We all want a bit of L-O-V-E, from homo sapiens, through to dolphins and of course the various sub-groups of the Heliconius toxic butterfly species.
Scientists are intrigued by two central American sub-species in particular – the red-winged Heliconius Melpomene Rosina and the white-winged Heliconius Cydno Chioneus. This pair have been part of the same ecosystem for a million years and competed for the same resources and yet have remained genetically distinct with very few instances of interbreeding.
One evolutionary explanation posits that these species haven’t blended through the generations because any off spring would have a blend of wing patterns. This would be a free-for-all for other predators who only identify danger in the distinct red or white-winged patterns of Melpomene and Cydno respectively. Therefore, being an easy target means hybrid butterfly babies don’t live long enough to pass on their own mixed genes.
But why won’t Melpomene and Cydno get it on? The recently published journal PLOS biology attributes this lack of romance to genetics. The team of researches believe to have found which parts of the genome determine mating preferences.
It’s also understood that there is a link between wing patterning and mating preference. The genes that are said to have an influence on mating preference are located very close to the Optix which is responsible for the colouring of the butterfly species’ wings. Although this is not firmly understood, scientists are optimistic that cameras and machine learning will help identify exactly what the processes are.
This case in genetics is called ‘reproductive isolating’ and it’s definitely a great topic for biologists to explore in their personal statements and interviews.
The maternal bond between mother and child is like no other. Incredibly, research is now suggesting that part of a mother’s off spring stays with her forever as foetal cells will enter the mother’s body and find themselves a home in the mother’s tissue.
Over many millions of years, the mechanics at play between baby and mother have allowed for optimal development for her baby to grow. What is most intruiging is that some of the foetal cells will enter the mother’s body and due to their malleable nature, are able to develop into tissue by receiving information from surrounding cells in their ultimate landing spot.
Researchers are referring to this as ‘microchimerism’ after the creature called ‘Chimera’ in Greek mythology which is depicted as having a lion’s head, a goat’s body and a snake tail.
Researchers are now attempting to put this phenomenon into an evolutionary perspective and to work out why this transferal of cells from foetus to mother has come to be. Although our understanding is in its primitive stages, there is speculation that these cells may influence the mother’s ability to get pregnant again.
There are, however, theories that these cells that enter the mother’s body behave like cancer cells and put the mother at greater risk of certain cancers.
Biologists and Medics could use this fascinating topic of microchimerism to make a super memorable personal statement!
Fasting has a long history and is central to many of the world’s religions: Yom Kippur is a fast day in Judaism, Ramadan is a fast month in Islam, and Lent is a 40-day fast in Christianity for Roman Catholics.
Uses of fasting can similarly be traced as far back as our primitive cultures, with examples as far ranging as: coming-of-age rites, appeasing violent deities, rituals to avoid catastrophes, and as a preparation tool for war. Fasting has even been used as a form of political protest, with the Suffragettes, the Irish Republicans and Gandhi all using hunger strikes to convey their message.
Described by Paracelsus as the ‘physican within’, the health benefits of fasting, as well as the spiritual benefits, have also be long extolled. The ‘nature cure’ became popular in the 1920s with fasting being used to treat everything from heart disease to headaches. In recent years, the rise of the 5:2 diet (where only 500 of calories are consumed on two days a week) and the 16:8 (where eating is restricted to an 8-hour window) have refreshed the concept of fasting in the public’s eye.
Students applying for History could investigate further into past beliefs around fasting and how charlatans have used extreme restrictive diets as a con in the past. Those applying for Theology might like to investigate other examples of abstinence in religion.
In the human world, we often find examples of where people can exhibit multiple talents; in the sports world there can be pro dribblers, shooters and passers, in the showbiz world, skilled actors, singers and dancers. In the ornithological sphere, new studies would suggest that these multiple gifts do not exist amongst our feathered friends.
Peacocks, for example, are incredibly beautiful with iridescent green and blue plumage, but emit a shrill scream. Christopher Cooney of the University of Oxford has carried out analysis of 518 species of bird, comparing their calls to their feather colours. The focus of the study was the difference in appearance between the males and females of the species, with sexual selection determining physicality and thus the ability to better attract a mate.
Scientists concluded that there was a trade-off between good looks and a sweet singing voice with few possessing both of the gifts in question. It was found that those with fancy feathers usually have a droning or screaking single note cry.
The study revealed that if one sex of a certain species has showy plumage then vocal talents are less likely to exist. If both sexes look more similar, males tend to have a more elaborate musical range.
Why this happens is still unknown, but it may be due to the conditions that these birds live in – although the work of Cooney does not prove this. Those species that inhabit thick wooded areas, in which the visibility at ground level is poor, may have to develop a loud and characterful voices in order to find each other.
Cooney’s team favour the theory that birds only develop one key attraction trait as the evolution process is time consuming and a second trait may be of little use.
Students hoping to go to Oxbridge to study Biology or Natural Sciences (Biology) might like to explore other animals that exhibit these evolutionary traits.
Do animals grieve? The question is a contentious one among scientists. In the era of the internet, the emotional lives of animals are on display like never before; pets welcoming owners home or even appearing to say “I love you”, wild animals cuddling with favoured humans. More recently we’ve been following the plight of the orca known as J35, who carried her dead calf for 17 days after its death. The story struck a chord with many, but divided scientists; was J35 really grieving for her child, or were we merely projecting our own emotions and rituals onto the animal kingdom? Some zoologists, such as Jules Howard, warn against anthropocentrism in our interpretation of animal behaviour. Howard argues that there is very little scientific evidence behind this, only our own desire to see ourselves reflected in our furry friends. After all, he says, this kind of behaviour has only been displayed a few times. Are all other orca mothers coldly indifferent to their dead offspring? It’s perfectly possible that J35 was simply confused. “If you believe J35 was displaying evidence of mourning or grief”, he says, “you are making a case that rests on faith not on scientific endeavour, and that makes me uncomfortable as a scientist”.
Others disagree, arguing that the scientific evidence for death-related animal behaviours is lacking simply because we are not looking for it. According to this view plenty of anecdotal evidence exists, which could be studied in greater detail were it not for the scientific bias against the idea that non-human animals could experience grief and sadness. Famously, when Koko the gorilla (who could communicate using sign language) heard of her pet kitten’s death, her instructor reported that she signed “bad, sad, bad” and “frown, cry, frown, sad”. Chimpanzees have also been seen to react to the deaths of other chimpanzees, cleaning the body and avoiding the area for a few days. This does not of itself indicate grief, although it could suggest that some species observe social and familial bonds after death or that they have death-related rituals which could be compared in some ways to human funerals.
Applicants for Biology, especially those interested in zoology, might wish to look into the debate surrounding death-related animal behaviour. Do you think it is scientifically valid to assign any human emotion to animals? Those interested in bioethics could consider the issue from a moral perspective—what would it mean for our treatment of animals if they could indeed feel grief?
Recent research has shown that species that use the most energy day to day are actually more likely to go extinct than metabolically “lazier” species. The study, conducted by a team of researchers based at the University of Kansas, examined 299 forms of molluscs who made the Atlantic ocean their home at some point over the last five million years and concluded that mollusc species with a higher resting metabolic rate died out faster than their more sluggish counterparts (pun intended). Professor of ecology and evolutionary biology Bruce Lieberman, who worked on the project, suggests, “the probable explanation is that things that were more sluggish or lazy had lower energy or food requirements and thus could make do with little when times were bad”. The team of researchers also found that this link between high metabolism and extinction was strongest when the species was found in a relatively small habitat, rather than being spread out. Despite the extinction of these high-energy species, it was found that the overall metabolic rate of the community (made up of different species) remained largely unchanged over time, even as different species came and went.
So far, this research has been limited to sea molluscs, so there is no clear indication of whether the same principle is true for other types of animal in different habitats; for example vertebrates, or land-dwelling species. Lead author of the paper Luke Strotz points out that “at the species level, metabolic rate isn’t the be-all, end-all of extinction – there are a lot of factors at play”. This is especially the case with extinction triggered by human action, such as pollution or deforestation. Nevertheless, the work of the research team could prove useful for conservationists in predicting which species are most at risk of extinction in the future, and therefore where resources should be allocated.
Students applying for Biology or Natural Sciences (B), especially those interested in ecology and conservation, might like to learn about current research on evolution and extinction. How far do you think the conclusions of this study can be applied? Is the same trend likely to hold true for mammals?
Intelligent design, often used as an argument for the existence of God, posits that the natural world shows signs of having been designed by some form of intelligence rather than as the result of an undirected process such as natural selection. Proponents often cite the harmony and complexity of various elements of the human body. Intelligent design itself has received very little scientific support. But such issues have recently come to the fore since astronaut Tim Peake stated, “I’m not religious [but] it doesn’t necessarily mean that I don’t seriously consider that the universe could have been created from intelligent design”. Further to arguing that intelligent design has no evidential basis, many opponents are taking issue with the very idea that the human body and nature in general shows signs of perfection (and therefore of creative intelligence). Clearly, all human systems have flaws that allow them to malfunction. Our cells can develop cancer, our immune system can attack us, our eyes fail us. Evolutionary biologist Matan Shelomi asks, “who designed these faulty things? The answer can’t be a God, because a God so incompetent in designing vision sensors isn’t worth worshiping.”
It must be said that such critics have somewhat misrepresented the argument about the human eye and the main thrust of the intelligent design theory, which is less about perfection and more about complexity and codependence of elements. ‘Irreducible complexity’ describes a system in which all the parts work together to achieve a certain function, and which would not work if any one small part were omitted; advocates for intelligent design propose that many biological mechanisms can be described in this way, and therefore that natural selection could not bring about these mechanisms. Darwin himself conceded, “if it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down”; however, he added, “I can find out no such case.” In fact, in the 20th century Herman Muller contemplated a sort of irreducible complexity—but rather than seeing it as an obstacle to evolution he described it as the expected result of evolution by natural selection: “being thus finally woven, as it were, into the most intimate fabric of the organism, the once novel character can no longer be withdrawn with impunity, and may have become vitally necessary”. Moreover, the irreducible complexity argument ignores the phenomenon of expiation, whereby an already existing trait may change function during the course of evolution.
Applicants for Biology or Natural Sciences (B) should be familiar with both historical and contemporary research on evolution. Those interested in Theology or Philosophy may wish to look into intelligent design as well as arguments from teleology.
The process of turning wild wolves into loyal and friendly domestic dogs began well over 10,000 years ago—between 15,000 and 12,000, depending on which researcher you ask. Much more recently, however, scientists have managed to achieve domestication in about 60 years with a different canine—the fox. Adorable Instagram star Juniper fox is living proof that foxes can indeed be domesticated and can live happily alongside humans and other animals, admittedly with a lot of work. Studying the process of domestication scientifically has allowed us to examine how it works on a genetic level.
In a recent study published in Nature Ecology and Evolution, scientists analysed the genomes of red foxes and found that certain groups of genes indicated the difference between friendlier and more aggressive individuals. Many of these genes corresponded to genes found in previous studies looking into the domestication of dogs, indicating that researchers were on the right path. Helpfully, scientists could study foxes that had already been bred to have different behavioural traits, as geneticists have been studying foxes to learn about evolution since 1959 when Russian scientist Dmitri Belyaev first started working with them to test his hypothesis that sociable behaviour and friendliness was genetically determined. Within ten generations of carefully selecting and breeding the friendliest individuals as well as the fiercest, Belyaev and his team produced two distinct lines of come-pet-me and don’t-mess-with-me foxes.
His deliberate breeding of foxes provided later generations of researchers with convenient groups already bred for certain behaviours. After his death, scientists such as Anna Kukekova took over the study of his foxes by sequencing the genomes of Belyaev’s two lineages as well as a third group of foxes who had not been selected or bred for any behaviour characteristics. This study found many groups of genes that differed between the fox lineage, including several that corresponded to regions identified in studies of dogs. This overlap indicated that even between different species, the process of domestication focuses on similar clusters of genes.
For now, the identification of the genetic component behind domestication remains general rather than specific. Geneticist Elaine Ostrander explains the slow process in terms of zeroing in on an address; “before you get to the right house, you have to get to the right street. Before you can get to the right street, you have to get to the right city, state and so on.”
Students interested in applying for Biology or Natural Sciences might like to learn more about domestication as an evolutionary process and how researchers map genomes to study the progression of a species.
New research is questioning our understanding of how genetic information is passed on. We tend to think of genetic material as being transferred ‘vertically’, from parent to child down generations within a species. However, it appears that a significant proportion of genetic material in humans and other animals ‘jumps’ from other species—transferring ‘horizontally’. This foreign DNA can be a significant factor in how species evolve. Scientists already knew that genetic material could be transferred horizontally between bacteria; in fact, this is how bacteria infecting humans are able to quickly develop resistance to antibiotics. Until now, however, the extent and role of this mechanism in humans and other animals was unclear.
So how does this all work? Firstly, this foreign genetic material isn’t genes as such but non-coding genetic elements that fill the spaces between genes. These transposable gene elements make up over half of our genome, and yet we still know little about them and what they do. According to Atma Ivancevic, lead author of a study published on this topic, this genetic material seems bent on replicating itself as much as possible. By looking for traces of two types of transposable elements, Bovine-B (BovB) and L1, researchers aimed to track them and see how, and how far, they spread. They found that some BovB material had hopped multiple times between frogs and bats, probably originating in snakes, and makes up about a quarter of the genome of cows and sheep. L1s were also found to be present in many animal and plant species.
So if this genetic material isn’t transferred through reproduction, how does it operate? A crucial clue came when Ivancevic and her team found such material present in parasitic creatures such as leeches and ticks, which strongly suggested that transposable genetic elements were introduced to the DNA of various species using parasites as their vehicles of dispersion. Although being ‘foreign’, transposable elements are not necessarily all bad news; although admittedly L1s may have links to cancer and neurological disorders, other gene elements are likely to be beneficial, and others still appear to do nothing at all. “We have evidence that they are doing good and bad things, almost accidentally,” says Ivancevic.
Applicants for Biology or Natural Sciences should familiarise themselves with recent developments in evolutionary biology, as well as being well-versed in the fundamentals. How does research such as this add to our understanding of evolution and the role of genetics?
On the 25th of July 2018, scientists announced an exciting discovery: promising signs were identified of a potential lake lying beneath layers of ice on Mars’s south pole. Researchers have long harboured suspicions that there might be water lurking on the planet, but the research led by Roberto Orosei of the Italian National Institute for Astrophysics is the first to point towards a proper body of water, and a large one at that—the lake is estimated to be around 12 miles in width.
The lake was spotted using low-frequency radio wave technology which can penetrate deep beneath the thick layers of ice. However, the low frequency also means that the results gleaned are not as precise, because the resolution of the reflected signal is relatively low. Because of this, the team’s conclusions are not yet certain, although they are confident that the existence of a lake is the most likely option presented by the data.
Could extraterrestrial life be swimming around in this polar lake? It is certainly not a welcoming environment. Firstly, the temperature presents an obstacle to life. The lower limit for the majority of organisms on earth is around –40° Celsius; the ice layer on Mars is around –68° C. Secondly, for the water to exist in liquid form at such low temperatures is has to be very salty—another condition that poses a challenge to life. Similar conditions do exist on earth, for example in deep sea brine pools or in Antarctica’s subglacial lakes, and certain organisms (known as extremophiles) have adapted to life in or around these conditions. So although a Martian lake might kill off even the hardiest of such terrestrial species, it is not unthinkable that Martian organisms may be able to survive there. Finding out whether this is indeed the case would likely involve drilling below the ice, something which is not only beyond our current technological abilities but which would face opposition from the scientific communities. However, signs of methane variation in the planet’s atmosphere has been picked up as a possible sign that Mars’s liquid water may host life.
Applicants for physical and biological science degrees alike may be interested in the ongoing discussion about the potential Martian lake. How likely is it given the evidence that such a lake really exists? How likely is it that life can thrive and survive there?