gene

Stretches of DNA, the hereditary material of cells, that each direct the production of a particular protein and influence an individual’s traits. (Chapter 11)

gene frequencies

The assortment and abundance of particular variants of genes relative to each other within a population. (Chapter 11)

genetically modified organisms (GMOs)

Organisms that have had their genetic information modified to give them desirable characteristics such as pest or drought resistance. (Chapter 16)

genetic diversity

The heritable variation among individuals of a single population or within a species as a whole. (Chapter 11, 12)

genetic drift

The change in gene frequencies of a population over time due to random mating that results in the loss of some gene variants. (Chapter 11)

geothermal energy

The heat stored underground, contained in either rocks or fluids. (Chapter 23)

geothermal heat pump

A system that transfers the steady 55°F (12.5°C) underground temperature to a building to help heat or cool it. (Chapter 23)

geothermal power plants

Power plants that use the heat of hydrothermal reservoirs to produce steam and turn turbines to generate electricity. (Chapter 23)

global warming

The observed and ongoing rise in the Earth’s average temperature that is contributing to climate change. (Chapter 21)

green building

Construction and operational designs that promote resource and energy efficiency, and provide a better environment for occupants. (Chapter 25)

green business

Doing business in a way that is good for people and the environment. (Chapter 6)

Green Revolution

Plant-breeding program in the mid-1900s that dramatically increased crop yields and led the way for mechanized, large-scale agriculture. (Chapter 16)

Green Revolution 2.0

Programs that focus on the production of genetically modified organisms (GMOs) to increase crop productivity. (Chapter 16)

green tax

A tax (a fee paid to the government) assessed on environmentally undesirable activities (e.g., a tax per unit of pollution emitted). (Chapter 20, 24)

greenhouse effect

The warming of the planet that results when heat is trapped by Earth’s atmosphere. (Chapter 21)

greenhouse gases

Molecules in the atmosphere that absorb heat and reradiate it back to Earth. (Chapter 21)

greenwashing

Claiming environmental benefits about a product when the benefits are actually minor or nonexistent. (Chapter 17)

gross primary productivity

A measure of the total amount of energy captured via photosynthesis and transferred to organic molecules in an ecosystem. (Chapter 10)

ground-level ozone

A secondary pollutant that forms when some of the pollutants released during fossil fuel combustion react with atmospheric oxygen in the presence of sunlight. (Chapter 20)

groundwater

Water found underground in aquifers. (Chapter 14)

growth factors

Resources individuals need to survive and reproduce that allow a population to grow in number. (Chapter 9)