Competitions

Biological mechanisms to interact with electromagnetic radiation, also known as light, have evolved in almost every living creature. A major application of this is in distinguishing different objects: incident light makes contact with a surface and is altered upon reflection. Sunlight strikes the rings of the blue-ringed octopus and interacts with its compounds, which absorb all wavelengths except blue, imparting a blue tint. Blue is often a hue associated in nature with poisonous material; this serves a dual purpose: animals can avoid potential food items like berries that exhibit a blue tint to prevent their toxic effects, and the prey can improve survivability by deterring predators. Pigmentation also serves a purpose in concealing animals from predators and threats by blending into their surroundings, or mimicking patterns observed on more threatening animals Similarly, the ripeness of fruit, the health of an animal, the quality of a water supply and an object’s temperature are some traits often communicated by the colour of an object which results from its interaction with incident light. The tendency of light to permeate out from its source coupled with the incredible speed with which it reaches distances makes it an invaluable means for a living organism to scope out their surroundings. The visible spectrum of light passes through water largely unfettered which makes it suitable to use as a scanning tool underwater where life initially evolved. Electromagnetic radiation (EMR) emanates large amounts of energy away from an object and into its surroundings. Light can voyage across the vacuum of space since it doesn’t require any medium to travel across. This property enables dissipation of energy from a disproportionally excited, energetic object like a star to its colder surroundings which includes the surfaces of planets where life tends to exist. Light, through the energy it carries, is indispensable to life through keeping water liquid. This prevents the destruction of biological molecules which can largely only exist and perform their designated functions if their surrounding medium is aqueous.

Light produced by the Sun is at the base of every food-chain on Earth. Every lifeform derives energy from light, either by direct photosynthesis, or indirectly via the consumption of these photoautotrophs. Living things need to conform to the conservation of energy and entropic principles which means they cannot generate energy from nothingness, they must procure it from their surroundings in some form. Chemical means of energy generation exist on Earth in chemoautotrophs, harnessing the breaking and reforming of chemical bonds in compounds present in the environment to produce usable energy. However, there are limited compounds that are present in a habitat that can be utilised which becomes a limiting factor when the number of feeders increases. Light from a star is an effectively infinite resource that is available in every exposed part of the Earth for several hours on end. Thus, very sophisticated cellular machinery has evolved to optimally harvest this source of energy. More archaic autotrophs like cyanobacteria and certain algae adapted by producing pigments that absorb wavelengths of light. Dedicated organelles formed from one of the rarest biological phenomena – endosymbiosis, have several functional units involved in capturing and garnering energy from sunlight in plant cells. Complex, multi-layered structures called thylakoids are suspended in a specialised stromal matrix in the chloroplast for the sole purpose of siphoning energy from light. A sophisticated electron transport chain akin to that involved in aerobic respiration evolved to channelise this energy and entrap it in a biologically accessible form – through simple and complex sugars that can be catabolised to release energy in any cell. This process essentially reverses the chemical reaction that occurs during elementary, aerobic respiration (glucose + oxygen -> carbon dioxide + water) with the use of the energy from light and forming glucose as well oxygen. These two products are crucial to the cycle of life, the light-driven process of photosynthesis effectively replenishes their amounts in nature allowing non-autotrophic organisms to utilise them for their bodily processes. Life’s dependence on light is illustrated by the heightened population densities of individual species and higher species variety viewed in the tropics where there is more direct sunlight. Civilisations also tend to cluster close to the tropics due to higher farming potential, longer days, greater rainfall and more tolerable temperatures. Most organisms, even non-photosynthetic ones, have evolved to depend on or harness light in different aspects. Humans, for instance, synthesize vitamin D through a pathway that requires sunlight for one of the steps. Sunlight regulates melatonin production which is instrumental in the sleep cycle, metabolism and stress management. Intense sunlight, on the contrary, causes DNA damage to exposed cells and is carcinogenic upon chronic exposure. Organisms thus evolve pigments like melanin to capture some of this light and prevent it from tampering with their genetic code. Lives of animals are structured by light availability: most animals are diurnal, they function during the day using the ample illumination to find their way around the habitat, hunting, foraging and mating. Nocturnal animals capitalise on the rest period that diurnal animals undergo in periods of low light intensity during the night, they have evolved specialised senses to bypass – such as higher rod cell density in their eyes, to take advantage of the lower visibility from the lack of light to prey on other animals.

Although its effect is less apparent, distance is another key driver of evolution. Allopatric speciation is a facet of evolution that directly results from distance being introduced between members of a species. Should a barrier form between two sects of species, different selection pressures tend to take over each half of the habitat leading to different adaptations, offering a survival advantage, and consequently differing traits being seen in following generations of each half. Minor deviations may instill notable differentiation in species, for example plant height for grazing animals, predator type and abundance which lead to natural selection of diverging characteristics. This would be even more exacerbated when looking at the prospect of interplanetary travel wherein humans residing in civilisations harboured on different planets will have vastly different stresses in their environment. Lowered gravity, for instance, can down-regulate bone density and muscle thickness as the body needs to resist lower gravitational forces acting on its skeleton and joints. This can be viewed in astronauts aboard the International Space Station who need to exercise more rigorously to maintain their previous level of muscle mass. Similarly, other potential differences like duration and intensity of light on the other planets, atmospheric composition can factor in as selection pressures that induce adaptations out of the subset of residing humans. These traits get magnified in every generation as two adapted individuals breed. An accumulation of enough of these adaptive traits leads to splitting off that branch of human into a separate species that is no longer compatible to reproduce with earthly humans.

For more complex creatures, distance also dictates group formation, as proximal individuals tend to bunch into a tribe to maximize survival chances. Proximity ensures effective communication, sharing of resources and surveillance by other members of the tribe. In most social animals like chimpanzees, gorillas and even humans, members of one’s own group are looked upon favourably while those belonging to other groups are often competition for one or the other reason. Whether another member of your species is an ally, or an adversary is often only dictated by the distance between the point of origin of the two. Organisms belonging to the same region and bearing matching physical properties are more likely to be genetic relatives, therefore it makes less evolutionary sense to exhibit hostility towards each other as it endangers the proliferation of their own set of genes. Distance from resources is a crucial determining factor for living things, a habitat located close to the equator is also closer to the Sun almost perennially due to the earth’s geoid shape and receives more light and heat for most of the year. This has numerous implications including denser plant life due to greater light availability, higher species density and larger populations. At a higher order, tribes closer to flowing rivers have access to more fertile soil present along the banks carried downstream from hills, clean, running water and fresh-water fauna. These benefits culminate in riverside locales being the most suitable for the advent of complex civilisation as shown by early settlements like those along the Indus River or the Nile. On a larger scale, this might be reflected in planets naturally located in the Goldilocks Zone having liquid water seeing life develop sooner than their counterparts due to fewer stages of evolution being necessary for life to become viable. Consequently, they would have more time to develop and create technology, becoming more advanced solely based on their distance from their star. Another manifestation of distance would be between multiple inhabited planets: this would play into the tribe-forming aspect discussed previously, possibly leading to interplanetary alliances or warfare which changes the course of life on those planets indelibly.