Ensure you understand the basic concepts of biology before taking an upcoming exam with this engaging collection of text and video lessons. For example, a branch of biology called virology studies viruses, which exhibit some of the characteristics of living entities but lack others. It is quite a broad branch itself, and depending on the subject of study, there are also microbial physiologists, ecologists, and geneticists, among others. For example, each tree in a forest is an organism. Living things are highly organized following a hierarchy that includes atoms, molecules, organelles, cells, tissues, organs, and organ systems. An organism that evolves characteristics fit for the environment will have greater reproductive success, subject to the forces of natural selection. Many multicellular organisms (those made up of more than one cell) produce specialized reproductive cells that will form new individuals. Forensic scientists provide scientific evidence for use in courts, and their job involves examining trace material associated with crimes. Examples of adaptations are diverse and unique, from heat-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which it feeds. To see an animation of this DNA molecule, click here. From our own bodies to the world we live in, discoveries in biology can affect us in very direct and important ways. An ecosystem consists of all the living things in a particular area together with the abiotic, or non-living, parts of that environment such as nitrogen in the soil or rainwater. This is just a small sample of the many fields that biologists can pursue. Basic Concepts of Biology - Chapter Summary. As an environment changes, natural selection causes the characteristics of the individuals in a population to track those changes. For this and other reasons, the knowledge of biology gained through this textbook and other printed and electronic media should be a benefit in whichever field you enter. Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles. Test your knowledge of the entire course with a 50 question practice final exam. Organelles are small structures that exist within cells and perform specialized functions. covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may In most multicellular organisms, cells combine to make tissues, which are groups of similar cells carrying out the same function. Nucleic Acids. A phylogenetic tree is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both. Prokaryotes are single-celled organisms that lack organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes; in contrast, the cells of eukaryotes do have membrane-bound organelles and nuclei. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through a process called homeostasis or “steady state”—the ability of an organism to maintain constant internal conditions. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. Proteins. Using easy-to-understand descriptions and illustrations, we'll explore the circulatory, respiratory and digestive, systems, among other types, after which you'll have the chance to take a brief quiz and see how well you understood the material. Before Linnaeus, the use of common names to refer to organisms caused confusion because there were regional differences in these common names. Microbiology is the study of the structure and function of microorganisms. Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). The source of this diversity is evolution, the process of gradual change during which new species arise from older species. An organ system is a higher level of organization that consists of functionally related organs. When viewed together, these eight characteristics serve to define life. This book is Creative Commons Attribution License Another field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. A molecule is a chemical structure consisting of at least two atoms held together by a chemical bond. 5. then you must include on every digital page view the following attribution: Use the information below to generate a citation. Both the Archaea and the Bacteria are prokaryotes, an informal name for cells without nuclei. For example, a branch of biology called virology studies viruses, which exhibit some of the characteristics of living entities but lack others. Professionals have written this chapter to help you brush up on the basic concepts of biology. Basic Concepts of Biology Chapter Exam Instructions. The atom is the smallest and most fundamental unit of matter. Because of its interdisciplinary nature, this sub discipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches. Prokaryotes are single-celled organisms that lack organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes; in contrast, the cells of eukaryotes do have membrane-bound organelles and nuclei. Once you complete this chapter, you should be ready to complete the following: We've made these learning materials self paced so you can work as slowly or quickly as you need to. 2005. For example, the North American blue jay is known uniquely as Cyanocitta cristata. Evolutionary biologists study the evolution of living things in everything from the microscopic world to ecosystems. It turns out that although viruses can attack living organisms, cause diseases, and even reproduce, they do not meet the criteria that biologists use to define life. Woese’s tree was constructed from comparative sequencing of the genes that are universally distributed, found in some slightly altered form in every organism, conserved (meaning that these genes have remained only slightly changed throughout evolution), and of an appropriate length. It includes land, water, and portions of the atmosphere. Forensic science is the application of science to answer questions related to the law. 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