Themes in the Study of Life Chapter 1 Themes in the Study of Life

What is Biology?

What is Biology? Scientific study of Life Filled with QUESTIONS Good Questions Questions that can be investigated

What is Life?

What is Life? 7 Properties of Life

What is Life? 7 Properties of Life Order Evolutionary adaptation Responding to the environment Growth and development Reproduction Energy processing Regulation

What are the Major Themes of Biology

Major Themes of Biology New properties emerge at each level in the biological hierarchy Organisms interact with their environments, exchanging matter and energy Structure and function are correlated at all levels of biological organization Cells are an organism’s basic units of structure and functions The continuity of life is based on heritable information in the form of DNA Feedback mechanisms regulate biological systems

Evolution “Nothing makes sense except in the light of evolution” - Who Said This?

Evolution “Nothing makes sense except in the light of evolution” Dobzhansky

Evolution “Nothing makes sense except in the light of evolution” Dobzhansky Core Theme Evolution accounts for the unity and diversity of life Its importance will demonstrate a large role in this course Can always refer to Section 1.2 throughout the semester

How do scientists pose and answer questions about the natural world?

How is Biology examined?

How is Biology examined? Reductionist approach Holistic approach Systems biology

How is Biology examined? Reductionist approach

How is Biology examined? Reductionist approach Reduce complex systems to simple components

How is Biology examined? Reductionist approach Reduce complex systems to simple components Holistic approach

How is Biology examined? Reductionist approach Reduce complex systems to simple components Holistic approach Larger-scale, with the objective of understanding how the emergent properties work together

How is Biology examined? Reductionist approach Reduce complex systems to simple components Holistic approach Larger-scale, with the objective of understanding how the emergent properties work together Systems biology

How is Biology examined? Reductionist approach Reduce complex systems to simple components Holistic approach Larger-scale, with the objective of understanding how the emergent properties work together Systems biology Goal is to construct models for the behavior of a whole systems

What is inquiry?

What is inquiry? Inquiry is the search for information and explanation that often focuses on specific questions

Scientists use two main forms of scientific inquiry Discovery Science Hypothesis-Based Science

Scientists use two main forms of scientific inquiry Discovery Science

Scientists use two main forms of scientific inquiry Discovery Science Describing nature More qualitative in nature Can have quantitative aspects Describes natural processes Uses observation to gather information (directly or indirectly) with tools Recorded observations are called data

Scientists use two main forms of scientific inquiry Hypothesis-Based Science

Scientists use two main forms of scientific inquiry Hypothesis-Based Science Describing nature More qualitative in nature Can have quantitative aspects Describes natural processes Uses observation to gather information (directly or indirectly) with tools Recorded observations are called data

What is a hypothesis?

What is a hypothesis? Tentative answer to a well-framed question Explanation on trial Educated Guess that is based on experience and the data available from Observation

What makes a Good Hypothesis?

What makes a Good Hypothesis? Testable Falsifiable Cannot be PROVEN Gains credibility by surviving attempts to falsify it

What makes a Good Hypothesis? Testable

What makes a Good Hypothesis? Testable A way to check the validity

What makes a Good Hypothesis? Testable A way to check the validity Falsifiable

What makes a Good Hypothesis? Testable A way to check the validity Falsifiable There must be some observation or experiment that could reveal if such an idea is NOT true Generally, scientists frame two or more alternative hypotheses and design experiments to falsify

What makes a Good Hypothesis? Testable A way to check the validity Falsifiable There must be some observation or experiment that could reveal if such an idea is NOT true Generally, scientists frame two or more alternative hypotheses and design experiments to falsify Cannot be PROVEN

What makes a Good Hypothesis? Testable A way to check the validity Falsifiable There must be some observation or experiment that could reveal if such an idea is NOT true Generally, scientists frame two or more alternative hypotheses and design experiments to falsify Cannot be PROVEN Testing supports a hypothesis not by Proving it, but instead by not eliminating it through the falsification It’s impossible to test ALL alternative hypothesis

What makes a Good Hypothesis? Testable A way to check the validity Falsifiable There must be some observation or experiment that could reveal if such an idea is NOT true Generally, scientists frame two or more alternative hypotheses and design experiments to falsify Cannot be PROVEN Testing supports a hypothesis not by Proving it, but instead by not eliminating it through the falsification It’s impossible to test ALL alternative hypothesis Gains credibility by surviving attempts to falsify it

What are the Types of Data?

Types of Data Qualitative Quantitative

Types of Data Qualitative

Types of Data Qualitative Recorded descriptions rather than numerical General observations Colors

Types of Data Qualitative Quantitative Recorded descriptions rather than numerical General observations Colors Quantitative

Types of Data Qualitative Quantitative Recorded descriptions rather than numerical General observations Colors Quantitative Recorded measurements Numerical in nature

What are theTypes of Reasoning

Types of Reasoning Inductive Reasoning Deductive Reasoning

Types of Reasoning Inductive Reasoning

Types of Reasoning Inductive Reasoning From induction Derive generalizations from a large number of specific observations Ex: If every organisms that you have studied is made of cells, then it would be acceptable to induce that all organisms are made of cells.

Types of Reasoning Inductive Reasoning Deductive Reasoning From induction Derive generalizations from a large number of specific observations Ex: If every organisms that you have studied is made of cells, then it would be acceptable to induce that all organisms are made of cells. Deductive Reasoning

Types of Reasoning Inductive Reasoning Deductive Reasoning From induction Derive generalizations from a large number of specific observations Ex: If every organisms that you have studied is made of cells, then it would be acceptable to induce that all organisms are made of cells. Deductive Reasoning Logic flows from general to specific Usually take the form of prediction of experimental or observational results If all organisms are made of cells, and humans are organisms, then humans are composed of cells

Scientific Method Ask a Question Do Background Research Construct a Hypothesis Test Your Hypothesis by Doing an Experiment Analyze Your Data and Draw a Conclusion Communicate Your Results

What is Experimental Design?

Integrating Experimental Design into Science

Experimental Design: The Process Paper airplane - everybody builds one Observe the plane’s flight Ready, set, hold it … How do we determine which is best? 5 minutes to modify, make one change Write your hypothesis on your plane

Leading Questions How did you act on your plane? What did you purposefully change about your plane? How did you determine your plane’s response? What remained the same about about your plane?

Experimental Design Diagram

Experimental Design Problems Compost & Bean Plants After studying about recycling, members of John's biology class investigated the effect of various recycled products on plant growth. John's lab group compared the effect of different aged grass compost on bean plants. Because decomposition is necessary for release of nutrients, the group hypothesized that older grass compost would produce taller bean plants Three flats of bean plants (25 plantslflat) were grown for 5 days. The plants were then fertilized as follows: (a) Flat A: 450 g of three-month-old compost, (b) Flat B: 450 g of six-month-old compost, and (c) Flat C: 0 g compost. The plants received the same amount of sunlight and water each day At the end of 30 days the group recorded the height of the plants (cm).

Experimental Design Diagram

Scenario 2 Metals & Rusting Iron In chemistry class, Allen determined the effectiveness of various metals in releasing hydrogen gas from hydrochloric acid. Several weeks later, Allen read that a utilities company was burying lead next to iron pipes to prevent rusting Allen hypothesized that less rusting would occur with the more active metals. He placed the following into separate beakers of water: (a) 1 iron nail, (b) 1 iron nail wrapped with an aluminum strip, (c) 1 iron nail wrapped with a magnesium strip, (d) 1 iron nail wrapped with a lead strip. He used the same amount of water, equal amounts (mass) of the metals and the same type of iron nails. At the end of 5 days, he rated the amount of rusting as small, moderate, or large. He also recorded the color of the water.

Experimental Design Diagram

Perfumes & Bee's Behavior JoAnna read that certain perfume esters would agitate bees. Because perfume formulas are secret, she decided to determine if the unknown Ester X was present in four different perfumes by observing the bees' behavior. She placed a saucer containing 10 ml of the first perfume 3 m from the hive. She recorded the time required for the bees to emerge and made observations on their behavior. After a 30-minute recovery period, she tested the second, third, and fourth perfumes. All experiments were conducted on the same day when the weather conditions were similar, e.g., air, temperature and wind.

Experimental Design Diagram

Fossils and Cliff Depth Susan observed that different kinds and amounts of fossils were preset in a cliff behind her house. She wondered why changes in fossils content occurred from the top to the bank. She marked the bank at five positions: 5,10,15, 20, and 25m from the surface. She removed 1 bucket of soil from each of the positions and determined the kind and number of fossils in each sample.

Experimental Design Diagram Title: The effect of depth on the different types and amounts of fossils. Hypothesis: If depth increases in a fossil bank, then different fossils will occur. Independent Variable: Depth of soil Modifications 5 10 15 20 25 # of Trials 1 1 1 1 1 Dependent Variable: Amount and type of fossils. Constant: 1 bucket Control ?

Aloe vera and Planaria Jackie read that Aloe vera promoted healing of burned tissue. She decided to investigate the effect of varying amounts of aloe vera and regeneration of planaria. She bisected the planaria to obtain 10 parts (5 heads and 5 tails) for each experimental group. She applied concentrations of 0%, 10%, 20%, and 30% Aloe vera to the groups. Fifteen ml of Aloe vera solutions were applied. All planaria were maintained in a growth chamber with identical food, temperature, and humidity. On day 15, Jackie observed the regeneration of the planaria parts and categorized deeloped as full, partial, or none.

Experimental Design Diagram Title: The effect of aloe vera on regeneration of planaria. Hypothesis: If more aloe vera is used then there will be an increased amount of aloe vera. Independent Variable: Percentage of Aloe Vera Modifications 10% 20% 30% # of Trials 10 10 10 Dependent Variable: amount of regeneration Constant: food, temperature, humidity Control : 0% aloe vera