Chapter 1 The Science of Biology

How Scientist Work Scientific Method 1. Asking a question 2. Forming a hypothesis 3. Setting –up a controlled experiment 4. Recording & Analyzing Results 5. Drawing a conclusion Evaluate hypothesis – support or reject 6. Publishing & Repeating Investigations

Controlled Experiments _________________________ Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or CONTROLLED. _____________________  The variable that is deliberately changed ______________________  The variable that is observed & that changes in response to the manipulated variable.

Spontaneous Generation Ex. People would write recipes for living things. Francisco Redi tested this hypothesis w/ the meat & fly experiment

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Uncovered jarsCovered jars Several days pass Maggots appearNo maggots appear Responding Variable: whether maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Section 1-2 Figure 1-8 Redi’s Experiment on Spontaneous Generation

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

Biogenesis _________________________________________ _________________________________________ Early scientists debated Spontaneous generation & Biogenesis Until Louis Pasteur Experiment with flasks of straight and curved necks & bacteria entering these flasks demonstrated that life comes from life

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

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

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

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

When are experiments not possible? ____________________________________ ___________________________________ ____________________________________ ____________________________________ ____________________________________

Theory ____________________________________ ____________________________________ ____________________________________

Video 1 It’s Alive!, Part 1

Characteristics of Living things 1. Made up of cells 2. Reproduce ________________________  Two cells from different parents unite to produce the 1 st cell of the new organism. ________________________  The new organism has a single parent 3. Universal Genetic code _________

4. Grow & develop 5. Obtain & use energy ________________  The building up or breaking down of materials 6. Respond to their environment __________________  Signal which an organism to.  Ex. Light or temperature ___________________  Maintaining a constant internal condition 7. Change over time ________________

Video 2 It’s Alive!, Part 2

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

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

Microscopes Light microscopes 1000x _______________________________________ _______________________________________ Electron microscopes Produce magnified images by focusing beams of electrons. (can’t use living specimens) ______________________________________

Laboratory Techniques Cell culture _______________________________________ _______________________________________ _______________________________________ Cell fractionation _______________________________________