Antarctica: A continent mostly covered in ice, which sits in the southernmost part of the world.

breed: (verb) To produce offspring through reproduction.

climate change: Long-term, significant change in the climate of Earth. It can happen naturally or in response to human activities, including the burning of fossil fuels and clearing of forests.

conservation: (v. conserve) The act of preserving or protecting something. The focus of this work can range from art objects to endangered species and other aspects of the natural environment.

continent: (in geology) The huge land masses that sit upon tectonic plates. In modern times, there are six established geologic continents: North America, South America, Eurasia, Africa, Australia and Antarctica. In 2017, scientists also made the case for yet another: Zealandia.

crustaceans: Hard-shelled water-dwelling animals including lobsters, crabs and shrimp.

endangered: An adjective used to describe species at risk of going extinct.

extinction: (adj. extinct) The permanent loss of a species, family or larger group of organisms.

global warming: The gradual increase in the overall temperature of Earth’s atmosphere due to the greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity.

krill: Tiny shrimplike crustaceans that live in the ocean and are the main food source of some whales.

network: A group of interconnected people or things. (v.) The act of connecting with other people who work in a given area or do similar thing (such as artists, business leaders or medical-support groups), often by going to gatherings where such people would be expected, and then chatting them up. (n. networking)

penguin: A flightless black-and-white bird native to the far Southern Hemisphere, especially Antarctica and its nearby islands.

population: (in biology) A group of individuals (belonging to the same species) that lives in a given area.

predation: A term used in biology and ecology to describe a biological interaction where one organism (the predator) hunts and kills another (the prey) for food.

primary: An adjective meaning major, first or most important.

pup: A term given to the young of many animals, from dogs and mice to seals.

risk: The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)

satellite: A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space.

sea: An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.

species: A group of similar organisms capable of producing offspring that can survive and reproduce.

threatened: (in conservation biology) A designation given to species that are at high risk of going extinct. These species are not as imperiled however, as those considered “endangered.”