Unit 4: Human Population, Food, and Agriculture

Total Fertility Rate

Average number of children born to a woman during her lifetime

Replacement-Level Fertility

Average number of children a couple must have to replace themselves in the population

Infant Mortality Rate

Number of babies out of every 1,000 that die before their first birthday

• can be given as a percentage (out of 100) so watch out for labels

Crude Birth Rate

Number of births per 1000 people in a populationC

Crude Death Rate

Number of deaths per 1000 people in a population

Immigration

Movement of people into a population

Emigration

Movement of people out of a population

Population growth rate formula

(Births + Immigration) - (Deaths + Emigration) = raw growth rate

• divide by ten to get a percentage

Rule of 70

Doubling time = 70/% growth rate

• make sure it’s a percentage first

Demographic Transition Model: STAGE ONE

• high birth and death rates

• low life expectancy

• population rate is close to zero

• looks like a pyramid

Demographic Transition Model: STAGE TWO

• high birth rates, decreasing death rates

• population begins to increase

• result of improved healthcare and infrastructure

Demographic Transition Model: STAGE THREE

• birth rates decrease but still exceed death rates

  • population increases

Demographic Transition Model: STAGE FOUR

• birth rates are about equal to death rates

• small, stable population

• can lead to negative population growth

Soil layers

O horizon: decomposing organic matter + leaf litter

A horizon: weathered parent material + humus

B horizon; subsoil, higher concentration of mineral particles

C horizon: weathered parent material on top of bedrock

D/R: bedrock

Undernutrition

Not enough calories

Overnutrition

Overconsumption of caloriesK

Kwashiorkor

condition occurring mainly in children who have low protein diets

Marasmus

condition ccurring mainly in children who have low calorie and low protein dietsresulting in severe wasting and stunted growth. A

Anemia

low ironlevels in the blood causing fatigue and weakness.

Goiter

condition from having too little iodine

• swollen neck results from an enlarged thyroid gland

Types of agriculture

Plantation agriculture

Organic agriculture

Subsistence agriculture

Slash and burn

Swidden (sustainable slash and burn)

Green Revolution

• high yielding monoculture crops

• large inputs of inorganic fertilizer

No-till agriculture

farming without plowing

• Advantages: less erosion and exposure

• Disadvantages: pest species can accumulate in unplowed stubble

Terracing

convert slope to flat terraces that follow the slope’s contour

Contour plowing

plow across slope of hill instead of up and down

• slows runoff, preventing erosion

Windbreaks

shrubs and trees planted around fields to reduce topsoil erosion

Strip cropping

Alternating strips of erodible crops (eg. corn) and dense crops (eg. alfalfa)

Cover cropping

plant fast growing species when soil is exposed between different crops

Desertification

fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture

Soil salinization

trace amounts of salt build up and reaches a concentration that prevents crops from growing

Broad spectrum pesticides

Kill all

Chlorinated hydrocarbons

• very persistent pesticide

• broad spectrum

Organophosphates

• very toxic immediately, less so long term

• broad spectrum

Carbamates

• insecticides

• estrogen mimics - can potentially harm all organisms

Narrow spectrum pesticides

only kills specific species and has less impact on non-target organisms.

Pesticide treadmill

A cycle where farmers must continually increase pesticide use due to resistance development in target pests, leading to higher costs and environmental impact

Integrated Pest Management (IPM)

A sustainable farming approach that combines biological, cultural, and chemical practices to manage pest populations while minimizing environmental impact

• Biggest Little Farm

Factory farms/feedlots

large-scale animal confinement operations

• substantial use of antibiotics

• incredible water consumption

• air and water pollution

• disease

Long line fishing

• up to 80 miles of fishing line is strung out with thousands of hooks attached

• can catch other species (dolphins, whales, etc.)

Purse seine fishing

Net surrounds a large school of fish

• includes all fish in area

• often catches dolphins

Drift-net fishing

net hangs in water from surface to 50ft deep and extends up to 40 miles

• catch many non-target species (dolphins and sea turtles)

Trawler fishing

• baskets are dragged across ocean floor

• devastate entire ecosystem