Unit A: Biology Today This chapter focuses on the principles of biology. Biology is the scientific study of life. A notable contradiction to science is pseudoscience which is something that sounds scientific but is not based on complete evidence. Life encompasses a wide variety of things, but all life has a set of seven characteristics which are order, regulation, growth and development, energy processing, response to the environment, reproduction, and evolution.
Life exists in many levels ranging from the biosphere to molecules and atoms. A cell is the lowest structural level that can sustain the activities required for life. Cells exist in one of two categories: prokaryotic or eukaryotic. A prokaryotic cell is simple, small, and lacking a nucleus while a eukaryotic cell is larger and more complex, containing many membrane-enclosed organelles. Biological domains further differentiate between kinds of cells. There are three major biological domains, two of which are classified for prokaryotes and the other for eukaryotes. They are Domain Bacteria, Domain Archaea, and Domain Eukarya.
Evolution is also a major theme in biology. Evolution is the concept of life evolving over the course of time. Charles Darwin is responsible for the concept of evolution through natural selection. His idea of natural selection was about the adaptation to the environment over time by populations in order to survive.
Discovery science and hypothesis driven science are the two main processes of science. Scientists follow the scientific method to test their findings. Theories and scientific laws sometimes result from many repeated experiments. A theory is a comprehensive explanation while a law is a more a generalized description. The basis of science requires that experiments be repeatable, as scientists repeat each other’s experiments to check for verification. This is why it is very important for scientists to be honest with their