Altruism is the act of putting yourself at a disadvantage so that other members of your group can prosper. Many species exhibit altruism, as it is a key to survival (there’s actually this monkey that was born with no hands and no feet, but the members of its troop bring him food and water so that he can survive, even though that means that the other monkeys get less food). The main reason that this applies to evolution is to think in terms of the “selfish gene” theory of evolution.
This theory suggests that our bodies (our brains, our concept of self, hearts, organs, skin, bones, cells, etc. Everything that we are) only exist to support the duplication and passing of genes and that our bodies are only vessels for our genes. We have such complex bodies because it takes all of these to support and protect our genes. This theory holds that it is our genes that drive evolution because it is our genes that want to survive, not us. As long as our genes are passed on to our posterity, then we are useless vessels.
Animals of the same species fight because they want THEIR genes to be passed on, not their competitor’s. Animals have defense mechanisms like quills on a porcupine or human ability to run long distances and all of the other genetic variations in the global gene pool for the express purpose of protecting their genes.
Now that I have explained that, I’ll now relate it to altruism. I’ll just explain family-first altruism because it’s less complicated than group-oriented altruism. So, recall the definition of altruism (the act of putting oneself at a disadvantage for the betterment of the group).
Let’s say that you are a monkey in central Africa and you are standing watch in case of danger (monkeys, specifically chimps, are known to form watch patterns with monkeys standing guard to alert the troop of danger). Suddenly, you see a lion (theoretically) but it cannot see you yet. It is inching closer to your troop and crouching down to get ready to pounce. You can do one of two things. You can either a) keep quiet and hide so that the lion doesn’t eat you but would eat other members in your troop, or b) you could alert the troop to the danger and expose yourself and your position to the lion.
If you keep quiet, yes, you would keep yourself safe and, therefore, your genes safe, but the members of your troop would be killed and eaten. In which case, you and your genes would actually be at a disadvantage because you, a lone monkey, would not be able to defend yourself from danger later in life. In which case, your genes and the genes of yours that are present in the troop genome would all be lost and extinct, so this would not be beneficial to your genes.
If you alerted the troop of the danger, you would most likely be killed by the lion, but your troop would have time to mobilize and defend itself from the threat. You might wonder how this benefits your genes if your genes just want to survive. But if you think of it, the members of your troop have similar genes to yours. They are members of what we consider to be family so you actually share the same genes. Because of this, your genes are actually present in the troop genome. Because they are present in the genome, your genes do not need you to protect them because they have already been passed on to others. It is for this reason that alerting the troop would be more beneficial. You would die, but your genes would live on in the members of your troop because your troop was saved from a threat. You’re being altruistic by doing this because you are sacrificing yourself for the protection of your troop.
This is how altruism relates to evolution. Altruism is actually the act of your genes being selfish, which sounds like the opposite of what the definition of altruism is. Altruism helped to drive evolution because it relied on genes taking steps of self-preservation. (This last paragraph was kind of wishy-washy and weird, so feel free to just scratch it if it confuses you)
<em>Lactobacillus </em>is a genus of gram-positive, facultative or microaerophilic bacteria that produce lactic acid. <u>They are normally found in different parts of the body such as the mouth, digestive tract and vagina</u>. Lactobacilli usually do not cause disease, although they can cause dental caries. Some lactobacilli have a homofermentative metabolism, that is, they produce lactic acid from sugars, which makes their environment acidic and inhibits the growth of pathogenic bacteria. Some species of Lactobacillus are used in the industry for the production of yogurt, cheese and other fermented foods.
<em>Escherichia coli</em> is a bacterium that is part of the microbiota of the gastrointestinal tract of various animals. It is a gram-negative bacillus, facultative anaerobe, and the most abundant commensal of the microbiota of the gastrointestinal tract where, together with other microorganisms, it is essential for the correct functioning of the digestive process. It also participates in the production of B and K vitamins.
<em>Rhizobium </em>is a genus of gram-negative soil bacteria that fix atmospheric nitrogen and live in symbiosis with certain plants (such as leguminous plants) in their roots, after a process of infection induced by the plant itself through the secretion of lectin, to which they provide the nitrogen necessary for the plant to live and which in return gives it shelter. Fixation is the combination of molecular nitrogen (N2) with hydrogen or oxygen to give ammonium or oxides that are incorporated into the biosphere. Molecular nitrogen, which is the major component of the atmosphere, is inert and not directly usable by most living things. Therefore, it involves the incorporation of a significant amount of nitrogen into the biosphere.
<u>Therefore, all three are considered beneficial</u>.
