Voices from the Noise

There is an outline of an egg with a shape of a bird embryo. A lizard is embracing the egg and is outlined by a circle.

Diverging

Created by

valkyrrever

The bar was crowded at this time of the day. Creatures of all shapes were talking, whispering, bubbling, screaching. The air was heavy with noise, movement, and smells. Yet a group of them, feathered humanoids, stood out. Maybe they just looked cleaner than others, maybe lighter with their moves, or maybe because of their voices that warbled above the rest.

It was absolutely clear. She had feathers. They didn’t develop fully yet, looking more like scales or flakes of dry skin (that’s what she had mistaken it for at first). Definitely feathers. First, she noticed them on her elbows, and her father bought her extra rich cream. Now they appeared on her shoulders and shins. She wasn’t alone with this – at least four of her friends shared something similar. It wouldn’t have been too bad if not for one thing – at times she wouldn’t understand her own parents, she knew it had something to do with the changes in her body. They seemed to start looking different too, more relaxed, more distant, almost as if they were slowing down. Sometimes they looked at her with such a studying, unblinking gaze that she felt threatened or unseen. Mostly it just made her feel lost.

One year later she finished school and moved away. Other kids who would join the same program at the University grew closer and closer to her with each passing day. They would even look more alike. She felt so light and cheerful around them, more than ever like herself. So when she came back home for holidays she and her parents would mostly stay silent. She had to ask twice to understand what they were saying. Even her own room looked too small, too cramped for her. She could finally breathe again when she left the house two days before her planned departure.

They positively invented their own language without knowing it. There could be no other explanation as to why her parents couldn’t follow anymore. Neither her parents nor her friends left behind in her hometown. She was all covered with feathers by now and felt agitated all the time. She would sing songs out loud and dance on the streets together with her friends. It was much easier to transport her body from A to B by leaping, running, and floating in the air than just walking. It wasn’t something her parents had taught her. But it felt right, even if she couldn’t control it.

The distance from her parents grew with each passing year. They loved sunny quiet places, big portions of food at proper time, and had nothing to say to her. She needed something else, some movement, some adventures, some challenges. One day she found her parents sleeping on the chairs in the garden outside the house. They would sleep for three days straight. She packed up her things to never come back. Even without them, she finished the University and found a job. She managed her everyday life, too, maybe not the same way they had taught her but good enough for her. With new and different things going on around her she never bothered to look back.

At her place everything was in order – exactly as she liked it: top floor, huge windows, right in the middle of the bustling city. Friends stayed close, and parents were long time left behind in their slow old-fashioned village. She didn’t try to call them anymore; they didn’t understand each other and her parents were as good as non-existing, somehow like her grandparents. This year her own daughter was graduating from school. She was perfectly winged and feathered, except for one soft almost velvet spot on her left shoulder blade.

How do we become different species?

Let’s begin with the definition of the species. A species is the smallest classification unit biologists use to group organisms based on their evolutionary (and thus, genetic) relatedness. A species is a group of organisms that can successfully breed and give rise to fertile offspring; so the core of the definition relies on the inherited genetic uniformity of the group that allows it to reproduce. Implicitly, the definition of the species also suggests the visual similarity of organisms. While it is clear that a seagull and an ant are not the same, it is not as clear when we look closer at various gulls. The closer organisms are in terms of evolution, the blurrier the boundaries between species are. It happens that two individuals of closely related species produce a hybrid offspring that is fertile itself and can breed with either one of the parental species or with similar hybrids. What’s more, in bacteria genetic material is transferred so easily and in such ubiquitous manners that the defined criteria of the species seem to be less relevant for them. Besides vertical gene transfer from the parent to the progeny, bacteria transfer genes horizontally, not from parents to the offspring but from any organism to any other organism.

What makes a species then? The difference lies in the details. It is a combination of factors that rely on the genome structure, morphology and physiology of the individuals, their behaviour, interaction with the environment, and many more. Inside individual species these aspects are uniform. To accumulate these differences and evolve from the same ancestor into a different species organisms need lots of time. The current classification of all living organisms relies on the hypothesis about their shared ancestry. There was an organism called the Last Universal Common Ancestor (LUCA) that gave rise to all the current diversity of species. This ancestor was a unicellular organism that most closely resembled bacteria. How long did it take though to come from LUCA to a bird, a flower or a human? LUCA lived approx. 3.7 – 4.2 billion years ago, first birds – 165-150 million years ago, first flowering plants between 130-270 million years ago, and Homo sapiens as a species is around 300000 years old.

There are some conditions that mediate new species formation (speciation) by ensuring a prolonged (hundreds to thousands of years) period of no genetic exchange between two groups. The simplest way to explain this is through a geographical barrier that separated two groups of the same species – a river, a mountain ridge or just a long distance that prevented them from mating. By the force of evolutionary pressure, a uniform group of organisms splits and evolves in a manner that ensures their adaptability to new conditions. If it takes long enough time, these changes would be so big that the new groups don’t look alike anymore, have different behaviour, different genomes, and different ecological niches. All these aspects would prevent them from breeding with each other, as well as with the parental group. But no matter how alien our parents may look to us at times, modern humans are exactly the same species.

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