Biology L111: Evolution and Diversity

Instructor: Michael J. Wade

AIs: Tiffany ClarkHarald Parzer

The Thursday Discussion section 14008 that meets at 11:15A-12:05 on Thursdays in

JH 440 has been moved to

JH 248 at the same time and day.

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The Thursday Discussion section 14008 that meets at 11:15A-12:05 on Thursdays in JH 440 has been

moved to JH 248 at the same time and day.

Class Website

http://www.indiana.edu/~mjwade/L111/

Postings of Syllabus, Discussion Questions, Lecture Notes, and Grades

http://www.indiana.edu/~mjwade/L111/

Outline for Week 1Outline for Week 1 What is Science?What is Science?

What do scientists do?What do scientists do? What is Biology?What is Biology?

What is Life?What is Life? Evolution by Natural Selection explainsEvolution by Natural Selection explains

Two Fundamental PatternsTwo Fundamental Patterns of Natureof Nature Adaptation Adaptation DiversityDiversity

Logic of Darwin’s TheoryLogic of Darwin’s Theory

What is Science?What is Science? From Latin From Latin scientiascientia = “to know” = “to know” Science is a way of viewing the world that Science is a way of viewing the world that

focuses on focuses on objectiveobjective information, and putting information, and putting that information to work to build an that information to work to build an understanding of processes acting in the natural understanding of processes acting in the natural world to cause patterns. world to cause patterns.

Scientists test hypothesesScientists test hypotheses using using observationsobservations, , manipulationsmanipulations or or experimentsexperiments, or , or mathematical mathematical modelsmodels..

What Scientists DoWhat Scientists Do All science begins with All science begins with observationsobservations about the about the

natural world; scientists are ‘natural world; scientists are ‘pattern pattern detectorsdetectors.’.’

Scientists suggest anScientists suggest an hypothesishypothesis to explain or to explain or to account for the pattern of observations.to account for the pattern of observations.

Scientific hypotheses must be Scientific hypotheses must be falsifiablefalsifiable (i.e. (i.e. testable)testable)

ExperimentsExperiments are used to test an hypothesis, are used to test an hypothesis, and/or to eliminate one or more competing and/or to eliminate one or more competing hypotheses.hypotheses.

In a In a controlled experimentcontrolled experiment, all variables, but , all variables, but one, are kept constant.one, are kept constant.

Theory Theory ≠≠ Hypothesis HypothesisTheory = Tested and Supported Theory = Tested and Supported

HypothesesHypotheses In science, a In science, a theorytheory is: is:

A set of hypotheses with supporting evidenceA set of hypotheses with supporting evidence.. A body of interconnected concepts, supported by A body of interconnected concepts, supported by

mathematical or logical reasoning and experimental mathematical or logical reasoning and experimental evidence.evidence.

This is different from the colloquial use of This is different from the colloquial use of “theory”“theory” Opinion-based rather than evidence-based.Opinion-based rather than evidence-based. A hunch, a guess, or a belief about cause and A hunch, a guess, or a belief about cause and

effect.effect.

Scientific Theories are constantly compared with new Scientific Theories are constantly compared with new physical discoveries and experimental results.physical discoveries and experimental results.

New Theories explain MORE not LESS.New Theories explain MORE not LESS.

Process of ScienceProcess of ScienceFigure 1.4

Hypothesis 5 Hypothesis 5 becomes part of becomes part of “Theory”“Theory”

X

X

Rejected HypothesesAre NOT

part of Theory

Many Lines ofSupporting

New Evidence

From Greek From Greek bios =bios = life life and and ologyology = science or = science or study ofstudy of

What is Life?What is Life?

Seven Basic characteristics of living organisms:Seven Basic characteristics of living organisms: cellular organizationcellular organization Sensitivity and response to the environmentSensitivity and response to the environment growth, development, and reproductiongrowth, development, and reproduction energy utilizationenergy utilization evolutionary adaptation or ‘fit to the evolutionary adaptation or ‘fit to the

environment’environment’ homeostasishomeostasis DNA and RNA, replication and informationDNA and RNA, replication and information

Biology is the Study of LifeBiology is the Study of Life

Hierarchical Hierarchical Organization of LifeOrganization of Life

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

CELLULAR LEVEL

Atoms

Molecule

Macromolecule

Organelle

Cell

ORGANISMAL LEVEL

Tissue

Organ

Organ system

Organism

Fig. Fig. 1.21.2

POPULATIONAL LEVEL

Population

Species

Community

Ecosystem

Darwin

Evolutionary Biologists:

1] Identify patterns in the diversity of life, especially puzzling ones, that appear to be problematic for the theory.

2] Hypothesize processes or forces that might be creating those patterns. They provide an explanation for the pattern in terms of one or more of the five evolutionary processes.

3] Test the adequacy of their hypotheses by experimentation and by further study of the history of life.

The term, “evolution,” appears many times a week in national newspapers, like the Washington Post.

1. NATIONAL FIREARMS MUSEUM -- Permanent exhibits tracing the evolution of firearms and their role in the history of the United States. Open daily 10 to 4. National Rifle Association, 11250 Waples Mill Rd., Fairfax.

2. NATIONAL MUSEUM OF HEALTH & Medicine -- Open indefinitely: "Evolution of the Microscope"; Open daily 10 to 5:30. Armed Forces Institute of Pathology, Walter Reed Army Medical Center, Building 54, 6900 Georgia Ave. NW.

3. THE ART BEAT: Review of Braswell’s stage musical, "Paying the Price" which debuts at the Kennedy Center on Labor Day The play, says Braswell, recounts his father's evolution from a happy-go-lucky enlistee to a battle-weary prisoner of war in Romania.

In colloquial contexts, “evolution” is a synonym for

“change over time.”

Usually, the change is “for the better,” so that evolution

is interpreted to mean “improvement with time.”

Evolution is a process of change and it does result in

adaptation over time. But, NOT all change is evolution

and adaptation is NOT always improvement.

Change Change

in Kinds in Numbers

Pleistocene (2 mya) Today

14 species of elephants 3 species # declined

3-4 species of hominid 1 species # increased

50 species of Hawaiian > 500 species # did not change

Drosophila (fruit flies)

Evolution Ecology

Ecology: Study of the change in the numbers and distribution of organisms.

Evolution: Study of the change in the kinds of organisms.

Darwin’s theory of Evolution by Natural Selection is the corner stone of modern biological science.

"Nothing in biology makes sense but in the light of evolution.”

Theodosius Dobzhansky(1900-1975)

Evolutionary Geneticist Genetic Model of Speciation

Charles Robert DarwinBorn 1809

Voyage of the H. M. S. BeagleDecember, 1831- October, 1836

On the Origin of Species (1859)

Two Patterns of the Two Patterns of the NatureNature

AdaptationAdaptation:: The remarkable “fit” between organisms The remarkable “fit” between organisms

and environment.and environment. TheThe Diversity of OrganismsDiversity of Organisms: :

Why there are so many different species Why there are so many different species (5 to 50 million living species)?(5 to 50 million living species)?

Fossil record indicates that >99% of Fossil record indicates that >99% of species that have ever existed are extinctspecies that have ever existed are extinct

500,000 beetle species alone500,000 beetle species alone