Author: More than a Dodo

Digital reconstruction of a Cambrian ocean

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Meet the First Animals

The latest exhibition in our Contemporary Science and Society series, First Animals, tells the tale of Earth’s mysterious early animals, which evolved in the sea over half a billion years ago. Here, Dr Imran Rahman, Deputy Head of Research at the Museum, introduces some of the fossils that form a key part of this story.

From sponges to sea slugs and hagfish to humans, all animals alive today trace their roots back to a common ancestor that lived in the ocean more than 600 million years ago. We have no direct evidence of this first animal, but the fossil record reveals some of its earliest descendants. Our First Animals exhibition explores the evidence for Earth’s earliest animal life, attempting to answer the ‘what’, ‘when’, ‘how’ and ‘why’ of the origin of animals.

Yunnanozoon lividum from the Chengjiang fossil site had a long body with several filament-covered arches at the front and a fin-shaped structure towards the back. It cannot be confidently assigned to any known animal group.

First Animals features the oldest animals yet recovered from the fossil record, including specimens from 571-million-year-old rocks in Newfoundland, Canada. These represent the remains of originally entirely soft-bodied organisms, which have proven difficult to classify because they look so different to living species. However, new research on their anatomy and how they grew, including work by Museum researcher Dr Frankie Dunn, suggests they were early animals.

Charnia masoni consisted of alternating branches arranged along a frond. It is thought to be one of the oldest animal fossils yet found.

Microscopic fossils record the first animal skeletons, which first appeared about 550 million years ago. These include the remains of complete animals, as well as fragments such as spines and scales. Work by Museum researcher Dr Duncan Murdock using a particle accelerator to generate X-ray images of these tiny fossils has allowed us to reconstruct how the skeletons changed as they grew. This helps to establish the modern groups to which these ancient animals belonged, and unravels the mystery of why animals evolved hard skeletons when they did.

Virtual cross-sections through small shelly fossils created using X-ray imaging.

The most complete evidence for the early evolution of animals comes from sites of exceptionally-preserved fossils, or Lagerstätten, which retain impressions of soft tissue as well as hard parts, and include rare soft-bodied animals like worms and jellyfish.

First Animals brings together extraordinary specimens from three key fossil sites: Sirius Passet in northern Greenland (518 million years old), Chengjiang in Yunnan province, China (518 million years old) and Burgess Shale in British Columbia, Canada (508 million years old). This includes 55 unique fossils loaned by Yunnan University in China, as well as specimens from the University of Bristol and the Royal Ontario Museum.

The mollusc Halkieria evangelista from the Sirius Passet fossil site had a long body covered in hundreds of overlapping hard plates, with a large shell plate at either end.
The arthropod Haikoucaris ercaiensis from the Chengjiang fossil site had a semicircular head shield with a pair of large grasping appendages, a segmented body and a short tail.
The worm Ottoia prolifica from the Burgess Shale fossil site had a spiny proboscis and a long trunk that was divided into a series of fine rings.

These exceptionally-preserved fossils reveal the evolutionary diversification of life during the so-called ‘Cambrian explosion’. Through careful study of the fossils, scientists have begun to reconstruct the very first animal ecosystems, which are brought to life in the exhibition through a series of stunning digital reconstructions and the Cambrian Diver interactive installation. This allows visitors to explore a 360-degree oceanic environment in a virtual submersible craft, coming face-to-face with some of the first animals on Earth!

Digital reconstruction of the sea floor 518 million years ago, based on specimens from the Chengjiang fossil site, Yunnan province, China.
Video by Mighty Fossils.

 

First Animals is open until 24 February 2020. Entry is free, no booking required. www.oum.ox.ac.uk/firstanimals.

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Birds of paradise

By Eileen Westwig, Life Collections Manager

The latest in our Presenting… series of single-case displays takes a look at one of the world’s most spectacular groups of birds – Paradisaeidae, or the birds of paradise.

A beautiful male Magnificent Riflebird (Lophorina magnifica)

The first bird of paradise to arrive in Europe was a skin that came to Spain in 1522. Many of these early skins were prepared by native hunters without wings or feet to better show off the bird’s spectacular plumage. Upon arrival in Europe, the apparent lack of wings and legs led to the myth that these birds originated from paradise and floated high in the skies, only to fall down to earth after their death.

Birds of paradise are members of the family Paradisaeidae, which contains more than 40 recognised species. Their closest relatives are crows and jays, of the Corvid family.

They inhabit the rainforests of Papua New Guinea, Eastern Indonesia and Eastern Australia and mainly feed on fruit and some insects. Hybridisation, when two birds of different species crossbreed, is quite common and can explain why many of the early described species were so “rare”.

Male Paradise Riflebird (Lophorina paradiseus) showing off iridescent plumage on its chest
Female Paradise Riflebird (Lophorina paradiseus) without colourful plumage, which helps to blend into the environment

Most species of birds of paradise are sexually dimorphic, meaning males exhibit the spectacular plumage these birds are best known for, whilst females have much less ornamentation and coloration. The male’s display feathers are highly specialised and have evolved from basic feathers. Like all feathers, they are shed and regrown every single year, which puts quite a strain on the males.

One of the first few Westerners to see these birds in their native habitat was naturalist and explorer Alfred Russel Wallace. He described the encounter, from a 19th-century Westerner’s point of view, in Narrative of Search after Birds of Paradise (1862) as:

Nature seems to have taken every precaution that these, her choicest treasures, may not lose value by being too easily obtained. […] In […] trackless wilds do they display that exquisite beauty and that marvellous development of plumage, calculated to excite admiration and astonishment among the most civilized and most intellectual races of man…

The Presenting… Birds of paradise case will be on display until 3 September 2019.

Image: (c) Mark Garrett

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All hail the swift

Image: Maciej Szymański

By Chris Jarvis, Education Officer

This week is Swift Awareness Week and that means it’s time to celebrate our screaming summer visitors – the avian ones, that is.

Here at the Museum we eagerly await the return of these long distance migrants each May. This is not only because for many of us they herald the start of summer, but also because the swifts that nest each year in the Museum tower are part of the longest-running continuous study of any bird species in the world.

Taking the long view of these amazing birds we know that, like all birds, they evolved from a particular group of dinosaurs. Birds, in effect, are living dinosaurs. The earliest fossil swift, the ‘Scania Swift’, is around 49 million years old and shows us that by this time they had already evolved in forms that are virtually indistinguishable from today’s birds. Today, they have diversified into around 100 different species including our Common Swift (Apus apus).

Swifts in the tower nests as seen on webcam
Swift chicks in a nestbox in the Museum tower, shown on the webcam feed

Swifts have taken life on the wing to the extreme. Not only are they the fastest recorded bird in level powered flight, reaching speeds of nearly 70mph, but once launching themselves from the nest that they hatched in they may not land for the next two years of their lives!

They are so adapted to life in the air that they are capable of eating, mating and even sleeping on the wing. During sleep, it is thought that the two hemispheres of the brain take it in turns to nap as the swift slowly circles at heights of up to 30,000 feet. They do not even land to collect nesting material, instead relying on whatever feathers or pieces of plant material are floating in the air to build their nests.

During this two-year flight they will follow their food – the seasonal blooms of flying insects that appear after summer rains – on a 14,000 mile annual migration to southern Africa and back, living in perpetual summer.

Whilst for a long time scientists thought swifts were closely related to similar looking birds, swallows and martins, DNA analysis has revealed that they are the product of another amazing type of evolution – called convergent evolution – where organisms with similar lifestyles independently evolve similar traits. It turns out that whilst swifts may look like swallows, they are actually more closely related to hummingbirds; swallows, on the other hand, are more closely related to kingfishers than to swifts.

Swifts flying around the Museum tower
Swifts circle the entrances to the nest areas in the Museum’s tower. Image: Gordon Bowdery

Studies show that the population of breeding swifts in the UK has roughly halved between 1995 and 2016. The causes of this decline are debated: Lack of nest sites, lack of food, and changes to global weather patterns have all been implicated. The truth is that a bird which lands only once a year is extremely difficult to study.

We hope for a successful breeding season here in the tower, but if you would like to observe them yourself you can watch the swifts on our nest cam and compare the ups and downs of their populations over the years on our website.

 

 

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Exceptional Chinese fossils come to Oxford in new partnership

by Imran Rahman, Deputy Head of Research

China is world-famous for its unique and exceptionally preserved fossils, which range from some of the oldest animals on Earth, to spectacular feathered dinosaurs. We are therefore very excited to announce that the Museum, along with other institutions from across Europe, is a partner in a major new venture with Yunnan University in China: the International Joint Laboratory for Palaeobiology and Palaeoenvironment.

Collaboration between this Museum and Yunnan University dates back to the 1990s, driven by the work of Professor Derek Siveter – a former Senior Research Fellow and current Honorary Research Associate at the Museum. He collaborated with Professor Hou Xianguang, director of the International Joint Laboratory for Palaeobiology and Palaeoenvironment, to study fossils from the internationally renowned Chengjiang biota, which was discovered by Hou Xianguang in 1984.

Museum researchers Duncan Murdock, Jack Matthews and Derek Siveter (l-r) visit the Precambrian-Cambrian Section

The Chengjiang fossil site is important and exciting because it preserves both the soft and hard parts of a range of early animals. This fossil record captures the rapid diversification of life about 520 million years old – in an event referred to as the Cambrian explosion. Derek Siveter was instrumental in a successful bid to have the Chengjiang biota designated a UNESCO World Heritage site in 2012, preserving it for future generations.

In December 2018, Museum researchers Duncan Murdock, Imran Rahman and Jack Matthews travelled with Derek to Kunming, China, for the first meeting of the International Joint Laboratory for Palaeobiology and Palaeoenvironment. The lucky researchers spent three days on field trips to the region’s most spectacular fossil sites, including Lufeng World Dinosaur Valley and the Chengjiang biota itself, followed by two full days of scientific talks and discussions.

The International Joint Laboratory is funded by the Ministry for Education of China and includes the University of Leicester, the Natural History Museum, London, the University of Munich, and the Bavarian State Collection of Zoology, along with Oxford University Museum of Natural History and Yunnan University.

The arthropod Haikoucaris ercaiensis. Sometimes referred to as a ‘short-great-appendage’ arthropod, Haikoucaris had a pair of prominent grasping appendages adjacent to the head (right-hand side of this image). Credit: Scott Billings
The arthropod Leanchoilia illecebrosa. Sometimes referred to as a ‘short-great-appendage’ arthropod, Leanchoilia illecebrosa had a pair of prominent grasping appendages adjacent to the head (right-hand side of this image). Credit: Scott Billings

A significant first outcome of this new partnership will be the loan of iconic Chengjiang fossil specimens from Kunming to Oxford for our First Animals exhibition which opens on 12 July and runs until February 2020. Most of these fossils have never been outside of China before, and some have never been seen by the public before. We invite you to visit First Animals to see these exceptional fossils first hand!

The arthropod Saperion glumaceum. Saperion had a flattened, segmented body and jointed appendages (not visible in this specimen). Credit: Scott Billings.
The arthropod Saperion glumaceum. Saperion had a flattened, segmented body and jointed appendages (not visible in this specimen). Credit: Scott Billings.

Top image: The comb jelly Galeactena hemispherica. Unlike modern comb jellies, which are soft-bodied animals, Galeactena and its relatives had hardened ‘spokes’ on the sides of the body (appearing as dark bands in this photograph). Credit: Scott Billings.

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Bacteria that changed the world: Leuconostoc

In our Bacterial World exhibition we offer a selection of ten bacteria that have changed the world, some in profound ways. In this series of short fact-file posts we present one of the ten each week. This week’s bacteria are…

Leuconostoc
– the food-fermenters

Where they live
Vats of bubbling syrup in sugar factories first yielded samples of Leuconostoc. In 1878, a scientist called Philippe van Tieghem found and studied the bacteria, which people use to make fermented food all over the world.

Why they are important
Leuconostoc bacteria play a part in creating traditional dishes in many countries, including sauerkraut, kimchi, kefir and sourdough bread.

How they are named
Van Tieghem named Leuconostoc after another bacterium that he thought it resembled. Today, however, new bacteria are named according to rules that are governed by the International Committee on Systematics of Prokaryotes.

How they work
In a pickled food dish like sauerkraut or kimchi, Leuconostoc converts the sugars in vegetables into lactic acid, preserving them and leading to a characteristic sour taste. A similar process takes place in the starter culture for making milk into kefir, and for giving sourdough bread its flavour.

Top image: Coloured scanning electron micrograph (SEM) of Leuconostoc citreum. Copyright: Science Photo Library

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Bacteria that changed the world: Lactobacillus acidophilus

In our Bacterial World exhibition we offer a selection of ten bacteria that have changed the world, some in profound ways. In this series of short fact-file posts we present one of the ten each week. This week’s bacteria are…

Lactobacillus acidophilus
– the gut-guzzlers

Where they live
Lactobacillus acidophilus is one of the hundreds of species of bacteria that live in your gut. This particular species is found all through the gut from your mouth to your anus.

Why they are important
In your gut, this species digests lactose in milk, splitting it into the simpler sugars glucose and galactose. People suffering from diseases such as HIV and cancer tend to have abnormal levels of Lactobacillus in their gut – either too many bacteria, or too few.

How they are named
Lacto is Latin for milk and bacillus refers to the rod shape of these bacteria. Acidophilus means ‘acid-loving’ in Latin – this species makes sure that its home remains slightly acidic by releasing its own acid, which helps to keep other bacteria at bay.

How they work
Not only does Lactobacillus acidophilus produce sugar from milk, but it may also produce tryptophan – an essential nutrient that we cannot produce ourselves.

Top image: Coloured transmission electron micrograph of the Gram-positive rod-shaped bacteria Lactobacillus acidophilus. Copyright: Science Photo Library