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Do Now . Thinking outside the box. With only using four lines and not picking up your pen or pencil. Connect all the dots below: *** *** ***. Answer. Thinking outside the box. With only using four lines and not picking up your pen or pencil. Connect all the dots below: ***

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Do Now

  • Thinking outside the box. With only using four lines and not picking up your pen or pencil. Connect all the dots below:

    ***

    ***

    ***


Answer

  • Thinking outside the box. With only using four lines and not picking up your pen or pencil. Connect all the dots below:

    ***

    ***

    ***


Homework

  • Due Friday –Vocab 1-95

  • 91. Photovoltaics

  • 92. Law of Averages

  • 93. Habitat versus Niche

  • 94. Directional Selection

  • 95. Disruptive Selection

  • Test Friday & Saturday on Chapters 13 & 14.

  • Read pages 383 starting at Airborne substances…to 388 stop at Dose – response…


Lead poisoning

  • Lead poisoning = caused by lead, a heavy metal

    • Damages the brain, liver, kidney, and stomach

    • Causes learning problems, behavior abnormalities, and death

  • Exposure is from drinking water that flows through lead pipes or from lead paint

  • Education led to declines in poisoning, but China still used it in toy paint until recently


Remember the video about the computers be recycling?

  • Polybrominateddiphenyl ethers (PBDEs) = has fire-retardant properties

    • Used in computers, televisions, plastics, and furniture

    • Persist and accumulate in living tissue

    • Mimic hormones and affect thyroid hormones

    • Also affect brain and nervous system development and may cause cancer

  • Concentrations are rising in breast milk

    • Now banned in Europe, concentrations have decreased

    • The U.S. has not addressed the issue


New Material

  • Despite our technology, disease kills most of us

  • Disease has a genetic and environmental basis

    • Cancer, heart disease, respiratory disorders

    • Poverty and poor hygiene foster illnesses


New Material

  • Infectious diseases kill 15 million people/year

    • Half of all deaths in developing countries

  • Public health decreases some infectious diseases such as (AIDS) and is spreading


New Material

  • Our mobility spreads diseases

    • Remember Spanish Influenza during WW I.

    • West Nile Virus spread from Africa to all lower 48 U.S. states in 5 years

    • And early on AIDS

  • New diseases are emerging such as

    • H5N1 avian flu, H1N1 (Swine Flu)


  • Toxicology studies poisonous substances

    • Toxicology = the study of the effects of poisonous substances on humans and other organisms

    • Toxicity = the degree of harm a toxicant can inflict

    • Toxicant = any toxic substance (poison)

      • “The dose makes the poison” = toxicity depends on the combined effect of the chemical and its quantity

    • Environmental toxicology = deals with toxic substances that come from or are discharged into the environment

      • Studies health effects on humans, other animals, and ecosystems


    Toxicology studies poisonous substances

    • What is the most dangerous place in a home for poisonous substances?

    • Under the kitchen sink?


    Chemicals are in the air, water, and soil

    • 80% of U.S. streams contain 82 contaminants

      • Antibiotics, detergents, drugs, steroids, solvents, etc.

    • 92% of all aquifers contain 42 volatile organic compounds (from gasoline, paints, plastics, etc.)

      • Less than 2% violate federal health standards for drinking water

      • DDT - Rachel Carson’s Silent Spring (1962) showed DDT’s risks to wildlife, and ecosystems and possibly people


    Toxicants

    • Carcinogens = cause cancer

      • Hard to identify because of the long time between exposure and onset of cancer

    • Mutagens = cause DNA mutations

      • Can cause cancer

    • Teratogens = cause birth defects in embryos

    • Neurotoxins = assault the nervous system

    • Allergens =overactivate the immune system

    • Endocrine disruptors =affect the endocrine (hormone) system


    Endocrine disruptors

    • Hormones stimulate growth, development, sexual maturity

    • Synthetic chemicals

      • Can Block hormones and / or mimic hormones


    Bisphenol A

    • Bisphenol A binds to estrogen receptors

    • Phthalates in plastics disrupt hormones

      • Found in toys, perfumes, makeup

      • Can cause Birth defects, cancer, reproductive effects


    Airborne substances

    • Chemicals can travel by air

      • Their effects can occur far from the site of use

    • Pesticide drift = airborne transport of pesticides

    • Synthetic chemicals are found globally

      • In arctic polar bears, Antarctic penguins, and people in Greenland


    Some toxicants persist

    • Toxins can degrade quickly and become harmless or they may remain unaltered and persist for decades

      • Rates of degradation depend on the substance, temperature, moisture, and sun exposure

    • Breakdown products = simpler products that toxicants degrade into may be more or less harmful than the original substance

      • DDT degrades into DDE, which is also highly persistent and toxic.


    New Material

    • Toxicants in the body can be excreted, degraded, or stored fat-soluble toxicants are stored in fatty tissues

    • Bioaccumulation = toxicants build up in animal tissues

    • Biomagnification = concentrations of toxicants become magnified

      • Near extinction of peregrine falcons and bald eagles


    Not all toxicants are synthetic

    • Toxic chemicals also exist naturally and in our food

      • Don’t assume natural chemicals are all healthy and synthetic ones are all harmful. For example mushrooms

    • Environmentalists say synthetic toxins:

      • Are harder to metabolize and excrete

      • Persist and accumulate

      • Enter people in ways other than in food


    Human studies

    • Case history approach = studies individual patients

      • Autopsies tell us about lethal doses

      • Don’t tell about rare, new, or low-concentration toxins

      • Don’t tell about probability and risk

    • Epidemiological studies = large-scale comparisons between exposed and unexposed groups

      • Studies can last for years

      • Yield accurate predictions about risk

      • Measure an association between a health hazard and an effect – but not necessarily the cause of the effect


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