Reading notes: overview: chemical foundations of biology, biology is a multidisciplinary science, drawing on insights from other sciences. Living organisms and the world they live in are subject to the basic laws of physics and chemistry: life can be organized into a hierarchy of structural levels, at each successive level, additional emergent properties appear. This change in characteristics when elements combine to form a compound is an example of an emergent property: a. Those of its elements: of the 92 natural elements, only about 20-25% are essential elements that an organism need to live a healthy life and reproduce. Just 4 elements-oxygen (o), carbon (c), hydrogen (h), and. Some trace elements, such as iron (fe) are need by all form of life; other are required by only certain species. Iodine is only need by vertebrate animals: some naturally occurring elements are toxic to organisms. For example, the element arsenic has been linked to numerous diseases and can be lethal.