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The Study Of Life. Chapter 1. Do Now:. If a scientist hypothesizes that a vitamin could extend a person’s life-expectancy, then: 1) What is an experiment that can be made to test this hypothesis? 2) What would be the independent variable? Dependent variable?
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The Study Of Life Chapter 1
Do Now: • If a scientist hypothesizes that a vitamin could extend a person’s life-expectancy, then: • 1) What is an experiment that can be made to test this hypothesis? • 2) What would be the independent variable? Dependent variable? • 3) Give one example each of qualitative and quantitative data that can be collected in this experiment
1.1 Introduction to Biology • MAIN IDEA: All living things share the characteristics of life.
The Science of Life Biology = the science of life • Study the origins and history of life and once-living things (evolution, cell theory) • Study the structures of living things (atoms, cells, body systems) • Study how living things interact (ecology) • Study how living things function (energy, respiration, photosynthesis)
What do biologists do? (Don’t copy) • Study the diversity of life • Classification of species • Jane Goodall’s study of chimp behavior • Research diseases • Find causes, cures, and treatments • Mary-Claire King is focused on finding the genetic cause of breast cancer • Develop technologies • technology – use of science knowledge to meet human needs
What biologists do cont’d (Don’t copy) • Improve agriculture • Genetically engineered crops • Genetically altered livestock • Organic pesticides • Preserve the environment • Protect species to prevent extinction • Reproductive strategies • Deal with issues of waste, pollution, global warming, etc.
The Characteristics of Life • How do we know something is, or once was, alive? • All organisms share the same characteristics.
1. All organisms are made of one or more cells. • Cell – basic unit of structure and function in all living things • Can be unicellular (one cell) • Can be multicellular (more than one cell)
2. All organisms display organization. • Arranged in an orderly way • Unicelled organisms – structures or sections within cells that have certain functions • Multicelled organisms – specialized cells tissues organs organ systems organism
3. All organisms grow and develop. • Growth – addition of mass (cells, structures) • Ex: A flower stem becomes longer. • Development – changes during an organism’s lifetime • Ex: A seed changes into a seedling plant.
4. All organisms reproduce. • Reproduction occurs among members of the same species. • Not necessary for the individual organism’s survival, but instead for the continuation of the species
5. All organisms respond to stimuli. • Anything that is part of an organism’s internal or external environment is a stimulus. • A reaction to it is a response. • Ex: A door slams, and you turn your head toward the sound. Label stimulus or response: A fly bites you, and you swat at it. A plant grows toward the sun.
6. All organisms require energy. • From food • Some organisms like plants (producers) make their own food using sunlight (photosynthesis) or chemicals (chemosynthesis). • Organisms that can not make their own food (consumers) eat other organisms. • Energy growth, development, performing life functions
7. All organisms maintain homeostasis. • Balance within an organism by regulating internal conditions • If something happens within or to an organism to upset its normal state, processes start that will restore its balanced state. • Ex: -Hibernation –A panting dog • When you get a fever…
8. Organisms develop adaptations that evolve over time. • Inherited characteristics • Help the survival of a species in changing conditions • Do not occur overnight or to an individual • Ex: camouflage, insect immunity to pesticides
1.2 The Nature of Science • MAIN IDEA: Science is a process based on inquiry that seeks to develop explanations.
Definitions and Word Origins • Science – study of our natural world • Inquiry – seeking explanations; based on unbiased observation and experimentation • Pseudoscience – “fake” science; areas of “study” that have no real basis in science
Science relies on evidence. • Observations, data, experiments, etc. • Theory – idea with a LOT of evidence in support of it; many observations and experiments with the same results • studied by MANY different people • ex: Big Bang Theory, evolution • Pseudoscience – • no evidence, data, or facts support it; • Ex: astrology, palm reading
Science challenges accepted ideas and questions results. • Scientists welcome new ideas; findings • Scientists often debate ideas • Scientists look for accurate explanations (if something new is discovered that contradicts a known idea, it will be researched further) • Pseudoscience – will disregard ideas that go against what they think is true.
Science tests claims. • Ideas are researched thoroughly according to specific procedures. • Experiments can be repeated by others, and can be retested for accuracy. • Pseudoscience – no research or experimental procedures
Science undergoes peer review. • Conferences and meetings are held so scientists can review each others’ work. • Scientists evaluate each other for accuracy. • Pseudoscience? NO!
Science uses the metric system. • Same system all over the world, so consistent • SI = International System of Units • Based on powers of 10, so easier to do calculations • Basic units: Length = meter, mass = kilogram, volume = liter, time = second
Science in Everyday Life • Jobs useful to society: • Doctors, nurses, pharmaceutical employees, forensics lab workers, environmentalists, genetic counselors…..
EVERYONE should have a sense of… • Science literacy – ability to understand issues of science • Issues in daily life – cloning, stem cell research, AIDS research, drugs/alcohol… • Ethics – moral values on certain issues
1.3 Methods of Science • MAIN IDEA: Biologists use specific methods when conducting research.
Ask a Question • Inquiry begins with an observation. • Observations may pose questions • Questions must be testable
Form a Hypothesis • Educated guess • Testable explanation of the question Testable or Not? • Catherine has seizures due to a lack of sleep. • Birds telepathically send each other signals to each other so they can fly in patterns.
Collect Data • Information collected from observations • Qualitative and quantitative • Gathered through controlled experiments or investigations • Data organized in charts, tables, lists, etc.; labeled and clear
Controlled Experiments • A control group in an experiment is a group used for comparison. • The experimental group is the group exposed to the factor being tested.
Experimental Design • Independent variable—only one factor in a controlled experiment can change at a time • Dependent variable—results from or depends on changes to the independent variable • Constant – factor that does not change
Analyze Data • Organization of data, calculations • Graphs make patterns easier to see • Conclusions are drawn from the interpretation of the data • Determine if results support hypothesis or not
Report Conclusions • Research may be published in journals, magazines, etc. • Reviewers and other scientists determine if findings are valid
