Chapter 1: Exploring Life and Sciences1. Biology- The scientific study of life.2. Atom- The smallest unit of matter that retains all of the chemical properties of an element. Join together to form molecules.3. Molecule- The smallest unit of an element or compound, made up of two or more atoms held together by a strong chemical bond.4. Cell- Any of the membrane-bound compartments of which all living things other than viruses are composed. 5. Multicellular- Having or consisting of many cells or more than one cell to perform all vital functions.6. Tissue- A mass or layer of cells that are all of the same type or, if of distinct types, that occur in regular association and perform a joint function.7. Organ- A discreet portion of an organism serving a particular function or set of functions.8. Organ System- A group of organs that work together to perform one or more functions.9. Organism- A living thing that has an organized structure, can react to stimuli, reproduce, grow, adapt, and maintain homeostasis.10. Species- A group of closely related organisms that are very similar to each other and are usually capable of interbreeding and producing fertile offspring.11. Population- A group of organisms of one species that interbreed and live in the same place at the same time.12. Community- The assemblage of interacting organisms (either of the same or different species) coexisting in a particular area and time.13. Ecosystem- A system that includes all living organisms in an area as well as its physical environment functioning together as a unit.14. Biosphere- A global ecosystem composed of living organisms and the nonliving factors from which they derive energy and nutrients.15. Energy- The capacity or potential to do work.16. Metabolism- The process involving a set of chemical reactions that modifies a molecule into another to essentially maintain the living state of a cell or an organism.17. Photosynthesis- A process carried out in plants, algae, and bacteria, which uses energy from sunlight to convert carbon dioxide and water into glucose and oxygen.18. Homeostasis- The tendency not to stray from the range of favorable or ideal internal conditions.19. DNA (Deoxyribonucleic Acid)- A nucleic acid that generally is double-stranded and helical, and a crucial biomolecule for containing the genetic information for cell growth, division, and function.20. Genes- A unit of hereditary information located on a chromosome, composed of DNA, and specifying a particular product (either a protein or an RNA molecule).21. Mutation- Occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene.22. Evolution- The change in genetic composition of a population over successive generations, which may be caused by natural selection, inbreeding, hybridization, or mutation.