. Biology 1020: Principles of Biology Instructor: Dr. Scott Bowling.

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Biology 1020:Principles of Biology

Instructor: Dr. Scott Bowling

http://www.auburn.edu/academic/classes/biol/1020/bowling/

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Today’s Lecture Topics

Active learning

Course syllabus / other initial business

Chapter 1: The Science of Biology


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• Groups of 3-4• 1 sheet of paper; answer:

– WHO ARE YOU? (first and last names)– WHY ARE YOU HERE? (in this class)– WHAT DO YOU WANT? (out of this class)

Answers are group answers, not individual – introduce yourselves, list your names, discuss the other two questions, then write group summaries for them.

You have five minutes – begin!


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Scientific MethodCharacteristics of living things Information transfer in living systemsDiversity of Life / classification of living

systemsEnergy flow in living systems


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• Discuss how the scientific method works, and the difference between inductive and deductive reasoning.

• Come up with examples of inductive and deductive reasoning.

• Do NOT worry about learning the scientific method as “step one – step two – etc.”


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• Discuss testable models, including terms for them and why “testable” matters. How does this relate to the supernatural?


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Biology is Studied Using the Scientific Method

Science is based on a systematic thought process

uses deductive and inductive reasoning makes testable models of how the universe

works


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deductive reasoning summarize the information at hand draw conclusions from that information proceeds from the general to the specific

inductive reasoning generalization from several specific observations proceeds from the specific to the general must be careful, because it is impossible to prove the

accuracy of the generalization


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Deductive reasoningProceeds from the general to the specific If starting general assumptions are true,

then the conclusion must be trueExample:

All birds have wings.Sparrows are birds.Deduced conclusion would be:

Sparrows have wings.


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Inductive reasoning Drawing a generalization from several specific

observations Proceeds from specific to general Example:

Sparrows are birds, and they have wings. Falcons are birds, and they have wings. In fact, all birds that I have ever seen or heard of

have wings. By inductive reasoning, the conclusion would be:

All birds have wings.


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Inductive reasoning Impossible to prove the accuracy of the

generalizationDespite this shortcoming, it forms basis of

most science

…this is the main reason why science is an unfolding, evolving process


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The scientific method in a nutshell: summarize existing observations make a model about how the universe

works (using those observations) test the model revise the model as needed and repeat

(and repeat, and repeat, and repeat….)


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summarizing existing observations may also involve collecting new information or observations if there aren’t enough already

then a hypothesis is made; this is a testable model that:

explains the existing observations makes predictions that can be tested often more than one hypothesis is made


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More observations are made to test the correctness of the hypothesis; where possible, an experiment is conducted

In an experiment conditions are controlled to provide a better and more reliable test

Experimental or treatment group - the individuals given the specific treatment or condition being tested (may be more than one treatment group)

Control group - the individuals not given the specific treatment (may be more than one control group)


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observations and measurements are taken of the experimental and control groups

the data are compared the data should provide evidence to either reject

(disprove) or support (but never prove) the hypothesis

care must be taken that the experimental and control groups receive the same treatments except for the specific effect being tested; avoid things such as the placebo effect


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Analysis of Experiments Experimenter must

interpret the results (often using statistics)

Taking small sample sizes often results in errors in the estimate of the entire population

The larger the sample size, the more reliable the results


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The Scientific Method

Summarize existing observations (and make new ones)

Formulate a hypothesis, a model that:Explains existing observationsMakes testable predictionsCan never be proven true, only supported or

disproved

Test the hypothesis (experiment)


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01.04 Scientific MethodSlide number: 2

Observation

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.


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Question

Observation



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Question

Observation

Hypothesis 1Hypothesis 2Hypothesis 3Hypothesis 4Hypothesis 5

Potentialhypotheses



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Question

Observation

Experiment


Potentialhypotheses



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Question

Observation

Rejecthypotheses1 and 4

Experiment


Potentialhypotheses



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Question

Observation


Experiment

Hypothesis 5Hypothesis 3Hypothesis 2

Remainingpossiblehypotheses


Potentialhypotheses



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Question

Observation


Experiment

ExperimentHypothesis 5Hypothesis 3Hypothesis 2



Potentialhypotheses


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Question

Observation


Experiment




Potentialhypotheses


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Question

Observation


Experiment



Last remainingpossible hypothesisHypothesis 5


Potentialhypotheses


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Question

Observation


Experiment



Last remainingpossible hypothesisHypothesis 5

Predictions

Experiment 1 Experiment 2 Experiment 3 Experiment 4

Predictionsconfirmed


Potentialhypotheses


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The Scientific Method

The recursive nature of the process: experiments provide more observations at any time more observations may be added in

and more testable models may be produced …this may in turn lead to more experiments, and

the process continues this generally leads to progress towards more and

more reliable models of how nature works creative thinking often plays a major role when

rapid progress occurs


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Scientific Method

Hypothesis, theory, and law A well supported hypothesis that links together

a large body of observations is considered a theory.

A theory that links together significant bodies of thought and yields unvarying and uniform predictions over a long period of time becomes considered a principle or law.


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• Discuss how the scientific method works, and the difference between inductive and deductive reasoning.

• Come up with examples of inductive and deductive reasoning.

• Do NOT worry about learning the scientific method as “step one – step two – etc.”


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• Discuss testable models, including terms for them and why “testable” matters. How does this relate to the supernatural?


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Scientific Method

caveats: Scientific models can only be proven false, never

proven true. Correlation does not equal causation. Testable predictions cannot include the supernatural

(the supernatural cannot, by definition, be tested scientifically); thus, the supernatural is outside the realm of science.

The term “theory” has a very different meaning in science than in most everyday conversations.


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Scientific Method

science and technology – the goal of science is to understand nature the goal of technology is to apply scientific

knowledge for a specific purpose


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Scientific Method

Characteristics of living things Information transfer in living systems Diversity of Life / classification of living systems Energy flow in living systems


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• Explain the characteristics of living matter to each other. Answer the “Fido” question (will be described in class).


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Characteristics of Living Things Generally, life on Earth is defined such that all

living things… are made up of cells grow & develop regulate their metabolism perceive and respond to stimuli reproduce


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Characteristics of Living Things

All living things are made up of cells The cell is the basic unit of life, both in structure

and function; it is living material bounded by a membrane

Cells come from and give rise to other cells Some organisms are unicellular; some are

multicellular


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All living things grow & develop growth - increase in size and/or number of

cells growth may be different in different locations

development – changes in roles of cells during life cycle of an organism individual changes as development proceed

throughout life


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Characteristics of Living ThingsAll living things regulate their metabolism

metabolism - the sum of the chemical reactions and energy transformations that take place within a cell

homeostasis - the tendency of an organism to maintain a relatively constant internal environment


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Characteristics of Living ThingsAll living things perceive and respond to

stimulistimulus - physical or chemical changes in the

internal or external environment of an organismcells “talk” to each other through cell signaling

via special molecules (such as hormones, neurotransmitters)

organisms signal state via behavior


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All living things reproduceAll life arises from previous living formsReproduction can be asexual (copying):

Simple – cells merely splitMany unicellular organisms reproduce this wayVariation only by mutation in genes


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Characteristics of Living ThingsAll living things reproduce

Reproduction can be sexual:Sex = genetic recombinationComplex, typically involves fusion of specialized egg

and sperm cells to form a zygote (fertilized egg)Genes provided by parentsProvides for variation in offspring


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• Explain the characteristics of living matter to each other. Answer the “Fido” question (will be described in class).


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What is the primary way that information is transferred from one living generation to the next?

What (in biology) is a Domain?

What are the six kingdoms? (modern classification)

Why is energy important for life?


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Scientific Method Characteristics of living things

Information transfer in living systems

Diversity of Life / classification of living systems Energy flow in living systems


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• Discuss the role of information in life, and how it is dealt with (on the molecular level).


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Organisms Contain an Information System

Information must be transferred from one cell generation to the next

In multicellular organisms, information must also be transferred from one generation to the next


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Cells have an information system made up of nucleic acids – specifically: DNA (deoxyribonucleic acid)

The information is encoded in regions of DNA called genes, the units of heredity

Genes are instructions that use a special, unique code

Instructions are generally for the production of specific proteins

The nucleic acid code is virtually identical in all species


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Organisms pass on their DNA to the next generation

Characteristics of each generation depend upon DNA


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Information is also exchanged between cells

Hormones are chemical signals used for intercellular signaling

Physical signals may also be used for intercellular communication


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• Discuss the role of information in life, and how it is dealt with (on the molecular level).


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Scientific Method Characteristics of living things Information transfer in living systems

Diversity of Life / classification of living systems

Energy flow in living systems


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• Explain the binomial system and taxonomic hierarchy.

• What is a species name?

• What do the two words in a species name represent, and how do you write them?

• How will you memorize the hierarchy?


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The Diversity of Organisms Biologists use a hierarchical binomial system

for classifying organisms. about 1.8 million living species have been

identified, likely millions more

Taxonomy - the science of classifying and naming organisms

Carolus Linnaeus – 18th century Swedish botanist; developed a system of classification that is the basis of what is used today

binomial system because a combination of two names, genus and specific epithet, uniquely identifies each species


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Species - basic unit of classification or taxonomy if sexual, a group of organisms that can interbreed

and produce fertile offspring if asexual, grouped based on similarities (DNA

sequence is best)

Genus - a group of closely related species Species name has two parts (binomial)

Genus and specific epithet (using Latin or Latinized language)

The specific epithet usually describes something about the organism, or is based on the name of the discover


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Species name has two parts (binomial)Genus name is always capitalizedspecific epithet is never capitalizedThe complete species name is always

italicized (or underlined)Example: Homo sapiens or Homo sapiensMay abbreviate genus name if used

already and context is clear: H. sapiens


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Taxonomic classification is hierarchical

• A group of related genera make up a Family• Related families make up an Order• Related orders Class• Related classes Phylum or Division• Related phyla or divisions Kingdom• Related kingdoms Domain, the highest level of

classification in the modern system.

The gold standard for “related” is based on DNA sequence similarities, but other criteria are used as well (we don’t have the complete DNA sequence of all known species)


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Taxonomic classification is hierarchical

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Dashing King Philip came over for great…


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• Explain the binomial system and taxonomic hierarchy.

• What is a species name?

• What do the two words in a species name represent, and how do you write them?

• How will you memorize the hierarchy?


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• What are the three domains and six kingdoms?

• How do you decide which kingdom to put a eukaryote into?


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The most widely accepted classification

system today includesthree domains and six kingdoms


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Two domains consist of prokaryotes, organisms with no true cellular nucleus

Domain Archaea – Kingdom Archaebacteria bacteria typically found in extreme environments distinguished from other bacteria mainly by ribosomal

RNA sequence include methanogens, extreme halophiles, and

extreme thermophiles

Domain Bacteria – Kingdom Eubacteria very diverse group of bacteria examples: blue-green algae, Escherichia coli


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Domain Eukaryaeukaryotes, organisms with a discrete cellular

nucleus; divided into four kingdoms


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Domain EukaryaProtista

Single celled and simple multicellular organisms having nuclei

includes protozoa, algae, water molds, and slime molds

“lump group” for eukaryotes that do not fit in the other 3 kingdoms within eukarya


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Domain EukaryaProtista

NOTE: This kingdom is likely on the way out, to be replaced by several kingdoms based on genetic/evolutionary relationships instead


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Domain EukaryaFungi

organisms with cell walls consisting of chitinmostly multicellular, multi-tissuedincludes molds, yeasts, mushroomsmostly decomposers


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Domain Eukarya (cont.) Plantae (plants)

complex multicellular organisms having tissues and organs

Plant cells have walls containing cellulose most contain chlorophyll in chloroplasts, and carry

on the process of photosynthesis Nonvascular (mosses) and vascular (ferns, conifers,

flowering plants) Mostly producers

NOTE: kingdom is being replaced by Viridiplantae, which includes green algae


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complex multicellular organisms having tissues and organs

Plant cells have walls containing cellulose most contain chlorophyll in chloroplasts, and carry

on the process of photosynthesis Nonvascular (mosses) and vascular (ferns, conifers,

flowering plants) Mostly producers


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NOTE: kingdom is being replaced by Viridiplantae, which includes green algae


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Domain Eukarya (cont.)Animalia (animals)

Complex multicellular organisms that depend on other organisms for nourishment

Cells lack wallsTypically have organs and organ

systemsMost forms are motile


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• What are the three domains and six kingdoms?

• How do you decide which kingdom to put a eukaryote into?


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Scientific MethodCharacteristics of living things Information transfer in living systemsDiversity of Life / classification of living

systems

Energy flow in living systems


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• What is the importance of energy in living systems?

• What are autotrophs and heterotrophs?


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Life Depends on a Continuous Input of Energy

All life depends upon energy

Original source mostly the sun

Energy flows through cells, organisms

Energy flows through ecosystems (the concept of a food chain or food web)


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Energy is used: To maintain existing cellular structures and

components (replacement of damaged or worn out materials within the cell)

To produce materials to support growth, development, and reproduction

To support: movement, either of cell itself or of materials into

and out of the cell signaling responses, such as hormone production

and perception, nerve impulses, etc. other forms of cell work, such as symbiotic

relationships with other organisms, defense against pathogens


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Producers (autotrophs) manufacture their own food from simple materialsusually produce food by the process of

photosynthesis:

Carbon dioxide + Water + light energy ───> Carbohydrate (food) + Oxygen


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Energy is released from food mostly by oxidative respiration

Carbohydrate (food) + Oxygen ───> Carbon dioxide + Water + energy

overall, producers use carbon dioxide and water and release food and oxygen


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Consumers (heterotrophs) obtain energy by eating other organisms

ultimate source of food is producersuse food and oxygen, and release carbon

dioxide and water


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Decomposers obtain energy by breaking down the waste products, by products, and dead bodies of producers and consumersStill heterotrophs (ultimate source of food

is producers)Decomposition recycles nutrients from

dead bodies back to living ones; without decomposers, living systems would starve for energy

Decomposers are usually bacteria and fungi


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• What is the importance of energy in living systems?

• What are autotrophs and heterotrophs?


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Themes learning biology is not just learning a set

of facts and concepts; you need to organize that information

watch for the recurrence of certain themes that come up repeatedly in biology (major examples on next slides)

in addition, an awareness of the process of scientific inquiry and the application of science (technology) are important aspects of any study of biology


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Figure 1.3


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Themes The cell Information management

heritable information regulation interaction with the environment

Energy management Structure and function Unity and diversity Emergent properties Evolution – the core unifying theme that explains

much of the observations connected with the other themes


. Biology 1020: Principles of Biology Instructor: Dr. Scott Bowling.

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Transcript of . Biology 1020: Principles of Biology Instructor: Dr. Scott Bowling.