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Introduction to biology
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Biology Bios-: greek for life -logy: study of A biologist uses the scientific method to study living things Biology is the study of life Zoology Botany Microbiology Ecology Marine Biology Genetics Cell biology Anatomy and physiology Paleontology
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So….What makes something “living”? Made up of cells Reproduce Genetic code Growth and development Obtain and use materials (resources) and energy Respond to their environment Maintain a stable internal environment As a group, they change over time
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Made Up of Cells Cell o Collection of living matter enclosed by a barrier o Smallest structural unit of all living things o Prokaryotic cells Cell without a nucleus, DNA is in cytoplasm o Eukaryotic Cells Cell with a nucleus that contains the genetic material (DNA) o Unicellular “uni-” means one Organism that is made of one cell Example: bacteria Prokaryotic cells o Multi-cellular “multi-” means many Contain hundreds, thousands, even trillions of cells Many cells work together to make the living organism function Cells vary in size, shape and function Example: plants and animals
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Ability to Reproduce Asexual reproduction o Organism has single parent o Genetically identical to parent o Splits in half Sexual reproduction o Cells from two different parents unite to form new organism o Increases genetic variety and survival of species
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Based on a Genetic Code DNA nucleic acid that carries all the information about the organism All living organisms have DNA, the “blue prints” of life
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Growth and Development Growth means increase in size, such as certain bacteria Development refers to cells dividing to o Includes periods of rapid growth and dramatic change o Sometimes different stages (think caterpillar) o During development, cells multiply and are assigned specific functions and roles within the multi-cellular organism…DIFFERENTIATION
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Obtain and Use materials and Energy Obtain energy by taking in resources o Plants-sunlight o Lizard-insects Metabolism o Combination of chemical reactions through which an organism builds up or breaks down materials to carry out life processes
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Respond to their Environment Stimulus o A signal to which an organism responds External Stimuli o From environment outside organism o Example- water in soil stimulates germination Internal Stimuli o Comes from inside an organisms body o Low sugar levels in blood will stimulate you to feel hungry
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Maintain a Stable internal environment Homeostasis When organisms maintain a stable internal environment that is different from the external environment Examples: shivering and sweating
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As a group, they change over time Evolution o Process of change o When a group of organisms change over time o Could occur over hundreds or millions of years Adaptation o An inherited trait that’s helps an organisms ability to survive and reproduce in a particular environment o Over a short period of time Natural selection o The most beneficial traits for a specific group of organisms is passed on o Organisms that have that specific trait will live longer and produce more offspring than those who do not have it o The mechanism by which evolution occurs
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Levels of Organization Molecular o DNA/RNA and other molecules Cellular o Different cells Groups of Cells o (cells tissues organs organ systems organism) Organism o A single species Population o A group of the same species Community o Many different groups of species and how they interact with each other in a specific area Ecosystem o All the living and nonliving interactions in an area Biosphere o How all the different parts (biomes) of Earth come together o Bio- means life o Sphere- earth o Life is found on land, in air, and in water o “living Earth”
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Life’s Diversity of Species Plants and animals…is there only one type? Species o A distinct life form o Biologists have identified more than one million species There are various estimates to the actual amount o New species are discovered daily o 5000 sp. of bacteria, 8600 sp. of birds, 30,000 sp. of fishes, 100,000 sp. of fungi, 280,000 sp. of plants and 1 million different species of…. INSECTS
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Domains Broadest category of classification Three main domains o Domain Archea: unicellular prokary. That live in extreme environments (very hot or very cold, extremely acidic or basic)) o Domain Bacteria : All other unicellular prokary. o Domain Eukarya : Organism made up of eukary. Cells Includes 4 kingdoms: Protists, Fungi, Plants, Animals
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Classification How do we organize all these species? We categorize all the different species in to broader categories From broadest to most specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Linnaean System of Classification) Binomial nomenclature o BREAK UP THE WORD… BI-TWO, NOMIAL-NAME, NOMENCLATURE-NAMING SYSTEM o This is how we identify a species o The African lion is called Panthera leo What’s the genus? o Panthera What is the species? o Panthera leo (you say both genus and species)
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Tools of Biology Technology continually changes the way biologists work.
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Imaging technologies provide new views of life. A microscope provides an enlarged image of an object. stoma –light microscopes (LM)
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stoma – scanning electron microscopes (SEM) Imaging technologies provide new views of life. A microscope provides an enlarged image of an object. –light microscopes (LM)
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Imaging technologies provide new views of life. o transmission electron microscopes (TEM) stoma – scanning electron microscopes (SEM) A microscope provides an enlarged image of an object. –light microscopes (LM)
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Imaging technology is used in medicine. –X-ray images
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o magnetic resonance imaging (MRI) Imaging technology is used in medicine. –X-ray images
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o functional MRI (fMRI) –magnetic resonance imaging (MRI) Imaging technology is used in medicine. –X-ray images
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Complex systems are modeled on computers. Computer models are used to study systems that cannot be studied directly. o heart attacks –effect of medicines on the human body –movement of water molecules into and out of a cell –spread of a disease through a population Computer models are used when experiments are not safe, ethical, or practical. Normal heartbeat Heart attack
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The tools of molecular genetics give rise to new biological studies. A gene is a segment of DNA that stores genetic information.
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Through our understanding of DNA, we can study genetics on a molecular level. –molecular genetics –genomics
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SCIENTIFIC METHOD Review
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Scientific Method Organized problem solving Not a single method
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Steps of the Scientific Method 1.Define the Problem 2.Collect Information About the Problem 3.Form a Hypothesis 4.Experiment 5.Collect Results 6.Conclusion 7.Repeat
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Step 1. Problem What are to trying to find out? - Usually based on observations - stated as a question Example: I notice that on warm nights crickets seem to chirp more often Problem =Does temperature affect the rate of cricket chirps?
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Step 2. Collect Information About the Problem Information can be gathered from: - your own observations - published research textbooks, articles, internet etc…
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Step 3. Form a Hypothesis A possible solution to your problem Must make a prediction Must be possible to be disproved - UFOs exist is not a scientific hypothesis because it is impossible to disprove
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Formal Hypothesis A formal hypothesis used in an experiment should be stated in If…Then form. - It relates directly to the experiment to be conducted and explains the expected outcome - If I do this….. then that will happen. Example: If I raise the temperature I keep crickets in, then they will chirp more.
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Step 4. Test Your Hypothesis-Experiment Experiment must be controlled - tests only one thing at a time A controlled experiment compares a control group with an experimental group The control group provides a normal standard against which the biologist can compare results of the experimental group. The experimental group is identical to the control group except for the one factor being tested - the variable being tested is the independent variable
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Experimental Design Needs to be repeatable Should test a large sample Should be without bias
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Variables Variable = anything that can change in an experiment Controlled variables = What do I keep the same? Independent variables = What do I change? aka Manipulated variables Dependent variables = What do I measure? aka Responding variables
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Cricket Experiment Control GroupExperimental Group 20 crickets grown in a 10 gallon aquarium 12 hours of light/day Fed 5 g Acme Cricket Food Kept at 25°C 20 crickets grown in a 10gallon aquarium 12 hours of light/day Fed 5 g Acme Cricket Food Kept at 30°C
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Step 5 Data and Results Data = observations or measurements - Quantitative = number data 10 chirps/minute - Qualitative = observations color changed to orange Results = Processed data – makes the meaning of the data more clear. Allows you to see trends or patterns. Calculate an average, graph of data etc..
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Graphing Your Data Independent Variable- the factor that is changed before the experiment begins. It goes on the x-axis. Sometimes called manipulated Dependent Variable- the factor that you ran the experiment to measure, sometimes called results. It goes on the y-axis. Sometimes called responding
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Sample Graph Dependent Variable: on the Y Axis Independent Variable on the X Axis
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Conclusions Was your hypothesis correct? - do the results support your hypothesis What are possible sources of error? What next? – What question could you study next? Why is this important?
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Repeat Your Work/Publish Repeat experiment to confirm your results. When scientists have completed their work, they publish their results - this informs other scientists of their findings
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Theory A hypothesis that has been tested repeatedly and shown to be correct becomes a theory Theories can explain current observations and predicts new observations A theory is as close to certainty as you get in science
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Vocabulary to Know and Love HHYPOTHESIS EEXPERIMENTAL GROUP CCONTROL GROUP VVARIABLE CCONTROLLED VARIABLES IINDEPENDENT/MANIPULATED VARIABLE DDEPENDENT/RESPONDING VARIABLE DDATA QQUANTITATIVE DATA QQUALITATIVE DATA RRESULTS TTHEORY
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