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Introduction to biology

BiologyBios-: greek for life-logy: study ofA biologist uses the scientific method to study living thingsBiology is the study of lifeZoologyBotanyMicrobiologyEcologyMarine BiologyGeneticsCell biologyAnatomy and physiologyPaleontology

So.What makes something living?Made up of cellsReproduceGenetic codeGrowth and developmentObtain and use materials (resources) and energyRespond to their environmentMaintain a stable internal environmentAs a group, they change over timeMade Up of CellsCellCollection of living matter enclosed by a barrierSmallest structural unit of all living thingsProkaryotic cellsCell without a nucleus, DNA is in cytoplasmEukaryotic CellsCell with a nucleus that contains the genetic material (DNA)Unicellularuni- means oneOrganism that is made of one cellExample: bacteriaProkaryotic cellsMulti-cellularmulti- means manyContain hundreds, thousands, even trillions of cellsMany cells work together to make the living organism functionCells vary in size, shape and functionExample: plants and animals

Ability to ReproduceAsexual reproductionOrganism has single parentGenetically identical to parentSplits in halfSexual reproductionCells from two different parents unite to form new organismIncreases genetic variety and survival of species

Based on a Genetic CodeDNA nucleic acid that carries all the information about the organismAll living organisms have DNA, the blue prints of life

Growth and DevelopmentGrowth means increase in size, such as certain bacteriaDevelopment refers to cells dividing to Includes periods of rapid growth and dramatic changeSometimes different stages (think caterpillar)During development, cells multiply and are assigned specific functions and roles within the multi-cellular organismDIFFERENTIATION

Obtain and Use materials and EnergyObtain energy by taking in resourcesPlants-sunlightLizard-insectsMetabolismCombination of chemical reactions through which an organism builds up or breaks down materials to carry out life processes

Respond to their EnvironmentStimulusA signal to which an organism respondsExternal StimuliFrom environment outside organismExample- water in soil stimulates germinationInternal Stimuli Comes from inside an organisms bodyLow sugar levels in blood will stimulate you to feel hungry

Maintain a Stable internal environmentHomeostasisWhen organisms maintain a stable internal environment that is different from the external environmentExamples: shivering and sweating

As a group, they change over timeEvolutionProcess of changeWhen a group of organisms change over timeCould occur over hundreds or millions of yearsAdaptationAn inherited trait thats helps an organisms ability to survive and reproduce in a particular environmentOver a short period of timeNatural selectionThe most beneficial traits for a specific group of organisms is passed onOrganisms that have that specific trait will live longer and produce more offspring than those who do not have itThe mechanism by which evolution occurs

Levels of OrganizationMolecularDNA/RNA and other moleculesCellularDifferent cellsGroups of Cells(cellstissuesorgansorgan systemsorganism)OrganismA single speciesPopulationA group of the same speciesCommunityMany different groups of species and how they interact with each other in a specific areaEcosystemAll the living and nonliving interactions in an areaBiosphereHow all the different parts (biomes) of Earth come togetherBio- means lifeSphere- earthLife is found on land, in air, and in waterliving Earth

Lifes Diversity of Species Plants and animalsis there only one type?SpeciesA distinct life formBiologists have identified more than one million speciesThere are various estimates to the actual amountNew species are discovered daily5000 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

DomainsBroadest category of classificationThree main domainsDomain Archea: unicellular prokary. That live in extreme environments (very hot or very cold, extremely acidic or basic))Domain Bacteria: All other unicellular prokary.Domain Eukarya: Organism made up of eukary. CellsIncludes 4 kingdoms: Protists, Fungi, Plants, Animals

ClassificationHow do we organize all these species?We categorize all the different species in to broader categoriesFrom broadest to most specific:Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Linnaean System of Classification)Binomial nomenclatureBREAK UP THE WORDBI-TWO, NOMIAL-NAME, NOMENCLATURE-NAMING SYSTEMThis is how we identify a speciesThe African lion is called Panthera leoWhats the genus?PantheraWhat is the species?Panthera leo (you say both genus and species)

Tools of Biology

Technology continually changes the way biologists work.

Imaging technologies provide new views of life.A microscope provides an enlarged image of an object.

stomalight microscopes (LM)

stoma scanning electron microscopes (SEM)Imaging technologies provide new views of life.A microscope provides an enlarged image of an object.light microscopes (LM)

Imaging technologies provide new views of life.transmission electron microscopes (TEM)

stoma scanning electron microscopes (SEM)A microscope provides an enlarged image of an object.light microscopes (LM)

Imaging technology is used in medicine.

X-ray images

magnetic resonance imaging (MRI)

Imaging technology is used in medicine.X-ray images

functional MRI (fMRI)

magnetic resonance imaging (MRI)Imaging technology is used in medicine.X-ray images

Complex systems are modeled on computers.Computer models are used to study systems that cannot be studied directly.heart attackseffect of medicines on the human bodymovement of water molecules into and out of a cellspread of a disease through a populationComputer models are used when experiments are not safe, ethical, or practical.

Normal heartbeatHeart attack

The tools of molecular genetics give rise to new biological studies.A gene is a segment of DNA that stores genetic information.

Through our understanding of DNA, we can study genetics on a molecular level.

molecular geneticsgenomics

SCIENTIFIC METHODReview30Scientific MethodOrganized problem solvingNot a single method

Steps of the Scientific MethodDefine the ProblemCollect Information About the ProblemForm a HypothesisExperimentCollect ResultsConclusionRepeat 32Step 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?

33Step 2. Collect Information About the ProblemInformation can be gathered from: - your own observations

- published research textbooks, articles, internet etc

34Step 3. Form a HypothesisA 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

35Formal HypothesisA formal hypothesis used in an experiment should be stated in IfThen 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.

Step 4. Test Your Hypothesis-ExperimentExperiment 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

Emphasize that there is only one difference between two groups37Experimental DesignNeeds to be repeatable

Should test a large sample

Should be without bias

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 variables39Cricket ExperimentControl GroupExperimental Group20 crickets grown in a 10 gallon aquarium12 hours of light/dayFed 5 g Acme Cricket FoodKept at 25C

20 crickets grown in a 10gallon aquarium12 hours of light/dayFed 5 g Acme Cricket FoodKept at 30C

40Step 5 Data and Results Data = observations or measurements - Quantitative = number data 10 chirps/minute - Qualitative = observations color changed to orangeResults = Processed data makes the meaning of the data more clear. Allows you to see trends or patterns. Calculate an average, graph of data etc..41Graphing Your DataIndependent 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

Sample Graph

Dependent Variable: on the Y AxisIndependent Variable on the X AxisConclusions 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? 44Repeat Your Work/PublishRepeat experiment to confirm your results.

When scientists have completed their work, they publish their results - this informs other scientists of their findings

45TheoryA 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 scienceVocabulary to Know and LoveHYPOTHESISEXPERIMENTAL GROUPCONTROL GROUPVARIABLECONTROLLED VARIABLESINDEPENDENT/MANIPULATED VARIABLEDEPENDENT/RESPONDING VARIABLEDATAQUANTITATIVE DATAQUALITATIVE DATARESULTSTHEORY