We saw that chemistry can be interpreted as an abstraction over physics. We don't want to talk about all sciences, just some of them which may not look like as physics at first sight, but believe me, all is physics at their core, now let us talk about the biology. Biology is the study of life, and by life, we mean any living organisms. The study can be done on tiny microorganism level, or complex ecosystem consist of different types of organisms, the study can be done on structure, function, and ... for each organism or on the way organisms affect each other or live and evolve in an ecosystem.
Life on earth is based on Carbon, and complex life molecules made up of carbon bonded with other elements, mostly oxygen, hydrogen, and nitrogen. Not only in earth, scientists even believe that if life exists somewhere else in the universe, but it must also be carbon-based too. We don't want to talk about why carbon can build complex molecules like amino acids, RNA or DNA, but chemistry can explain the structure and behaviour of these complex molecules.
The tricky thing about life is that we have to explain somehow the way living things grow and change or even interact with other living organisms. I'm not sure if I can bring a good explanation here in this post, but let's give it a try.
For example, how suddenly a single mushroom can grow in lawns. Honestly, if we want to pay attention to details, the explanation could be impossible. But if we use abstraction, they way we did for chemistry, we can explain this phenomenon. (Although some may say fungus is not exactly a plant, mushroom is an example just came in my mind because I got a picture of one couple of weeks ago when I was walking.)
They can grow everywhere when they have required conditions to grow, I mean right soil, moisture and ... All of this requirement is nothing than those things that can be explained by chemistry. Moisture is nothing but water; the good quality soil is nothing but a mixture of organic debris like leaves, tree roots, animal waste, and ... Now all you need is mushroom spawn. OK suppose somehow wind brings some mushroom spawns or seeds to our soil. (What? How does the wind work? Everybody knows that how it works, in fact, this is one of the primary things we study in primary schools) or the seeds may also be distributed by birds or other moving animals.
OK, now we have seeds and required environment to grow. We need to explain the growth process itself which is nothing but cell division process. Again we don't want to get involved in cell cycle, mitosis or meiosis division and ... all of these is nothing but applying chemistry rules to the material we have through the time (we will talk about the time later). Although these division processes are highly complex, but there is no magic or some supernatural phenomena involved. So our mushroom can grow suddenly in the backyard without having any plan for it.
