Nature of Science Unit 1 Characteristics of Life Scientific Method History of the Scientific Method Organization of Living Things Unit 1 Characteristics of Life Scientific Method History of the Scientific Method Organization of Living Things

Warm Up: What is the Nature of Science?

What is Science Observing Interpret Explain Characteristics Of Life Scientific Tools And Procedures Metric System Microscopes

What is the Nature of Science? Knowledge attained through study or practice Set of methods or processes Using observation and experimentation to describe and explain the natural world Organized way of using evidence to learn about the natural world.

Do you agree or disagree? Science demands evidence Science is a social activity Science is a blend of logic and imagination Scientific ideas are subject to change Scientific ideas are durable Science avoids bias The natural world is understandable

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

Scientific Method What is the scientific method? It is a _______________ that is used to find _______________ to questions about the world around us. Is there only one “scientific method”? No, there are several versions of the scientific method. Some versions have more ___________, while others may have only a few. However, they all begin with the identification of a ______________ or a ____________________ to be answered based on observations of the world around us and provide an ________________ method for conducting and analyzing an experiment. What is a hypothesis? It is an ________________ ___________ based on observations and your knowledge of the topic. What is data? It is __________________ gathered during an experiment.

Defining the Variables Independent Variable: what you change, this is what you control Dependent variable: the factor in an experiment that you want to observe, the data or what you measure Experimental Group: How will each group be different? (the group exposed to the independent variable) Constants: the things that stay the same for all the experimental groups Control Group: the group that you compare to – No treatment – Experimenter Selected group

Scientific Method ________________ How will you test your hypothesis? Develop a procedure for a reliable experiment and address safety rules. _____________________ What do you think will happen? Predict the answer to your question or the outcome of the experiment. __________ What do you want to know or explain? Use observations you have made to write a question that addresses the problem or topic you want to investigate.

______________________________ Write a conclusion that summarizes the important parts of your experiment and the results. ______________________________________________________ Is the data reliable? Does your data and observations from the experiment support your hypothesis? ____________________________________ Follow the steps in your procedure to perform your experiment. Record data and observations!

Communicate the Results Write a conclusion that summarizes the important parts of your experiment and the results. _______________________________________ Is your data inaccurate or the experiment flawed? Analyze the Data Is the data reliable? Does your data and observations from the experiment support your hypothesis? Perform an Experiment Follow the steps in your procedure to perform your experiment. Record data and observations ____________________ Rewrite your procedure to address the flaws in the original experiment.

Experimental Design Template Problem Statement: (Stated as a testable question) Hypothesis: (If....Then statement describing the effect that changing the independent variable has on the dependent variable) Independent Variable (IV): Dependent Variable (DV): Constants: Controls: Experimenter selected control:

Graphing

Prior to the 1600's many people believed that nonliving things could spontaneously turn into living things. For example, it was believed that piles of straw could turn into mice. That is obviously not the case. Living vs. Non-Living

Redi’s Experiment on Spontaneous Generation 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.

Needham Looked at growth in broth. Did not believe Redi’s experiment. Tried to prove that spontaneous generation could occur under the right conditions. Assumption: heating the gravy killed all the microorganisms

Spallanzani’s Experiment Gravy is boiled.Flask is open. Gravy is teeming with microorganisms. Gravy is boiled. Flask is sealed. Gravy is free of microorganisms. Hypothesis? Independent Variable? Dependent Variable? Controls?

Pasteur’s Experiment of Spontaneous Generation Broth is boiled.Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

Pasteur Biogenesis (generating from life) All Living things come from other living things! Biogenesis (generating from life) All Living things come from other living things! Why did microorganisms grow after Pasteur broke the neck of the flask? Why did microorganisms grow after Pasteur broke the neck of the flask?

Theory: a well tested explanation that unifies a broad range of observations Can a Theory change over time? Yes, as new evidence is uncovered, a theory may be revised or replaced Can a Theory change over time? Yes, as new evidence is uncovered, a theory may be revised or replaced Scientific Theory vs. Scientific Hypothesis

Scientific Laws -generalizations derived from facts Scientific knowledge is based on observation and inference. Scientific laws describe what happens, but not how. Scientific laws are not meant to be absolutely true for every circumstance. Scientific laws may change with new evidence. Scientific knowledge is based on observation and inference. Scientific laws describe what happens, but not how. Scientific laws are not meant to be absolutely true for every circumstance. Scientific laws may change with new evidence.

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

Levels of Organization 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

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

Designing an Experiment State the Problem Form a Hypothesis Set Up a Controlled Experiment Record Results Analyze Results Draw a Conclusion Publish Results