Taxonomy – the science of species discovery
Our planet has life on it, and for that reason, it may be unique in the universe. Ironically enough, we know much more about some of the planets floating thousands of kilometres away than we do about most of the species living right here on Earth.
Deepsea jellyfish
A beautiful jellyfish photographed during a deepwater expedition to the Marianas Islands. Scientists have placed it in the genus Crossota .
Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas .
The science of discovery
So far, we’ve catalogued 1.9 million kinds of plants, animals and microbes. But this is only the tip of the iceberg. There are probably more than 10 million species sharing our planet, which means we only know about 20% of them.
The scientific discipline dedicated to describing, classifying and making sense of the biodiversity all around us is called taxonomy.
Taxonomists describe and classify new species by comparing characteristics shared by groups of organisms, which may be anatomical, behavioural or even molecular. For example, the exquisitely detailed claw of a crab, the reproductive behaviour of a bird or the DNA inside each cell of a plant are all characteristics that can be used to compare and classify different species.
Harvestmen mouthparts
Slice-through view of chelicerae – enlarged mouthpart appendages of the arachnid-like harvestmen (from the order Opiliones). The corresponding grey image shows what the external morphology looks like.
Scientists use different characteristics like these anatomical features to compare and classify different species.
Jaimi Gray made her image of harvestmen mouthparts available under a Creative Commons attribution license for this article.
When building their classifications, taxonomists try to piece together the evolutionary relationships between different taxa. Since all life is descended from a common ancestor, it’s possible to show how species have branched out into the diversity we now see all around us. This can be visualised with a cladogram, which is a diagram showing how different species or groups are thought to be related to each other.
Primate cladogram
This diagram shows the evolutionary relationships between members of the primate family.
Taxonomy is also concerned with the bigger questions, such as how species are even defined in the first place. The most common and probably the most intuitive definition of species is a group of organisms that are able to interbreed. However, defining species is not always as simple as this, and there are many other competing definitions.
Taxonomy in Aotearoa
New Zealand has at least 29 taxonomic collections spread between museums, universities, Crown research institutes and other research centres. These collections hold about 12 million specimens, and about 80% of these are invertebrates, owing to their incredible diversity. Other specimens include non-invertebrate animals, plants, microbes and fossils, and each collection has its own speciality. We have approximately 360 taxonomists working in New Zealand, although only a subset of these are employed in full-time roles. Some of the larger organisations employing taxonomists as scientists and curators include:
Crown research institutes such as Landcare Research, GNS Science, Scion, NIWA and the Cawthron Institute
museums such as Te Papa, Auckland Museum, Canterbury Museum and Otago Museum.
tertiary education providers including University of Auckland, University of Canterbury, Lincoln University, Massey University, University of Otago and Unitec.
Landcare Research houses the largest collection – the New Zealand Arthropod Collection – and employs many taxonomists to describe species, revise outdated classifications, curate the collection and publish important identification resources.
Apoidea diagrams
A species of plasterer bee ( Leioproctus purpureus ) from the superfamily Apoidea.
The diagram is from volume 57 of the Fauna of New Zealand series on New Zealand bee fauna.
The series are taxonomic studies that typically include diagrams and illustrations alongside other information.
Fauna of New Zealand is a series of monographs (in-depth taxonomic study on a particular group) that details land-based invertebrates. Each volume typically includes a checklist of taxa in that group and an introduction to the group as well as descriptions of new and existing species alongside diagrams and illustrations. Electronic copies of every volume are also available online.
Why is taxonomy important?
Taxonomic expertise is built up over many years and represents a very specialised form of knowledge, particularly for people who are experts in certain taxa. Describing and classifying biodiversity is the foundation upon which all the life sciences rest. The ability to communicate clearly about different species or higher groups is only possible when they have an unambiguous name and confident classification.
There are many other reasons why taxonomy is important.
New Zealand has signed international agreements that require countries to identify, classify and protect their species for the benefit of humankind (for example, the UN Convention on Biological Diversity ). In order to conserve and monitor our native biodiversity, we need to know what species we have, where they are found and how their numbers or diversity are changing over time. Authoritative taxonomic expertise is essential for accurate identifications as well as delimiting closely related species and building the kinds of resources that other people can use to identify and monitor biodiversity.
Our economy is built on living things and the products they produce. Taxonomy provides the skills needed to identify species that may have economic potential. Our undiscovered native species may possess structures, substances or behaviours that lead to novel foods, fibres, medicines or fuels. If New Zealand wants to be taken seriously as an innovator during the current biotech revolution, it needs to invest in taxonomy.
Brown marmorated stink bug
The brown marmorated stink bug (BMSB) is a serious crop pest and a biosecurity risk to New Zealand. They can infest horticultural crops (i.e. apples, corn, wine grapes, kiwifruit and a range of stone fruit varieties), causing damage to flowers, stems, leaves and fruit of host plants. Fortunately strict import rules have made it harder for live BMSB to enter New Zealand on risky cargo such as vehicles, machinery and parts.
Taxonomists and taxonomic collections are important for identifying pests and diseases.
Biosecurity is fundamental to the New Zealand economy. All of our top exports – dairy, meat, seafood, fruits and vegetables, wine, timber – are expected to be pest-free and disease-free. When they aren’t, ongoing access to export markets is jeopardised, which puts jobs at risk. Identifying pests and diseases at the border is one of the most important reasons for training taxonomists and investing in taxonomic collections.
Student activities
In Native plant leaves – DIY classification system , students get a taste of classification without having to work through the complexities of the Linnaean system.
Develop a classification system is an activity where students work in small groups and come up with their own classification system for a number of marine organisms.
The classification of megaherbs has megaherb image cards for students to group species of megaherbs according to their physical structures (leaf shape, leaf size, flower structure and flower colour).
Related content
Read about classifying marine organisms and learn about plant collections in museums and how scientists classify ferns .
The article Māori knowledge of animals explores animal groupings using frameworks of whakapapa. It includes the Māori knowledge of animals interactive and has links to six articles that feature specific animal groupings.
When an elusive new species of gecko was discovered, the researchers understood the importance of an appropriate name – it was given the te reo Māori common name te mokomoko a Tohu .
Useful links
Classification is not a field that stays still. With technological developments and improvements such as genetic sequencing, new information is becoming available. This means scientists and taxonomists sometimes have to reassess classifications. Learn more in Leon Perrie’s thought-provoking blog Why do scientific names change? .
Included under the Taxonomy section on the Royal Society Te Apārangi website is a video featuring Sir David Attenborough and various articles.
Species Aotearoa is seeking to boost taxonomy and biosystematics in Aotearoa New Zealand to address the urgent need for fundamental information about our biota.
Access the New Zealand Threat Classification System (NZTCS) database here .
Find out more about incorporating te reo Māori and understanding the importance of whakapapa in taxonomy:
This Newsroom article , looks at what is the best way to go about incorporating te reo Māori in taxonomy. For more detailed information see Using te reo Māori and ta re Moriori in taxonomy , New Zealand Journal of Ecology (2019) 43(3): 3388.
The use of the Māori language in species nomenclature , Journal of Marine and Island Cultures , Vol 2, Issue 2, Dec 2013, Pages 78-84.
Read this story from Te Ara – the Encyclopedia of New Zealand, The first naturalists: European discovery of plants and animals , it includes how in the Māori world view, all things were linked by genealogies (whakapapa) .
Living things: definition, classification, history, characteristics, and more info , is a useful reference material from Biology Online Dictionary and Tutorials .
Acknowledgement
This article was written by Tom Saunders .
