A View of LifeChapter 01

A View of LifeA View of Life 2

OutlineOutline

Defining Life - Emergent PropertiesDefining Life - Emergent Properties

Materials and EnergyMaterials and Energy

Reproduction and DevelopmentReproduction and Development

Adaptations and Natural SelectionAdaptations and Natural Selection

Biosphere OrganizationBiosphere Organization

Human PopulationHuman Population

BiodiversityBiodiversity

ClassificationClassification

The Scientific MethodThe Scientific Method

A View of LifeA View of Life 3

Defining Life (1)Defining Life (1)

Living things vs. nonliving objects:Living things vs. nonliving objects:

Comprised of the same chemical elementsComprised of the same chemical elements

Obey the same physical and chemical lawsObey the same physical and chemical laws

The cell is the smallest, most basic unit of all The cell is the smallest, most basic unit of all lifelife

Familiar organisms are multicellularFamiliar organisms are multicellular

Some cells independent – single-celled Some cells independent – single-celled organismsorganisms

4Defining Life

A View of LifeA View of Life 5

Defining Life (2)Defining Life (2)

Emergent Properties – Biological organizationEmergent Properties – Biological organization

Levels range from extreme micro to globalLevels range from extreme micro to global

Each level up:Each level up:

­More complex than preceding levelMore complex than preceding level

­ Properties:Properties:

A superset of preceding level’s propertiesA superset of preceding level’s properties

Emerge from interactions between componentsEmerge from interactions between components

6Levels of Biological Organization

A View of LifeA View of Life 7Living Things:Living Things:Acquire & Process FoodAcquire & Process Food

EnergyEnergy - the capacity to do work - the capacity to do work

The sun:The sun:

­ Ultimate source of energy for nearly all life on Ultimate source of energy for nearly all life on EarthEarth

­ Drives photosynthesisDrives photosynthesis

MetabolismMetabolism - all the chemical reactions in a - all the chemical reactions in a cellcell

­ HomeostasisHomeostasis - Maintenance of internal - Maintenance of internal conditions within certain boundariesconditions within certain boundaries

8Acquiring Nutrients

A View of LifeA View of Life 9Living Things:Living Things:Respond to StimuliRespond to Stimuli

Living things detect changes in environmentLiving things detect changes in environment

ResponseResponse often involves movement often involves movement

Vulture can detect and find carrion a mile Vulture can detect and find carrion a mile awayaway

Monarch butterfly senses fall and migrates Monarch butterfly senses fall and migrates southsouth

Microroganisms follow light or chemicalsMicroroganisms follow light or chemicals

Even leaves of plants follow sunEven leaves of plants follow sun

Responses collectively constitute Responses collectively constitute behaviorbehavior

A View of LifeA View of Life 10Living Things:Living Things:Reproduce and DevelopReproduce and Develop

Organisms live and dieOrganisms live and die

Must reproduce to maintain populationMust reproduce to maintain population

Multicellular organisms:Multicellular organisms:

Begins with union of sperm and eggBegins with union of sperm and egg

Developmental instructions encoded in genesDevelopmental instructions encoded in genes

­ Composed of DNAComposed of DNA

­ Long spiral molecule in Long spiral molecule in chromosomeschromosomes

11Rockhopper Penguins & Offspring

A View of LifeA View of Life 12Living Things:Living Things:Adapt to ChangeAdapt to Change

AdaptationAdaptation

Any modification that makes an organism Any modification that makes an organism more suited to its way of lifemore suited to its way of life

Organisms, become modified over timeOrganisms, become modified over time

However, organisms very similar at basic levelHowever, organisms very similar at basic level

­ Suggests living things descended from same Suggests living things descended from same ancestorancestor

­ Descent with modification - Descent with modification - EvolutionEvolution

­ Caused by Caused by natural selectionnatural selection

A View of LifeA View of Life 13

Organization of the BiosphereOrganization of the Biosphere

PopulationPopulation - Members of a species within an - Members of a species within an areaarea

CommunityCommunity - A local collection of interacting - A local collection of interacting populationspopulations

EcosystemEcosystem - The communities in an area - The communities in an area considered with their physical environmentconsidered with their physical environment

­ How chemicals are cycled and re-used by How chemicals are cycled and re-used by organismsorganisms

­ How energy flows, from photosynthetic plants How energy flows, from photosynthetic plants to top predatorsto top predators

14Terrestrial Ecosystems:A Grassland

15Marine Ecosystems:A Coral Reef

A View of LifeA View of Life 16

Human PopulationsHuman Populations

Ecosystems negatively impacted by human Ecosystems negatively impacted by human populationspopulations

Destroyed for agriculture, housing, industry, etc.Destroyed for agriculture, housing, industry, etc.

Degraded and destabilized by pollutionDegraded and destabilized by pollution

However, humans depend upon However, humans depend upon healthyhealthy ecosystems ecosystems forfor

FoodFood

MedicinesMedicines

Raw materialsRaw materials

Other ecosystem processesOther ecosystem processes

A View of LifeA View of Life 17

BiodiversityBiodiversity

Biodiversity:Biodiversity:

The total number of species (est. 15 million)The total number of species (est. 15 million)

The variability of their genes, andThe variability of their genes, and

The ecosystems in which they liveThe ecosystems in which they live

Extinction:Extinction:

The death of the last member of a speciesThe death of the last member of a species

Estimates of 400 species/day lost worldwideEstimates of 400 species/day lost worldwide

A View of LifeA View of Life 18

ClassificationClassification

Taxonomy:Taxonomy:The rules for identifying and classifying The rules for identifying and classifying organismsorganisms

Hierarchical levels (taxa) based on Hierarchical levels (taxa) based on hypothesized evolutionary relationshipshypothesized evolutionary relationships

Levels are, from least inclusive to most Levels are, from least inclusive to most inclusive:inclusive:­ Species, genus, family, order, class, phylum, Species, genus, family, order, class, phylum, kingdom, and domainkingdom, and domain

­ A level usually includes more species than the A level usually includes more species than the level below it, and fewer species than the one level below it, and fewer species than the one above itabove it

A View of LifeA View of Life 19

Levels of ClassificationLevels of Classification

Z. maysZ. maysH. sapiensH. sapiensSpeciesSpecies

ZeaZeaHomoHomoGenusGenus

PoacaePoacaeHominidaeHominidaeFamilyFamily

CommelinalesCommelinalesPrimatesPrimatesOrderOrder

LiliopsidaLiliopsidaMammaliaMammaliaClassClass

AnthophytaAnthophytaChordataChordataPhylumPhylum

PlantaePlantaeAnimaliaAnimaliaKingdomKingdom

EukaryaEukaryaEukaryaEukaryaDomainDomain

CornCornHumanHumanTaxonTaxon

A View of LifeA View of Life 20

DomainsDomains

BacteriaBacteria

Microscopic unicellular prokaryotesMicroscopic unicellular prokaryotes

ArchaeaArchaea

Bacteria-like unicellular prokaryotesBacteria-like unicellular prokaryotes

Extreme aquatic environmentsExtreme aquatic environments

EukaryaEukarya

Eukaryotes – Familiar organismsEukaryotes – Familiar organisms

21Domains:The Archaea

22Domains:The Bacteria

A View of LifeA View of Life 23

KingdomsKingdoms

ArchaeaArchaea – Kingdoms still being worked out – Kingdoms still being worked out

BacteriaBacteria - Kingdoms still being worked out - Kingdoms still being worked out

EukaryaEukarya

Kingdom Kingdom ProtistaProtista

Kingdom Kingdom FungiFungi

Kingdom Kingdom PlantaePlantae

Kingdom Kingdom AnimaliaAnimalia

24Domains:The Eukaryote Kindoms

A View of LifeA View of Life 25

Scientific NamesScientific Names

Binomial nomenclatureBinomial nomenclature (two-word namess) (two-word namess)

UniversalUniversal

Latin-basedLatin-based

First word represents First word represents genusgenus of organism of organism

Second word is Second word is specific epithetspecific epithet of a species of a species within the genuswithin the genus

Always Italicized asa Always Italicized asa Genus speciesGenus species ( (Homo Homo sapienssapiens))

Genus may occur alone (Genus may occur alone (HomoHomo), but not ), but not specific epithetspecific epithet

A View of LifeA View of Life 26The Scientific Method:The Scientific Method:Observation and HypothesisObservation and Hypothesis

Begins with Begins with observationobservation

Scientists use their five sensesScientists use their five senses

Instruments can extend the range of sensesInstruments can extend the range of senses

HypothesisHypothesis

A tentative explanation for what was A tentative explanation for what was observedobserved

Developed through inductively reasoning Developed through inductively reasoning from specific to generalfrom specific to general

27The Scientific Method:

A Flow Diagram

A View of LifeA View of Life 28The Scientific Method:The Scientific Method:ExperimentationExperimentation

ExperimentationExperimentation Purpose is to challenge the hypothesisPurpose is to challenge the hypothesis Designed through deductively reasoning Designed through deductively reasoning

from general to specificfrom general to specific Often divides subjects into a Often divides subjects into a control groupcontrol group

and an and an experimental groupexperimental group PredictsPredicts how groups should differ if how groups should differ if

hypothesis is validhypothesis is valid­ If prediction happens, hypothesis is If prediction happens, hypothesis is

unchallengedunchallenged

­ If not, hypothesis is unsupportableIf not, hypothesis is unsupportable

A View of LifeA View of Life 29The Scientific Method:The Scientific Method:ResultsResults

ResultsResults

Observable, objective results from an Observable, objective results from an experimentexperiment

Strength of the data expressed in probabilitiesStrength of the data expressed in probabilities

The probability that random variation could The probability that random variation could have caused the resultshave caused the results

­ Low probability (less than 5%) is goodLow probability (less than 5%) is good

­ Higher probabilities make it difficult to dismiss Higher probabilities make it difficult to dismiss random chance as the sole cause of the resultsrandom chance as the sole cause of the results

A View of LifeA View of Life 30The Scientific Method:The Scientific Method:Conclusion and ReviewConclusion and Review

The results are The results are analyzedanalyzed and and interpretedinterpreted

ConclusionsConclusions are what the scientist thinks are what the scientist thinks caused the resultscaused the results

Findings must be reported in scientific Findings must be reported in scientific journalsjournals

Peers reviewPeers review the findings and the conclusions the findings and the conclusions

Other scientists then attempt to Other scientists then attempt to duplicateduplicate or or dismissdismiss the published findings the published findings

A View of LifeA View of Life 31

Scientific TheoryScientific Theory

Scientific TheoryScientific Theory::

Joins together two or more related Joins together two or more related hypotheseshypotheses

Supported by broad range of observations, Supported by broad range of observations, experiments, and dataexperiments, and data

Scientific PrincipleScientific Principle / / LawLaw::

Widely accepted set of theoriesWidely accepted set of theories

No serious challenges to validityNo serious challenges to validity

A View of LifeA View of Life 32Controlled Experiments:Controlled Experiments:The VariablesThe Variables

Experimental (Experimental (IndependentIndependent) variable) variable

Applied one way to experimental groupApplied one way to experimental group

Applied a different way to control groupApplied a different way to control group

Response (Response (dependentdependent) variable) variable

Variable that is measured to generate dataVariable that is measured to generate data

Expected to yield different results in control Expected to yield different results in control versus experimental groupsversus experimental groups

A View of LifeA View of Life 33Controlled Experiments:Controlled Experiments:Observation & HypothesesObservation & Hypotheses

Observations:Observations:

Nitrate fertilizers boost grain crops, but may Nitrate fertilizers boost grain crops, but may damage soilsdamage soils

When grain crops are rotated with pigeon pea When grain crops are rotated with pigeon pea it adds natural nitrogenit adds natural nitrogen

Hypothesis:Hypothesis:

Pigeon pea rotation will boost crop production Pigeon pea rotation will boost crop production as much as nitratesas much as nitrates

Pigeon pea rotation will NOT damage soilsPigeon pea rotation will NOT damage soils

34Root Nodules

A View of LifeA View of Life 35Controlled Experiments:Controlled Experiments:Experimental DesignExperimental Design

Experimental DesignExperimental DesignControl GroupControl Group­Winter wheat planted in pots without fertilizerWinter wheat planted in pots without fertilizer

Experimental GroupsExperimental Groups­ 1-Winter wheat planted in pots with 45 kg/ha 1-Winter wheat planted in pots with 45 kg/ha nitratenitrate

­ 2-Winter wheat planted in pots with 90 kg/ha 2-Winter wheat planted in pots with 90 kg/ha nitratenitrate

­ 3-Winter wheat planted in pots that had grown a 3-Winter wheat planted in pots that had grown a crop of pigeon peascrop of pigeon peas

All groups treated identically except for aboveAll groups treated identically except for above

36Crop Rotation Study

A View of LifeA View of Life 37Controlled Experiments:Controlled Experiments:ResultsResults

Experimental Prediction:Experimental Prediction:Wheat production following pigeon pea Wheat production following pigeon pea rotation will be equal or better than following rotation will be equal or better than following nitrate fertilizernitrate fertilizer

ResultsResults45 kg/ha produced slightly better than 45 kg/ha produced slightly better than controlscontrols

90 kg/ha produced nearly twice as much as 90 kg/ha produced nearly twice as much as controlscontrols

Pigeon pea rotation did not produce as much Pigeon pea rotation did not produce as much as the controlsas the controls

A View of LifeA View of Life 38Controlled Experiments:Controlled Experiments:Conclusion & RevisionConclusion & Revision

ConclusionConclusion

Research hypothesis was not supported by Research hypothesis was not supported by resultsresults

However, research hypothesis was not proven However, research hypothesis was not proven false by negative resultsfalse by negative results

Revised experimentRevised experiment

Grow wheat in same pots for several Grow wheat in same pots for several generationsgenerations

Look for soil damage in nitrate pots and Look for soil damage in nitrate pots and improved production in pigeon pea potsimproved production in pigeon pea pots

A View of LifeA View of Life 39Controlled Experiments:Controlled Experiments:Revised Results & ConclusionRevised Results & Conclusion

ResultsResultsAfter second year:After second year:­ Production following nitrates declinedProduction following nitrates declined­ Production following pigeon pea rotation was Production following pigeon pea rotation was greatest of allgreatest of all

After third yearAfter third year­ Pigeon pea rotation produced 4X as much as Pigeon pea rotation produced 4X as much as controlscontrols

Revised conclusionsRevised conclusionsResearch hypothesis supportedResearch hypothesis supportedPigeon pea rotation should be recommended Pigeon pea rotation should be recommended over nitratesover nitrates

40A Field Study

A View of LifeA View of Life 41

ReviewReview

Defining Life - Emergent PropertiesDefining Life - Emergent Properties

Materials and EnergyMaterials and Energy

Reproduction and DevelopmentReproduction and Development

Adaptations and Natural SelectionAdaptations and Natural Selection

Biosphere OrganizationBiosphere Organization

Human PopulationHuman Population

BiodiversityBiodiversity

ClassificationClassification

The Scientific MethodThe Scientific Method

A View of LifeEnding Slide Chapter 01