Science Week 2019: engineering a dinosaur

Dr Clare Sansom, Senior Associate Lecturer in Birkbeck’s Department of Biological Sciences reports on the 2019 Rosalind Franklin Memorial Lecture, delivered by Professor Emily Rayfield on how computational tools are reshaping our understanding of form and function in fossil animals.

Since 2016, the School of Science at Birkbeck has held an annual lecture named for one of its most distinguished alumni, Rosalind Franklin. This lecture, which is always given by a notable woman scientist, forms part of the school’s Athena SWAN programme. Each Rosalind Franklin lecturer’s research field is closely aligned to one of the three departments that make up the School; Biological Sciences, Earth and Planetary Sciences, and Psychological Sciences. This was the year of the earth sciences, and the lecturer, Emily Rayfield, was a professor of paleobiology at the University of Bristol. She gave an engaging talk about how computer modelling is helping us understand the biology and behaviour of fossil animals, beginning with the dinosaurs.

Emily drew a contrast between the techniques used to study living animals and prehistoric ones. With living animals, there is a chance, at least, that we will be able to observe their behaviour, but with prehistoric ones all we have to go on is the fossils they leave behind. So how can we approach a question such as, what – and how – did dinosaurs eat? We can begin to understand this problem by relating the skulls, and particularly the jawbones, of living animals to their diets. Plotting the measured bite force of reptiles’ jaws, including those of the closest living relatives of dinosaurs, the crocodiles and alligators, against the size of those jaws, and then scaling up to the size of dinosaur jaw bones has suggested that the largest would have had a bite force of over 10 tonnes.

It is possible to get some idea of what fossil animals ate by, literally, looking at their dung. Fossilised faeces, or coprolites, are frequently found, and geologists can estimate the size of the creatures that produced them, as well as finding clues to their diets. The largest that have been seen are likely to have come from Tyrannosaurus rex, which measured over 40’ from nose to tail and stood about 12’ tall at the hips. Skeletal fragments found in dinosaur coprolites include those from some of the first birds. Fossilised bite marks and teeth, which differ in shape and size between herbivorous and carnivorous animals, can also fill gaps in the picture of dinosaur diets.

Feeding is only one aspect of animal behaviour, although an important one. Emily opened out her question to ask what the shape of an extinct animal’s bones can tell scientists about its behaviour more generally. Bones all respond to externally applied forces of stress (load per unit area) and strain (stretch per unit length). Wolff’s Law, which dates from 1892, states that any change in the function of bones, and therefore in the stresses and strains that they are exposed to, is directly followed by changes in their shape. In human terms, if an individual overloads his or her bones by, for example, taking up a strenuous sport, the bones will gain mass, whereas disuse will cause bone loss in astronauts exposed to low gravity as well as the chronically sick.  Mechanical loads experienced in utero affect the shape of the developing embryo and, going back to the example of feeding, animals that experience different diets develop different-shaped jaws. This can be observed in individuals of the same species, with mice raised on only soft food developing less efficient jaws than those raised on hard pellets. It is also reflected in species differences in both living and extinct animals: animals and their environments may have changed dramatically since ‘deep time’, but the laws of physics – and the basic structure of the cells and tissues they operate on – have not.

Professor Emily Rayfield

It is, of course, impossible to measure the stresses and strains that a dinosaur bone will have been subjected to, but it is not impossible to deduce them. This is where computers come in, via a mathematical technique known as finite element analysis.  In this, a complex structure is broken down into a number of simple shapes. A force is applied to each element and a computer program is used to estimate how it moves and changes.

To apply this technique to a fossil, you need to start with a digital model of that fossil, and this can now be done quite easily using a CAT scanner similar to those used in medicine. The model is then completed by adding any bones missing from that specimen. The model can be used to estimate the functional loads on the bones and their stiffness.

Armed with all this data on the forms of, and loads experienced by, dinosaur skulls, it is possible to ask complex questions about their mechanics and evolution. It is now quite well known that modern birds evolved from a group of dinosaurs, and this begs the question of how they evolved their characteristic, but extremely diverse, beaks. Some herbivorous dinosaurs in the group known as the therapods (three-toed) had beaks and comparing models of similar sized dinosaur skulls with and without beaks has suggested that a beak reduced stress and strain during feeding. In most cases – except, interestingly, in the genus Spinosaurus – the skulls of ‘really, really big’ dinosaurs seem to have experienced proportionally less stress and strain than those of smaller ones.

At the end of the lecture, Emily moved on from the largest land-based fossils to look at some of the smallest: a group of primitive shrew-like mammals known as the ‘Jurassic fissure mammals’ that lived in crevices between rocks some 200 million years ago. Working with Pamela Gill, an expert on the physiology of these creatures, Emily examined the fossilised jaws and teeth of two species and predicted differences in the speed and strength of their bites. These differences were equivalent to those between modern bat species that eat different types of insect. This suggests that, even at the very beginning of the mammalian radiation, species that occupied similar niches were beginning to diversify their diets; and it provides another example of how studies of the mechanics of fossil bones can lead to insights into the lives of animals from hundreds of millions of years ago.

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‘Me, Human’ at the Science Museum: Your 500 million year old brain

Scientists from Birkbeck and collaborating institutions are in the ‘Who Am I?’ gallery all summer to present the ‘Me, Human’ project. Dr Gillian Forrester reflects on what led her to research this topic. 

Me, Human is a live scientific experiment which will investigate how traits from our 500 million year-old vertebrate brain still underpin some of our most important and human unique behaviours – like recognising faces and generating speech. At Live Science this summer you’ll use your eyes, ears and hands to find out more about how your ancient brain actually works. We are a multidisciplinary team of scientists at all levels of our careers from undergraduate students in psychology and biological anthropology to senior academics at leading London universities. We all have a passion to communicate science and demonstrate how we, as humans, share a common evolutionary history with other animals – and to reveal our extraordinary connection to the natural world.

We are all individuals, but we acknowledge that we might have inherited grandma’s nose or dad’s extrovert personality. Have you ever thought about what physical and psychological traits we humans – as a species – have inherited from our ancestors?

As a child, I was fascinated by our closest living relatives – the great apes. I wondered – what do gorillas and chimps think? How similar is their experience of life to mine? I scratched this itch by watching documentaries, reading books and eventually taking degrees in San Diego and Oxford. It was during my studies that I started to learn about brains and how they control behaviour. What struck me as truly incredible was that there are parts of the human brain that come from when humans and fish shared a common ancestor – over 500 million years ago!

As humans, we are able to think and act in ways unlike any other animal on the planet. Because of these unique capabilities, it is easy to forget that modern human abilities have their origins in a shared evolutionary history.

Although we are bipedal and comparatively hairless, we are indeed great apes. In fact, we are not even on the fringes of the great ape family tree – we are genetically closer to chimpanzees than chimpanzees are to gorillas. As such, we share many brain and behaviour traits with our great ape cousins. But our similarities to other animals date back much farther than our split with an ancestor common to both humans and great apes (approximately six million years ago). Some brain and behaviour traits date back over 500 million years –present in early vertebrates and remain preserved in modern humans.

It is our similarities and differences to other species that allow us to better understand how we came to be modern humans.

One of our oldest inherited traits is the ‘divided brain’. While our left and right halves of the brain (hemispheres) appear physically similar, they are in charge of different behaviours. Because the left and right hemispheres control physical behaviour on the opposite side of the body, we can see these dominances revealed in the everyday actions of animals (including humans).

Animal studies have highlighted that fishes, amphibians, reptiles, and mammals also possess left and right hemispheres that differentially control certain behaviours. The divided behaviours of these animals provide a window into our ancestral past, telling the story of our shared evolutionary history with early vertebrates.

Studies suggest that the right hemisphere emerged with a specialisation for recognising the threat in the environment and controlling escape behaviours and the left hemisphere emerged as dominant for producing motor action sequences for feeding (as pictured above). The divided brain allows for any organism to obtain nourishment while keeping alert for predators. We can think of the brain as acting like an ‘eat and not be eaten’ parallel processor.

Considering the consistency in brain side across different animal species, it seems likely that there has been a preservation of these characteristics through evolutionary time. Effectively, we have lugged our useful brain and behavioural traits with us throughout our evolutionary journey.

But why should we care?

Little is known about how these old brain traits support modern human behaviours, like the way we navigate social environments, kiss, embrace, nurture babies and take a selfie! – inhibiting a better understanding of how, when and why our human unique capabilities emerged and also how they still develop during human infancy and childhood.

By taking part in Me, Human at Live Science you will learn about cutting-edge research and engage with fun psychology experiments.  This project challenges you to use your eyes, ears and hands to find out more about how ancient brain traits still control some of your most human unique behaviours. Work with scientists to explore how you use a divided brain to experience the world around you. We invite Science Museum visitors to solve puzzle boards, test your grip strength, hold and manipulate objects, recognise faces and react to different sounds. Watch your brain in action, using portable brain-imaging, as you take part in activities that will help us to better understand human brains and behaviours.

The Me, Human team at the Science Museum.

Come and join me and the Me, Human project team on this journey of exploration to find out what it is to be human and how we are connected to all animals in the natural world. Open until Monday 30 September 2019.

Dr Gillian Forrester

  • Director of the Me, Human Project
  • Reader in Psychology
  • Senior Fellow of the Higher Education Academy
  • Deputy Head of Department, Psychological Sciences, Birkbeck, University of London

Visit the exhibition at the Science Museum, London. Follow the Me, Human team on Twitter. #mehuman #livescience. 

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Birkbeck brings Higher Education to union learners

On Wednesday 26th June, Union Learning Reps (ULRs) and organisers from unions, including PCS, Unison and USDAW came together for Birkbeck’s first ULR Skills Workshop on the theme of bringing Higher Education to union learners. In this blog, event organiser Sophie Swain of Birkbeck’s Access and Engagement (A&E) reflects on the day and the importance of trade union engagement.

My role as Access and Outreach Officer (Adult and Community) involves supporting trade union members with their transition into higher education.  Alongside Birkbeck’s 10% fee discount for trade union members, I coordinate an outreach programme providing information, advice and learning activities for trade union members who do not currently have a qualification above level 4 or whose jobs may be affected by automation.

This outreach work reflects the importance of the trade union movement in promoting learning and development, and I work closely with officials and reps who are involved with supporting trade union members to access further learning.

Together with a toolkit produced in conjunction with unionlearn, June’s event is intended to be the first in a series with the aim of equipping ULRs and organisers with useful knowledge and skills to both help them in their role and in providing advice and guidance for members considering studying at university.

Following an introduction to Birkbeck, attendees at the event took part in a coaching skills session led by Head of Access, Sahar Erfani, in which they were able to put into practice new techniques for supporting members to explore their options around further study. Andrew Liddell from Birkbeck’s Development and Alumni department spoke about Degree Apprenticeships at Birkbeck and Lucy Crittenden of Birkbeck Futures ran a session on how to promote the benefits of higher education to employers. Emily Harber and Andrew Jones of Linking London led an interactive workshop on the various higher education qualifications and the many different entry levels and to finish a number of attendees took part in a campus tour led by a member of Team Birkbeck.

Feedback from attendees was overwhelmingly positive. Sue Lapworth, ULR at PCS’s Criminal Justice Branch in Croydon said “I really enjoyed the event, it was good to learn what Birkbeck can offer our members and to look round the University. I enjoyed networking with other ULRs and the staff at the college, I am in a better position to advise members who may be interested.” Another event is planned for the Autumn.

To find out more about the union outreach work taking place at Birkbeck, email union-learning@bbk.ac.uk or visit http://www.bbk.ac.uk/professional-services/access/trade-union-outreach

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Science Week 2019: The New Science of Astrobiology and the Search for Life in the Universe

Mauro Pirarba BSc, a first year Planetary Sciences Graduate Certificate student and Fellow of the Royal Astronomical Society discusses Professor Ian Crawford’s  talk, given during Science Week, on astrobiology and the search for life in the universe.

How common is life in the universe?

Sadly, we don’t have an answer to this basic question. All we can say is that life arose at least on one planet: the Earth. Fossils in very ancient rocks tell us that there were unicellular organisms around 3.5 – 3.8 billion years ago and it is probable that the first life forms were even older, i.e. life appeared on Earth “easily”, as soon as conditions were not too harsh.

If that is the case, we would expect microbial life to have arisen independently in other places in the solar system where conditions were similar to the early Earth a thick atmosphere that protected the surface from radiation, mitigated temperature variations and allowed the presence of liquid water on the surface.

Although water was once abundant on Mars, things changed dramatically billions of years ago, making the surface of the planet a very inhospitable place for life. Our only chance to find extant or past life on Mars is to look under the surface, something that the current NASA rovers cannot do. This will be within the grasp of ESA’s Rosalind Franklin rover, landing on Mars in 2021. Still, the search will only be skin-deep. Future robotic missions, the collection of samples to be returned to the Earth for sophisticated analyses and possibly the start of the human exploration of the red planet will one day give us a definite answer about the possibility that life arose on Mars.

ESA’s Rosalind Franklin rover

However, the search for life in the solar system does not end at Mars and Professor Crawford’s audience got particularly excited about a moon, Europa. This is heated by tidal forces while orbiting Jupiter, resulting in the formation of an ocean under its thick icy crust. Water, energy and a rich chemistry could provide all the ingredients for life to have arisen on Europa, perhaps in a similar way to what may have happened along mid-ocean ridges on Earth.

We can also extend our search for habitable worlds beyond our solar system. Over the last 20 years thousands of planets orbiting other stars have been discovered. Trying to image these specks of light in the glare of their stars is still a formidable challenge, but large telescopes or sets of instruments flown into space will make it possible. Such instruments will be able to “analyse” the atmosphere of these worlds and look for hints about their potential habitability.

The Search for Extra Terrestrial Intelligence (SETI), offers a different and “targeted” approach to the search for life in the universe, in the sense that it is restricted to technological civilizations interested in communicating with other intelligent beings that have been able to build radio telescopes. The search was started by Frank Drake in the 1960s and has so far not found a single artificial radio signal.

Drake equation, Optimistic Solution

Can we conclude that we are the only intelligent species who built radio telescopes in the galaxy?

No, we can’t, or at least not yet, according to Professor Crawford.

Drake came up with an equation to try and estimate the number of technological civilisations in our galaxy. Most of the terms in the equation were unknown in the 60s, but astronomers have since constrained a number of them. In the most optimistic scenario (giving the highest possible value to each term) and assuming that the average technological civilsiation lasts for 1000 years, at present there should be 1000 of them. The vastness of our galaxy justifies our failure in detecting them so far.

On the other hand, considering that it took over three billion years for life on Earth to “invent” multicellular organisms and out of the many millions of species that inhabited the planet only one has evolved to become a technological civilization, we could conclude that we may be alone in the (observable) present universe.

The reality, as Professor Crawford concluded, could be anywhere between those extremes and our inability to constrain them is a measure of our ignorance.

The closing slide of the presentation could have not been more appropriate:

“The discussions in which we are engaged belong to the very boundary regions of science, to the frontier where knowledge… ends and ignorance begins.” William Whewell (1853)

In spite of all the progress made by our species over the last century and a half, those words still hold true.

Does anyone want to join the search?

 

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