Our earth in the solar system is the only known planet capable of allowing life to exist. Around 13.8 billion years ago, Bing bang explosion happened, which gave rise to the universe. Then it took millions of years for the floating rocks to solidify and form into galaxies and solar systems. Followed by millions of years, a single cell organism came into life in an ocean. These organisms then grouped themselves together to increase their survival rate. They tried various combinations, called Mutations to find the best possible combination of DNA sequence to survive in an environment. Mutation helped them to achieve enough varieties to let them fight against the attacking organisms. No one knows why we exist but Mother Nature has created certain constraints under which every organism can thrive.
For example, take cheetahs, it’s aerodynamically designed body type makes it one of the fastest animals. But it has its own side effects, the body temperature of a cheetah can easily reach maximum which could even kill it. And its mouth is not as heavy as a lion due to its head size.
Cheetahs cannot have a lion’s body still be able to run like it does now. The constraints prevent them to over develop the body parts relative to other animals.
Tigers have their eyes in front while deer have eyes sideways. This gives tigers opportunity to spot deer from a longer distance while deer, due to its sideways eyes, can see a wider area to help them notice a tiger when they are close by.
So organisms survival is directly proportional to its ability to use the strength optimally. Every organism is programmed to produce its offspring, and to survive. When there is a tie between the two, a few animals1 choose sex over survival due to their instinct. Why should organisms produce offspring? Because it’s easier to destroy an old car than to maintain it.
Since nature has given equal opportunity to your competitor and you, and there are constraints in which you can use resources, organisms uses sex to produce offspring that may not be easily affected by the enemy. It’s like restructuring your house when your enemy is about to identify your place to confuse him.
As we have seen earlier, we primarily want to survive and produce our next generation as our default instinct. Sexual attractions are nature’s way to make sure we reproduce. Sexual selection depends on strength and talent. Many animals choose their partner based on its ability to fight with other males and win. This ensures the females choose males with quality genes to have stronger offsprings. Some birds choose their partners based on their talent in building nests.
Evolution and our culture have worked together. Human consumed milk only during infancy, as we domesticated animals, the lactose enzyme got mutated to support milk consumption during later ages. This allowed us to depend on milk as one of the primary sources of protein and calcium. We can see a few lactose intolerant people who cannot consume milk products because of the old un-mutated gene showing up again.
Humans have taken greater advantage of evolution. We have almost beaten every animal in evolution by packing enough neurons in our brain to still be able to deliver through mom’s birth canal, thanks to our malleable head which gets harder as we grow. This is not the case with other mammals where they have a rigid head, which prevents them from having a larger brain.
If you look at other animals, most would show their traits right-away, like dolphins are born swimming. They come pre-programmed for their environment while a human child can’t even walk for many months. This is our strength, where we are born with a less wired structure to help us accommodate almost any environments from frozen land to high mountains. Pre-programmed animals can’t easily learn new things and it will affect their survival rate. Human evolution and neurons cannot be separated, they form our cognitive ability.
Story of neurons
Neurons are the brain’s cells, building blocks of our brain. Everything we perceive is because of the connections among neurons and electric impulse they create.
So it's obvious that neurons play a bigger role in our day to day life and our behavior. Our brain is 7 times larger than it should be, based on the body to brain ratio found among other animals. And hence we have around 87 billion neurons on an average adult.
We have more number of neurons in the cerebral cortex which is responsible for higher cognitive functions” and intelligence. That is the reason an elephant which has a 3 times higher number of neurons than us is still not super intelligent.
What's the deal with neurons? Neurons require large amount of energy to operate, the connections are costly. To save energy, it kind of caches2 the connections. Say, you learn to drive a car, the neurons form a new route inside your brain, every day it gets stronger and stronger. After a few months, driving a car almost becomes automatic thanks to the synapses, connections among set of neurons, you can use pre-made connections to perform seamlessly.
These synapses cause most of the behaviors, like a sportsman’s ability to react to challenge instinctively. As many as two million new neuron connections (synapses) are made per second in an infant’s brain.
Many people get excited when they learn new things, as new neuron connections are being established. Change in food habits was an important factor as well in human evolution. Our intelligence increased when we spent less time on gathering food. Through fire, we started cooking food, which reduced the load on our digestive system. Easy supply of energy to the brain has improved our intelligence, human species thrived!
Human intelligence combines hereditary and habits. Half of our IQ is inherited while the rest comes from family and peers. As we grow up, we express our own, innate intelligence. We choose our environment that better suits our natural tendencies. There is a saying: “Hereditary loads the gun, habits pull the trigger.”
Our brain and neurons are complex to understand. “The Human Brain Project”, a large research team in Switzerland, is trying build a working model of a human brain. Humans want to understand the brain and build a digital model. This may bring in digital immortality. Alcor Life Extension Foundation3 is a pioneer in this domain, they freeze the human bodies in a hope that one day we may be able to review them.
Let’s get into genes, which are fundamental units in every cell including neurons. Human genes play a crucial role in our life they decide our appearance, how we survive, and react to an environment. Various genes control our behaviors. But the genes themselves need to get switched on to show their strength. But our stress levels are directly linked to their ability to get activated. Our vulnerability to infection, cancer and heart diseases are linked to stress we undergo.
In fact, how risk-taking we are is decided by the length of a particular gene. We see some people are more risk-taking than others. Dopamine level in our brain dictates the risk-taking ability. People with long set of a particular gene, have low responsiveness to dopamine, so they must take more adventurous approach with life to get the same excitement.
Each organism, through evolution, is actually trying to pass the set of genes or information to its next generation. The genome seems an immortal, unbroken chain of link from the first gene to the genes active in your body now.