SLCC ENSC 1000 Exam 2

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Thomas Malthus

wroteAn Essay on the Principle of Populationin which he showed that human populations increase exponentially.

Karl Marx

view, that population growth resulted from poverty, resource depletion, pollution, and other social ills

Malthus vs. Marx

Malthus - poverty causes overpopulation
Marx - overpopulation causes poverty

Demography

encompasses vital statistics about people such as births, deaths, distribution, and population size

Organisms considered in imminent danger of extinction are called?

endangered

The number of children born to an average woman in a population during her life?

Total Fertility Rate

These are chemicals used to kill biological pests?

pesticides

Crude Birth Rate

Number of births in a year per thousand. (Not adjusted for population characteristics such as number of women of childbearing age.)

Total Fertility Rate

number of children born to an average woman in a population during her life

Zero Population Growth

Occurs when births plus immigration in a population equal deaths 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.

Crude Death Rate

The number of deaths per year per 1,000 people.

Natural Increase

crude birth rate minus crude death rate

Total growth rate

includes immigration, emigration, births and deaths.

the primary cause of most population growth in last 300 years.

Declining mortality

Family Planning

allows couples to determine the number and spacing of their children

Health

a state of complete physical, mental, and social well-being (not just the absence of disease or infirmity)

Disease

an abnormal change in the body's condition that impairs physical or psychological function

Disability-adjusted life years (DALYs)

combine premature deaths and loss of healthy life resulting from illness or disability

Pathogens

disease-causing organisms. They include:-Viruses-Bacteria-Protozoans-Parasitic worms including flukes

Antibiotics

chemicals that kill or inhibit the growth of bacteria

Toxicology

the study of poisons and their effects on living systems.

Dangerous chemicals are divided into two broad categories:

Toxic and Other Hazards

Toxic chemicals

known poisons that damage or kill cells/tissues

Other Hazards (chemicals)

dangerous but not toxic

Ecotoxicology

deals with the interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphere.

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

Antibodies

proteins produced by our bodies that recognize and bind to foreign cells or chemicals

Immune System Depressants

pollutants that depress the immune system instead of activating it.

Endocrine Disrupters

disrupt normal hormone functions

Neurotoxins

metabolic poisons that specifically attack nerve cells; most are extremely toxic and fast acting.

Different types of Neurotoxins

Heavy Metals, Anesthetics and Chlorinated Hydrocarbons, and Organophosphates and Carbamates

Heavy Metals

kill nerve cells.

Anesthetics and Chlorinated Hydrocarbons

disrupt nerve cell membranes

Organophosphates and Carbamates

inhibit signal transmission between nerve cells.

Mutagens

Agents that damage or alter genetic material. Can lead to birth defects or tumors.

Teratogens

specifically cause abnormalities during embryonic growth and development

Carcinogens

substances that cause cancer

Solubility

one of most important characteristics in determining the movement of a toxin through the environment or through the body to its site of action

Chemicals are divided into two major groups

those that dissolve more readily in water
those that dissolve more readily in oil

Bioaccumulation

selective absorption and storage of toxins

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. Example: DDT

Antagonistic Reaction

one material interferes with the effects, or stimulates the breakdown, of other chemicals

Additive Reaction

effects of two chemical occurring together are added to one another

Synergistic Reaction

one substance exacerbates the effect of the other

Acute Effects

caused by a single exposure and results in an immediate health problem

Chronic Effects

Long-lasting, perhaps permanent. Can be result of single large dose or repeated smaller doses.

Risk Assessment

scientific process of estimating the threat that particular hazards pose to human health-Risk Identification-Dose Response Assessment-Exposure Appraisal-Risk Characterization

Food security

the ability to obtain sufficient, healthy food on a day-to-day basis, is a combined problem of economic, environmental, and social conditions.

Malnourishment

nutritional imbalance caused by a lack of specific dietary components or an inability to absorb or utilize essential nutrients

Kwashiorkor

protein deficiency disease "displaced child" occurs mainly in children whose diet lacks high-quality protein

Marasmus

protein deficiency disease "to waste away" - caused by a diet low in protein and calories

Genetic engineering

removes DNA from one organism and splices it into the chromosomes of another.

transgenic organisms

Genetically modified organisms are also called transgenic organisms

6 components of soil

-sand and gravel
-silts and clays
-dead organic material
-soil fauna and flora
-water
-air

soil horizons

horizontal layers that soils are stratified into including the O horizon and A horizon

O horizon (organic layer)

Leaf litter, most soil organisms and partially decomposed organisms

A horizon (surface soil)

Mineral particles mixed with organic material. Food comes from the A horizon.

E horizon (washed out)

Depleted of soluble nutrients

B Horizon (Subsoil)

Often dense texture due to clays

C Horizon

Weathered rock fragments with little organic material

Parent Material

the mineral material on which the soil is built, can be bedrock

Arable land

land suitable for growing crops

Sheet Erosion

thin layer of surface removed

Rill Erosion

small rivulets of running water gather together and cut small channels

Gully Erosion

rills enlarge to form bigger channels too large to be removed by normal tillage

gully

A large channel in soil formed by erosion.

Stream bank Erosion

washing away of soil from banks of streams and rivers

Desertification

conversion of productive land to desert

Intensive farming practices responsible for erosion

Row crops leave soil exposed•Weed free-fields•Removal of windbreaks•No crop-rotation or resting periods for fields•Continued monoculture cropping can increase soil loss tenfold

Waterlogging

water saturation of soil that fills all air spaces and causes plant roots to die from lack of oxygen

Salinization

mineral salts accumulate in soils; lethal to plants

Biological Pests

organisms such as insects or fungi that compete with humans to consume agricultural crops.

Organophosphates

most abundantly used synthetic pesticides.•Roundup-most commonly used organophosphate herbicide•Genetically modified Roundup resistant crops have been produced•Other organophosphates are used as insecticides and inhibit cholinesterase, an enzyme necessary for nervous system function.•Quickly degrade and do not persist.•Dangerous to workers and can be lethal

Chlorinated Hydrocarbons

pesticide type that is fast acting and highly toxic to sensitive organisms

Fumigants-small molecule

pesticides 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.•Extremely dangerous to workers and restricted or banned in some areas.

Inorganic Pesticides

compounds of toxic elements such as mercury or arsenic

Natural Organic Pesticides

generally extracted from plants and include such pesticides as nicotine or pyrethrums

Microbial Agents and Biological Controls

living organisms or toxins derived from them that are used in place of pesticides

Widespread use of pesticides brings a number of environmental and health risks

Non-Target Species, Pest Resurgence,

Persistent Organic Pollutants

chlorinated hydrocarbons like DDT that are stable, soluble in fats and toxic

Integrated Pest Management

flexible, ecologically bases strategy that is applied at specific times against specific pests

Contour Plowing

plowing across slope to slow flow of water

Strip Farming

planting different crops in alternating strips along land contours

Terracing

shaping land to create level shelves of earth to hold water and soil

Genetic Diversity

measures variety of different versions of same genes within a species

Species Diversity

measures number of different kinds of organisms within a community

Ecological Diversity

measures richness and complexity of a community

Species Richness

total number of species in a community

Species Evenness

relative abundance of individuals within each species

Reproductive isolation

organisms that breed in nature and produce fertile offspring

Phylogenetic species concept

emphasizes the branches on a taxonomic tree (cladisticrelationships)

Evolutionary species concept

defines species in terms of evolution and historic terms

Genome

total DNA sequence that characterizes a species

Extinction

is the elimination of a species on earth.

Natural extinction

In undisturbed ecosystems, the background rate appears to be one species per decade

Permian period

5% of marine species and nearly half of all plant and animal families died out 250 million years ago.

End of Cretaceous

Dinosaurs and 50% of existing genera disappeared.

Habitat fragmentation

the reduction of habitat into small, isolated patches.

E.O. Wilson

summarizes the human threat to wildlife with HIPPO (habitat destruction, invasive species, pollution, population, and overharvesting)