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Chapter 1: The Study of Life

Chapter 1: The Study of Life

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Chapter 1: The Study of Life

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  1. Chapter 1: The Study of Life

  2. Introduction to Biology Objectives for section 1: • Define Biology • Identify possible benefits from studying biology • Summarize the characteristics of living things

  3. The Science of Biology • Biology: The science of life (the study of Life and living organisms) • Biology gives us an organized way of studying living things – how they interact and function - their origins and history; - develop concepts, principles and theories that allow people to understand their environment.

  4. What Biologists Do • Study the diversity of life • Research diseases • Develop technologies • Improve agriculture • Preserve the environment (Basically they study problems and propose solutions)

  5. Characteristics of Life An organism is anything that has or once had all of these characteristics: • Living things are made of one or more cells Unicellular -- one-celled (bacteria, protists) Multicellular -- many-celled (humans, plants) Cells are the basic units of structure and function in all living things.

  6. Characteristics of Life 2) Living things display organization • specialized parts perform particular functions, like in a factory celltissueorganorgan systemorganism

  7. 3.All living things grow and develop growth – an ability to increase in size; either by increasing cell size or by adding on other cells - increase in amount of living material, forming new structuresdevelopment: all change during life of an organism Characteristics of Life

  8. Characteristics of Life 4) Living things Reproduce reproduction; production of offspring • necessary for the continuation of a species • Offspring are not identical to the parent (mutations) • Change over time (evolution) species - a group of similar looking organisms that can interbreed successfully (fertile)

  9. Characteristics of living things 5) Living things adjust to their environment environment: living things interface with surroundings

  10. stimulus: condition in environment which requires an organism to adjust response: reaction to a stimulus adaptation: structure, behavior, or internal process enables an organism to respond to stimuli and better survive (are inherited)

  11. 6. Living things require energy. a. Energy: the ability to do work or make things move; 1. powers life, homeostasis, movement, growth, reproduction, bioluminescense 2. flows through communities (one way) b. Organisms either make food for themselves (Producers = plants) or have to find and eat food for energy (Consumers = animals)

  12. 7. Living things maintain homeostasis: regulation of an animal’s internal environment to maintain conditions suitable to their environment • examples: • Regulate blood sugar levels • Regulate calcium levels in bloodstream • Regulate body temperature (energy is important here!)

  13. 8. Living things have adaptations that evolve over time… Certain features make them better able to survive and reproduce. Adaptations are any inherited characteristic that results from evolution example: drip tips on the leaves of rainforest trees. evolution: gradual change in the characteristics of species over time

  14. How do you know if an organism is living? • Some living things do not display all 8 of the characteristics of life… • Certain bacteria and fungi do not seem to respond to their environment • Mules (hybrid of donkey + horse) cannot reproduce, they do not produce viable germ cells. a sterile mule cannot pass on its genes, even if the genes are well adapted. Some individuals never develop to full term and never survive outside of the mothers womb. Furthermore, some offspring are able to pass on their genes, but over the course of multiple generations, in a small population, mutations begin to accumulate and second or third generations are not able to pass on their genes, ending the line of descent.

  15. The Nature of Science Section Objectives: • Explain the characteristics of science • Compare something that is scientific with something that is pseudoscientific • Describe the importance of the metric system and SI

  16. What is science? • A body of knowledge based on the study of nature. • The essential characteristic is scientific inquiry, which can be both a creative process as well as rooted in unbiased observations and experimentation.

  17. Science relies on evidence • We combine what we already know with consistent evidence gathered from MANY observations and experiments Theory: - different from what common folk say. An explanation of natural phenomenon that is supported by a large body of scientific evidence obtained from many different experiments and observations over time

  18. Examples: • CELL THEORY • This theory says that new cells are formed from other existing cells, and that the cell is a fundamental unit of structure, function and organization in all living organisms. • THEORY OF EVOLUTION • The change in groups of living things over time. Evolution is the process of inheritable differences becoming more common or rare within large groups (populations) of organisms. • based on countless experiments and observations • have extensive supporting evidence - allows scientists to predict new facts & relationships

  19. Have you ever read your horoscope in the newspaper? • How was it determined? • Was it based on sound scientific methods Astrology is PSEUDOSCIENCE!

  20. Pseudoscience: • Areas of study that try to imitate science • Often driven by cultural or commercial goals • They do NOT provide science-based explanations about the natural world Examples: astrology, horoscopes, psychic readings, tarot cards, face reading (Physiognomy), head reading (Phrenology), palmistry.

  21. Expands scientific knowledge • A constant re-evaluation of what is known • This often leads to new info • Nearly every new finding leads to further questioning and research (with pseudoscience, little research is done… new questions or research is NOT WELCOMED)

  22. Scientists challenge report of one Argentine ant supercolony flooding California A team of California scientists made headlines four years ago when it reported finding one of the largest insect colonies in the world -- a 600-mile-long subterranean network of Argentine ants stretching from Northern California to the Mexican border. According to the researchers, this "supercolony" is made up of billions of closely related workers -- all direct descendants of a small group of Argentine ants that were accidentally introduced into California more than a century ago. Graduate student Nicole Heller, left, and biological sciences Professor Deborah Gordon discussed the Jasper Ridge project in Gordon's office. The project analyzed the DNA from ants in the biological preserve and found obvious genetic differences among some of them, suggesting that the ants came from different colonies. Photo: L.A. Cicero Challenges accepted theories • Debate is welcomed • Conferences and meetings • Disagreements occur, lead to additional experimentation

  23. Questions results • Any observations or data that are not consistent with current scientific understanding are of interest… • These lead to further investigation • Example: bats used to be grouped with birds due to wings, but later were found more related to mammalian limbs. (pseudoscience discards or ignores observations that are inconsistent with beliefs)

  24. Tests claims • Science-based claims are based upon a large amount of data and observations • This data is from unbiased investigations and carefully controlled experimentation. • Conclusions are reached from the evidence, (pseudoscience makes claims that cannot be tested, mix fact and opinion.

  25. Undergoes peer review • Work is reviewed before it is made public. • Review is done by scientists in the same field or who are conducting similar research • They evaluate the procedures used and the results

  26. Uses metric system • A system that has units with divisions that are all powers of 10. • Unit standard were established in 1960 • Called SI, or International System of Units Meter Gram Liter Second Length Mass Volume Time

  27. Science Literacy • Forensics = study that applies science to matters of legal interest • Literacy • It is important that you are able to understand science and its process with reasoning and thinking skills.

  28. Ethics = the study of what is right or wrong - science ethical issues affect politics, moral, social - once research is done it is people of society make a decision

  29. Section 1.3: observation Methods of Science • Describe the difference between an and an inference • Differentiate among control, independent variable, and dependent variable • Identify the scientific methods a biologist uses for research

  30. 1. Ask a question Observation = a direct method of gathering info about a natural phenomenon in an orderly way. Inferences = combining what you already know with what you have learned to begin making logical conclusions. (an assumption based upon prior experiences) Ex: when we see smoke, we infer fire

  31. Ohh… This liquid is green and it is leaking from a brown can. I also smell it. Observation: when studying something describe only facts that you can see, touch, smell and hear. You are not making any guesses. THIS IS NOT AN OPINION!! Observation

  32. Based on my observations, I think that this can is old and is leaking a toxic substance. Inference Inference: using your observations to make a guess about an object or an outcome THIS CAN BE A SCIENTIFIC OPINION

  33. Scientific Methods: A series of problem-solving procedures that might include: • observations • forming a hypothesis • Experimenting • Gathering and analyzing data • Drawing conclusions

  34. Important to note… • This is the way scientific method is usually shown on diagrams or reported in journals • This is not how science is actually conducted. • Science often proceeds in a cyclical manner with one question raising another and one observation… and one experiment… • It is not always linear.

  35. 2. Form a hypothesis • Hypothesis: testable explanation for a question, problem, or situation. - Scientists are able to hypothesize by making inferences using their background experience, reading, lab work, imagination, logic, curiosity • Serendipity: the occurrence of accidental or unexpected, but fortunate results… scientists who made breakthroughs that they were not even looking for

  36. 3. Collect the Data: Experiment: to investigate a phenomenon in a controlled setting to test a hypothesis. • Controlled experiments = have: 1) a control group – a group used for comparison, do not have the experimental variable 2) an experimental group – the group exposed to the factor that is being tested

  37. Collect the Data: • Experimental design: independent variable – the tested factor, it might affect the outcome of the experiment, what is being manipulated or changed dependent variable – what is measured, this results from or depends on the changes made to the independent variable constant – a factor that remains fixed (also called control factor)

  38. In summary: • Independent variables answer the question "What do I change?” • Dependent variables answer the question "What do I observe?” • Controlled variables answer the question "What do I keep the same?” • Constant variables (control factors) answer the question "What uninteresting variables might influence the effect of the IV on the DV?"

  39. Collect the Data: Data Gathering • Data = information gained from observations, many experiments use both: Quantitative = numerical data that is easy to analyze statistically (averages, graphs) measurements of time, temp.,length, mass, area, volume, density, etc… Qualitative = descriptions from 5 senses, give a more in depth and rich description (sometimes is the only data you can get)

  40. Collect the Data: • Investigations – what we call it when the procedure involves observation and collection of data rather than controlled manipulation of variables (this is not using a control group…) Examples: • using computers to model natural behavior of organisms & systems • discovering and identifying new species

  41. 4. Analyze the Data: • Has my hypothesis been supported? • Are more data needed? • Are different procedures needed? • Display data in graph or table, this helps to look for patterns or trends • Meetings are held with other biologists to examine for avoiding bias, repeating their trials, and if sample size is large enough • You also learn from an unsupported hypothesis

  42. 5. Report Conclusions: • Findings/conclusions are reported in scientific journals • First is peer reviewed for • Originality • Competence of scientific method used • Accuracy • Then is published for review by public and other scientists (ex: journal of the american medical association)

  43. 6. Student Scientific Inquiry: • You will have some opportunities to design your own experiments • Lab safety – there are specific lab safety symbols to help alert you to specific dangers. • Make sure you are aware of all lab safety equipment and how to use it