Chapter 1: Biology, the Study of Life

Chapter Outline

I. Fire Ants Have a Good Defense
A. Fire ants take their name from their ability to sting. B. Fire ants sting in order to defend their home. C. The queen and worker ants live in chambers within and beneath a mound. D. The purpose of the queen is to produce eggs, which develop into larvae.
E. Most offspring are sterile worker ants, but a few are male and female ants with the ability to reproduce. 1. These male and female ants mate and start another colony. F. The colony can be viewed as a superorganism. The queen serves as the reproductive system, while the workers serve as the digestive and urinary systems, as well as all the other systems. 1. Ants communicate by pheromones. G. This is a successful social system from an evolutionary point of view.

II. Science Helps Us Understand the Natural World
-Critical concepts include: the nature of science, science as one way of knowing, how to design a scientific experiment with a control group, and how science leads to technology.

1.1 Scientists use a preferred method A. Biology is the scientific study of life. B. Science is a way of making sense of the natural world around us. C. Biology uses the scientific method to investigate what life is and how it works. D. The scientific method consists of four parts: making observations, formulating a hypothesis, performing experiments and making observations, and coming to a conclusion. E. Making Observations 1. Observations are details of the natural world we notice using our senses. 2. Observations also include the integration of previous data. F. Formulating a Hypothesis 1. A scientist uses inductive reasoning, which is creative thinking to combine isolated facts into a cohesive whole. 2. A hypothesis is developed following observations and is a possible explanation for a natural event. 3. A good hypothesis is testable. G. Performing Experiments and Making Observations 1. Scientists often perform an experiment, a series of procedures to test a hypothesis. a) When an experiment is done in a laboratory, all conditions are kept constant, except for an experimental variable, which is deliberately changed. b) One or more test groups are exposed to the experimental variable, but the control group is not. 2. Scientists often use a model, a representation of an actual object. 3. The results of an experiment or further observations are referred to as the data. a) Mathematical data are often displayed in graphs or tables. H. Coming to a Conclusion 1. Scientists analyze the data in order to reach a conclusion about whether a hypothesis is supported or not. a) The data can support a hypothesis, but they do not prove it “true.” They can, however, prove it false. 2. Scientists report their findings in scientific journals in order to allow other scientists to have access to them. 3. Experiments and observations must be repeatable. I. Scientific Theory 1. A scientific theory is one supported by a broad range of observations, experiments, and data from a variety of disciplines. 2. Five basic theories are present in biology. a) The Cell Theory: all organisms are made of cells, and new cells come from preexisting cells. b) The Gene Theory: all organisms contain coded information that dictates their form, function, and behavior. c) The Evolution Theory: all organisms have a common ancestor, but each is adapted to a particular way of life. d) The Homeostasis Theory: all organisms have an internal environment that must stay relatively constant within a range protective of life. e) The Ecosystem Theory: all organisms are members of populations that interact with each other and with the physical environment within a particular locale.