Defining Life (1)

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Defining Life (1)
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• How do you know if something is alive?
• What are properties of living things that
  non-livings things do no possess?
• What is the smallest living thing you can think
  of?

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So what is required of life?
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• Living things are

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Defining Life (1)

• Living things vs. nonliving objects
• Comprised of the same chemical elements
• Obey the same physical and chemical laws
• The cell is the smallest, most basic unit of all
  life
• Familiar organisms are multicellular
• Some cells independent single-celled organisms

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Defining Life
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Levels of Biological Organization
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Living ThingsAcquire Process Food

• Energy - the capacity to do work
• The sun
• Ultimate source of energy for nearly all life on
  Earth
• Drives photosynthesis
• Metabolism - all the chemical reactions in a cell
• Homeostasis - Maintenance of internal conditions
  within certain boundaries

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Acquiring Nutrients
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Living ThingsRespond to Stimuli

• Living things detect changes in environment
• Response often involves movement
• Vulture can detect and find carrion a mile away
• Monarch butterfly senses fall and migrates south
• Microroganisms follow light or chemicals
• Even leaves of plants follow sun
• Responses collectively constitute behavior

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Living ThingsReproduce and Develop

• Organisms live and die
• Must reproduce to maintain population
• Multicellular organisms
• Begins with union of sperm and egg
• Developmental instructions encoded in genes
• Composed of DNA
• Long spiral molecule in chromosomes

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Rockhopper Penguins Offspring
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Living ThingsAdapt to Change

• Adaptation
• Any modification that makes an organism more
  suited to its way of life
• Organisms, become modified over time
• However, organisms very similar at basic level
• Suggests living things descended from same
  ancestor
• Descent with modification - Evolution
• Caused by natural selection

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So what is required of life?

• Living things
• eat
• give off wastes
• reproduce
• breathe
• die
• respond to their environment
• adapt
• contain heritable material

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Organization of the Biosphere

• Population - Members of a species within an area
• Community - A local collection of interacting
  populations
• Ecosystem - The communities in an area considered
  with their physical environment
• How chemicals are cycled and re-used by organisms
• How energy flows, from photosynthetic plants to
  top predators

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Terrestrial EcosystemsA Grassland
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Marine EcosystemsA Coral Reef
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Classification
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• What kinds of music do you listen to?
• What kinds of music are there?

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Classification

• Taxonomy
• The rules for identifying and classifying
  organisms
• Hierarchical levels (taxa) based on hypothesized
  evolutionary relationships
• Levels are, from least inclusive to most
  inclusive
• Species, genus, family, order, class, phylum,
  kingdom, and domain
• A level usually includes more species than the
  level below it, and fewer species than the one
  above it

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Levels of Classification
Corn
Human
Taxon
Eukarya
Eukarya
Domain
Plantae
Animalia
Kingdom
Anthophyta
Chordata
Phylum
Liliopsida
Mammalia
Class
Commelinales
Primates
Order
Poacae
Hominidae
Family
Zea
Homo
Genus
Z. mays
H. sapiens
Species
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Domains

• Bacteria
• Microscopic unicellular prokaryotes
• Archaea
• Bacteria-like unicellular prokaryotes
• Extreme aquatic environments
• Eukarya
• Eukaryotes Familiar organisms

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DomainsThe Archaea
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DomainsThe Bacteria
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Kingdoms

• Archaea Kingdoms still being worked out
• Bacteria - Kingdoms still being worked out
• Eukarya
• Kingdom Protista
• Kingdom Fungi
• Kingdom Plantae
• Kingdom Animalia

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DomainsThe Eukaryote Kindoms
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Scientific Names

• Binomial nomenclature (two-word namess)
• Universal
• Latin-based
• First word represents genus of organism
• Second word is specific epithet of a species
  within the genus
• Always Italicized asa Genus species (Homo
  sapiens)
• Genus may occur alone (Homo), but not specific
  epithet