Rotifers have been recorded from all parts of the world, and the distribution pattern for the different species may vary from truly cosmopolitan to endemic. In particular, the bdel-loid genera Philodina and Rotaria and various monogonont genera, such as Brachionus, Keratella, Lecane, and Lepadella, contain some extremely abundant species that have been recorded from most places in the world. Other species also are rather common but have a more limited distribution, being restricted, for example, to the Eurasian continent or the Holarctic or pantropical regions. Furthermore, some species appear to be endemic. For instance, no less than 11 species from the genus Notholca are endemic to Lake Baikal.

Among the key factors of rotifer success in terms of distribution are their cryptobiotic capabilities and their ability to produce resting eggs (see Habitat and Reproductive biology). Both resting eggs and dormant bdelloids may disperse over large distances with the aid of wind or water. Furthermore, resting eggs from many species have sculptured shells with tiny spines and hooks that enable them to attach to other animals (for example, birds) and spread by epizoic dispersal.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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