Scientific Method 1 2 3 4 5 Observation

Scientific Method 1. 2. 3. 4. 5. Observation Gather Information Hypothesis Experiment Conclusion

What is an Observation? Definition: Using senses to gather information Observations lead to questions “what is the effect of …on …? ”

Two types of Observations 1. Qualitative: l l Using your senses to describe something Ex: Mrs. Horton has blonde hair 2. Quantitative: l l Using tools to take a numerical measurement Ex: Mrs. Horton is 5 ft 7 in.

Hypothesis l l Predicts the answer to a question Hypotheses are based on--l l l Past Experience Observations Research

The format for writing a hypothesis “IF. . . THEN. . . because…. ” l Example : IF I exercise, THEN my heart rate will increase BECAUSE heart rate is dependent upon activity levels.

What is an Experiment l Experiments test your hypothesis l The experiment tests ONE VARIABLE l (variable is a factor that changes) EX: = increasing or decreasing your exercise level Experiments need a CONTROL GROUP l (control group is something to compare results to) l EX: = your heart rate at rest. Constants: the parts of the lab that must remain the same EX: = temperature, type of exercise, time

Types of Variables 1. Independent Variable: l Variable that is manipulated (changed) during the experiment. l 2. Example: rest, stand, walk, run Dependent Variable: l Is the data collected through observation and measurement l Example: heart rate

Conclusion: § States if the experiment support the hypothesis? Analysis …Paragraph explaining your results and discussing these questions. § § § If you did the experiment again, what would you do differently? What did you learn? Possible Errors

Theory = hypothesis supported by many experiments over time Examples of theories: Gravity or Evolution

Making Conversions

How to Create Bar and Line Graphs

Draw the Axes

Identify the Axes Y- Axis X- Axis

Identify the Axes Y- Axis Dependent Variable (what is observed and measured) X- Axis Independent Variable (what is changed by the scientist)

DRY MIX One way to remember which data goes on which axis is the acronym DRY MIX. D. R. Y. M. I. X. D- Dependent R- Responding Y- Y-axis M-Manipulated I- Independent X- X-axis

Title l Write an appropriate title for the graph at the top. l The title should contain both the independent and dependent variables. l Example: How Temperature Affects The Respiration Rate of Goldfish

Scale The min and max numbers used on each axis. (Does not have to begin at zero). l The min and max numbers used should be a little lower than the lowest value and a little higher than the highest value. l Chose a scale that will take up most of the graph paper l This allows you to have a smaller range which emphasizes the comparisons/trends in the data. l

The Best Scale Graph #1 The Y-axis scale is from 0 -100 but the largest value is only 35. Graph #2 The Y-axis scale is now from 0 -40. ---2 nd Graph does a better job emphasizing the comparisons between coins.

Steps to Find Scale 1. 2. 3. 4. 5. 6. 7. Find the range of the data for the Y Axis (67 -32= 35) Count number of lines/boxes on axes (20) Divide the range number by the number of boxes (35÷ 20=1. 75) round to 2 to make easier Each box will be worth 2 degrees days Repeat for the X Axis (6/20=0. 33) Each box is worth less than a days , 3 box =1 days Each third line should be labeled with 1 day

But How Do I Round? l l l When doing your scale you often have round up You can never round down Make sure to round to next number that can give you an easy interval at some point Practice with these #’s. 17, . 23, . 70, . 85, 1. 3, 1. 8. 20, . 25, . 75, 1. 0, 1. 5, 2. 0

Intervals l l Look at your minimum and maximum values you set up for both the Y and X-axis. (For most bar graphs, the X-axis will not have numerical values. ) Decide on an appropriate interval for the scale you have chosen. The interval is the amount between one value and the next. It is highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc. Intervals are specific to the data and will change based on the data

Intervals The interval for the Y-axis is 8 The X-axis does not have numerical data and does not need an interval.

Labels Both axes need labels so we know exactly what the independent and dependent variables are. l The dependent variable must be specific and include the units used to measure the data (such as “number of drops”). l DV label IV label

Labels DV label IV label

TAILS Another handy acronym to help you remember everything you need to create your graphs…. . T. A. I. L. S. Title Axis Interval Labels Scale

TAILS Title: Includes both variables Axis: IV on X-axis and DV on Y-axis Interval: The interval (4) is appropriate for this scale. Label: Both axes are labeled. Scale: Min and max values are appropriate.

Bar Graphs vs Line Graphs

Bar Graphs • Bar graphs are descriptive. • They compare groups of data such as amounts and categories. • They help us make generalizations and see differences in the data.

Line Graphs • Line graphs show a relationship between the two variables. They show how/if the IV affects the DV. • Many times, the IV plotted on the X-axis is time. • They are useful for showing trends in data and for making predictions. • Can be used to compare multiple sets of data, using different lines within the same graph

Example

Multiple Sets of Data When graphing multiple data sets on the graph, use a distinctive color of pen, or style of line, for each data set. l Place an example of the color or line style off to the side of the graph (Key) l Label it with the name of the information being displayed. For example: Seedlings l

Six Criteria of Science : Consistent, Observable, Natural, Predictable, Testable, Tentative.

Consistency : The results of observations and/or experiments are reasonably the same when repeated. 1. 2. Green plants will grow towards a light source. Walking under a ladder will cause bad luck.

Observability : The event or evidence of the event, can be observed and explained. The observations are limited to the basic human senses or to extensions of the senses. 1. 2. Some plants eat meat. Extraterrestrial beings have visited Earth.

Natural : A natural cause (mechanism) must be used to explain why or how the event happens. 1. Green plants convert sunlight into energy. 2. With a rod, Moses parted the sea so his people could cross to the other side. .

Predictability : Specific predictions can be used to foretell an event. Each prediction can be tested to determine if the prediction is true or false. 1. 2. Without sunlight (or artificial light), green plants will die. If you are a "Scorpio", your horoscope for today is "You'll be saying 'I feel rich !' Lunar position highlights back pay, refunds, correction of accounting error. "

Testability : the event must be testable through the processes of science, and controlled experimentation. 1. 2. The Bermuda Triangle causes ships and planes to sink and disappear. Life comes from life and cannot come from non -life.

Tentativeness : Scientific theories are changeable and correctable, even to the point of theory being proven wrong. Scientific theories have been modified and will continue to be modified 1. 2. Pluto was once a planet but due to it’s orbits, is now considered a dwarf planet. We know that the world began about 6000 years ago, and nothing will change that.

Evolution= Gradual change over time

Adaptations are inherited traits that increase a group’s chance of survival & reproduction This type of finch has a thick beak adaptation for cracking open seeds

Variation Within a species, there is variation Variation = differences between members of a population Species = group that can breed & produce healthy offspring

The Scientists Jean Baptist Lamarck vs. Charles Darwin

Jean Baptiste Lamarck Evolution occurs as structures develop through use, or disappear because of disuse, and these “acquired characteristics” are passed to offspring. EXAMPLE: Over a giraffes lifetime it can stretch it’s neck and it’s offspring will be born with long necks…. Valid?

Darwin and The Monkey! THIS IS NOT WHAT HIS THEORY SAYS

Who was Charles Darwin l Studied l Hated medicine the sight of blood l Received a BA in Theology l Had 10 children l Darwin was a Naturalist on the HMS Beagle

Theory of Evolution l In The Galapagos Islands, Darwin collected species of finches (13) l Each had a specialized diet and beak structure l These finches all closely resembled a South American finch ancestral species l On the trip Darwin saw things he could only attribute to a process called: “Natural Selection”

Darwin’s Finches

Theory of Evolution Hypothesized that the differences were do to gradual change l Darwin referred to such change as “descent with modification” – evolution; l Wrote Origin of Species l He still wondered “How does evolution occur? ” l

After his voyage, Darwin made the following inferences: 1. 2. 3. 4. 5. There is variation within populations Some variations are favorable Not all young produced in each generation can survive Individuals that survive and reproduce are those with favorable variations Favorable traits will increase in future generations.

Darwin called this process by which populations change in response to their environment: Natural Selection

Evolution happens because of natural selection Selection acts on individuals, populations evolve

Change creates advantages for some species & disadvantages for others Fossils reveal changes in species over millions of years

Evidence for Evolution 1. l Fossils show change over time l l – scientists can date fossils & use them to support theory of evolution common ancestors reveal whether species are related Anatomy of living species also shows relatedness

How Anatomy supports Evolution 2. Homologous Structures l l Traits similar in different species because they share a common ancestor Ex: human arm, dog front limb, horse leg, whale fin These “ look the same. ” They have the same bones but different function.

How Anatomy supports Evolution 3. Analogous structures l Distantly related species have structures that have the same function but are different in structure l Ex: wing of butterfly & bird These “ work the same. ” They have different bones but the same function.

How Anatomy supports Evolution 4. Vestigial structures l l l Structures reduced in size & often unused Remains of functional structures inherited from an ancestor Ex: leg & hip bones in pythons & whales

How DNA Supports evolution 5. Molecular Evidence l Also called biochemical evidence l Compares biomolecules such as DNA or amino acid sequences between organisms l Related organisms have more of the same molecules in common

So…. . Where Do New Species Come From?

How do new species form? 1. Geographic Isolation l l When members of a population are separated Ex: polar, grizzly, & black bears

2. Reproductive Isolation l When members of a population can’t breed even though they live nearby l Ex: different mating seasons or different mating calls

Different Types of Evolution 1. 2. 3. 4. Divergent evolution Convergent evolution Coevolution Adaptive radiation

Divergent Evolution -Isolated populations evolve independently Ex: polar & grizzly bears changed independently due to different habitats

Convergent Evolution -Unrelated species become more alike because they live in similar environments Ex: shark & dolphin

Coevolution -Species that interact closely adapt to one another Ex: Flowers & Pollinators (Birds, Bees and Butterflies too)

Adaptive Radiation Evolution of many diverse species from one common ancestor Ex: famous Galapagos finches discovered by Darwin

Questions?