**adaptation**: (in biology) The development of new programs, processes, policies and structures to make communities and their inhabitants better able to head off — or at least withstand — the dangerous impacts of a warming climate. Those impacts may include drought, flooding, wildfires, extreme heat and extreme storms.
**ancestor**: A predecessor. It could be a family forebear, such as a parent, grandparent or great-great-great grandparent. Or it could be a species, genus, family or other order of organisms from which some later one evolved. For instance, ancient dinosaurs are the ancestors of today's birds. (antonym: descendant)
**array**: A broad and organized group of objects. Sometimes they are instruments placed in a systematic fashion to collect information in a coordinated way. Other times, an array can refer to things that are laid out or displayed in a way that can make a broad range of related things, such as colors, visible at once. The term can even apply to a range of options or choices.
**asteroid**: A rocky object in orbit around the sun. Most asteroids orbit in a region that falls between the orbits of Mars and Jupiter. Astronomers refer to this region as the asteroid belt.
**avian**: Of or relating to birds.
**bat**: A type of winged mammal comprising more than 1,400 separate species — or one in every four known species of mammal. (in sports) The usually wooden piece of athletic equipment that a player uses to forcefully swat at a ball. (v.) Or the act of swinging a machine-tooled stick or flat bat with hopes of hitting a ball.
**birds**: Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t.
**_Brachiosaurus_**: With very long necks and short tails, these enormous dinosaurs have been likened to huge giraffes. Unlike most dinos, their front legs were longer than their hind limbs. Their body shape would have allowed these mammoth creatures to reach their heads as much as 12 meters (39 feet) above the ground — high enough to browse the leaves of tall trees. Big adults could have weighed nearly 80 metric tons and reached a length of nearly 25 meters (82 feet).
**carnivore**: An animal that either exclusively or primarily eats other animals.
**cold-blooded**: Adjective for an animal whose body temperature varies with that of its environment.
**common ancestor**: Also known as shared ancestor. It's an ancestor that two or more descendants have in common. Two siblings share a parent as a common ancestor. This also applies on the level of species and groups of organisms. Two or more species can share a common ancestor at the genus level. Two or more genera can share a common ancestor at the family level, and so on. Tigers and lions have a common ancestor, as do humans and Neandertals.
**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.
**Cretaceous**: A geologic time period that included the end of the Age of Dinosaurs. It ran from roughly 145.5 million years ago until 65.5 million years ago.
**defense**: (in biology) A natural protective action taken or chemical response that occurs when a species confronts predators or agents that might harm it. (adj. defensive)
**descendant**: A blood relative of a person who lived during a previous time.
**digest**: (noun: digestion) To break down food into simple compounds that the body can absorb and use for growth. Some sewage-treatment plants harness microbes to digest — or degrade — wastes so that the breakdown products can be recycled for use elsewhere in the environment.
**_Dimetrodon_**: A reptile that lived around 280 million years ago, well before dinosaurs. It’s body was shaped somewhat like a small crocodile, but with a large scale flaring up from its back. This animal was a meat-eater and probably dined primarily on aquatic animals, from sharks to a meter-long amphibian known as Dipocaulus.
**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).
**diversity**: A broad spectrum of similar items, ideas or people. In a social context, it may refer to a diversity of experiences and cultural backgrounds. (in biology) A range of different life forms.
**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 an artificial environment, such as a company, classroom or the internet.
**evolution**: (v. to evolve) A process by which species undergo changes over time, usually through genetic variation and natural selection. These changes usually result in a new type of organism better suited for its environment than the earlier type. The newer type is not necessarily more “advanced,” just better adapted to the particular conditions in which it developed. Or the term can refer to changes that occur as some natural progression within the non-living world (such as computer chips evolving to smaller devices which operate at an ever faster speed).
**evolutionary**: An adjective that refers to changes that occur within a species over time as it adapts to its environment. Such evolutionary changes usually reflect genetic variation and natural selection, which leave a new type of organism better suited for its environment than its ancestors. The newer type is not necessarily more “advanced,” just better adapted to the conditions in which it developed.
**femur**: In humans, the large bone in the upper leg. It is commonly known as the thighbone. In tetrapods (creatures with four limbs), it’s the large bone in the upper hind limbs.
**fossil**: Any preserved remains or traces of ancient life. There are many different types of fossils: The bones and other body parts of dinosaurs are called “body fossils.” Things like footprints are called “trace fossils.” Even specimens of dinosaur poop are fossils. The process of forming fossils is called fossilization.
**fraud**: To cheat; or the resulting effects of something done by cheating. Or to make a mistake and intentionally cover up the error.
**fused**: An adjective for something that has features that have been joined or merged together into a single thing. (in electrical devices) An adjective for devices that contain parts known as fuses.
**geologic**: An adjective that refers to things that are related to Earth’s physical structure and substance, its history and the processes that act on it. People who work in this field are known as geologists.
**gut**: An informal term for the gastrointestinal tract, especially the intestines.
**hadrosaur**: A duck-billed, plant-eating dinosaur that lived during the late Cretaceous Era.
**ichthyosaur**: A type of giant marine reptile that looks similar to a porpoise. Its name means “fish lizard.” It was not related to fish or marine mammals, however. And although not a dinosaur, it lived at the same time as dinosaurs.
**insight**: The ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.
**Jurassic**: A period lasting from about 200 million to 145.5 million years ago, it’s the middle period of the Mesozoic Era. This was a time when dinosaurs were the dominant form of life on land.
**kin**: Family or relatives (sometimes even distant ones).
**lizard**: A type of reptile that typically walks on four legs, has a scaly body and a long tapering tail. Unlike most reptiles, lizards also typically have movable eyelids. Examples of lizards include the tuatara, chameleons, Komodo dragon, and Gila monster.
**mammal**: An animal distinguished by possessing hair or fur, the secretion of milk by females for the feeding of their young, and (typically) the bearing of live young. They also are warm-blooded (or endothermic).
**marine**: Having to do with the ocean world or environment.
**Mesozoic**: An era in geologic history that contained three related periods which became renowned for their large reptiles: the Triassic (which spanned from 251 to 199.6 million years ago), the Jurassic (which spanned from 199.6 to 145.5 million years ago), and the Cretaceous (which spanned from 145.5 to 65.5 million years ago).
**mosasaur**: A type of extinct marine reptile that lived at the same time as dinosaurs.
**niche**: A small or narrow pocket that sets something apart, or perhaps offers a region of protection. (In ecology) The term for the role that an organism plays in its community.
**non-avian**: An adjective that means not having to do with birds. It’s frequently used to refer to those dinosaurs that aren’t birds.
**Ornithischian**: One of the two major groups of dinosaurs, the other being Saurischian. Ornithischian hip bones were arranged like those in today’s surviving dinosaurs — birds
**paleontologist**: A scientist who specializes in studying fossils, the remains of ancient organisms.
**pelvis**: Bones that make up the hips, connecting the lower spine to leg bones. There is a gap in the middle of the pelvis that is larger in females than in males and can be used to tell the sexes apart.
**physical**: (adj.) A term for things that exist in the real world, as opposed to in memories or the imagination. It can also refer to properties of materials that are due to their size and non-chemical interactions (such as when one block slams with force into another). (in biology and medicine) The term can refer to the body, as in a physical exam or physical activity.
**plesiosaur**: A type of extinct marine reptile that lived at the same time as dinosaurs and is noted for having a very long neck.
**predator**: (adjective: predatory) A creature that preys on other animals for most or all of its food.
**prehistoric**: An adjective for something that happened tens of thousands to millions of years ago, periods before people began deliberately recording events.
**pterosaur**: Any of various extinct flying reptiles of the order Pterosauria. These animals lived 245 million years ago to 65 million years ago. Although not true dinosaurs, they lived during the reign of dinosaurs. Among members of this order were the pterodactyls of the Jurassic and Cretaceous periods, which were characterized by wings consisting of a flap of skin supported by the very long fourth digit on each forelimb.
**pubic bone or pubis**: The term for either of the two bones that make up the sides of the pelvis.
**pygostyle**: The bony plate that forms the back end of the backbone in most birds. It is made from a series of vertebrae that have merged into one solid bony structure.
**reptile**: Vertebrate animals belonging to a group known as Reptilia. Most reptiles have skin that is covered with scales or horny plates. Snakes, turtles, lizards and alligators are all reptiles. Once considered their own separate group, birds now belong to this order. With the exception of modern birds, most reptiles are cold-blooded (or ectothermic).
**Reptilia**: A taxonomic of animals that includes reptiles (such as snakes, turtles, alligators and ancient dinosaurs). Most researchers now agree that birds also belong to this order.
**Saurischians**: One of the two major groups of dinosaurs (the other being the ornithischians). Saurischian hip bones are described as “lizard”-like. That's because their bones point forward the way they do in modern lizards. Ironically, modern birds are saurischians.
**sauropod**: A very large, four-legged, plant-eating dinosaur with a long neck and tail, small head and massive limbs.
**species**: A group of similar organisms capable of producing offspring that can survive and reproduce.
**stegosaurs**: Plant-eating dinosaurs that had large, protective plates or spikes on their backs and tails. The best known: stegosaurus, a 6 meter (20-foot) long creature from the late Jurassic that lumbered around the Earth some 150 million years ago.
**system**: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body's circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation's railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.
**theropod**: A usually meat-eating dinosaur that belonged to a group whose members are typically bipedal (walk on two legs). They range from small and delicately built to very large.
**titanosaur**: A group of dinosaurs with long necks and whiplike tails that ate plants. Named for Titanosaurus, they were noted for their large size.
**trait**: A characteristic feature of something. (in genetics) A quality or characteristic that can be inherited.
**_Tyrannosaurus rex_**: A top-predator dinosaur that roamed Earth during the late Cretaceous period. Adults could be 12 meters (40 feet) long.
**unique**: Something that is unlike anything else; the only one of its kind.
**_Velociraptor_**: A genus of predatory bird-like dinosaurs with a relatively large brain and a long, sharp claw on each foot. Its fossils were first discovered in the 1920s in what is now Mongolia. The roughly meter-tall animal moved on two feet and injured/maimed
prey with one of its sharp talons. [\[3\]](#_msocom_3) Those "killer claws" could also have been used to pin down prey as it was eaten alive, new data suggest — similar to how today's birds of prey use their talons. The _Velocirator_ likely would _not_ have been as daunting as its namesake portrayed in the _Jurassic Park_ movie franchise. Many scientists believe that movie version was actually _Deinonychus_, a dinosaur twice this dino’s size and known from fossils unearthed in the United States during the 1960s.
**vertebrate**: The group of animals with a brain, two eyes, and a stiff nerve cord or backbone running down the back. This group includes amphibians, reptiles, birds, mammals and most fish.
**warm-blooded**: Adjective for animals (chiefly mammals and birds) that maintain a constant body temperature, typically above that of their surroundings. Scientists generally prefer the term endothermic to describe animals that generate heat to control their body’s temperature.
**wetland**: As the name implies, this is a low-lying area of land either soaked or covered with water much of the year. It hosts plants and animals adapted to live in, on or near water.