IN RELATION TO RACHEL CARSON’S SILENT SPRING Christina Casanova Michael Derby George Koutsothanasis

 Population density results from the interplay of births, deaths, immigration and emigration of organisms in an environment.  In an attempt to control and decrease the population density of just insects and unwanted plants, all of our environment has suffered the harsh effects caused by insecticide sprays such as DDT.

 The chemicals sprayed by the Department of Agriculture have altered the life history traits of organisms in the area such as birds, insects, and soil- dwelling organisms.  Some of these organisms have even grown a resistance, or immunity, to the poisonous chemicals, creating an even bigger population problem for the environment.

 Unfortunately, most organisms that live through chemical spraying become sterile. This completely throws off reproduction rates and a region’s ability to reach its potential carrying capacity.  An exponential growth model shows possible growth in an unlimited environment. When pesticides and insecticides are introduced, an environment becomes limited.

 Populations are regulated by both biotic and abiotic influences.  Instead of letting nature take its course, humans are compelled to control and convenience the environment to themselves.  An eco-friendly alternative to chemical spraying would be providing more predators of unwanted organisms or spending more money on the sanitation of disease ridden plants.

 Chemical spraying affects the global human population as well. Humans are permeable. As toxic gases are entering the lungs of humans and poisonous chemicals rain down on cities, they stay there.  More and more people are reporting sicknesses and fatalities to chemical poisoning as spraying continues to be condoned by the United States Department of Agriculture.

 Rachel Carson’s “Silent Spring” reveals that while humans affect all environments we come in contact with, the “new” environment thus created, may in many aspects affect both population density and dispersion.  Chemicals, “The devils of mans’ own creation” affect both death rates and reproductive rates, which in turn affect survivorship curves and demography.  Along with such, chemicals affect behavior, physiology, and development, having the affects to kill and alter both the ‘good’ and the ‘bad’.

 While a typical exponential population model represents population in an unlimited, idealized environment, other factors, many of which are listed in Rachel Carson’s “Silent Spring” (I.e. malathion, and DDT), alter the models efficiency, increasing death rates and adding restrictions on the abilities of organisms.  In comparison, unlike the typical logistic grown model, the per capita rate of increase would either increase or decrease as the carry capacity is or is not reached.  Rachel Carson reveals that DDT and other pesticides affect human population (our global human population and carrying capacity) on an “irrecoverable” level.

 Regional patterns of population are altered by mans assaults upon the environment (“the contamination of air, earth, rivers, and sea.”), where the applications of chemicals in agricultural are concentrated.  The global human population has been growing exponentially since This is especially threatening, because an increasing number of humans means an increasing demand for land. As soon as that land gets settled on, people are going to want to grow crops and control unwanted “pests.” Since these pests are constantly developing an “immunity” to pesticides, humans must make them ever stronger and more lethal.  Infant mortality in humans may increase if we continue to use carcinogenous pesticides, that may be fatal to newborns. Even if the infant doesn’t die, it may be born with defects and disorders.

 The life expectancy at birth is also a factor that is affected by pesticides. If infants are exposed to poisonous chemicals from such a young age, then they will not be expected to live as long as they should.