Biology 1020: Principles of Biology - Auburn University · Chapter 1: The Science of Biology. •...

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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 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 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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Scientific Method 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 reasoning

Proceeds from the general to the specific

If starting general assumptions are true, then the conclusion must be true

Example:

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 generalization

Despite this shortcoming, it forms basis of most science

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


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Scientific Method

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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Scientific Method

summarizing existing observationsmay 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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Scientific Method 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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Scientific Method 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 observations

Makes testable predictions

Can never be proven true, only supported or disproved

Test the hypothesis (experiment)


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01.04 Scientific Method

Slide number: 2

Observation

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


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Slide number: 3

Question

Observation



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Slide number: 4

Question

Observation

Hypothesis 1Hypothesis 2Hypothesis 3Hypothesis 4Hypothesis 5

Potentialhypotheses



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Slide number: 5

Question

Observation

Experiment


Potentialhypotheses



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Slide number: 6

Question

Observation

Rejecthypotheses1 and 4

Experiment


Potentialhypotheses



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Slide number: 7

Question

Observation


Experiment

Hypothesis 5

Hypothesis 3

Hypothesis 2

Remainingpossiblehypotheses


Potentialhypotheses



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Slide number: 8


Question

Observation


Experiment

ExperimentHypothesis 5

Hypothesis 3

Hypothesis 2



Potentialhypotheses


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Slide number: 9


Question

Observation


Experiment


Hypothesis 3

Hypothesis 2



Potentialhypotheses


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Slide number: 10


Question

Observation


Experiment


Hypothesis 3

Hypothesis 2


Last remainingpossible hypothesis

Hypothesis 5


Potentialhypotheses


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Slide number: 11


Question

Observation


Experiment


Hypothesis 3

Hypothesis 2


Last remainingpossible hypothesis

Hypothesis 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






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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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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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All 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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All living things perceive and respond to stimuli

stimulus - physical or chemical changes in the internal or external environment of an organism

cells “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 reproduce

All life arises from previous living forms

Reproduction can be asexual (copying):

Simple – cells merely split

Many unicellular organisms reproduce this way

Variation only by mutation in genes


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Characteristics of Living Things All living things reproduce

Reproduction can be sexual:

Sex = genetic recombination

Complex, typically involves fusion of specialized egg and sperm cells to form a zygote (fertilized egg)

Genes provided by parents

Provides 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






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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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Information System 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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Information System

Organisms pass on their DNA to the next generation

Characteristics of each generation depend upon DNA


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Information System

Information is also exchanged betweencells

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






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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 systemfor 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 capitalized

specific epithet is never capitalized

The complete species name is always italicized (or underlined)

Example: Homo sapiens or Homo sapiens

May 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 includes

three 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 Eukarya

eukaryotes, organisms with a discrete cellular nucleus; divided into four kingdoms


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Domain Eukarya Protista

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 Eukarya Protista

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 Eukarya Fungi

organisms with cell walls consisting of chitin

mostly multicellular, multi-tissued

includes molds, yeasts, mushrooms

mostly 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 walls

Typically have organs and organ systems

Most 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 Method






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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 materials

usually 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 producers

use 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 consumers

Still 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 - Auburn University · Chapter 1: The Science of Biology. •...

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Transcript of Biology 1020: Principles of Biology - Auburn University · Chapter 1: The Science of Biology. •...