Chapter 1 The Science of Biology

Section Outline Section 1-1 1–1 What Is Science? A. Science is an organized way of using evidence to learn about the world. B. The goal of science is to investigate and understand the natural world, explain events in the natural world, and make useful predictions. C.Science is a body of knowledge that has been built up by scientists after centuries of using the scientific method.(We stand upon the shoulders of giants-Isaac Newton)

1-2 How Scientists Work Scientific Method Observation- Gather information (data; Quantitative & Qualitative) about something in an orderly way and ask a question Form a hypothesis- a proposed scientific explanation for a set of observations; a testable educated guess Controlled Experiment- includes variables (factors that change) a. Manipulated Variable (Independent)- variable that is deliberately changed b. Responding Variable (Dependent)- variable that is observed and changes in response to the manipulated variable c. Controlled Variable (Control)- variable that is kept the same for use as a comparison d. In a good experiment, only one variable is manipulated at a time.

1-2 How Scientists Work Scientific Method continued Recording and Analyzing Results- collecting data (information obtained from experiments) a. In science, we must be able to replicate our experiments. Recording our process and data accurately is a must. b. By recording our data we are able to build upon past knowledge Drawing a Conclusion- using the evidence to validate or refute the hypothesis. Sometimes it is a good thing to be wrong! Every experience is a learning experience!

Flowchart Flow Chart “Designing an Experiment” State the Problem Section 1-2 Flow Chart “Designing an Experiment” State the Problem Analyze Results Form a Hypothesis Draw a Conclusion Set Up a Controlled Experiment Publish Results Record Results

1-2 How Scientists Work Theory- a well tested explanation that unifies a broad range of observations. Sometimes a particular hypothesis becomes so supported from numerous investigations scientists consider it a theory.

Figure 1-8 Redi’s Experiment on Spontaneous Generation Section 1-2 OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Figure 1-10 Spallanzani’s Experiment Section 1-2 Gravy is boiled. Flask is open. Gravy is teeming with microorganisms. Flask is sealed. Gravy is free of microorganisms. Gravy is boiled.

Figure 1-11 Pasteur’s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

1-3 Studying Life Characteristics of Living Things 1. Made Up of Cells- smallest unit of an organism considered alive Reproduction- producing new organisms a. Sexual- cells from two different parents unite b. Asexual- new organism comes from only one parent 3. Based on a Genetic Code- directions for life processes come from DNA 4. Growth and Development 5. Need for Materials and Energy- metabolism is the combination of chemical reactions happening in your body 6. Response to the Environment- A stimulus is a signal to which an organism responds. A reaction to a stimulus is called a response. 7. Maintaining Internal Balance (homeostasis) 8. Evolution- change over time

Characteristics of Living Things Section 1-3 Characteristic Examples Living things are made up of units called cells. Many microorganisms consist of only a single cell. Animals and trees are multicellular. Living things reproduce. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. Living things are based on a universal genetic code. Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Living things grow and develop. Flies begin life as eggs, then become maggots, and then become adult flies. Living things obtain and use materials and energy. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Living things respond to their environment. Leaves and stems of plants grow toward light. Living things maintain a stable internal environment. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Taken as a group, living things change over time. Plants that live in the desert survive because they have become adapted to the conditions of the desert.

Figure 1-21 Levels of Organization Section 1-3 Biosphere The part of Earth that contains all ecosystems Biosphere Ecosystem Community and its nonliving surroundings Hawk, snake, bison, prairie dog, grass, stream, rocks, air Community Populations that live together in a defined area Hawk, snake, bison, prairie dog, grass Population Group of organisms of one type that live in the same area Bison herd

Figure 1-21 Levels of Organization continued Section 1-3 Organism Individual living thing Bison Tissues, organs, and organ systems Groups of Cells Nervous tissue Brain Nervous system Smallest functional unit of life Cells Nerve cell Groups of atoms; smallest unit of most chemical compounds Molecules Water DNA

1–4 Tools and Procedures Section Outline A Common Measurement System- Metric System- decimal system of measurement whose units are based on multiples of 10 2. Microscopes (we will learn more in Chapter 7) 1. Compound Light Microscopes- allow light to pass through the specimen and use two lenses 2. Electron Microscopes- use electrons to produce images of specimens (images are1000 times more detailed than light microscope) D. Laboratory Techniques 1. Cell Cultures- cells are reproduced so they can be studied 2. Cell Fractionation- cells are broken up and the parts are separated for studying individual cell parts.

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