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Bio 220 Exam 2 Study Guide Directions: This study guide was created from the exam bank of questions. It is designed to give indications about what concepts will be important to review in preparation for the midterm. Use the PowerPoint slides along with reading the textbook and notes taken during lecture to study effectively. Do not concentrate solely on the definitions. Population Growth and Environment Factors that limit population size (disease, war, famine, etc.) o Population growth is checked by famine, disease, and cultural factors (e.g., late marriage). o Regulate population through cultural taboos, abstinence and infanticide. Effects of population on the environment are not due to numbers alone. o I = PAT I = environmental impact P = population size A = affluence T = technology Carrying capacity (K) o the maximum number of individuals that the environmental resources of a given region can support. Physical carrying capacity = “packing density, limited only by space and resources” Cultural carrying capacity is always less Malthus vs. Marx o Malthus Human population growth causes environmental degradation Thomas Malthus (1798) wrote An Essay on the Principle of Population in which he showed that human populations increase exponentially. o Karl Marx Human population growth results from poverty and resource depletion Demography o the application of population ecology to the study of humans Demographers study population size Density and distribution, Age structure, sex ratio, And birth, death, immigration, and emigration rates Encompasses vital statistics about people such as births, deaths, distribution, and population size
Crude birth and death rates o Crude Birth Rate Number of births in a year per thousand. (Not adjusted for population characteristics such as number of women of childbearing age.) o Crude Death Rate – number of deaths per thousand persons in a given year Poor countries average about 20 while wealthier countries average about 10. Some rapidly growing countries have very low crude death rates due to a high proportion of young people. Total fertility rate and zero population growth o Total Fertility Rate - number of children born to an average woman in a population during her life o Zero Population Growth - Occurs when births plus immigration in a population equal death plus emigration. ZPG Is a rate of 2.1 children per couple, not 2.0, because some people do not have children and some children do not survive to reproductive age. Population momentum o Even if total fertility rates were to fall, the population would continue growing as young people enter reproductive age Natural growth rate o Natural Increase - crude birth rate minus crude death rate o Total growth rate- includes immigration, emigration, births and deaths. Factors that affect life expectancy o Agricultural developments, o Better sources of power o Better health care and hygiene Dependency ratio o The number of non-working compared to working individuals in a population. Poverty and population growth factors o Poorer societies have higher growth rates than wealthier societies o They have higher fertility and growth rates, with lower contraceptive use Consistent with the demographic transition theory
• Viruses • Bacteria • Protozoans • Parasitic worms including flukes Antibiotic resistance o Antibiotics - chemicals that kill or inhibit the growth of bacteria o Many people do not finish the full-course, creating resistant strains of bacteria. Toxicology o the study of poisons and their effects on living systems. Ecotoxicology o deals with the interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphere. Toxic vs. hazardous material o Toxic – known poisons that damage or kill cells/tissues Can be general or very specific. Often harmful even in dilute concentrations. o Other Hazards - dangerous but not toxic Flammable, explosive, irritant, acid, caustic Classification of toxins o Carcinogen Carcinogens - substances that cause cancer Cancer is the 2nd leading cause of death. 1 in 2 males and 1 in 3 females in the U.S. will have cancer in their lifetime. o Allergen Allergens - substances that activate the immune system Antigens - substances that are recognized as foreign by white blood cells and stimulate the production of specific antibodies o Immune System Depressants pollutants that depress the immune system o Endocrine disruptors Endocrine Disrupters - disrupt normal hormone functions Examples : o DES- Synthetic estrogen o BPA (Bisphenyl A)- used in plastics o DEHP - used in packaging
o Phytoestrogens - naturally occurring in plants i.e soy o Environmental Estrogens - environmental contaminants (e.g., BPA, dioxins) which cause reproductive problems in animals even at very low doses o Mutagen Mutagens - Agents that damage or alter genetic material. Can lead to birth defects or tumors o Teratogen Teratogens - specifically cause abnormalities during embryonic growth and development o Alcohol - Fetal Alcohol Syndrome o Neurotoxin Neurotoxins - metabolic poisons that specifically attack nerve cells; most are extremely toxic and fast acting. o Examples: Heavy Metals - kill nerve cells. Anesthetics and Chlorinated Hydrocarbons - disrupt nerve cell membranes. Organophosphates and Carbamates - inhibit signal transmission between nerve cells Factors that determine toxicity (length of exposure, persistence etc.) o Length of exposure o Dosage o Persistence of the chemical o Route of entry o Sensitivity of organism o Age Acute vs. chronic toxicity o Acute
Body Burden o Accumulation of synthetic chemicals that can be found in the following: Pesticides Cosmetics Industrial solvents Heavy metals POP’s (Persistent organic pollutant) o organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. o Because of their persistence, POPs bioaccumulate with potential significant impacts on human health and the environment. Manufactured by humans Don't break down easily Polluting and toxic Soluble in fat Able to be transported long distances Risk assessment o the process of determining potential adverse environmental health effects on purpose exposed to pollutants and potentially toxic materials. assessment process criteria might consider whether safe levels of exposure are established based on the exposure effects of the most sensitive or least sensitive organisms, if plants that comprise the ecosystem should be considered target organisms, or if only humans should be considered the target organism Assessment of risk from exposure to certain chemicals does not necessarily predicate the acceptance or remediation of exposure- related risk. The media, politicians, lobbyists, government officials, and other private interests often play a role in how specific risk assessment results are presented, which influences the public’s opinion on the need, urgency, and funding for remediation. o Various affected parties may resort to the use of misinformation and disinformation to further their particular agendas Laws established to regulate clean air and water o (EPA) Clean Air Act regulated air emissions from both stationary and mobile sources the law that defines EPA's responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer; the last major change in the law, the Clean Air Act Amendments of 1990, was enacted by Congress in
1990; legislation passed since then has made several minor changes o The Clean Water Act “Discharges of pollutants into the waters of the United States and regulating quality standards for surface waters” the law that gives the EPA the authority to set effluent limits on an industry-wide (technology-based) basis and on a water-quality basis that ensure protection of the receiving water Seeks to clean up nation's water; provides billions of dollars in federal grants for sewage treatment plants; encourages innovative technology, including alternative water treatment methods and aquifer recharge of wastewater o Established in 1948 o Federal Water Pollution Control Act Seeks to clean up nation's water; provides billions of dollars in federal grants for sewage treatment plants; encourages innovative technology, including alternative water treatment methods and aquifer recharge of wastewater Food Farming Practices Factors that contribute to the cost of food o Time of year and growing periods o Yield if the crop
o FDR’s Vision New deal programs AAA (Agricultural Adjustment Administration) o Cut government pay and pension o Reduced the amount of crops grown through “domestic allotment” o Paid farmers for land they were not allowed farm in an effort to get back top soil. CCC (Civilian Conservation Corps) 1933 - aim to provide short-term relief *allowed men to live in army style camps and worked mostly outdoors. *Sent back wages to families *Planted trees, constructed roads Green revolution o Started over 50 years ago with the production of tropical, semi-dwarf, wheat and rice strains which are now grown in developing countries around the world. 25 bushels per acres or 160 per acre Semi-dwarf wheat- requires less water Winged bean- entire plant was edible o Drawbacks- Lots of pesticides and fertilizers used Poor farmers could not afford it. GMO’s- o History 1973 with GE bacteria First commercial product- insulin- 1982 First food- cheese- 1988 (UK) 1990 (US) First food crop- tomatoes- 1994 Not documented cases of harm from GMOs o Genetic engineering Removes DNA from one organism and splices in into the chromosomes of another- you get GMOS Can produce crops that are pesticide resistant and wider tolerance levels. Incorporate vaccines Animals are modified to grow faster o Benefits lower production costs, fewer pest problems, reduced pesticide use, and better yields
associated with the increased use of conservation tillage GMOs in rural India reduced insecticide use by 70% and increased yields by 80% o Potential Concerns Might produce super weed resistance to pesticide Native biodiversity may decrease Novel toxins may be created Technology may only be available to the rich, making family farms go away. may cause cancer in laboratory animals, the spread of herbicide-resistant genes from GMOs to wild relatives, as well as anticorporate concerns o GMOs caused cancer in laboratory rats was retracted because of experimenter bias and questionable research methods. o Safety Human health implications Outcrossing- inevitable out-crossing of transgenic plants with naturally occurring ones Super weeds Is it safe? Make it so the seeds can be used once and then the plant no longer can grow o annual seeds not perennials o Access and Intellectual Property Domination of world food production by a few companies and developing countries o Ethics Playing God Tampering with nature by mixing genes among species o Labeling Not mandatory in some countries Mixing GM crops with Non-GM confounds labeling attempts o Society New advances may be skewed to the interest of rich countries Examples of GMOs o Golden Rice- Rice that contains beta-carotene (vitamin A), which is not found in regular rice o Bt Corn-
o Biological Pests – organisms such as insects or fungi that compete with humans to consume agricultural crops Different kinds of chemicals used to kill weeds, insects, ect. o Herbicides kill plants o Pesticides chemicals that kill biological pests. Organophosphates – most abundantly used synthetic pesticides o Roundup- most commonly used organophosphate herbicide Genetically modified plants have been created Crops that are resistant to the herbicide *Quickly degrade and do not persist Chlorinated Hydrocarbons - fast acting and highly toxic to sensitive organisms o Atrazine, Para dichlorobenzene (mothballs) and DDT are examples. o *Persist and concentrates in food chain Fumigants o small molecules (e.g., carbon tetrachloride) which are delivered as a gas to penetrate soil or other materials Used in fungus control on strawberries or to prevent insect/rodent damage to stored grains. o *Extremely dangerous for workers and restricted or banned in some areas Microbial Agents and Biological Controls- living organisms or toxins derived from them that are used in place of pesticides o Bacteria such as Bacillus thuringiensis kill beetles and caterpillars. o Parasitic wasps such as Trichogramma kill moth caterpillars and eggs. o Ladybugs are used to control aphids Problem- lady bugs fly so if used for pesticide they may fly away rather than stay in one place. o Biocides
kill a wide variety of living organisms kills anything that is living it generalizes everything o Fungicides kill fungi o Insecticides kill insects grasshoppers, caterpillars, grubs, ect. o May target bugs in larva stage or adult stage Pesticide and herbicide resistance o Pesticide Natural selection and the ability of organisms to evolve rapidly Human tendencies to overuse pesticides speeds up this process. o A few resistant pests survive the pesticide and survive to repopulate the area with more resistant pests. o Resistant pests require finding new pesticides o Herbicide Weeds becoming resistant to herbicides used to kill and get rid of them. Consequence of basic evolutionary processes o Once a weed population is exposed to a herbicide to which one or more plants are naturally resistant, the herbicide kills susceptible individuals, but allows resistant individuals to survive and reproduce. o With repeated herbicide use, resistant weeds that initially appear as isolated plants or patches in a field can quickly spread to dominate the population and the soil seed bank Non-target Species o Broadly sprayed pesticides might not reach intended target and instead kill beneficial organisms. Organic and Inorganic pesticides o Organic Generally extracted from plants and include such pesticides as nicotine or pyrethrums. Toxic to insects and may prevent wood decay o Inorganic compounds of toxic elements such as mercury or arsenic. Highly toxic, indestructible and persistent. Generally, act as nerve toxins.
The ability of a microorganism to withstand the effects of an antibiotic. It is a specific type of drug resistance. Evolves naturally via natural selection through random mutation, but it could also be engineered by applying an evolutionary stress on a population. CAFO’s (Confined Animal Feeding Operations) o Where animals are housed in giant enclosed and fed diets of soy and corn for rapid growth. Common in the US, Europe, and China Imprisoned and tortured in unhealthy, unsanitary and unconscionably cruel conditions The opposite of free ranged Being kept in small confined unsanitary areas where they are fed constantly and only let out when it is time to butcher or they die. o Health We can get sick from our food o Environment The manure goes into the water, along with the antibiotics that they had consumed in their lifetimes. Overuse of water- irrigation of plants, and water for the animals o Animal welfare Confined- Cannot act innate behaviors, unable naturally mate, aggressive behavior. Sanitation- Increase in disease (directly related to antibiotic resistance) o Sustainable options Third party certified Organic, food alliance, humanely raised USDA approved Local Fish sustainability o All major fisheries in the world have declined and many have become commercially unsustainable. is that it is one that is harvested at a sustainable rate, where the fish population does not decline over time because of fishing practices Organic farming o promotes smaller farm sizes over corporate farms and that organic food products are safer, tastier, healthier, higher-yielding, sustainable, more animal friendly, and feature a reduced danger from pesticides, hormones, and other chemicals.
o plants grown without most synthetic pesticides or fertilizers o adhere to certain tillage and cultivation practices and promote biodiversity o may use natural or non-synthetic pesticides, herbicides, and fertilizers; however, many of the natural pesticides, such as copper compounds and sulfur, are just as toxic and carcinogenic as the synthetic versions Integrated pest management techniques (IPM) o is a system of controlling pests integrating various techniques of pest control, without the need to use only pesticides. Techniques: habitat manipulation biological control use of resistant varieties modification of regular cultural practices.
