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

New research sheds light on why plants change sex

Plants with a particular breeding system change their sex depending on how much light they receive, new scientific research has revealed.

Cranesbill (Pixabay image)

The ability of plants to flower one year as male and the next as female, or vice versa, is well documented in ‘dioecious’ plants, however the causes of this ability to change gender have been largely unexplored in ‘gynodioecious’ plants until now.

Gynodioecy is a breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate stage between hermaphrodite plants (each flower has both male and female parts) and dioecious populations (each plant having either only male or female flowers).

The ability to change sex in response to the environment has been studied extensively in dioecious plants but this new research has revealed that gynodioecious plants also change sex depending on their environment.

The results of a four-year study by researchers at the University of Lincoln, UK, show that the level of light received by the plant has a significant effect on sexual expression and reproductive output. The study found that in habitats with high levels of light, plants were more likely to change their sexual expression, and the researchers believe this is because sex lability (readiness to change) is costly and related to the availability of resources.

Dr Sandra Varga, Marie Curie Research Fellow at the University of Lincoln’s School of Life Sciences, led the research. She explained: “The evolution and maintenance of such sexual polymorphism has been investigated by evolutionary biologists for decades. It is one of the most important developments in the evolution of plant breeding systems. However, understanding the causes and consequences is challenging because so many different factors might be involved in the process of changing from one sex to another.

“Our research clearly showed that sex expression was changeable over the course of the study, and was directly related to light availability.”

Throughout the study, the researchers observed the behaviour of 326 different plants for four years and transplanted them between locations with both high and low light levels to replicate the different environments they may encounter. For example, the wood cranesbill plants used in the study can often be found under dense forest canopies and in meadows and road verges.

The researchers monitored how the sex and reproductive outputs of the plants differed depending on their location, to garner a deeper understanding of how their behaviour is altered by their environment.

The paper is published in the American Journal of Botany and is available to read online.

Reshaping our ideas of bacterial evolution

The shape of bacteria does not influence how well they can move – this is the surprising finding of new research which could have major implications for the future of the scientific and medical industries.

Bacteria

Published in Nature’s new Ecology & Evolution journal, the results refute long-held theories that there should be a strong link between the evolution of shape in bacteria and their ability to move.

Setting them apart from larger living organisms such as fish, seals and whales – for which shape is very important to their ability to swim efficiently – this new discovery highlights the unusual nature of the environment in which bacteria live.

The extensive study was conducted by Dr Fouad El Baidouri and Professor Stuart Humphries from the School of Life Sciences at the University of Lincoln, UK, together with Dr Chris Venditti from the University of Reading and was funded by a Leverhulme Trust Research Leadership Award. The team drew together information on 325 different species of Firmicutes bacteria to help address a gap in global scientific knowledge about how the shape of single-cell organisms like bacteria affects their mobility, lifestyle and pathogenicity (ability to cause disease).

Professor Humphries explained: “Many evolutionary biologists have asked why animals are shaped the way they are, but until now the scientific community has relied on mathematical models to predict the relationship between shape and movement in bacteria. We expected swimming bacteria to be rod-shaped in order to reduce their energy costs, but experimental tests are rare and, surprisingly, analyses of this relationship in an evolutionary context are lacking entirely.

“Our research has produced evidence that these theoretical predictions don’t match reality, at least in this group of bacteria, and it therefore makes a major contribution to our understanding of the evolution of bacteria.”

The researchers employed new ways of exploring the evolution of bacteria to more accurately assess the form and function of the cells.

Dr El Baidouri said: “The main focus of our research is to understand why bacteria come in so many different forms, but in order to understand this we needed to find out which bacteria have which shape. With no datasets available, we saw a clear need to collect morphological and ecological data on bacteria – a task which took several months, and is still ongoing.

“We fully expected to confirm a widely-held belief, backed by strong theoretical predictions, that rod-shaped cells would move more effectively than coccoid (spherical) cells, and that shape and motility had co-evolved. We used a number of approaches to confirm our findings, and to our great surprise we didn’t find any association between the two traits.”

Contrary to recent evidence, the study also found that neither the ability to cause disease nor the lifestyle of these bacteria (whether it is free-living or host-associated) are affected by shape. These results suggest that, for this group of bacteria at least, they have an even greater evolutionary flexibility than previously thought.

First year Biology students visit home of Charles Darwin

First year Biology students from the University of Lincoln’s School of Life Sciences visit Down House the home of Charles Darwin.

The theme for the field trip was ‘plant adaptation, conservation and evolution’ and spent two days away in Kew.

Students visited the home of Charles Darwin, Kew Gardens, Royal Botanic Gardens in Kew, and the Millennium Seed Bank. They identified different types of plant species and learned how they adapt to many environments, as well as taking part in plant photo competitions and learning about plant conservation programmes.

Down House gave students the chance to learn more about Darwin and his theory of evolution, getting them to think about the impact of his book ‘Origin of Species’ and if it can explain many different species.

A follow-up essay of the field trip counts towards 30% of the module.

Biology group 2

Biology group 1

Evolutionary and ecological biologist joins team

An evolutionary biologist whose work examines the ecological conditions which produce the best wines has joined the University of Lincoln, UK.

Dr Matthew Goddard, who has spent his academic career investigating the underlying biological rules and forces that apply to all organisms, has become part of the Evolution and Ecology research group in Lincoln’s School of Life Sciences.

Having studied marine biology and applied zoology as an undergraduate, Dr Goddard’s fascination with patterns and processes in the natural world formed during his PhD and post-doctoral research.

His research looks at patterns in evolutionary biology, particularly the evolution and maintenance of sexual reproduction. His focus is the biology of microbes, particularly yeast since its cellular structure and DNA are organised in the same way as all higher organisms and a huge amount is known about its molecular biology.

Dr Goddard said: “I find the workings of the natural world wonderfully curious and am constantly amazed by the adaptations that organisms display. I find studying biology from the population perspective to be very informative since one can simultaneously consider both the ecological and evolutionary forces which shape a population’s genetic pool.

“Sex is a much more complicated way to reproduce than a-sexual organisms. This is a big problem in evolutionary biology, so the big question is why this much more complicated method of reproduction has evolved. There are hardly any experiments as there are only a few organisms that can do both, including fungi such as yeast. Using yeast, as it has both sexual and a-sexual modes of reproduction, the team I was working with showed compelling evidence that sex does confer greater rates of adaptation, which is why this method of reproduction permeates life.”

Following his post-doctoral research, Dr Goddard moved to The University of Auckland where he has spent many years working with the New Zealand wine industry. Here he investigated the biological diversity of microbes associated with vineyards and the production of wine.

Dr Goddard said: “Our work evaluated the microbial communities as they affect the way vines grow and therefore the quality of the fruit. Our main aim was to understand if these microbes differ in space and time. It all adds to the story behind the wine, which is important as the companies want to make their product stand out in some way.”

While at Lincoln, Dr Goddard will retain a position as Associate Professor at The University of Auckland and is leading a seven-year research project which will examine the effects of synthetic pesticides on the environment, focussing on vineyards and the way crops are produced.

Dr Goddard said: “There is no scientific evidence that organic farming is better for wine production, so in this project we will be objectively evaluating the effects of pesticides on the eco-system. In another strand of research, I will be looking at how mutualisms evolve – mutualism is the way two organisms of different species exist in a relationship in which each individual benefits. We are currently unaware of any general rule of how these beneficial associations evolved in the first place so I aim to understand – using orchids and moths – how they have begun to co-evolve. I believe the University of Lincoln is a great place to facilitate my research interests and it’s fantastic to be a part of this vibrant and dynamic environment.”

Dr Goddard will also be focussing on experimental ecology and evolution to uncover patterns operating in populations.