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AN INTRODUCTION TO BIOLOGY

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Title: AN INTRODUCTION TO BIOLOGY


1
AN INTRODUCTION TO BIOLOGY
2
WHAT WILL WE COVER?
  • The nature of biology
  • Levels of organization of life
  • Diversity of life
  • Unity of life
  • Introduction to evolution and natural selection
  • Nature of scientific inquiry

3
WHAT IS BIOLOGY?
  • Biology is a natural science
  • Literally, the study of life
  • Employs principles and methods common to all
    sciences
  • Biological knowledge is consistent with our
    understanding of chemistry, physics, etc.

4
WHAT IS BIOLOGY?
  • Biology has many subfields
  • Biochemistry
  • Ecology
  • Evolutionary biology
  • Genetics
  • Microbiology
  • Molecular biology
  • Primatology
  • etc.

5
WHAT IS BIOLOGY?
  • Biology intersects with many other fields of
    study
  • Anthropology
  • Chemistry
  • Geology
  • Physics
  • etc.

6
WHAT IS SCIENCE?
  • Science is more than just a collection of facts
  • Science is a way of knowing or understanding the
    natural world
  • Science is NOT the only way of understanding
  • Philosophy, theology, and other disciplines
    provide their own type of understanding

7
WHAT IS SCIENCE?
  • Science is based on the fundamental assumption
    that all events have natural causes
  • e.g., Lightning is the result of natural causes,
    not the result of Zeus having a bad day
  • e.g., Storms and earthquakes are not caused by
    Poseidon
  • e.g., The sun is not a fiery chariot driven
    across the sky
  • We may potentially understand these causes

8
WHAT IS SCIENCE?
  • Or maybe it is

9
BIOLOGICAL HIERARCHIES
  • Biology is literally the study of life
  • Extends from the microscopic scale to the global
    scale
  • This range is divided into different levels of
    biological organization

10
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • Biosphere
  • Ecosystems
  • Communities
  • Populations
  • Organisms
  • Organ systems
  • Organs
  • Tissues
  • Cells
  • Organelles
  • Molecules

11
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • Biosphere
  • Ecosystems
  • Communities
  • Populations
  • Organisms

12
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • The biosphere consists of all the environments on
    Earth that are inhabited by life
  • Ecosystems include all of the living things in
    one area, as well as the nonliving environmental
    components with which they interact
  • Communities include all organisms inhabiting a
    particular ecosystem
  • A population consists of all the individuals of
    one species living within a specified area
  • Organisms are individual living things

13
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • Organisms
  • Organ systems
  • Organs
  • Tissues
  • Cells
  • Organelles
  • Molecules

14
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • Multicellular organisms possess numerous organs
    arranged into organ systems
  • A tissue is a group of cells similar in structure
    and function
  • Cells represent the fundamental structural and
    functional unit of life
  • Some organisms consist of one cell (unicellular)
  • Some organisms consist of several cells
    (multicellular)
  • Organelles are specialized structures within a
    cell
  • Molecules are chemical structures consisting of
    multiple connected atoms

15
BIOLOGICAL HIERARCHIES
  • Hierarchy of biological organization
  • Biosphere
  • Communities
  • Populations
  • Organisms
  • Organ systems
  • Organs
  • Tissues
  • Cells
  • Organelles
  • Molecules

16
DIVERSITY OF LIFE
  • About 1.8 million different species have been
    identified to date
  • Most living species remain unidentified
  • Thousands are identified each year
  • The actual number of living species is unknown
  • Much higher than this number
  • Estimates range from 10 200 million
  • The vast majority of species ever having lived
    are now extinct

17
DIVERSITY OF LIFE
  • The 1.8 million identified species display
    significant diversity
  • 1,000,000 insects
  • 52,000 vertebrates
  • 290,000 plants
  • 100,000 fungi
  • 5,200 prokaryotes

18
UNITY OF LIFE
  • Despite significant diversity, all life possesses
    certain unifying traits
  • Composed of cell(s)
  • Require energy
  • Reproduce
  • Possess genetic material (DNA)
  • Evolve (characteristic of populations)
  • etc.

19
VIRUSES
?
  • Blur the boundary between life and non-life
  • Share some of the unifying features of life
  • Differ from normal life in some of these
    characteristics
  • Are viruses alive?

20
VIRUSES
  • Cellular life
  • Composed of cell(s)
  • Require energy
  • Reproduce
  • Possess DNA
  • Evolution (of populations)
  • etc.
  • Viruses
  • Not cellular
  • Only when infecting
  • Only within host
  • DNA or RNA
  • Very rapid evolution

21
UNITY AND DIVERSITY
  • Evolution accounts for lifes unity
  • Many similarities between organisms are due to
    shared ancestry

22
UNITY AND DIVERSITY
  • Evolution accounts for lifes diversity
  • Differences between closely related species are
    the result of evolutionary change
  • Often the result of adaptation to different
    environments

23
EVOLUTION
  • Evolution accounts for both the unity and the
    diversity of life
  • Vast explanatory power
  • Unifying theme of biology

24
EVOLUTION
  • except in Kansas

25
EVOLUTION
  • and in Dover, Pennsylvania

"breathtaking inanity"
26
EVOLUTION
  • and in other areas affected by various
    intellectually challenged school boards and
    legislative bodies in Arkansas, Georgia,
    Oklahoma, Wisconsin, etc.

27
(No Transcript)
28
  • Nothing in biology makes sense except in light
    of evolution
  • -- Theodosius Dobzhansky

29
EVOLUTION
  • Our discussions of evolution will center on two
    main points
  • Contemporary species arose from a succession of
    ancestors
  • Descent with modification
  • Inherited differences are the result of
    differences in reproductive success
  • Natural selection is the mechanism of adaptive
    evolution
  • Both of these topics will be covered in greater
    detail in future chapters

30
EVOLUTION
  • Differences in reproductive success will result
    in the evolution of adaptations in the
    population
  • Traits of individuals reproducing more than
    average will increase in frequency in future
    generations
  • Traits of individuals reproducing less than
    average will decrease in frequency in future
    generations

31
EVOLUTION
  • Differences in reproductive success will result
    in the evolution of adaptations in the population
  • Traits of individuals reproducing more than
    average will increase in frequency in future
    generations
  • Traits of individuals reproducing less than
    average will decrease in frequency in future
    generations

32
CLASSIFICATION
  • Taxonomy
  • Branch of biology involved in the naming and
    classification of species
  • Organisms are placed in groups based on
    similarities
  • Morphological similarities
  • Physiological / biochemical similarities
  • Genetic similarities
  • Multiple groups are combined into larger groups,
    again based on similarities

33
CLASSIFICATION
  • Taxonomic groupings reflect evolutionary
    relationships
  • Similarities are due to shared ancestry

34
CLASSIFICATION
  • Taxonomic groupings reflect evolutionary
    relationships
  • Similarities are due to shared ancestry

35
CLASSIFICATION
  • Taxonomic groupings reflect evolutionary
    relationships
  • Similarities are due to shared ancestry

36
CLASSIFICATION
  • All living things are classified into one of
    three domains
  • Bacteria
  • Archaea
  • Eukarya

37
CLASSIFICATION
  • Domain Bacteria and domain Archaea
  • Two prokaryotic domains
  • Organisms lacking a nucleus
  • Most members are unicellular and microscopic
  • Represent two very distinct branches of
    prokaryotes
  • Formerly combined in a single kingdom (Monera)

38
CLASSIFICATION
  • Domain Eukarya
  • Encompasses all eukaryotic cells
  • Organisms possessing a nucleus
  • Traditionally divided into four kingdoms
  • Protista
  • Fungi
  • Animalia
  • Plantae

39
CLASSIFICATION
  • Kingdoms animalia, plantae, and fungi are
    monophyletic groups
  • Each kingdom consists of an ancestral species and
    all of its descendents

40
CLASSIFICATION
  • Kingdoms animalia, plantae, and fungi
  • Distinguished partly by their modes of nutrition
  • Plants produce foods through photosynthesis
  • Fungi are mainly decomposers that absorb
    nutrients following the external breakdown of
    organic matter
  • Animals obtain food by ingestion

41
CLASSIFICATION
  • Kingdom Protista is defined by exclusion
  • Eukaryotes that are not animals, plants, or fungi
  • Not a monophyletic group
  • Should be split into multiple monophyletic
    kingdoms
  • The number of kingdoms is currently unclear
  • Most are unicellular
  • Some are multicellular
  • Some are very large

42
CLASSIFICATION
  • Each domain is divided into increasingly smaller
    groups
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

43
CLASSIFICATION
  • Each domain is divided into increasingly smaller
    groups
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

44
CLASSIFICATION
  • Each domain is divided into increasingly smaller
    groups
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

45
CLASSIFICATION
  • A specific scientific name is ultimately assigned
    to each species
  • Genus species
  • e.g., Homo sapiens
  • e.g., Escherichia coli
  • e.g., Bufonaria borisbeckeri
  • e.g., Esox lucius
  • etc.

46
CLASSIFICATION
  • DOMAIN Eukarya Bacteria
  • KINGDOM Animalia
  • PHYLUM Chordata Proteobacteria
  • CLASS Mammalia Gammaproteobacteria
  • ORDER Primata Enterobacteriales
  • FAMILY Hominidae Enterobacteriacaea
  • GENUS Homo Escherichia
  • SPECIES sapiens coli
  • STRAIN K12, O157H7, etc.

47
SCIENTIFIC INQUIRY
  • Scientific inquiry
  • The search for information and explanation
  • Drives progress in science

48
SCIENTIFIC INQUIRY
  • Two main processes of scientific inquiry in
    biology
  • Discovery science
  • Mainly concerned with describing nature
  • Hypothesis-based science
  • Mainly concerned with explaining nature

49
SCIENTIFIC INQUIRY
  • Recorded observations are called data
  • May be quantitative
  • May be qualitative

50
SCIENTIFIC INQUIRY
  • Discovery science
  • Mainly concerned with describing nature
  • Generalizations are derived based upon large
    numbers of specific observations
  • Inductive reasoning
  • e.g., The sun always rises in the east
  • e.g., All organisms are made of cells

51
SCIENTIFIC INQUIRY
  • Discovery science involves observations and
    generalizations
  • Provokes scientists to understand the natural
    causes and explanations for these observations
  • Such inquiry generally involves the proposing and
    testing of hypothetical explanations
  • Hypothesis testing

52
SCIENTIFIC INQUIRY
  • Hypothesis testing involves deductive reasoning
  • Specific expected results are extrapolated from
    general premises
  • Logic flows from the general to the specific
  • Opposite direction from inductive reasoning

53
SCIENTIFIC INQUIRY
  • Hypothesis-based science employs the scientific
    method
  • Idealized process of inquiry
  • Orderly series of steps used to address
    scientific questions
  • Elements of this process are used in most
    scientific research

54
SCIENTIFIC INQUIRY
  • Steps in the scientific method
  • Make observations
  • Ask a question
  • Formulate a hypothesis (and predictions)
  • Design an experiment to test this hypothesis
  • Collect data
  • Interpret the experimental results
  • Support or reject the hypothesis

55
SCIENTIFIC INQUIRY
56
SCIENTIFIC INQUIRY
  • Hypothesis
  • Tentative answer to a well-framed question
  • Generally an educated postulate
  • Based on past experience and data of discovery
    science
  • Based on observations
  • Makes predictions that can be tested through
    additional observations or experiments

57
SCIENTIFIC INQUIRY
  • Hypotheses are commonly used to solve everyday
    problems
  • Problems solved using hypotheses, predictions,
    and experiments
  • Our thought processes are rarely formally
    dissected in this manner

58
SCIENTIFIC INQUIRY
  • A scientifically useful hypothesis must be
  • Plausible
  • Reasonable
  • Testable
  • There must be some way to test the validity of
    the idea
  • Falsifiable
  • There must be some observation or experiment that
    could reveal that the idea is not true
  • A statement that is true by definition is not
    falsifiable

59
SCIENTIFIC INQUIRY
  • Certain predictions stem from a hypothesis
  • A hypothesis and its predictions are often
    written as an if , then statement
  • e.g., If cactus spines reduce herbivory, then
    herbivory will be more pronounced in cacti with
    fewer spines.
  • Experiments can be designed to determine the
    validity of these predictions

60
SCIENTIFIC INQUIRY
  • Designing a controlled experiment
  • An experimental group is compared to a control
    group
  • Ideally differ in only one factor
  • Independent variable

61
SCIENTIFIC INQUIRY
  • Designing a controlled experiment
  • An experimental group is compared to a control
    group
  • Ideally differ in only one factor
  • Independent variable

62
SCIENTIFIC INQUIRY
  • Designing a controlled experiment
  • Other potentially varying parameters are kept
    constant
  • Controlled variables or constants
  • What might be some constants in this experiment?

63
SCIENTIFIC INQUIRY
  • Designing a controlled experiment
  • The dependent variable is the parameter that is
    measured
  • Values of the dependent variable may differ
    between the experimental and control groups
  • These differences are the result of differences
    in the independent variable
  • The dependent variable is dependent upon the
    independent variable
  • What is the dependent variable in this
    experiment?
  • How would this be measured?

64
SCIENTIFIC INQUIRY
  • Review of variables
  • The independent variable is the variable
    intentionally allowed to vary between the control
    and experimental groups
  • Controlled variables (constants) are carefully
    controlled so as not to vary
  • The dependent variable is the parameter that is
    measured
  • Differences in the dependent variable are the
    result of differences in the independent variable

65
SCIENTIFIC INQUIRY
  • Designing a controlled experiment
  • For each of these hypotheses, list the
  • Independent variable
  • Dependent variable
  • Relevant constants

66
SCIENTIFIC INQUIRY
  • Presenting data
  • Data can be organized and presented in tables and
    graphs

67
SCIENTIFIC INQUIRY
  • Presenting data
  • Data can be organized and presented in tables and
    graphs

68
SCIENTIFIC INQUIRY
  • Interpreting results
  • Useful results must be reproducible
  • Experimental results must be viewed in light of
    the hypothesis being tested
  • Results may support the hypothesis
  • Note, the hypothesis is supported, not proven
  • Results may refute the hypothesis
  • Note that the hypothesis can be disproven
    (falsified)
  • What results would support your hypothesis?
  • What results would falsify your hypothesis?

69
FACT AND THEORY
  • The term fact does not convey absolute certainty
  • Science rejects the concept of absolute certainty
  • Scientists must always be willing to change their
    understanding in light of new information
  • At best, our understandings are granted
    provisional acceptance
  • A fact is confirmed to such a degree that it
    would be irrational to withhold provisional
    acceptance

70
FACT AND THEORY
  • The word theory has two very different meanings
  • In everyday speech
  • A theory can be little more than a hunch
  • Unproven idea
  • May or may not have supporting evidence
  • Akin to a hypothesis in science
  • In scientific communication (scientific
    theories)
  • General set of principles
  • Strongly supported by a large body of evidence
  • Explains some aspect of nature

71
FACT AND THEORY
  • A scientific theory explains a great diversity of
    observations
  • Supported by a massive body of evidence
  • Supported by numerous facts
  • Much broader in scope than a hypothesis
  • General enough to generate numerous new, testable
    hypotheses
  • Again, scientists must be willing to modify or
    reject any theory in light of new information

72
FACT AND THEORY
  • In science, the term theory does not imply that a
    concept is poorly supported
  • Many scientific theories are so thoroughly
    supported and widely accepted that they form the
    foundation of fields of study

73
FACT AND THEORY
  • Examples of thoroughly supported and widely
    accepted scientific theories
  • Cell Theory
  • Darwins Theory of Evolution
  • The Theory of Gravity
  • The Big Bang Theory
  • Einsteins Theory of Relativity
  • Germ Theory

74
FACT AND THEORY
  • The Theory of Gravity is both fact and theory
  • The occurrence of gravity is fact
  • Supported by a vast body of evidence
  • Sure, apples might begin levitating tomorrow, but
    considering events unsupported by any legitimate
    data is inappropriate
  • The mechanism by which gravity occurs is a theory
  • Isaac Newton explained rather well how gravity
    occurs
  • Albert Einstein and others have refined our
    understanding of the nature of gravity

75
FACT AND THEORY
  • The Theory of Evolution is both fact and theory
  • The occurrence of evolution is fact
  • Supported by a vast body of evidence
  • No competing scientific explanation for the unity
    and diversity of life exists
  • The mechanism by which evolution occurs is a
    theory
  • Charles Darwin described how evolution occurs by
    natural selection
  • Other evolutionary biologists have refined our
    understanding of evolution by means of natural
    selection

76
FACT AND THEORY
  • Arguing that something is just a theory is
    based upon either dishonesty or ignorance
  • Creationists commonly attempt to equate the two
    very different meanings of theory
  • Stated plainly, they are being intentionally
    misleading
  • Stated plainly, this is called dishonesty
  • Many non-scientists assume that these arguments
    are honest and rational
  • Mistakenly trust the untrustworthy
  • Mistakenly conclude that evolution is a frivolous
    idea

77
FACT AND THEORY
  • Evangelical Scientists Refute Gravity With New
    Intelligent Falling Theory
  • KANSAS CITY, KS As the debate over the
    teaching of evolution in public schools
    continues, a new controversy over the science
    curriculum arose Monday in this embattled
    Midwestern state. Scientists from the
    Evangelical Center For Faith-Based Reasoning are
    now asserting that the long-held theory of
    gravity is flawed, and they have responded to
    it with a new theory of Intelligent Falling.

For more on this imaginary yet profound article,
visit "theonion.com"
78
FACT AND THEORY
  • Students are expected to read Evolution as Fact
    and Theory, by Stephen Jay Gould, which can be
    found at the following website
  • http//www.stephenjaygould.org/library/gould_fact-
    and-theory.html

79
REFERENCES
  • Audesirk, Teresa, Audesirk, Gerald, and Beyers,
    Bruce E. Biology, Life on Earth, 6th edition.
    Prentice Hall, Inc. 2002.
  • Brooker, Robert J. Genetics, Analysis
    Principles, 2nd edition. McGraw-Hill Companies,
    Inc. 2005.
  • Campbell, Neil A. and Reese, Jane B. Biology,
    7th edition. Pearson Education, Inc. 2005.
  • Campbell, Neil A., Reese, Jane B., Taylor, Martha
    R., and Simon, Eric J. Biology, Concepts and
    Connections, 5th edition. Pearson Education,
    Inc. 2006.
  • Gould, Stephen Jay. Evolution as Fact and
    Theory. Discover 2 (May 1981) p34 37.
  • Nester, Eugene W., Anderson, Denise G., Roberts,
    C. Evans Jr., and Nester, Martha T.
    Microbiology, A Human Perspective, 5th edition.
    McGraw-Hill Companies, Inc. 2007.
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