EcoLOGY THE DELIATE BALANCE OF LIFE ON EARTut programs to control infectious diseases For example the rapid spread of West Nile virus WNV in the United States in the early 21st century resulted from the interaction of environmental factors with human and animal populations Mosquitoes spread the virus by biting infected birds and then bit ing humans and other animals One study in Florida noted that the number of WNV cases was especially high for years in which a dry spring season was followed by an especially wet summer Further studies of environmen tal factors suggested that the limited water resources resulting from a dry spring may drive mosquitoes to congregate in isolated patches of dense vegetation where condi tions remain humid These humid patches also serve as nesting sites for an array of wild birds In the close quarters of this temporary home mosquitoes feed on and infect more birds than usual When conditions change and the mosquitoes break out of their group ings and scatter more people than usual will be bitten by these mosquitoes and become infected Such insights gained from recognizing environmental factors promoting infection and transmission are crucial for fighting 12
THE NATURE OF ECOLOGY Mosquitoes spread the West Nile virus by biting infected birds then biting humans Chris Johns National Geographic Image Collection Getty Images WNV and many other diseases If the ecol ogy of the organisms is known scientists can use an environmental approach to disrupt infection and the transmission of infectious diseases while treating and preventing the disease through medication and vaccination This is but one example of the numerous ways in which scientists rely on an understanding of 13
Economy THE DELICA BALANCE OF LIFE ON EART the complex interactions and interdependen cies of living things and their environments EARLY STUDIES OF THE NATURAL WoRLD Long before the science of ecology was estab lished people in many occupations were aware of natural events and interactions A gaggle of geese migrating south is a natural harbinger of impending winter Shutterstock com 14
THE NATURE OF ECOLOGY Early humans knew that gulls hovering over the water marked the position of a school of fish Before the use of calendars to mark time people used natural cues to guide sea sonal endeavors For instance corn maize was planted when oak leaves were a certain size and the sight of geese flying south was a warning to prepare for winter Until about 1850 the scientific study of such phenomena was called natural history and a person who studied this was called a naturalist As natural history became sub divided into special fields such as geology zoology and botany naturalists began incor porating laboratory work with field studies This multidisciplinary approach gradually led to the establishment of ecology as a dis tinct field of study MoDERN Dar EcoLoGr The modern study of ecology encompasses many areas of science In addition to a solid understanding of biology ecologists must also have some knowledge of weather and climate patterns rock and mineral types soil and water Familiarity with mathemat ics and statistics is essential Whereas the 15
