Chapter 1- Notes PDF

Chapter 1 IMPORTANT TERMS AND NOTES 1.1 The Characteristics of Life The diversity of life seems overwhelming, and yet all living things have certain characteristics in common. Life Is Organized Organisms can be organized in a hierarchy of levels. A cell is th...

Chapter 1 IMPORTANT TERMS AND NOTES 1.1 The Characteristics of Life The diversity of life seems overwhelming, and yet all living things have certain characteristics in common. Life Is Organized Organisms can be organized in a hierarchy of levels. A cell is the smallest unit of life. Life Requires Materials and Energy Organisms need an outside source of materials and energy to maintain their organization or carry on life’s other activities. Life Has the Capacity to Reproduce and Develop All forms of life have the capability to make another organism like themselves. The union of sperm and egg proceeds through stages of development. Life Responds to Its Environment All life responds to external stimuli, often by moving toward or away from a stimulus such as the sight of food. Life Maintains an Internal Environment Many of the metabolic activities of a cell or organism function in maintaining homeostasis—a constant internal environment. Life Has the Ability to Adapt Evolution is the process by which a population changes over time. These changes are adaptations to the environment that enable an organism to successfully survive and reproduce and lead to the diversity of life. 1.2 The Classification of Life Taxonomy is the discipline of grouping and organizing organisms according to different characteristics. Systematics is the study the evolutionary relationships between species. Domains Biologists classify all life as belonging to one of three domains.: Archaea, Bacteria, and Eukarya. Eukaryotic Supergroups and Kingdoms Eukarya have been classified into four kingdoms: protists, fungi, plants, and animals. Supergroups have also been formed to account for evolutionary relationships between these four kingdoms. Additional Levels of Classification Other categories include phylum, class, order, family, genus, and species. Each of these categories is more specific than the one preceding it. Scientific Names Taxonomists use a specific binomial system in which each organism is identified by a Genus name followed by a species name, written in italics. 1.3 The Process of Science Science is an objective way of knowing about the natural world based on the scientific method, a standard series of steps used in gaining new knowledge that is widely accepted among scientists. Observation Nature is orderly and measurable, so a natural event, or phenomenon, can be understood more fully through observation. Hypothesis After making observations and gathering knowledge about a phenomenon, a scientist uses inductive reasoning to come up with a hypothesis, a tentative explanation for the natural event that can be tested and may predict the outcome. Predictions and Experiments Testing a hypothesis involves conducting experiments using deductive reasoning, good experimental design, and both test and control groups. Sometimes scientists use model organisms, such as mice, because they can control specific variables in the experiment. Presenting and Analyzing the Data Data may be presented in a variety of formats, including tables and graphs. Statistical Data In statistics, the standard error, or standard deviation, tells us how uncertain a particular value is. Statistical Significance There is always the possibility that the results are due to chance or to some factor other than the experimental variable. Scientific Publications Scientific studies are customarily published in scientific journals. Scientific Theory The ultimate goal of science is to understand the natural world in terms of scientific theories, or accepted explanations of how the world works. An Example of the Scientific Method If investigators want to determine which of two antibiotics is better for the treatment of ulcers, they try to vary just the experimental variables, in this case, the medications. Experimental Design The hypothesis is: Newly discovered antibiotic B is a better treatment for ulcers than antibiotic A, which is in current use. The investigators decide to use three experimental groups of people with ulcers: one control group and two test groups. The control group is not treated with either antibiotic but are given a placebo. Test group 1 is treated with antibiotic A, while test group 2 is treated with antibiotic B. Results and Conclusion After administering the same amount of medication or placebo the same way for a period of time, the investigators examine the patients for ulcers. A graph of the percentage of people who no longer have ulcers allows the researchers to conclude whether their hypothesis has been supported. 1.4 Science and the Challenges Facing Society Technology is the application of scientific knowledge to the interests of humans. Scientific investigations are the basis for the majority of our technological advances. Climate Change Climate change describes changes in normal cycles of Earth’s climate that can be attributed to human activity. This is mostly due to imbalances in the chemical cycling of carbon that cause a rise in temperature. Biodiversity and Habitat Loss It is estimated that presently we are losing hundreds of species every year due to human activities. The destruction of healthy ecosystems have many unintended negative effects. Emerging and Reemerging Diseases Changes in human behavior, new uses for technology, and increased exposure to animals or insect populations can all result in new diseases. Over the past decade, emerging diseases (avian influenza, swine flu, severe acute respiratory syndrome, and Middle East respiratory syndrome) have been in the news. In 2020, a global pandemic called COVID-19 caused by a novel SARS virus emerged. Both emerging and reemerging diseases (e.g., Ebola) have the potential to cause human health problems across the globe.