Scientists Say: Ecosystem

algae: Single-celled organisms, once considered plants (they aren’t). As aquatic organisms, they grow in water. Like green plants, they depend on sunlight to make their food.

atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H₂O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

decompose: Also known as decay or rot, it’s to break down compounds in once-living things so that their building blocks can be returned to the environment. Organisms that break down once-living things in this way are called decomposers.

dinosaur: A term that means terrible lizard. These reptiles emerged around 243 million years ago. All descended from egg-laying reptiles known as archosaurs. Their descendants eventually split into two lines. For many decades, they have been distinguished by their hips. The lizard-hipped line are believed to have led to the saurischians, such as two-footed theropods like T. rex and the lumbering four-footed Apatosaurus. A second line of so-called bird-hipped, or ornithischian dinosaurs, appears to have led to a widely differing group of animals that included the stegosaurs and duckbilled dinosaurs. Many large dinosaurs died out around 66 million years ago. But some saurischians lived on. They are now the birds we see today (and who have now evolved that so-called “bird-hipped” pelvis).

ecosystem: A group of interacting living organisms — including microorganisms, plants and animals — and their physical environment within a particular climate. Examples include tropical reefs, rainforests, alpine meadows and polar tundra. The term can also be applied to elements that make up some artificial environment, such as a company, classroom or the internet.

element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.

function: The specific role some structure or device plays. (in math) A relationship between two or more variables in which one variable (the dependent one) is exactly determined by the value of the other variables.

habitat: The area or natural environment in which an animal or plant normally lives, such as a desert, coral reef or freshwater lake. A habitat can be home to thousands of different species.

insect: A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.

link: A connection between two people or things.

molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O₂), but water is made of two hydrogen atoms and one oxygen atom (H₂O).

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)

nitrogen: A colorless, odorless and nonreactive gaseous element that forms about 78 percent of Earth’s atmosphere. Its scientific symbol is N. Nitrogen is released in the form of nitrogen oxides as fossil fuels burn. It comes in two stable forms. Both have 14 protons in the nucleus. But one has 14 neutrons in that nucleus; the other has 15. For that difference, they are known, respectively, as nitrogen-14 and nitrogen-15 (or ¹⁴N and ¹⁵N).

nutrient: A vitamin, mineral, fat, carbohydrate or protein that a plant, animal or other organism requires as part of its food in order to survive.

organism: Any living thing, from elephants and plants to bacteria and other types of single-celled life.

photosynthesis: (verb: photosynthesize) The process by which green plants and some other organisms use sunlight to produce foods from carbon dioxide and water.

protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Antibodies, hemoglobin and enzymes are all examples of proteins. Medicines frequently work by latching onto proteins.

rainforest: Dense forest rich in biodiversity found in tropical areas with consistent heavy rainfall.

solar: Having to do with the sun or the radiation it emits. It comes from sol, Latin for sun.

solar energy: The energy in sunlight that can be captured as heat or converted into heat or electrical energy. Some people refer to wind power as a form of solar energy. The reason: Winds are driven by the variations in temperatures and the density of the air, both of which are affected by the solar heating of the air, ground and surface waters.

sun: The star at the center of Earth’s solar system. It is about 27,000 light-years from the center of the Milky Way galaxy. Also a term for any sunlike star.