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Botany & Science

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Botany 1010

September 7, 1999Lecture #2

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Composition of Living Things

• All living things are composed of cells• The cell is the smallest unit of living matter• Single cell organisms• Multi-cellular organisms

– collections of specialized cells

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Characteristics of Living Things

• Living things have self regulating metabolisms

• homeostasis: automatic tendency to maintain appropriate internal environment

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Characteristics of Living Things

• Living Things Move• Respond to StimuliStimuli• Reproduce• Adapt to their environment

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Natural Selection

Charles Darwin: “The Origin of Species”• Present forms of life have descended from

previous forms of life…

• These changes were selected because they allowed the species to be more successful.

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Natural Selection Acts on ...Individuals

within a Specieswhich comprise a Population

which in total are a Meta-populationthat are part of a Community

whom make up an Ecosystem

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Natural Selection is apparent in ...Species• Group of organisms• Similar structural• Similar functional

characteristics• Breed with one another • Have a close common

ancestry – (common gene pool)

Population• A group of

organisms• Of the same species• Living in the same

geographical area• At the same time

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Natural Selection• Members of a population display variation

from one another• More organisms are born than survive to

reproduce• Limited resources force members to

compete for survival• Survivors live to reproduce and pass their

genetic code on to offspring

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new offspring have genetic traits from their parents

that increase their chance of survival in nature

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Biological OrganizationChemical

– Atoms– Molecules

Ecological– Communities– Ecosystems

Functional– Producers– Consumers– Decomposers

Cellular– Organelles– Cells are the basic unit

of life

Multi-cellular– Tissues– Organs– Organ Systems

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Levels of Biological Organization

Individuals

Species

Populations

Meta-populations

Community

Ecosystem

Biome

Biosphere

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Taxonomic or SystematicsClassify organisms by evolutionary relationships

• Kingdom– Phya

• Class– Order

» Family * Genus

> Species

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Taxonomic or SystematicsFive Kingdoms Of Life

• Moneran• Protista• Fungi

• Plantae• Animalia

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The Scientific Method

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What is the Scientific Method?And why do we care?

• Science is a process, a way of thinking• We stand on the shoulders of giants…• It is a process of critical review and

skepticism...

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What is the scientific method?

• Recognizing a problem• making careful observations• developing an educated prediction as to the

nature of the problem• testing your prediction• evaluating the results

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Deductive and Inductive Reasoning

• Deductive reasoning refers to using general principles or experience to infer more detailed predictions

• Inductive reasoning refers to using specific examples to draw a general conclusion.

• Examples?

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Guidelines for scientific thought

• A hypothesis should be consistent with what is already known

• a hypothesis must be testable• the test must be repeatable• it must be able to be proven false

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Why must a hypothesis must be able to be proven false?

• Affirming the consequent • Is something true simply because the test

says its true?• What problems can emerge in the design of

an experiment?• Modus tollens

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Skepticism and Objectivity

• Sources of error in the scientific method– Bias– Atypical sample

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Class exercise

• Are the conclusions born out in the explanation?

• What confounding factors could be present in the experiment?

• Could you make a case for affirming the consequence?

• Is this falsifiable?

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For next time...

• Chp 3, The Chemistry of Life• Matter is made up of …p. 38• Atoms are the basic particles…pp 38 - 44• Chemical bonds pp 44- 48• Water pp 48 -50