Chapter 1 Introduction Themes in the study of Life 1 Six themes of in the study of life 1st Theme New properties emerge at each level Emergent properties result from the arrangement and interaction of parts within a system Emergent properties characterize non biological entities as well For example a functioning bicycle emerges only when all of the necessary parts connect in the correct way Reductionism is the reduction of complex systems to simpler components that are more manageable to study An understanding of biology balances reductionism with the study of emergent properties 2nd Theme Organisms interact with their environment Every organism interacts with its environment including nonliving factors and other organisms Both organisms and their environments are affected by the interactions between them For example a tree takes up water and minerals from the soil and carbon dioxide from the air the tree releases oxygen to the air and roots help form soil The dynamics of an ecosystem include two major processes The flow of energy from sunlight to producers to consumers Cycling of nutrients in which materials acquired by plants eventually return to the soil Work requires a source of energy Energy can be stored in different forms for example light chemical kinetic or thermal The energy exchange between an organism and its environment often involves energy transformations Energy flows through an ecosystem usually entering as light and exiting as heat 3 rd Theme Structure and function are correlated at all levels of biological organization Structure and function of living organisms are closely related For example a leaf is thin and flat maximizing the capture of light by chloroplasts 4th Theme Cells are an organism s basic units of structure and function The cell is the lowest level of organization that can perform all activities required for life All cells Are enclosed by a membrane Use DNA as their genetic information 2 different types Prokaryotic cell No Nucleus Eukaryotic cell Contains Nucleus 5th Theme the continuity of life is based on heritable information in the form of DNA DNA controls the development and maintenance of organisms a 6th Theme Feedback mechanisms regulate biological systems Negative feedback means that as more of a product accumulates the process that creates it slows and less of the product is produced Positive feedback means that as more of a product accumulates the process that creates it speeds up and more of the product is produced 2 Evolution Unity and Diversity Evolution is the process of change that has transformed life on Earth Organisms living on Earth are modified descendents of common ancestors The 3 Domains of life Domain Bacteria and domain Archaea comprise the prokaryotes Domain Eukarya includes all eukaryotic organisms 3 How to Inquire about your observations Observations can lead us to ask questions and propose hypothetical explanations called hypotheses A hypothesis is a tentative answer to a well framed question A scientific hypothesis leads to predictions that can be tested by observation or experimentation For example Observation Your flashlight doesn t work Question Why doesn t your flashlight work Hypothesis 1 The batteries are dead Hypothesis 2 The bulb is burnt out A hypothesis must be testable and falsifiable