Biology and The Scientific Method

What is Biology? Biology is the study of life Biologist study: How living things work How living things interact with each other and the environment How living things change over time

The Scientific Method The scientific method is -an organized way of learning about how the natural world works. -a careful, organized series of steps taken to answer questions -a natural/instinctive human process Answer

Steps of the Scientific Method There are 6 main steps: Make an observation Ask a question and do research Form a hypothesis (possible explanation) Design an Experiment Collect and analyze data Draw Conclusions

Observations The process of science begins with an observation. Observation  Questions  Experimentation Example: I see people using fertilizer on their plants

1.It rained 2.The sprinkler was on 3.There is dew on the grass from the morning 4.A dog peed on the grass 1.The building is on fire 2.The sprinklers malfunctioned 3.The sprinklers are being tested 4.Someone pulled the fire alarm as a prank What’s your observation? Possible inferences ?

Asking a Question At the beginning of every experiment you should state the question you hope to solve by doing your experiment Example: Does fertilizer cause plants to grow faster?

Forming a Hypothesis A hypothesis is an educated explanation of how an aspect of the natural world works When forming a hypothesis remember: -It should be based on research (no guessing) one possible -It is one possible answer to your question -It must be testable -It is not always correct and that’s okay -It is posed as a statement of what you think will happen in your experiment based on what you have already observed Example: I think that plants grown with fertilizer will grow faster than plants grown without fertilizer because…

Designing an Experiment Steps to designing an experiment: -Materials- List and gather materials -Procedure- plan and record step by step instructions for how the experiment will be performed -Perform the experiment- experiments should be conducted without bias

Designing a controlled experiment In a controlled experiment two identical or near identical groups are formed but only one is tested The Experimental group is directly tested The control group is not tested so you have a normal standard you can compare results of the experimental group to.

Designing a controlled experiment Variables: The Manipulated/Independent Variable is what you are testing. It is the one thing you do to the experimental group that you do not do to the control group Responding/dependent variable is what you observe or measure due to the manipulated variable

Designing a controlled experiment Variables: What is the manipulated variable in this experiment? The fertilizer What would be the responding? The height of the plants

Collecting and Analyzing Data Data is collected, recorded, and organized throughout an experiment by: -Using the senses to make detailed descriptions and recording in journals -Using tools to take measurements (size, volume, weight, temperature, etc.) and recording in tables

Data is usually organized into graphs and charts and then analyzed: -to determine whether the results support or fail to support the hypothesis -to determine if results are reliable and possible sources of error -to draw conclusions about the experiment

Drawing Conclusions - After analyzing data you state whether or not your hypothesis is supported. -An experiment can only disprove, not prove a hypothesis. -If a hypothesis is incorrect you form and test a new hypothesis

After the experiment Sources of error Equipment error Human error Experiments must be repeatable with similar results to be accepted

Hypothesis vs. Theory Theory--Common Meaning: -contemplation or speculation. -guess or conjecture. Theory--Scientific Meaning: - set of related hypotheses confirmed to be true many times, and can explain a great amount of data Ex. Cell theory, gravitational theory

Hypothesis vs. Theory continued SimilaritiesDifferences Hypothesis: A proposed scientific explanation based on observations that can be tested. Theory: An explanation that is supported by reasoning, many observations, many experiments and is highly tested and supported.

The Characteristics of life

1. All living organisms are made up of one or more cells. I. Cells

All living things reproduce sexually or asexually All cells arise from pre-existing cells by division. II. Reproduction

All living organisms contain genetic material. Either DNA or RNA. It’s transmitted it during reproduction Carries instructions for building the organism III. Genetic Material

All living organisms grow and develop. Cell division forms 2 new cells from an existing cell Development=cell division, cell differentiation/ specialization IV. Growth and Development

All living organisms use energy 1.Energy flow (metabolism and biochemistry) occurs within cells.Energy flowmetabolismbiochemistry V. Energy

All living organisms respond to their environment VI. Response

All living organisms maintain a stable internal balance even though the environment (temperature, pH) is constantly changing VII. Homeostasis

Living organisms change over time VIII. Evolution

All living organisms die IX. Death