I would guess it comes from various instincts connected to survival. A deer eating in the wild, picks its natural food (bias) and then destroys it so it can be digested. They can do a number on your shrubs. The primary objective is not to destroy but to survive. The neighbors may do the math different. If add predator and prey, the predator also has a selected diet and needs to kill to eat. If territory is important in terms of food, the animal will first define their territory and will become biased against others; defend the territory. This last one is common in discussion forums. If you enter an established territory of thinking, there will be a defense mounted against the intruders; trolls. War is often connected to expanding territory against those who will defend their territory. The bias has to do with the selection one feels is best for survival of a growing tribe. The mother animal will defend her young. She is biased due to familiar scent. With biased ideas such as convention, law, racism, etc., there is a selection process going on based on what the mind is allowed to eat and the defense of the territory of these feeding grounds. If you are an atheists, you can only eat that philosophy. Religion would be a competitor. An intellectual omnivore is more adaptive and because he does not need specific food can live in a more crowded territory. He may cycle his food so as to not place unnecessary strain on the environment.
I can't speak to cognitive bias, but the origin of the desire to harm others is easy. It's a manifestation of our pack-social instinct. Like wolves, elephants and quite a few other species of mammal, we are programmed to form packs: small groups of individuals that hunt or forage together because it makes them more successful and/or safer. Usually a pack is an extended family that an individual is simply born into, but not always. Elephants petition to join a pack, and undergo a rite of passage, the way we apply for membership in the Rotary Club. Predatory species tend to be hostile to other packs because their food supply is limited. If one pack encroaches on another's territory, there probably won't be enough prey to feed both of them. Humans have always been obligate carnivores, going back several million years into more than one generation of ancestral species. And since we don't have the natural hunting tools (teeth, claws, speed, strength, etc.) that natural predators use, but instead use tools and strategy, we need to be a little more protective of our hunting grounds than wolves and lions--and wolves and lions are pretty tough on outsiders! This means that in the Paleolithic Era (the "Early Stone Age," before agriculture was invented and created a permanent food surplus), during a dry year when food was scarce, two tribes might have had to fight each other for sheer survival. Whoever got the food lived. In fact, the examination of Paleolithic skeletons using modern instruments has discovered that more than 50% of adult humans were killed by violence. In other words, more humans were killed by other humans than by all other causes combined. So it's a deep-seated instinct to be wary or even hostile to people outside our own community. We should be proud that we've managed to expand our definition of "community" to include people on the other side of the planet who are nothing more than abstractions.
The biological origin of the desire to harm others stems from evolutionary drives, namely: 1) to limit competition for scarce resources (food, water etc) to ensure survival and survival of one's progeny. Generally this is initially expressed as greed, which when denied, leads to anger. 2) to eliminate threats for reproductive partners. Expressed as jealousy, leading directly to anger.
There is at least one other important source of anger and the desire to harm others, and that is perception of social betrayal by them. This is evolutionary, apparently - several social species have shown this trait, including many primates. Cognitive bias is only tangentially related to the desire to harm others, and probably has different evolutionary roots; the predeliction for seeing patterns where there is only chance, say, would only overlap with desire to do harm by some coincidence.
There's no such thing as "biological origin of cognitive bias and the desire to harm others" First of all, what"cognitive bias" and "harm" mean, is very relative and subjective, except for a few cases. Current science can't explain almost any kind of human behavior (what you read in psychology/psychiatry books is pretty much pseudoscience)
