You may not be familiar with the scientific names of ambrosia beetles. These insects belong to the genus Coptoborus. But you are likely to recognize some iconic female characters from science fiction among a few of their species names. Consider C. katniss, C. scully and C. leia. The names of these and some other related beetles aim to grab your attention.
“We had wanted to do something fun like this for a while,” says Sarah Smith. She’s an insect biologist, or entomologist (En-toh-MOLL-uh-jist), at Michigan State University in East Lansing. The beetles’ features inspired their sci-fi names. C. leia, for example, is brown like Princess Leia’s buns. The pointy body shape of C. katniss reminded Smith of Katniss Everdeen and her bow and arrow.
top panel shows the beetle Coptoborus katniss, named after Hunger games character Katniss Everdeen, shown in bottom panel
The wing coverings of the beetle Coptoborus katniss (above) come to an arrowhead-like point. This reminded Michigan State entomologists of Katniss Everdeen from The Hunger Games (below).
Some names suit the beetles’ behavior too, says Anthony Cognato, another entomologist at Michigan State. He partnered with Smith on a new beetle study. Female ambrosia beetles venture out from nests to start families at new sites. This behavior may explain how these beetles spread throughout the tropics over the past 20 million years.
Their eye-catching names also draw attention to taxonomy. That’s the science of naming organisms. Taxonomy is a bedrock of biology, Cognato explains. A unique name lets scientists know which individuals fit within a species. Only then can they go on to discuss and study what makes this species different from others.
“This system of names provides the keys to unlock information,” adds Gustavo Hormiga. He’s at George Washington University in Washington, D.C. He studies spiders and other arachnids.
Imagine if you got a tick bite, Hormiga says. Some types of ticks carry Lyme disease, which causes rashes, fever and headaches. Other ticks don’t. A doctor deciding on treatment might ask if the bite was from a deer tick. This Ixodes scapularis can be a carrier of Lyme disease.
The way modern scientists classify and name organisms was first developed more than 250 years ago. But that doesn’t mean the process hasn’t changed. Since then, scientists have adapted the naming system to reflect how species evolve.
Some scientists, however, would like to start afresh with a new naming method. Many others are not ready for this. For most biologists, a name is not just a name. It’s also a way not only to distinguish what separates species, but also to understand species.
Linnaeus and his legacy
Modern taxonomy traces back to Carl Linnaeus (Leh-NAY-us). This Swiss naturalist wrote the book on it back in 1753. His Species Plantarum, as it was called, listed every plant species known at that time. It also marked the first time a binomial (two-part) nomenclature (naming system) came into common use for plants. Five years later, Linnaeus’s Systema Naturae used the same system to name animals. That book contained some now-familiar names, such as Homo sapiens and Boa constrictor.
Before binomial nomenclature, animal names involved long descriptions. Honeybees, for instance, were Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticus glabis, untrinque margine ciliates. This mouthful of Latin words describes the insects’ appearance. Soft short hairs, gray chest, brown belly and smooth back legs bordered with hairs on both sides. Linnaeus’s name for the species is much shorter: Apis mellifera, or “honey-bearing bee.”
The ordering of those two Latin words has a special meaning, too. The first describes the genus (GEE-nus). It’s the name for a related group. The second name specifies the particular species. The genus Canis, for instance, includes several species. They include the domestic dog (Canis familiaris) and the gray wolf (Canis lupus).
Modern scientists still use this binomial system, as when they named those sci-fi-inspired ambrosia beetles. The names also categorize organisms into groups, known as taxa. A group, or taxon (hence the field’s name: taxonomy), includes similar organisms. For example, the genus Canis makes up a taxon. The genus Vulpes, which includes foxes, makes up another taxon. Taxa (the plural form of taxon) also can describe larger categories, like the group of all mammals.
Linnaeus described five tiered rankings for animals. At the top were kingdoms. At the bottom were species. Over time, scientists added a few more ranks. The system now spans from kingdom down through phylum (FY-lum), class, order, family, genus and species. One way to keep track of these labels is to remember “King Phillip Came Over For Great Spaghetti.” The first letter of each word matches the first letter of a rank. Taxa can be defined at different ranks. For example, Mammalia (the group of all mammals) is a taxon at the rank of class.
Remember how a genus can include multiple species? In the same way, an order can contain multiple families. And a class can contain multiple orders. The nested nature of these taxa provides scientists with helpful information.
“If I told you [two species] were in the same family, you would know right away that they were also in the same class and in the same phylum — and in the same kingdom,” explains Diana Lipscomb. She’s a retired evolutionary biologist at George Washington University.
However, there aren’t rules for deciding what rank a group of species — or taxon — falls into. One scientist might not agree with another about what defines a family, for example. In fact, a third scientist might even think the taxon should belong to a different rank, such as an order.
The International Code of Zoological Nomenclature, the rules for animal naming, spells out official guidelines. But this code doesn’t enforce rules for defining a taxon’s rank. That includes determining families versus orders. Because of this, Hormiga notes, all ranks may not be really comparable.
Evolving with the times
In the 1970s, scientists fiercely argued about taxonomy. These were turbulent years, Hormiga says. In the end, the field shifted. Scientists began to categorize species based on their evolution rather than on just what they looked like. This evolutionary approach is known as phylogeny (Fy-LAH-juh-nee).
“Modern taxonomy must reflect phylogeny,” says Gonzalo Giribet. He’s a zoologist at Harvard University in Cambridge, Mass. Members inside a taxon should be more related to each other than to species outside the group. Scientists draw these relationships as branched trees. In fact, Charles Darwin described such a tree of life. His included both living and extinct organisms.
I might tell you, Hormiga says, “there is a family of spiders unique to some part of South America” and it has been classified on the basis of phylogenetic relationships. “Then what I’m saying is, this is a branch of the tree of life.”
Taxonomy and phylogeny are key parts of a scientific field known as systematics. You might notice the name is related to Linnaeus’s Systema Naturae. This field uses evolution to classify and name living things.
Systematists (SIS-teh-muh-tists) study a species’ evolution by looking at its genetic material: DNA and RNA. DNA is a molecule that stores genetic instructions in cells. In order to read those instructions, cells copy DNA into another molecule, RNA. Cells use that RNA to make proteins.
Ribosomes (RY-boh-soams) are the cellular machines that make those proteins. Each ribosome is made of proteins and RNA. Because ribosomes are so important to cells, changes in RNA sequences could prove a disaster. So mutations — copying changes — rarely happen in ribosomal RNA. Over millions and billions of years, however, a few changes can slowly accumulate as species evolve. The more different the RNA in two species is, the less related those species will be.
Scientists have used such analyses to divide life on Earth into three domains. Two describe much of all one-celled life: bacteria and archaea (Ar-KEE-ah). The third — eukaryotes (Yu-KAIR-ee-oats) — includes everything else. Eukaryotes can be one or more cells. All have cellular parts with distinct roles, such as DNA-containing nuclei. Plants fit in this group. So do all animals. So, too, do one-celled amoebas.
You can forgive Linnaeus for not coming up with this system. He lived long before scientists grasped the idea of evolution, much less genetics. As a result, new findings can force systematists to re-classify taxa. For example, Smith and Cognato moved some ambrosia beetle species into the genus Coptoborus. This was after they discovered that Coptoborous and the genus Theoborus were actually one and the same.
To many systematists, these changes are okay. “You’re making a hypothesis about what this organism is, who it’s related to and where it fits in on that tree of life,” says Lipscomb at George Washington. A big part of science is interpreting new data to improve our understanding of our world (and cosmos).
Bigger than kingdoms, perhaps?
Domains are just one update in taxonomy’s highest ranks. In Systema Naturae, Linnaeus described three living kingdoms: animals, plants and minerals. It’s no surprise that the mineral kingdom was jettisoned. Since then, scientists have defined more kingdoms. One popular model includes five: Animalia, Plantae, Fungi, Protista and Monera.
Kingdom Monera includes prokaryotes (Pro-KAIR-ee-oats). These are single-celled organisms without a nucleus. So it includes bacteria and archaea. The other four kingdoms cover eukaryotes. So you can likely guess what Animalia, Plantae and Fungi include. Kingdom Protista becomes a grab-bag for anything that’s not an animal, plant or fungus but still has cells with nuclei.
In terms of evolution, that last group has a problem. Some of its members are more related to animals or plants than to other protists.
Researchers studying single-celled organisms don’t consider Protista a true taxon, says Alastair Simpson. He’s a biologist at Dalhousie University in Halifax, Canada. Instead, he says, it’s more helpful to talk about supergroups. These divide eukaryotes into about a dozen groups based on how they evolved.
Simpson was a co-creator of the supergroup concept in the early 2000s. The choice of the name “supergroup” was intentional. “We deliberately didn’t want something that sounded like a rank,” Simpson says. “We thought supergroups would be silly enough.”
Animals and fungi fall under one supergroup: It’s called Obazoa. Other supergroups highlight the diversity of single-celled eukaryotes once lumped together. Simpson coauthored a recent paper describing a new single-celled species, Hemimastix kukwesjijk. Its name comes from the traditions of the Mi’kmaq First Nation of Nova Scotia, Canada. In their Indigenous language, the name translates as “little ogre.”
These microbes “are evolutionarily distant from everything else that we know about,” Simpson says. As a result, he and his colleagues believe that the phylum containing the new species actually makes up a supergroup — a category bigger than a kingdom.
Should biologists start over from scratch?
Some scientists have been developing a new system for naming species. “We’ve developed this alternative approach” so names wouldn’t change as much as in a rank-based system, explains Kevin de Queiroz. A zoologist, he is the curator of reptiles and amphibians at the National Museum of Natural History. It’s part of the Smithsonian Institution in Washington, D.C.
The new naming system is called PhyloCode. That’s short for International Code of Phylogenetic Nomenclature. As its name implies, species names are tied to how strongly they are linked through evolution, says de Queiroz. He’s a PhyloCode developer. And although many people may not have heard of the PhyloCode, de Queiroz is part of a team that has spent the last 20 years getting it ready for prime time. PhyloCode’s sixth edition was published in 2020. It was the first to be published as a printed book. A companion volume, Phylonyms, provides details about how to define groups.
How does it work? With the current naming system, the name “Iguanidae” is the family (based on the -idae ending) containing the genus Iguana. But remember, scientists decide ranks for taxa. If a scientist decides “Iguana” should apply to a bigger or smaller group, the update could cause names to shift for other taxa and species.
PhyloCode instead defines names based on how species are linked by evolution. A new version of Iguanidae is defined as a specific ancestor of the green iguana (Iguana iguana) and all its descendants. You can think of this as a branch on the tree of life. This branch that defines Iguanidae excludes the common agama and chameleon.
These new types of definitions no longer rely on ranks, although they don’t necessarily throw them out. Ranks can still provide information about how groups relate to each other on the tree of life. There’s no problem with using ranks to show how mammals (a class) are part of a larger branch of animals (a kingdom), for example. “But you shouldn’t be using [ranks] to determine how the names are applied,” de Queiroz argues.
This proposal to change the naming system for all living things has produced a range of responses. There are boosters like de Queiroz. Many outright oppose it. Others fall somewhere in between.
“I agree with [de Queiroz] in principle,” says herpetologist Darryl Frost. Yet Frost is not completely on board. “Do I have any issues with them in terms of practicality,” he asks? “Yeah, I do.” Frost studies reptiles and amphibians at the American Museum of Natural History in New York City.
And he isn’t alone in having concerns. “PhyloCode is not a very widely accepted concept,” Simpson says. He’s a contributor to Phylonyms and has written chapters about protists. One problem with the new system, he says, is that a name can stay the same while the ideas behind it changes. Time will tell whether biologists come to fully embrace PhyloCode — and how it integrates existing names or naming systems.
Taxonomy and biodiversity
New developments in taxonomy are more important than ever. Humans have made a big impact on the Earth’s multitude of species — and generally not in a good way.
“Species are going extinct at a tremendous rate,” Hormiga says. “Once they’re extinct, they’re gone forever.” Unfortunately, there’s a shortage of trained taxonomists to describe every living thing on the planet that has yet to be named.
This presents a huge challenge, as taxonomy is crucial to slowing the biodiversity crisis. Why? Explains Frost, “You have to name it if you’re going to conserve it.”
Power Words
More About Power Words
amphibians: A group of animals that includes frogs, salamanders and caecilians. Amphibians have backbones and can breathe through their skin. Unlike reptiles, birds and mammals, unborn or unhatched amphibians do not develop in a special protective sac called an amniotic sac.
ancestor: A predecessor. It could be a family forebearer, 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)
arachnid: A group of invertebrate animals that includes spiders, scorpions, mites and ticks. Many have silk or venom glands.
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.
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.
beetle: An order of insects known as Coleoptera, containing at least 350,000 different species. Adults tend to have hard and/or horn-like “forewings” which covers the wings used for flight.
behavior: The way something, often a person or other organism, acts towards others, or conducts itself.
biodiversity: (short for biological diversity) The number and variety of species found within a localized geographic region.
biologist: A scientist involved in the study of living things.
boa constrictor: A species of large snake that is native to tropical areas of Central and South America. It kills prey by coiling around its victim and squeezing.
colleague: Someone who works with another; a co-worker or team member.
conserve: To protect, as from loss or degradation.
curator: Someone who manages a collection of items, for instance in a museum, library or art gallery. This person’s primary job is to design exhibits, organize and acquire collections and do research on the artifacts included in the collection.
diversity: (in biology) A range of different life forms.
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.
domain: (in biology) The highest taxonomic rank of organisms, above that of kingdom.
entomologist: A biologist who specializes in the study of insects. A paleoentomologist studies ancient insects, mainly through their fossils.
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; adj. evolutionary) 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).
extinct: An adjective that describes a species for which there are no living members.
family: A taxonomic group consisting of at least one genus of organisms.
First Nations: The term for Indigenous communities in Canada (who are not Inuit peoples of the far North). They are comparable to Native American tribes in the United States.
Indigenous: (in anthropology) An adjective (and capitalized) for people that have lived for eons in some region, developing a culture that reflects the resources, climate and ecosystems of that place.
fungus: (plural: fungi) One of a group of single- or multiple-celled organisms that reproduce via spores and feed on living or decaying organic matter. Examples include mold, yeasts and mushrooms.
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.
genus: (plural: genera) A group of closely related species. For example, the genus Canis — which is Latin for “dog” — includes all domestic breeds of dog and their closest wild relatives, including wolves, coyotes, jackals and dingoes.
herpetologist: A scientist who works on the biology of reptiles and amphibians.
Homo: A genus of species that includes modern humans (Homo sapiens). All had large brains and used tools. This genus is believed to have first evolved in Africa and over time evolved and radiated throughout the rest of the world.
hypothesis: (v. hypothesize) A proposed explanation for a phenomenon. In science, a hypothesis is an idea that must be rigorously tested before it is accepted or rejected.
information: (as opposed to data) Facts provided or trends learned about something or someone, often as a result of studying data.
Lyme disease: A disease caused by the bacterium Borrelia burgdorferi. It can be carried by blacklegged ticks and can be spread to people through their bite. Symptoms can include headache, fever, a bullseye-shaped skin rash and being very tired. If it is not treated early with antibiotics, the infection can move into heart, joints and nervous system.
mineral: Crystal-forming substances that make up rock, such as quartz, apatite or various carbonates.
mutation: (v. mutate) Some change that occurs to a gene in an organism’s DNA. Some mutations occur naturally. Others can be triggered by outside factors, such as pollution, radiation, medicines or something in the diet. A gene with this change is referred to as a mutant.
naturalist: A biologist who works in the field (such as in forests, swamps or tundra) and studies the interconnections between wildlife that make up local ecosystems.
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.
order: (in biology) It is that place on the tree of life directly above species, genus and family.
organism: Any living thing, from elephants and plants to bacteria and other types of single-celled life.
phylogeny: A term for the evolutionary history of a species or group of species.
phylum: (plural: phyla) A scientific term for a related group of living things. The modern animal kingdom includes about 35 phyla.
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).
prokaryote: Any single-celled organism that does not have a nucleus or membrane-bound organelles.
protist: A broad group of mostly single-celled organisms that are neither plants nor animals. Some, like algae, may appear plant-like. Those known as protozoans may appear animal-like. And still others appear fungi-like.
reptile: Cold-blooded vertebrate animals, whose skin is covered with scales or horny plates. Snakes, turtles, lizards and alligators are all reptiles.
RNA: A molecule that helps “read” the genetic information contained in DNA. A cell’s molecular machinery reads DNA to create RNA, and then reads RNA to create proteins.
science fiction: A field of literary or filmed stories that take place against a backdrop of fantasy, usually based on speculations about how science and engineering will direct developments in the distant future. The plots in many of these stories focus on space travel, exaggerated changes attributed to evolution or life in (or on) alien worlds.
species: A group of similar organisms capable of producing offspring that can survive and reproduce.
supergroup: (in taxonomy) A major branch of the Tree of Life for organisms that are eukaryotes (ones whose cells have a nucleus). A supergroup is defined by the organisms’ evolutionary history (or phylogeny). Scientists originally described five to eight supergroups. New ones continue to be discovered, especially as scientists learn more about protists (certain single-celled organisms). A supergroup is not a taxonomic rank.
systematics: The field of biology that studies evolutionary relationships among living things. People who work in this field create “family trees” that show which creatures descended from common ancestors. The same people often practice “taxonomy,” naming new species or other groupings that they identify. People who work in this field are known as systematists.
taxa: (sing. taxon) The groupings that distinguish organisms and their relatedness to each other. Most biologists order these taxa in ascending rank as species, genus, family, order, class, phylum, kingdom and domain.
taxonomy: The study of organisms and how they relate or have branched off (over evolutionary time) from earlier organisms. Often the classification of where plants, animals or other organisms fit within the Tree of Life will be based on such features as how their structures are formed, where they live (in air or soil or water) or where they get their nutrients. Scientists who work in this field are known as taxonomists.
tick: A small eight-legged blood-sucking arthropod, related to spiders and mites. Although they look like bugs, these are not insects. They attach themselves to the skin of their host and feed on their blood. But in the process, they may spread any germs that could have been present in the blood of an earlier host.
tree of life: A diagram that uses a branched, treelike structure to show how organisms relate to one another. Outer, twiglike, branches represent species alive today. Ancestors of today’s species will lie on thicker limbs, ones closer to the trunk.
unique: Something that is unlike anything else; the only one of its kind.