UNIT 1: INTRODUCTION TO BIOLOGY TIMBERLANE HIGH SCHOOL MEGHIN MARLEY
WHAT IS SCIENCE?• An organized way of using evidence to learn about the natural world.• The word science can also be used to describe what humans already know about the natural world.• It’s important to avoid opinions and biases in science so actual facts can be presented.
HOW DO HUMANS EXPLORE SCIENCE?• Observe• Describe• Experiment• Read• Research• Explore• What are some words or processes that come to mind when you think about exploring science?
OBSERVATION• Involves observing something with one or more of your senses• Using your senses to gather information• Which senses do you believe would be most useful in gathering scientific information or data?• Sight• Sound• Touch• Smell• And sometimes even taste
OBSERVATION• 1. Quantitative- involves numbers, counting or measuring• 2. Qualitative- observations that cannot be counted or measured• Observations are used in collecting data and the formation of evidence
EVIDENCE INTERPRETATION• What happens after the observations are made?• How are the observations used to provide an understanding of the process you are trying to explain?• Inference: a logical explanation or interpretation based on prior knowledge/experience of the subject
HOW ARE SCIENTIFIC IDEAS TESTED?• Once someone has formed a scientific question what is the next step?• The Scientific Method can be used to test a hypothesis.
THE BASIC STEPS• 1. Ask a Question• 2. Form a Hypothesis• 3.Design and Conduct an Experiment• 4. Analyze Results of the Experiment• 5. Draw Conclusion
THE SCIENTIFIC METHOD• http://www.youtube.com/watch?v=LMg_asQ3Hto
HYPOTHESIS• Can answer a scientific question• Can describe scientific information• A possible explanation• Hypotheses can be tested usually through controlled experimentation• Sometimes hypotheses are wrong• In an If…then format
ALTERNATIVE HYPOTHESES• H 1, H 2, H 3• Alternative hypotheses are more likely to be correct• Multiple alternative hypotheses can be generated and tested.
THE SCIENTIFIC METHOD• Monty Python• http://www.youtube.com/watch?v=k2MhMsLn9B0
NULL HYPOTHESIS• H0• The null hypothesis is a hypothesis which the researcher tries to disprove, reject or nullify• The null often refers to the common view of something, while the alternative hypothesis is what the researcher really thinks is the cause of a phenomenon.
THE STEPS• Do all scientific investigations include all the steps?• No• Do some investigations include more steps?• Yes• The scientific method is the basis for scientific investigation, but it is not set in stone.• It is a process to help direct scientific inquiry, more steps, research, or experimentation can be necessary.
CR: 3Why is the scientific method importantfor answering scientific questions? Doyour best to describe the process ofthe scientific method step by step.
THE PROCESS OF SCIENTIFIC INVESTIGATION• The Process of Scientific Investigation can be done in a series of stages, formal research and testing is carried out in this manor.• 1. Observations• 2. Form Hypotheses• 3. Predictions• 4. Experimentation• 5. Make conclusions
EXPERIMENTAL DESIGN• Developing and setting up a controlled experiment to test your hypothesis• Controlled Experiment: When only one variable is changed at a time• Manipulated variable: variable that is deliberately changed• Responding variable: variable that is observed and changes in response to the manipulated variable
MORE ON VARIABLES• Independent Variable- researcher can control, concentration of a chemical, timing of measurements• (manipulated variable)• Dependent Variable- response that is measured• (responding variable)
CONTROLLED EXPERIMENTS• What does it mean to have a controlled experiment?• When an experiment is run, one variable is altered and the all other variables will remain constant.• A controlled experiment will be run the same way but no variables will be altered and all other variables will be kept constant.
DRAWING CONCLUSIONS• Data from experiments is evaluated• The hypothesis is supported or rejected
THEORIES• Once you have supported your hypothesis through testing does it become a theory?• What is a theory?• A theory is a well supported explanation involving a broad range of observations for a particular phenomenon • Multiple investigations have been done and proven the hypothesis to be true
THEORIES• Theories can be widely excepted, but should not be considered absolute truth• New evidence may be uncovered• New technologies can lead to new discoveries
REDI’S EXPERIMENT• In ancient times people did not understand many biological lifecycles, people accepted the idea that some organisms, fruit-flies, maggots, would suddenly just appear• Spontaneous Generation- sudden appearance of organisms from non-living matter
REDI’S EXPERIMENT• In 1668 Francesco Redi observed flies on meat and several days later the appearance of maggot, he wanted to test his hypothesis that maggots came from flies and developed a controlled experiment.• He used 8 jars, 4 he left open to the air and 4 he covered with muslin, a fabric that prevented flies from getting to the meat.
REDI’S EXPERIMENT• What was the control group?• The jars that were left uncovered • This was the way meat was typically kept• His hypothesis was that flies were causing the production of maggots on the meat• He was able to prove that the flies were causing the maggots by covering the jars, preventing the flies from laying eggs in the meat.
VARIABLES IN REDI’S EXPERIMENT• Manipulated Variables: • Muslin covering the jars• Responding Variables: • The maggots appearing or not• Variables that were controlled: • Jars, type of meat, location, temperature, time
JOHN NEEDHAM• Mid-1700’s• Englishman• Used a sealed jar of gravy to try and disprove Redi’s claim on spontaneous generation• He took a jar of gravy and sealed it• He then heated the gravy “killing off all possible microorganisms”• After several days he examined the gravy, found microorganisms and claimed they could have only came from the gravy, since the jar was sealed.
JOHN NEEDHAM• Why do you think there were organisms in the gravy?• Do you think Needham’s findings disproved the work of Redi?• Was Needham’s experiment controlled?
SPALLANZANI’S EXPERIEMENT• Italian Scholar• An improvement on Needham’s experiment• He believed that the gravy had not been heated enough to kill all the existing microorganisms• Preformed a similar experiment to Redi’s
SPALLANZANI’S EXPERIMENT• Spallanzani claimed that the gravy left open grew microorganisms that had entered from the air, the sealed flask had no living organisms.• He concluded that non-living gravy could not produce living things• What was the control group in Spallanzani’s experiment?• Gravy flask left unsealed• The manipulated variable was the sealing of the flask• The responding variable was microorganism growth• He sealed the flask and prevented microorganism growth
LOUIS PASTEUR• Famous problem solver, Microbiologist• In 1864 Louis Pasteur designed a flask with a curved neck so that air could get into the flask, but microorganisms could not• Other works of Pasteur • Saved French wine industry when wine was souring • Saved the silk industry through discovery of a silkworm disease • Discovered and worked with infectious diseases • Vaccine for Anthrax bacterial infection in 1881
CAN EVERYTHING SCIENTIFIC BE TESTED BY EXPERIMENTATION?• Animal and insect life cycles • The Great White Shark is hard to keep in captivity• Ecological Interactions • How do you simulate all the different environmental factors in a controlled way?• Human Ethics • Stem cell research • Testing on humans and animals
ALTERNATIVES TO CONTROLLED EXPERIMENTS• Field Studies • Observation of animals or other living things in their natural environment• Studies involving large amounts of people or subjects • More samples gives more reliable data• Control of as many factors as possible • In a medical study for cancer, people with other health issues may be eliminated• It is important to research what is already out there. What has been done on the subject?• Cite your sources!
So how are we going to usethis information aboutscience and the process ofscientific investigation tolearn about Biology?
SO WHAT IS BIOLOGY?• Textbook definition: A field of science that seeks to understand the living world. The study of life.• The study of things that are “living”.• What does it mean to be “alive”?• What are some characteristics that help people determine whether something is living or non?
THE CHARACTERISTICS OF LIFE• Made up of units called cells• Maintain stable internal conditions: homeostasis• Grow and develop• Reproduce• Based on a universal genetic code• Obtain and use materials and energy• Respond to their environment• When looking at a species as a whole, living things can change over time or evolve
THE CELL• What is a Cell?• A cell is a collection of living matter surrounded by a membrane that separates it from its surrounding environment.• How are cells organized?
CELLULAR ORGANIZATION• All living things are made up of one or more cells• Cells can be simple to very complex• Cells can grow and reproduce• Single-Celled Organisms • Algae • Bacteria • Paramecia, A protist• There are around 100 trillion cells in the human body
HOMEOSTASIS• Living things must expend energy to keep their cells within certain limits for proper form and function• Organisms are able to maintain certain internal environments even when the environment outside of them is constantly changing• An organisms ability to do this allows them to survive
UNIVERSAL GENETIC CODE• Information needed to live and grow is stored in complex molecules called DNA• DNA stores the information for genes and traits of an organism• DNA is the method for passing down genetic information to the next generation
USE OF MATERIALS AND ENERGY• Organisms must use materials from the earth and energy from the sun to live and grow• Chemicals/Nutrients from the earth• Energy from the sun helps plants and other photosynthetic organisms produce food
METABOLISM• Living things need energy• Life functions require energy• Transforming energy from one form to another with in cells is metabolism
RESPOND TO THEIR ENVIRONMENT• Organisms can detect and react to different signals within their environment• Stimuli: signal to which an organism responds
EVOLVE OVER TIME• Populations of organisms change over time• Natural selection: Individuals more well suited for their environment will do better and will reproduce more then other individuals
CR:4• What does it mean to be alive? Discuss what it means to you; think about the characteristics of life.• Or• Design an experiment: If you were given an unknown substance, what kinds of tests could you preform to find out if that item was living or non- living?
CHARACTERISTICS OF LIFE ASSIGNMENT• Today you will explore all the characteristics of life for a single organism• Pick any organism you would like, tell you instructor what you choose; grab paper, pencils, markers, whatever you would like to use• Make a flow diagram of your organism fulfilling all the different characteristics of life.
SCIENTISTS OF BIOLOGY• Zoologists: Animals• Botanists: Plants• Ethologists: Animal Behavior• Paleontologists: Life in the past
LEVELS OF ORGANIZATION• Molecules• Cells• Groups of cells• Organism• Population community• Ecosystem• Biosphere
• CR:5• Describe how you fulfill the 8 characteristics of life. Use your notes if you can’t remember all 8.