Astrobiology Paper Explores the Link Between Terrestrial Extinctions and the Milky Way

A new paper exploring the link between terrestrial extinctions and the Milky Way galaxy has been published by Dr Michael Gillman (School of Life Sciences, University of Lincoln), Dr Hilary Erenler (University of Northampton) and Dr Phil Sutton (School of Mathematics & Physics, University of Lincoln).

The paper, Mapping the location of terrestrial impacts and extinctions onto the spiral arm structure of the Milky Way, was published in the International Journal of Astrobiology and looks at data from asteroid impacts, as well as other significant historic changes in the climate of Earth, and the location of the Solar System in the Milkyway galaxy. It was found that asteroid impacts, relating to mass extinction events on Earth, were clustered around the passages through the higher density regions of the spiral arms.

Abstract

High-density regions within the spiral arms are expected to have profound effects on passing stars. Understanding of the potential effects on the Earth and our Solar System is dependent on a robust model of arm passage dynamics. Using a novel combination of data, we derive a model of the timings of the Solar System through the spiral arms and the relationship to arm tracers such as methanol masers. This reveals that asteroid/comet impacts are significantly clustered near the spiral arms and within specific locations of an average arm structure. The end-Permian and end-Cretaceous extinctions emerge as being located within a small star-formation region in two different arms. The start of the Solar System, greater than 4.5 Ga, occurs in the same region in a third arm. The model complements geo-chemical data in determining the relative importance of extra-Solar events in the diversification and extinction of life on Earth.

Image of spiral galaxy NGC 3344 taken by the Hubble Space Telescope.

 

Find out more about the School of Life Sciences, University of Lincoln.

Dr Giles Yeo to deliver talk at School of Life Sciences, University of Lincoln

Dr Giles Yeo, from the University of Cambridge, Horizon and the BBC’s “Trust me I’m a Doctor” will be providing an informed and entertaining seminar titled “The genetics of obesity: Can an old dog teach us new tricks?” on Friday 4th May 1-2 pm, in the School of Life Sciences seminar series at the Joseph Banks Laboratories (JBL3C01).

Dr Yeo is a geneticist with nearly 20 years’ experience studying obesity and the brain control of food intake. He obtained his PhD from the University of Cambridge in genetics in 1998 (studying the genetics of the fugu fish) and has been there ever since. He was in the initial vanguard that described a number of genes that when mutated, resulted in rare forms of severe obesity, thus uncovering key pathways in the brain that control food intake.

Dr Giles Yeo
Dr Giles Yeo

His current research focuses on understanding how these pathways differ between lean and obese people, and the influence of genes in our feeding behaviour. Giles also presents science documentaries for the BBC. His critically acclaimed investigative piece ‘Clean eating – The dirty truth’, for BBC Horizon, was screened in January 2017 and prompted an important national debate about dieting advice and evidence-based science. More recently he featured weekly on BBC2’s ‘Trust Me I’m a Doctor’ as one of the new ‘doctors’.

For more details contact Professor Jon Whitehead (jwhitehead@lincoln.ac.uk). (Please note, this talk is open to staff and students only).

Conflict Between Sexes Could Replace Evolution of New Species

New research shows that males and females of the same species can evolve to be so different that they prevent other species from evolving or colonising habitats, challenging long-held theories on the way natural selection drives the evolution of biodiversity.

According to Darwin’s theory of natural selection, first introduced in his book On the Origin of Species (1859), new environments such as mountains and islands with abundant food and habitats, offer species the ‘ecological opportunity’ to colonise an area using those resources.

New research from the UK has shown that exactly the same mechanism of evolution that creates new species also operates within the same species when males and females compete for the ecological resources available in different habitats, such as bushy areas or stony patches with abundant food. The conflict between the sexes can lead to one sex becoming bigger, more colourful or adapting to eat different food, just like a traditional process of evolution by natural selection can lead an ancestor to split into two different species.

This process of evolution between the sexes expands the biodiversity of the area – a development that evolutionary biologists previously thought only occurred when the number of different species using different resources or ‘niches’ increases. This new research challenges that assumption, showing that different species and different sexes of the same species can occupy these niches.

This new research which explored the evolution of lizards in the Chilean Andes Mountains and Argentinean Patagonia, shows that different sexes of the same species can fill niches as well, meaning new species are actively prevented from evolving.

This is because there is no new environment for them to occupy – a necessary condition for new species to evolve under Darwin’s theory of natural selection.

Conducted by academics from the Universities of Lincoln, Exeter and Sheffield, the study demonstrated that biodiversity can now be seen as the formation of new, different species, or, as the formation of different sexes which are distinct enough to be equivalent to different species in the way they ‘saturate’ ecological niches.

Dr Daniel Pincheira-Donoso, Senior Lecturer in Evolutionary Biology at the School of Life Sciences at the University of Lincoln and lead researcher on the study, said: “Our research reveals evidence for this intriguing phenomenon that the evolution of sexes within a species could replace the evolution of new species, which begins to add a new layer to our understanding of the evolution of biodiversity.

“It is important to stress that the diversity of life on our planet applies not only to the evolution of different species, but also to the independent evolution of males and females within the same species, which potentially has very important implications.”

The findings have been published in the scientific journal Global Ecology and Biogeography.

Article reblogged from here

The School of Life Sciences ranks highly in NSS 2017 Results

Students have rated the University of Lincoln in the top 20 in the UK for academic support, learning resources and learning community and was also ranked in the top third of institutions in the UK for overall satisfaction in the National Student Survey 2017.

The School of Life Sciences scored highly, with rankings listed below.

  • BSc (Hons) Animal Behaviour and Welfare (NSS subject area – Animal Science) – Animal Sciences at the University of Lincoln ranked number 1 in the UK for academic support, with 100% of students studying BSc (Hons) Animal Behaviour and Welfare stating they are satisfied overall according to the National Student Survey 2017.
  • BSc (Hons) Biochemistry (NSS subject area – Molecular Biology, Biophysics and Biochemistry) – Biochemistry at the University of Lincoln ranked number 1 in the UK for overall satisfaction and learning resources, second for academic support, and third for learning community according to the National Student Survey 2017.
  • BSc (Hons) Biology (NSS subject area – Biology) – Biology at the University of Lincoln ranked in the top 20% in the UK for academic support and learning opportunities, with 100% of students stating that staff are available when they are needed according to the National Student Survey 2017.
  • BSc (Hons) Biomedical Science (NSS subject area – Other subjects allied to Medicine) – 100% of students studying BSc (Hons) Biomedical Science at the University of Lincoln agreed the course was intellectually stimulating, and the subject ranked in the top 20% in the UK for academic support according to the National Student Survey 2017.
  • BSc (Hons) Biovetinary Science (NSS subject area – Animal Science) – Animal Sciences at the University of Lincoln ranked number 1 in the UK for academic support, and 100% of students studying BSc (Hons) Biovetinary Science stated they have access to course-specific resources when needed according to the National Student Survey 2017.
  • BSc (Hons) Zoology (NSS subject area – Zoology) – Zoology at the University of Lincoln ranked number 1 in the UK for assessment and feedback, learning opportunities and organisation and management, and second in the UK for academic support, learning community, learning resources and student voice according to the National Student Survey 2017.

Find out more about the School of Life Sciencesor take a look at our Undergraduate Programmes on offer.

Bush-cricket research published in JEB

Multi-disciplinary research funded by the Leverhulme Trust has shed light on the very early evolutionary stages of the sound generating organs in bush-crickets and their related species (known as orthopterans). The research was published in the Journal of Experimental Biology.

Orthopterans are the largest group of acoustically active insects on earth and the findings were part of collaborative research with evolutionary biologists at the University of Lincoln with teams in Canada and France.

The study takes a detailed look at a small and rare group of orthopterans, called ‘grigs’, which are the sole remaining living family of an ancient super-family of crickets called ‘haglids’. Until now, most of our scientific knowledge about haglids has been derived from fossilised remains, which are known to date back to the Jurassic period at least.

This new research reveals that grigs, and the way they create sounds using their wings, are of major importance in helping us to understand the early evolutionary stages in the centuries-old lineages of modern field and bush-crickets.

Dr Fernando Montealegre-Z, a Leverhulme grant holder and leading entomologist from the University of Lincoln’s School of Life Sciences, explained: “There are less than 10 species of grigs alive today, nearly 100 species extinct, so our research into these rare animals is very significant as it tells us a great deal about how orthopterans have evolved.

“Our work focuses on the relationship between form and function in the sound-generating organs of the different cricket groups. Both common field crickets and bush-crickets are categorised by the males of the groups producing female-attracting calls by rubbing together specialised regions of their forewings.

Such sound generation is made possible by specially evolved forewing morphologies. By contrast, the forewings of grigs lack most of the specialised features seen in their relatives. In other words, they are more reminiscent of the forms we see in the fossilised remains of now extinct species.”

Previous studies have concluded that grigs are more closely related to bush-crickets than to common field crickets. However, grigs and common crickets both use two symmetrical forewings for creating sound, while bush-crickets have a strong asymmetry between their forewings and use different wing areas for sound production.

By using state-of-the-art laser measurement techniques, the research team found that the sound-producing areas on the wings of grigs are in fact the same as in bush-crickets.
Benedict Chivers, a PhD student funded by the Leverhulme grant at the University of Lincoln, said:

“Our findings suggest that the sound generators in grigs represent an early evolutionary stage in the bush-cricket lineage. Grigs are therefore highly important for our investigations into the early evolutionary stages of a tremendous group diversity.

“We identified vibrating areas on seemingly unspecialised wings and found that these can function as highly tuned resonators – this is particularly interesting because there are multiple examples of similarly ‘unspecialised’ wings within the fossil record, and until now our understanding of how these worked was relatively poor. We now believe that both the morphology and function of grigs’ wings represent a transitional stage between the unspecialised wings of their fossilised ancestors, and the adapted form of modern bush-crickets.

“Thanks to this new research, scientific efforts to discover the vibrational and sound-producing properties of fossilised wings will be significantly improved, so that we can better understand the acoustic world in which now extinct species once lived.”

The researchers also found that there is a ‘mirror area’ on the wings of grigs which is shared by both bush-crickets and field crickets. They believe this finding points to a single ancestral pattern, from which the field and bush-cricket lineages went on to diverge. Following this initial study, more work can now be done to examine the early stages of species development.