Nature of Science Unit 1 Scientific Method History of the Scientific Method Characteristics of Life Organization of Living Things Period 4 stopped here

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 Tenets. Period 2 stopped here!

Review? 5th Period Start here

Scientific Method Is there only one “scientific method”? No. 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. Question, problem Organized Educated guess (or prediction) Evidence, information, observations

Defining the Variables Independent Variable: what you change, this is what you manipulate 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) Control Group: the group that you compare to No treatment Constants: the things that stay the same for all the experimental groups

Scientific Method Observe, Define the Problem, Develop a Question Develop a procedure How will you test your hypothesis? Develop a procedure for a reliable experiment and address safety rules. (Research) State the Expectations What do you think will happen? Predict the answer to your question or the outcome of the experiment. Observe, Define the Problem, Develop a Question 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.

Communicate the Results Analyze the Data Perform and Experiment Write a conclusion that summarizes the important parts of your experiment and the results. Analyze the Data Is the data reliable? Does your data and observations from the experiment support your hypothesis? Perform and Experiment Follow the steps in your procedure to perform your experiment. Record data and observations!

Communicate the Results Analyze the Data Perform an Experiment 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.

We will finish this unit’s notes and work on our virtual seed lab through taking data. I will receive direct instruction on the Nature of Science and Intro to Biology and clear up any confusion on the Virtual Seed Lab.

Living vs. Non-Living 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.

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 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.

Spallanzani

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. Spallanzani was another

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

Key Experiments Redi began to disprove spontaneous generation, Pasteur came up with the idea of biogenesis

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 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 or why Scientific laws are meant to be true for nearly every instance Scientific laws may occasionally change with new evidence.

Characteristics of Living Things Examples Living things are made up of units called CELLS. 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. Living things reproduce. 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. Butterflies begin life as eggs, then become caterpillars, and then become adult butterflies. 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. Start here! 3. DNA 5. Photosynthesis and Respiration 8. Evolution 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.

Important Terms Metabolism – the set of chemical reactions through which an organism builds up or breaks down materials to carry out life processes Photosynthesis and Cellular Respiration Homeostasis – the process by which organisms maintain a relatively stable internal environment Water concentrations Evolution – change in an organism over time Did humans evolve from monkeys?

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 Bison 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

How to make a wet-mount slide 1 - Get a clean slide and coverslip from your teacher. (hold correctly – by the edges!) -Place ONE drop of water in the middle of the slide. Don 't use too much or the water will run off the edge and make a mess! Place your specimen in the water drop. -Place the edge of the cover slip on one side of the water drop. - Slowly lower the cover sllp on top of the drop. Cover Slip Lower slowly To supplement before microscope lab! 5 -Place the slide on the stage and view it first with the red-banded objective. Once you see the image, you can rotate the nosepiece to view the slide with the different objectives. You do not need to use the stage clips when viewing wet-mount slides!