Lecture 2 Defining Life 2025 PDF

Defining Life Lecture 2 Life forms a hierarchy of organization WHAT IS BIOLOGY? What is a common characteristic of ALL living organisms?  Nucleic acids are a vital part of all living beings ▪ Deoxy nucleic acid (DNA) ▪ Ribonucleic Acid (RNA) ▪ Information for assembly and function How do we k...

Defining Life Lecture 2 Life forms a hierarchy of organization WHAT IS BIOLOGY? What is a common characteristic of ALL living organisms?  Nucleic acids are a vital part of all living beings ▪ Deoxy nucleic acid (DNA) ▪ Ribonucleic Acid (RNA) ▪ Information for assembly and function How do we know that something is alive? What characteristic(s) here seem to indicate life? Play video Consider these whole plants Look closely at their cells Play video What are these cattle doing that seems like a function associated with life?  All living things take in matter and energy from their environment and change them into new forms And that function (process) is called...?  Energy is stored as chemical energy. Sugar Oxygen Oxygen Electromagnetic energy in sunlight Photosynthesis captures Cellular respiration electromagnetic energy releases chemical energy from sunlight. from sugar molecules. Carbon dioxide Released chemical energy is made and available for other Water metabolic processes. © Cengage Learning 2017 What else can living organisms do? There are two general mechanisms of reproduction What about this?  A. Egg B. Larva C. Pupa D. Adult Jack de Coningh/Animals Animals What are these living organisms doing? Do ALL Living Organisms Communicate?  What other forms of communications exist? How do single cells communicate? Play Video What else are we missing about living organisms?  Characteristics of Living Systems 1. Genetic Information ▪ usually in the form of DNA 2. Movement: ▪ via self-propulsion, usually directed 3. Metabolism: ▪ chemical transformation of nutrients 4. Reproduction: ▪ generation of two cells from one, or a new cell from two 5. Differentiation: ▪ synthesis of new substances or structures that modify the cell 6. Communication ▪ generation of, and response to, signals (including chemical) 7. Evolution ▪ genetic changes in cells that are transferred to offspring Cell Smallest unit with the capacity to live and reproduce, independently or as part of a multicellular organism. Things to know from this lecture ▪ List the 7 characteristics of living organisms discussed in lecture ▪ Explain, describe and be able to provide an example for each characteristic ▪ Think of examples outside the ones we looked at in class ▪ Try to think of examples other than human-related ▪ Think about these 7 characteristics and relate them to a single cell ▪ Does a single cell do all of these 7 characteristics of living organisms? NEXT LECTURE ▪ Read Chapter 2 ▪ As you read think of the following questions: ▪ How is chemistry related to life? ▪ What chemical elements are usually associated with living organisms? ▪ How do the different type of chemical bonds relate to living organisms? ▪ What is the importance of molecular shape for living organisms? ▪ How is water related to life? ▪ List the characteristics of water that make life possible