Population Bomb
This statistic, abbreviated TFR, is the average number of children a woman is expected to have in her lifetime — 2.1 is considered "replacement level" in developed nations.
What is total fertility rate?
Bees pollinating crops, wetlands filtering water, and forests sequestering carbon are all examples of these freebies nature provides. What are ecosystem services?
What are ecosystem services?
Norman Borlaug's high-yield wheat and rice varieties — plus heavy fertilizer, pesticide, and irrigation use — defined this mid-20th-century agricultural transformation.
What is the Green Revolution?
This measurement — short for "lethal dose, 50%" — is the amount of a chemical needed to kill half the test population.
What is LD50?
The San Andreas Fault is the classic example of this type of plate boundary, where two plates slide past each other horizontally.
What is a transform (boundary)?
A country with a wide-based, pyramid-shaped version of this diagram is growing fast; one shaped like a column is stable; one that's top-heavy is shrinking.
What is an age structure diagram (population pyramid)?
Remove this kind of species — like the sea otter or the gray wolf — and the entire ecosystem unravels, even though it may not be the most abundant organism.
What is a keystone species?
These tightly packed industrial livestock operations — abbreviated with four letters — are efficient but generate massive waste lagoons and antibiotic resistance.
What are CAFOs (concentrated animal feeding operations)?
DDT, PCBs, and dioxins all belong to this category of toxin — they resist breakdown, travel globally, and accumulate in fat tissue. The Stockholm Convention targets them.
What are POPs (persistent organic pollutants)?
Layer A is the topsoil, rich in organic matter; Layer C is weathered parent rock. The label for these stacked layers in soil science is this.
What are (soil) horizons?
Divide 70 by the annual growth rate as a percent, and you get this — the number of years for a population to double.
What is doubling time (the Rule of 70)?
This theory predicts that bigger landmasses closer to the mainland will host more species than small, remote ones — useful for designing nature reserves, too.
What is the theory of island biogeography?
This pest-control approach combines biological controls, crop rotation, and targeted pesticide use only when needed — abbreviated IPM.
What is integrated pest management?
A single fish has a bit of mercury in its tissue. The tuna that eats 100 fish has 100x that. The osprey that eats the tuna has more still. Name this phenomenon.
What is biomagnification?
During this Pacific climate pattern, trade winds weaken and warm water sloshes east toward South America — causing droughts in Australia and floods in Peru.
What is El Niño?
This four-stage model describes how birth and death rates shift as a country industrializes — from "pre-industrial" through "industrial" to "post-industrial."
What is the demographic transition (model)?
A bare volcanic rock slowly colonized by lichens, then mosses, then shrubs, then trees demonstrates this type of ecological succession — the kind that starts from scratch.
What is primary succession?
The most water-efficient irrigation method, this technique delivers water slowly through tubes directly to plant roots — but it's expensive to install.
What is drip irrigation?
BPA, atrazine, and phthalates are infamous examples of these chemicals, which mimic or block hormones and can cause developmental problems at very low doses.
What are endocrine disruptors?
All the land area that drains into a common body of water — like the Mississippi River system — gets this name. Yours might be smaller than you think.
What is a watershed (drainage basin)?
Symbolized by the letter K, this is the maximum population size an environment can sustain indefinitely given available resources.
What is carrying capacity?
Cowbirds laying eggs in warbler nests, and increased predation along forest borders, are both consequences of this phenomenon — created when habitat is fragmented.
What is the edge effect?
Planting a single crop variety across vast acreage maximizes efficiency but leaves fields vulnerable to disease and pest outbreaks — see the Irish Potato Famine.
What is monoculture?
Plotted on these graphs, the x-axis shows exposure and the y-axis shows effect — and the steepness reveals how dangerous a chemical is at low doses.
What is a dose-response curve?
Weather happens in the troposphere, the ozone layer protects us from the stratosphere, but THIS is the outermost layer where the International Space Station orbits.
What is the thermosphere?