a view of life 1 defining life (1) how do you know if something is alive? what are properties of...

A View of LifeA View of Life 1

Defining Life (1)Defining Life (1)

How do you know if something is alive?How do you know if something is alive?

What are properties of living things that non-What are properties of living things that non-livings things do no possess?livings things do no possess?

What is the smallest living thing you can think What is the smallest living thing you can think of?of?

A View of LifeA View of Life

So what is required of life?So what is required of life?

Living “things” are:Living “things” are:

2

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

5Levels of Biological Organization

A View of LifeA View of Life 6Living 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

7Acquiring Nutrients

A View of LifeA View of Life 8Living 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 9Living 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

10Rockhopper Penguins & Offspring

A View of LifeA View of Life 11Living 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

So what is required of life?So what is required of life?

Living “things”Living “things”eateatgive off wastesgive off wastesreproducereproducebreathebreathediedierespond to their environmentrespond to their environmentadaptadaptcontain heritable materialcontain heritable material

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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

16ClassificationClassification

What kinds of music do you listen What kinds of music do you listen to?to?

What kinds of music are there?What kinds of music are there?

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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

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Levels of ClassificationLevels of Classification

Z. maysZ. maysH. sapiensH. sapiensSpeciesSpecies

ZeaZeaHomoHomoGenusGenus

PoacaePoacaeHominidaeHominidaeFamilyFamily

CommelinalesCommelinalesPrimatesPrimatesOrderOrder

LiliopsidaLiliopsidaMammaliaMammaliaClassClass

AnthophytaAnthophytaChordataChordataPhylumPhylum

PlantaePlantaeAnimaliaAnimaliaKingdomKingdom

EukaryaEukaryaEukaryaEukaryaDomainDomain

CornCornHumanHumanTaxonTaxon

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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

20Domains:The Archaea

21Domains:The Bacteria

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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

23Domains:The Eukaryote Kindoms

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Scientific NamesScientific Names

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

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