Excerpt from The Practical Value of Birds Because of the fact that some species of insects and other pests which are normally kept within reasonable bounds, may, during especially favorable seasons or cycles of seasons increase so rapidly as to become very harmful, these birds which take a mixed diet are particularly valuable. Thus a bird species which ordinarily is largely vegetarian lives through seasons Of scarcity of insects, and then is ready to turn its attention to an insect diet whenever the insects become overabundant; whereas, if the birds were all exclusively insectivorous, comparatively few would survive seasons unfavorable to ih sects and thus be on hand to aid in the warfare against those pests when seasons favorable to insect life occur. A species which is harmless, or even beneficial, in its natural habitat, may become injurious when transported to a new environment, where the natural checks upon its increase are wanting, or the lack of its natural food, or the presence Of a food which is more enjoyable, may cause a marked change in its food habits. It is said that the Skylark, green linnet and black thrush are considered beneficial in Europe, where they are native, but in New Zea land, into which country they have been introduced, they have developed traits which render them far from desirable additions to the fauna Of that It will be interesting to watch the effect of the introduction of the Little Gray Owl into New Zealand for the purpose of fighting the English sparrow Such importations are now, as a result of disastrous experience, prohibited by law in some countries, including the United States. The introduction Of a species may disturb the balance as much as the extermination of one. European rats, accidentally introduced into Jamaica, became a great nuisance. The Indian mongoose was imported to destroy the rats. It turned its attention to game birds, poultry, young pigs and lambs, and became a great pest, also destroying many birds, snakes and lizards, which feed largely upon insects. This was followed by an increase of insect pests. Disaster also followed the introduction Of the mongoose into Hawaii, and its importation into the United States was barely prevented. Rabbits. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
This new edition introduces more problem-solving strategies and new conceptual and challenge problems. Also, each Chapter Review has been enhanced with Learning Goals to reinforce the mastery of concepts for students.
This laboratory manual contains 42 experiments for the standard sequence of topics in general, organic, and biological chemistry.
The book guides students through basic chemistry problem solving with engaging visuals and a focus on developing the math skills necessary to be successful in the course.
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Basic Chemistry
Basic Chemistry, Books a la Carte Edition
Essential Laboratory Manual for General, Organic and Biological Chemistry
The main objective in writing this text is to make the study of chemistry an engaging and a positive experience for students by relating the structure and behaviour of matter to real life.
The eText pages look exactly like the printed text, and include powerful interactive and customization functions. This is the product access code card for MasteringChemistry with Pearson eText and does not include the actual bound book.
Health, Environmental, and Green Chemistry Notes throughout the text relate chemistry chapters to real-life topics in health, the environment, and medicine that are interesting and motivating to students.