IB 105 exam 3 - Environmental Health and Technology Virus :...

IB 105 exam 3
Download Document
Showing pages : 1 - 2 of 8
This preview has blurred sections. Sign up to view the full version! View Full Document
Environmental Health and Technology Virus : microscopic particles that can reproduce only by infecting host cells, example: influenza Bacteria : single-celled organisms with no membrane-enclosed nucleus, example: bubonic plague, anthrax, cholera Protozoans : single-celled organisms with a true nucleus, example: plasmodium Communicable/infectious disease : contagious, example: AIDS, SARS, influenza, ebola Non communicable : not contagious, example: many forms of cancer, cardiovascular disease Link between disease and environment : changes in environment increase risk for disease, changing climate patterns change where disease can occur, increased UV can increase cancer risk, lack of sanitary freshwater promotes illness, desertification reduces ability to receive adequate nutrition, we put toxic chemicals into the environment Emergent disease : one not previously known or one that has been absent for at east 20 years, important factor in spread of disease is speed and frequency of travel, SARS and Avian flu, drug-resistant form of tuberculosis Pandemic : occurring over a wide geographic area and affecting an exceptionally high proportion of population (AIDS/ 1918 infuenza) 1918 influenza pandemic : ~25% americans got it, 2.5% died, killed 675,000 american people, (10x as WW), worldwide 5—100 million Why modern technology hasn’t eradicated all disease ? Antibiotic and pesticide resistance, many disease causing bacteria now resistant to antibiotics, mosquitoes that transmit malaria have developed resistance to many insecticides PCB : polychlorinated biphenyis, various synthetic organic chemicals ranging from oily liquids to waxy solids, used in hundreds of industrial and commercial applications like electrical, heat transfer, and hydraulic equipment, have been demonstrated to cause variety of adverse health effects/cancer in animals, effects on immune system reproductive system, nervous/endocrine, studies in humans provide supportive evidence for potential carcinogenic and non-carcinogenic effects, not used in US Animal testing : most commonly used toxicity test is to expose a population of laboratory animals to measured doses of specific toxins LD 50 : dose at which 50% of test population is sensitive Playground : wood made with CCA (chromated copper arsenate), its toxic when it gets wet and so children playing on it is dangerous, no longer produced, antibiotics only kill bacteria Global Climate Change Major greenhouse gases : CO2, methane, nitrous oxides, chlorofluorocarbons (CFCs)
Background image of page 1
Greenhouse effect : heat from sun is absorbed in Earth’s surface, some is reflected back up into atmosphere, some is absorbed and re-emitted in a directions by gases warming the Earth and lowering the Earth’s atmosphere CO2 increasing : more emitted than absorbed, burning coal, oil, and gas, industrial processes, deforestation, agriculture Global climate change : human activities are changing the composition of Earth’s atmosphere, human activities are strengthening Earth’s natural greenhouse effect,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.