing the distribution of the flagella. a. Chromatium • okeni, after Zopf; b, Chro- matium photomctriciim, after Engelmann ; c, Spirillum undula, after Migula; d, Vibrio cholera, after Fischer ; e, Bacilli of typhus, after Fischer ; /, Bacillus syncyaneus, after Fischer ; g, Clostridium butyricum, after Please note that t
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