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Label Detective: Are Bacteria ‘Ordinary Animals?’

KyleLee-Crossett17 October 2017

A few weeks ago, the Grant Museum opened a new exhibit, The Museum of Ordinary Animals: boring beasts that changed the world. As a detective of the mundane myself, I am a huge fan. But I’m particularly curious about the ordinary animals we can’t see.

Rather than focusing on a specific artefact label, I answer the title question by visiting two places in the Museum of Ordinary Animals exhibition that help raise questions about how things are organised and labeled in zoology more broadly.

Case notes: Bacteria are everywhere. As I mentioned in my previous post, we have 160 major species of bacteria in our bodies alone, living and working together with our organ systems to do things like digest nutrients. This is also happens with other animals — consider the ordinary cow, eating grass. Scientist Scott F. Gilbert tells us that in reality, cows cannot eat grass. The cow’s genome doesn’t have the right proteins to digest grass. Instead, the cow chews grass and the bacteria living in its cut digest it. In that way, the bacteria ‘make the cow possible’.

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The Ordinary Cow, brought to you to by bacteria. Credit: Photo by author

Scientifically speaking, bacteria aren’t actually ‘animals’; they form their own domain of unicellular life. But, as with the cow, bacteria and animals are highly connected. Increasingly, scientists say that the study of bacteria is ‘fundamentally altering our understanding of animal biology’ and theories about the origin and evolution of animals.

But, before we get into that, let’s go back to Charles Darwin (1809-1882). Darwin studied how different species of animals, like the pigeon, are related to each other, and how mapping their sexual reproduction shows how these species diversify and increase in complexity over time. This gets depicted as a tree, with the ancestors at the trunk and species diversifying over time into branches.

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Darwin’s Ordinary Tree of Pigeons. Photos by author

When scientists began to use electron microscopes in the mid-20th century, our ideas about what made up the ‘tree of life’ expanded. We could not only observe plants, animals, and fungi, but also protists (complex small things) and monera (not-so-complex small things). This was called the five kingdom model. Although many people still vaguely recollect this model from school, improved techniques in genetic research starting in the 1970s has transformed our picture of the ‘tree of life’.

It turns out we had given way too much importance to all the ordinary things we could see, when in fact most of the tree of life is microbes. The newer tree looks like this:

Credit: Wikipedia Commons

Credit: Wikipedia Commons

Now there are just three overarching domains of life: Bacteria, Eucarya (plants, animals, and fungi are just tiny twigs on this branch), and Archaea (another domain of unicellular life, but we’ll leave those for another day).

There’s a third transformation of the ‘tree of life’, and this one is my favourite. Since the 1990s, DNA technology and genomics have given us an even greater ability to ‘see’ the diversity of microbial life and how it relates to each other. The newest models of the tree look more like this:

Credit: Wikipedia Commons

Credit: Wikipedia Commons

This is a lot messier. Why? Unlike the very tiny branches of life (plants and animals) that we focused a lot of attention on early on in the study of evolution, most of life on earth doesn’t reproduce sexually. Instead, most microbes transfer genes ‘horizontally’ (non-sexually) across organisms, rather than ‘down’ a (sexual) genetic line. This creates links between the ‘branches’ of the tree, starting to make it look like….not a tree at all. As scientist Margaret McFall-Ngai puts it: ‘we now know that genetic material from bacteria sometimes ends up in the bodies of beetles, that of fungi in aphids, and that of humans in malaria protozoa. For bacteria, at least, such transfers are not the stuff of science fiction but of everyday evolution’.

Status: Are bacteria Ordinary Animals? We can conclusively say that bacteria are not animals. But, they are extremely ordinary, even if we can’t see them with the naked eye. In truth, they’re way more ordinary than we are.

 

 

Notes

As with the previous Label Detective entry, this post was deeply inspired by the book Arts of Living on a Damaged Planet, an anthology of essays by zoologists, anthropologists, and other scholars who explore how environmental crisis has highlights the complex and surprising ways that life on earth is tied together. Scott F. Gilbert and Margaret McFall-Ngai, both cited above, contribute chapters.

From Delphi to the Dodo: Finding Links Between Archaeology and Natural History

GemmaAngel1 October 2012

by Felicity Winkley

 

 

 

 

 

Initially, my response to the challenge of finding a link between my research and the zoological specimens in the Grant Museum was one of dread and panic. Such a thing could simply not be done – it would be impossible to engage a member of the public for long enough to travel the conversational distance from a dissected Thylacine to British archaeology. On closer inspection, however, I was to find that the museum which houses Grant’s collection of some 67,000 zoological specimens, is not, in fact, dissimilar to those great anthropological collections that were also assembled during the 19th century. The shadowy corners and densely-packed glass cases are reminiscent, certainly, of those at the Pitt Rivers Museum in Oxford, where the shelves overflow with ethnological artefacts.

And yet the similarities go beyond the simply aesthetic. Both Robert Edmund Grant ( 1793-1874  – pictured left) and Lieutenant-General Augustus Pitt Rivers (1827-1900 – pictured below) were undoubtedly, if unconsciously, influenced by a long-established tradition of collecting in England, which since the 17th century had been a gentlemanly pursuit acceptable to the social elite [1]. Indeed, for ambitious scholars it was even a method of propelling oneself up the social charts. Elias Ashmole (1617-1692) was the son of a saddler, but with a good eye and some wily investing he was able to accumulate a collection that when bequeathed to Oxford University (along with its own custom-made premises), would provide a lasting legacy to maintain both the collection and his own prestige [1]. But Ashmole was only one of any number of ‘Antiquarians’ as these collectors were soon to become known; men who, for Sweet, “were important actors in that explosion of print and ideas, that thirst for knowledge and understanding with some have called the British Enlightenment” [2].

The rise of the antiquarian popularised the collection of all kinds of objects and artefacts, from coins and medals, to maps and even fossils; the over-arching motivation was simply a thirst for information about the past, and particularly information that was not provided by the historical record. This lack of concern for the ‘what’ that was being studied, often meant that focus was instead placed upon the ‘where’, so that authors would compile an in-depth study of the local parish or county – a regional framework which brought their work into obvious connection with natural historians compiling similar studies. The connection between antiquaries and natural historians was cemented further still by their agreement on epistemological models, and a sympathetic “culture of inquiry” according to Sweet [2].

In order to find a link between my own research and the Grant Museum collections, I determined to find out whether this undeniable spirit of discovery which so connected antiquarians and natural historians during the 17th and 18th century persisted into the 19th century also – and I was very happy to discover that it did. Whilst the methodology had been modernised into a recognisable early archaeology, and the investigative locations had moved from the local county to the more exotic, there was still an undeniable relationship between antiquarian and natural historical research. Just as the history of the local parish had been a relative unknown several hundred years previously, by the 19th century researchers had begun travelling further afield to collect archaeological information alongside samples of foreign flora and fauna. And this is where Darwin comes in.

Charles Darwin (1809-1882) had studied under Robert Grant during the 1820s and was much influenced by his ideas; however, his focus was by no means limited to the comparative anatomical interest they both shared. Written records show that even later on in his career, Darwin was contributing to funding for voyages that would provide evidence for archaeological investigations as well as natural-historical studies. A trip, funded in part by the Royal Society (then The Royal Society of London for Improving Natural Knowledge), to Borneo in 1878, had the archaeological aim of finding evidence for early human occupation, but plainly also had great implications for Darwin and his colleague Alfred Russell Wallace as a potential source for proving the evolution of anthropoid apes [3]. Wallace had already visited Borneo in 1855, where his observation of orangutans native only to that island and neighbouring Sumatra, prompted his composition of the very paper that would inspire Darwin’s Origin of the Species. Darwin pledged a sum of twenty pounds to the voyage [3]. Any discovery, whether made by an archaeologist, anatomist, collector or naturalist, was seen as a contribution to enlightenment. As testament to the limitless horizons of this quest for knowledge, signing off his letter, Darwin adds:

“I wish someone as energetic as yourself [John Evans] would organise an expedition to the triassic lacustrine beds in S. Africa, where the cliffs are said to be almost composed of bones.”

Evidently, he was already planning the next adventure! [3]

 

[1] Swann, M. (2001) Curiosities and Texts: The Culture of Collecting in Early Modern England Philadelphia: University of Pennsylvania Press

[2] Sweet, R. (2004) Antiquaries: The Discovery of the Past in Eighteenth-Century Britain London: Hambledon and London (pp. xiv)

[3] Sherratt, A. (2002) Darwin among the archaeologists: The John Evans nexus and the Borneo Caves Antiquity 76 pp.151-157