Introduction to biology

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

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

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

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

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

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

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

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

Maintain a Stable internal environment Homeostasis When organisms maintain a stable internal environment that is different from the external environment Examples: shivering and sweating

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

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”

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

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

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)

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. stoma –light 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. o 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

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

o 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. 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

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 genetics –genomics

SCIENTIFIC METHOD Review

Scientific Method Organized problem solving Not a single method

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

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?

Step 2. Collect Information About the Problem Information can be gathered from: - your own observations - published research textbooks, articles, internet etc…

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

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.

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

Experimental Design Needs 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 variables

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

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..

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

Sample Graph Dependent Variable: on the Y Axis Independent Variable on the X Axis

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?

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

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

Vocabulary to Know and Love HHYPOTHESIS EEXPERIMENTAL GROUP CCONTROL GROUP VVARIABLE CCONTROLLED VARIABLES IINDEPENDENT/MANIPULATED VARIABLE DDEPENDENT/RESPONDING VARIABLE DDATA QQUANTITATIVE DATA QQUALITATIVE DATA RRESULTS TTHEORY