Themes in Biology

Biology- the study of all living things Properties of Living Organisms 1. Cellular structure and function cell: basic unit of structure and function of organisms, capable of all life functions 2. Reproduction - process by which organisms make more of the same organism - essential for life since no organism lives forever

3. Metabolism- sum of all chemical reactions in an organism - sun: main source of energy for all organisms to fuel - sun: main source of energy for all organisms to fuel chemical reactions chemical reactions Ex: plants capture suns energy and make glucose Ex: plants capture suns energy and make glucose which we eat which we eat 4. Maintain homeostasis - constant internal environment in an organism - organisms must respond to external environment to survive - organisms must respond to external environment to survive Ex: arctic seals- blubber Ex: arctic seals- blubber cactus- heavy waterproof layer cactus- heavy waterproof layer

5. Heredity – passing of traits from parent to offspring Mutations – change in the DNA which can be harmful or beneficial Ex: sickle cell anemia Bad- rbc do not carry oxygen properly Good- give resistance to malaria 6. Evolution – gradual change in a species over a period of time Darwin- said evolution occurred through natural selection - Organisms with favorable genes survived, reproduced, - Organisms with favorable genes survived, reproduced, and passed favorable genes to offspring. and passed favorable genes to offspring. 7. Interdependence – organisms dependence on each other within an environment

Purposes of Biology To solve real world problems: A. Studying ecosystems B. Genetically engineered crops C. Help fight diseases - AIDS - Cancer - Cystic fibrosis

The Scientific Method Steps 1. Make observations and ask a question ask a question 2. Form a hypothesis (educated guess based on (educated guess based on what is already known) what is already known) - prediction: expected outcome from the test assuming the hypothesis is correct expected outcome from the test assuming the hypothesis is correct

3. Test the hypothesis thru experimentation - controlled experiment A. control group: A. control group: “normal condition” “normal condition” - receives no experimental treatment or change in condition - receives no experimental treatment or change in condition B. experimental group: B. experimental group: “test group” “test group” - variable/ experimental factor being tested for - variable/ experimental factor being tested for a. independent variable: factor being varied a. independent variable: factor being varied b. dependant variable: factor being measured b. dependant variable: factor being measured

4. Collect and analyze data - use charts, tables, observations - use charts, tables, observations 5. Draw conclusions (formation of a theory) - can support or reject hypothesis - can be disproven through further experimentation 6. Share results or retest - publish data in scientific journals

Representing Data Graphically Charts/Graphs There are three basic components to most charts/graphs: Labels- defines the data:Labels- defines the data: - title, axis titles and labels, legends defining separate data series - title, axis titles and labels, legends defining separate data series Scales- define the range of the Y and the X axisScales- define the range of the Y and the X axis Graphical elements- represent the dataGraphical elements- represent the data - bars in bar charts - lines in times series plot - points in scatter plots - slices of a pie chart

Pie Charts

Bar Graphs

Line Graphs School System Enrollment

Scatter Plots (x,y)

Scatter Plots (x,y) Rules for Scatterplots (shows relationship between variables) Use two interval-level variables (x and y)Use two interval-level variables (x and y) Fully define the variables with the axis titlesFully define the variables with the axis titles Chart title should identify the two variables and the cases (e.g., cities or states)Chart title should identify the two variables and the cases (e.g., cities or states) X axis: independent variable (cause)X axis: independent variable (cause) Y axis: dependent variable (effect/result) Y axis: dependent variable (effect/result) Scale the axes to maximize the use of the plot area for displaying the data pointsScale the axes to maximize the use of the plot area for displaying the data points Use same interval measurements on each axisUse same interval measurements on each axis Do NOT connect dots, use a trend lineDo NOT connect dots, use a trend line

Scatter Plot Trend Lines NEGATIVE NEGATIVE indirect indirect relationship relationship (+, -) (+, -) NULL POSITIVE NULL POSITIVE no direct no direct relationship relationship (0,0) (+, +) (0,0) (+, +)

Theory - Explanation based on a set of related hypotheses that have been tested and confirmed many times but can be broken. -Theories unite and explain a broad range of observations -Generally accepted as scientific principle -In the general public, theories are considered statements of uncertainty

Scientific Law summarizing statement that is considered fact and can not be broken summarizing statement that is considered fact and can not be broken Ex: gravity

Measurement System International (SI)System International (SI) - standardized system of measurement - based on the number 10 - France, late 1700’s

SI Prefixes

Study for the test! “Eventually we will have to exchange our feet for meters”