Bio 220 Exam 2 Study Guide
Bio 220 Exam 2 Study Guide
Directions: This study guide was created from the exam bank of questions. It is designed to give
... [Show More] 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
• Be able to read an age structure diagram
o Structure types and explanations
Pyramid- population w/ many young and high death rate (short average lifetime)
• This is what you want to have
Inverted pyramid- top heavy
Column- birth rate and death rate are low and a high % of pop is elderly
Column w/ a bulge- event in the past caused a high birth or death rate for some age group
• Demographic Transition
o a model of economic and cultural change to explain the declining death and birth rates in industrializing nations
Stable preindustrial state of high birth and death rates change to a stable post-industrial state of low birth and death rates
As mortality decreases, there is less need for large families
• Parents invest in quality of life
• Life Span
o is the oldest age to which members of the species survive.
• Life Expectancy
o average age a newborn can expect to attain in any given society
Declining mortality is making the life expectancy go up as well as the use of different medicines and other technology advances.
Toxins in the Environment
• Infectious diseases and Pathogens
o Pathogens are disease- causing organisms. They include:
• 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
When the toxic effect of single or multiple exposures to a chemical result in sudden adverse effects, usually within 14 days of administration.
Establishing the health risks from acute toxicity is usually simpler and easier compared to chronic toxicity
o Chronic
occurs over a longer period and the adverse effects are less obvious.
Establishing the health risks of chronic toxicity can be challenging because factors such as aging, exposure to other toxins, and infectious diseases make it difficult to accurately attribute the health risks associated with long-term exposure to a specific toxin
• Effects of concentration toxicity
o The toxicity of chemicals is dependent on the chemical makeup, the concentration, the bioavailability of chemicals in its matrix, and the receptor organism under exposure.
o Some organisms are more susceptible to lower levels than others.
• Biomagnification and bioaccumulation
o Bioaccumulation -
selective absorption and storage of toxins (accumulate over time).
• Dilute toxins in the environment can build to dangerous levels inside tissues.
o Biomagnification -
Toxic burden of a large number of organisms at a lower trophic level is accumulated and concentrated by a predator at a higher trophic level.
• Fat soluble vs. water soluble chemicals
o Solubility -
one of most important characteristics in determining the movement of a toxin
o Fat Soluble
Need a carrier to move through the environment
Once inside the body they penetrate tissues easily and cross cell membranes.
They are stored in body fat and persist for many years.
o Water Soluble
move rapidly through the environment
have ready access to cells via tissue fluid
• 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
• Malnutrition vs. undernourished
o Types of deficiency vitamin A, iron, iodine etc.
o Malnutrition
Nutritional imbalance caused by a
lack of specific dietary components or an inability to
absorb or utilize essential nutrients
• Effects
o Marasmus (progressive emaciation caused by lack of protein and calories)
o Kwashiorkor (leads to neural development failure in infants and eventual learning disabilities)
o Undernourished
having insufficient food or other substances for good health and condition
• effects
o person has little or no ability to move or work
• Famines and Protein Deficiency
o Nutrient deficiency
Anemia- low hemoglobin levels in the blood
o Protein
Kwashiorkor- “displaced child” occurs mainly in children whose diet lacks high-quality protein.
• (discolored skin and bloated belly)
Marasmus- “to waste away” caused by a diet low in protein and calories.
• Significant sources of food-
o Wheat, rice, corn (foundation grains)
Others
• Cassava, sweet potatoes as well
• History of Farming
1929- stock market crashes
¼ of workforce was in poverty
Crop price fell 40-60% - famers had to sell their land
1930-36- Dust Bowl +central US- Kansas, Colorado, New Mexico,
Oklahoma, Texas
Food was in short supply
Forced people to move west to California
Farmers adjust and it leads to the Green Revolution
• New Deal and Civilian Conservation Corps
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-
Corn that contains chemicals normally found in bacterium that is toxic to insects but not humans
• Types of soil and erosion
o Sheet Erosion- Thin layer of surface removed
o Rill Erosion- Small rivulets of running water gather together and cut small channels
o Gully Erosion- Rills enlarge to form bigger channels too large to be
removed by normal tillage
o Stream Bank Erosion- Washing away of soils from banks of streams and Rivers
• Soil conservation
o Ground Cover protects soil
Have crop in the ground all year round
o Crop rotation
Different crops plants are grown sequentially allows farmers to address weed control
It also adds nutrients back into the soil
Managing Topography
o Contour Plowing- Plowing across slope to slow flow of water
o Strip Farming- Planting different crops in alternating strips along
land contours
o Terracing- shaping land to create level shelves of earth to hold water
and soil
o Plant Perennial species
Perennials- plants that grow each year without having
to replant- they are reoccurring for 2 or more
years.
• Desertification
- Conservation of productive land to desert
Intensive farming practices
*Row crops leave soil exposed
*Weed free fields
*Removal of wind breaks
*No crop rotation or resting time for fields
*Continued monoculture cropping can increase soil loss
tenfold.
• Agricultural advances
o Genetically modified organisms
o Creation of pesticides
• Kinds of pests
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.
• Super weeds
o Weeds, insects, or other pests that have over time become resistant to pesticides.
• WHO (World Health Organization)
o estimates 25 million people suffer pesticide poisoning, and 20,000 die each year.
o At least 2/3 of these result from occupational hazards in developing countries.
o Chronic, or long-term health effects are difficult toconclusively document, but effects may include:
Cancer, birth defects, neurological problems, Immune system problems
• Types of irrigation and crop management (strip farming, drip irrigation, crop rotation etc.)
o Gravity flow irrigation- Primarily used in the 70’s and 80’s
Requires leveling the field so water will flow in the same direction
Labor intensive, and requires monitoring to check for adequate flow
o Flood irrigation
Requires flat area with barrier built up around
Water is pumped into area and allowed to soak up
Dependent on water delivery schedule
o Drip irrigation
High efficiency system for arid regions
Water is supplied through tiny holes and delivered in small amounts
o Crop rotation
Different crops plants are grown sequentially allows farmers to address weed control
It also adds nutrients back into the soil
• Irrigation problems
o Waterlogging- roots are saturated with water and die due lack of oxygen
o Salinization- Mineral salts accumulate in soils; lethal to plants
• Antibiotic resistance
o Non-theraputic
Administrated in animal feed and water to compensate for poot living conditions and promote growth
Eneter through feed and through fertilized manure
Are the same or similar to human medicine.
• Some is not consumed by the animal and it goes into the waiste system.
• 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. [Show Less]