Looking for LUCA, everyone’s shared ancestor

acronym: A word made by combining some of the starting letter or groups of letters from a number of words. For instance, STEM is an acronym for Science, Technology, Engineering and Math. Radar is an acronym for RAdio Detection And Ranging. Even laser is an acronym for Light Amplification by Stimulated Emission of Radiation.

alien: A non-native organism. (in astronomy) Life on or from a distant world.

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)

ape: A group of rather large primates, all of which lack a tail. They include gorillas, chimpanzees, bonobos, orangutans, gibbons and humans. Most people tend to group humans into their own separate subcategory owing to a number of special traits. These include a larger brain, greater mental abilities (including being able to talk) and their ability to walk on two legs.

archaea: (singular: archaeon)  One of the three domains of life on Earth. This group consists of single-celled prokaryotes — organisms without a cell nucleus. Archaea are best known for living in extremely harsh environments, such as very salty water or highly acidic or hot places.

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.

ATP: Short for adenosine triphosphate. Cells make this molecule to power almost all of their activities. Cells use oxygen and simple sugars to create this molecule, the main source of their energy. The small structures in cells that carry out this energy-storing process are known as mitochondria. Like a battery, ATP stores a bit of usable energy. Once the cell uses it up, mitochondria must recharge the cell by making more ATP using energy harvested from the cell’s nutrients.

bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.

biology: The study of living things. The scientists who study them are known as biologists.

cataclysm: An enormous, violent, natural event. A meteor hitting Earth and wiping out most living species would qualify as a cataclysmic event.

cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

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.

chemical reaction: A process that involves the rearrangement of the molecules or structure of a substance, as opposed to a change in physical form (as from a solid to a gas).

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.

crater: A large, bowl-shaped cavity in the ground or on the surface of a planet or the moon. They are typically caused by an explosion or the impact of a meteorite or other celestial body. Such an impact is sometimes referred to as a cratering event.

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.

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 or a range of traits within the population of some species.

DNA: (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

environment: The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of things in the vicinity of an item of interest).

eukaryote: Any organism whose cells have a nucleus. Eukaryotes include all multicellular creatures (such as plants, animals and fungi) as well as certain types of single-celled microorganisms.

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. 

evolutionary biologist: Someone who studies the adaptive processes that have led to the diversity of life on Earth. These scientists can study many different subjects, including the microbiology and genetics of living organisms, how species change to adapt, and the fossil record (to assess how various ancient species are related to each other and to modern-day relatives).

family: A taxonomic group consisting of at least one genus of organisms.

focus: (in physics) The point at which rays (of light or heat for example) converge sometimes with the aid of a lens. (In vision, verb, “to focus”) The action a person’s eyes take to adapt to light and distance, enabling them to see objects clearly. (in behavior) To look or concentrate intently on some particular point or thing.

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.

gene: (adj. genetic) A segment of DNA that codes, or holds instructions, for a cell’s production of a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

genetic: Having to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

genome: The complete set of genes or genetic material in a cell or an organism. The study of this genetic inheritance housed within cells is known as genomics.

hydrothermal vent: An opening at the bottom of the ocean or a lake where hot water emerges from deep inside Earth. The water is rich in minerals and chemicals that can nourish ecosystems of worms, clams, microbes and other organisms.

infection: A disease that can spread from one organism to another. It’s usually caused by some type of microbe.

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).

membrane: A barrier which blocks the passage (or flow through) of some materials depending on their size or other features. Membranes are an integral part of filtration systems. Many serve that same function as the outer covering of cells or organs of a body.

Mercury: (in astronomy and here the term is capitalized) The smallest planet in our solar system and the one whose orbit is closest to our sun. Named after a Roman god (Mercurius), one year on this planet lasts 88 Earth days, which is shorter than one of its own days: Each of those lasts 175.97 times as long as a day on Earth.

metabolism: (adj. metabolic)  The set of life-sustaining chemical reactions that take place inside cells and bigger structures, such as organs. These reactions enable organisms to grow, reproduce, move and otherwise respond to their environments.

microbiology: The study of microorganisms, principally bacteria, fungi and viruses. Scientists who study microbes and the infections they can cause or ways that they can interact with their environment are known as microbiologists.

microscope: An instrument used to view objects — such as bacteria or the single cells of plants or animals — that are too small to be visible to the unaided eye.

model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.

molecule: A 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 air is made of two bound oxygen atoms (O₂). Water is made of two hydrogen atoms and one oxygen atom (H₂O).

morph: Short for metamorphose, it means to change or transform from one form to another (such as from a caterpillar to a butterfly) or from one shape to another. Or it can mean to evolve or mutate, where one or more parts of the genome undergo some sort of change in their chemistry — and potentially in their function. (in non-living systems) It refers to a thing, policy or activity that has undergone change, becoming something that looks or seems new and different.

multicellular: Having or consisting of many cells. This includes all animals and plants, and many types of fungus.

nucleus: Plural is nuclei. (in biology) A dense structure present in many cells. Typically a single rounded structure encased within a membrane, the nucleus contains the genetic information. (in astronomy) The rocky body of a comet, sometimes carrying a jacket of ice or frozen gases. (in physics) The central core of an atom, containing most of its mass.

organelle: Specialized structures, such as mitochondria, found within a cell.

organic: (in chemistry) An adjective that indicates something is carbon-containing; also a term that relates to the basic chemicals that make up living organisms.

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

primate: The order of mammals that includes humans, apes, monkeys and related animals (such as tarsiers, the Daubentonia and other lemurs).

primordial: An adjective that refers to something that goes back to the beginning of time or to the earliest existence of something.

progenitor: Ancestor, parent or originator. (in biology) Some individual — or thing (perhaps even a cell) — from which all others descend.

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.

scenario: A possible (or likely) sequence of events and how they might play out.

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

solar system: The eight major planets and their moons in orbit around our sun, together with smaller bodies in the form of dwarf planets, asteroids, meteoroids and comets.

synthetic biology: A research field in which scientists work on developing custom life forms in the lab. Because they make synthetic organisms, scientists who work in this field are known as synthetic biologists.

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.

theory: (in science) A description of some aspect of the natural world based on extensive observations, tests and reason. A theory can also be a way of organizing a broad body of knowledge that applies in a broad range of circumstances to explain what will happen. Unlike the common definition of theory, a theory in science is not just a hunch. Ideas or conclusions that are based on a theory — and not yet on firm data or observations — are referred to as theoretical. Scientists who use mathematics and/or existing data to project what might happen in new situations are known as theorists.

trillion: A number representing a million million — or 1,000,000,000,000 — of something.

Venus: The second planet out from the sun. Just as Earth does, it has an iron core and a rocky mantle and crust. Volcanoes on the planet’s surface spewed high levels of carbon dioxide, which built up in the planet’s atmosphere. Today the air pressure at the planet’s surface is 100 times greater than on Earth, and the atmosphere now keeps the surface of Venus a brutal 460° Celsius (860° Fahrenheit).