This PowerPoint combines Darwin information from both texts

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Chapter 15

• This PowerPoint combines Darwin information from
  both texts
• It provides a lot of background information that
  should better help you understand the development
  of Darwins theories as well as give you a more
  thorough foundation of the history of Earth.
• These PowerPoints will be onlineplease pay close
  attention in class as we will move quickly
  through them

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Plate Tectonics and Continental Drift Theory

• Complete the Chapter 15 WebQuest
  ContinentalDriftQuest (located on the Biology
  Exploring Life site
• Try to explain how Plate Tectonics and
  Continental Drift influenced evolution and
  biodiversity
• You will need to read "On the Move...Continental
  Drift and Plate Tectonics." this is linked on
  that site VERY USEFUL!

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The Fossil Record

• Fossils/Their Dating
• Fossil Record/Geologic Time Scale
• Continental Drift/Macroevolution
• Mass Extinctions

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Fossils

• Formed from remains of organisms buried by
  sediments, dust, or volcanic ash
• Soft body parts usually decay rapidly
• Hard body parts (shells, bones, or teeth) may
  become preserved long-lasting
• Hard body parts are hardened more
• Minerals dissolve in groundwater
• Seep into tissues of dead organisms and replace
  its organic material
• Plant/animal becomes petrified

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Fossils (cont.)

• Some rare fossils contain organic material
• Found as thin films
• Pressed between layers of sand stone or shale
• Ex. Idaho plant leaves millions of years old
  that are still green with chlorophyll
• Other Fossils footprints, animal burrows,
  sediment impressions

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Preserved specimens

• Sometimes an organism happens to die in a place
  where bacteria and fungi cannot decompose the
  corpse
• Ice
• Plant sap

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Fossil Record/Geologic Time Scale

• Fossil record is a rich storehouse of
  information about macroevolution
• Geologic Time Scale
• Precambrian
• Paleozoic
• Mesozoic
• Cenozoic

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Geologic Time Scale

• Periods are divided into epochs
• Boundaries between eras are marked by a major
  change in forms of life and possibly mass
  extinctions

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Dating Fossils

• Know age of fossils based on location in sediment
• Relative Ages reflect the order in which groups
  of species existed compared to one another
• Absolute Ages Actual ages in years

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Radiometric Dating

• Measurement of certain radioactive isotopes in
  objects
• Every isotope has a fixed rate of decay
• Number of years for 50 of original sample to
  decay half-life
• Unaffected by temperature, pressure and other
  environmental conditions
• Used to date rocks
• Fossils can sometimes be dated as well

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Figuring out age of Fossils

• Could contain isotopes of elements that
  accumulated in the organisms when they were alive
  
• When organism dies, intake of isotopes stops, but
  radioactive decay continues

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Carbon Dating

• Dinner and a movie usually works! Just kidding.
• Can only be used to find the age of recent
  fossils due to half-life of C-14 5,600 yrs
• Any fossil older than 50,000 must be estimated
  using the surrounding rocks that contain
  Uranium-238 and other radioactive isotopes that
  have longer half-lives

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Continental Drift

• Continents arent locked into place
• Landmasses on different plates change position
  relative to each other as a result of continental
  drift
• Solution to many biological puzzles
• Matching fossils in totally different locations
• Differing plants in locations that became isolated

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2 Major Events

• 1. 250 million years ago, near end of Paleozoic
  Era
• Plates moved 1 supercontinent Pangea
• Variety of changes
• Shoreline reduced
• Sea levels dropped
• Shallow coastal seas were drained, destroying
  shallow water environments and inhabiting species
• Continental interiors influenced as well
• Isolated, evolving species came together and
  competed cause mass extinctions

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2 Major Events (cont.)

• 2. 180 Million years ago Continental Drift
• Pangea broke up
• Each continent became isolated
• Species on each continent diverged in their
  evolution and adapted and diversified based on
  new, separate continents

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Mass Extinctions

• Long periods of relative stability broken by
  brief periods of great species loss
• Extinction of dinosaurs (end of Cretaceous Period
  65 million years ago)
• Climate was cooling
• Shallow seas receding
• Large meteor hit Yucatan Peninsula in Mexico
  during same time, sending dust into the
  atmosphere
• Blocked sunlight
• Reduced food production by photosynthesis

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The Positive to Mass Extinction

• Adaptive radiation of survivors
• In aftermath, biological diversity increased
  again
• Gives surviving organisms new opportunities
• Rise of mammals may have resulted from the void
  left by the extinction of dinosaurs

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Taxonomy Relfects Evolutionary History

• Identification, naming, and classification of
  species
• Common names cause confusion
• Common name can refer to many different species
• Doesnt reflect organism
• Universal scientific name needed for all
  scientists to clearly communicate

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Linneus

• Binomial Nomenclature two-part Latin naming
  system for naming each species
• Also a hierarchy of species into broader and
  broader groups
• Genus species (Ex. Panthera pardus)
• Closely related species are grouped into same
  genus

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Classification and Evolution

• Phylogenetic Tree reflects the hypotheses of
  evolutionary relationships
• Homologous structures
• Basic underlying similarities if evolved from
  single structure in a common ancestor
• Greater number of homologous structures more
  closely the species are thought to be related

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Convergent Evolution

• Not all structures are inherited from common
  ancestor
• Unrelated species from similar environments have
  adaptations that seem very similar analogous
  structures
• Wings of insects and birds evolved
  independently despite both are flight equipment
  and built from entirely different structures

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Theories of Evolution

• Early 1800s
• Jean Baptiste Lamarck attempted to explain
  Buffons observations
• Proposed that life evolves/changes
• Species are not permanent
• Evolution is a process of adaptation
• Today unfairly remembered for mistaken
  explanation of how adaptations evolve (make sure
  you know what these are pg. 293)

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Darwin

• Voyage of the Beagle
• December 1831
• Mission chart poorly known stretches of the S.
  American coastline for the British navy
• Charles Darwin, 22, was on the ship
• Interested in studying geology, plants, animals
  encountered on voyage
• Pivotal trip in that it changed the thinking of
  many

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Darwin (cont.)

• Darwins Observations
• Darwin spent a lot of time on shore while ships
  crew surveyed
• Collected many species of plants and animals
• Documented everything in extensive journals
  (observations, studies, personal thoughts)
• Journals documented Darwins thoughts from before
  the journey until he returned to port in England

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Darwin (cont.)

• Darwins Observations (cont.)
• Noticed that plants and animals all had definite
  S. Am. Character
• Distinct from species in Europe
• Deduced that species in S. Am. descended from
  ancestral species on that continent
• Intrigued by life on Galápagos Island
• Species were similar to plants and animals on
  nearest mainland (not exactly same)
• Allowed Darwin to suggest that species that left
  the mainland adapted to new lives on islands

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Darwin (cont.)

• Ideas from Geology
• Darwin read a lot despite puking
• Read from Lyells writings
• Proposed that gradual and observable geologic
  processes (erosion) could explain the physical
  features of todays Earth
• River erosion deep, river-carved canyon
• Mountain range rises earthquakes

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Still Darwin

• Ideas from Geology (cont.)
• Darwin personally experienced an earthquake in
  Andes Mountains
• He collected fossils of ocean organisms high in
  the Andes
• Concluded that (based on Lyells work) that the
  earthquakes gradually lifted the rock.
• 2 conclusions
• Slow processes of mountain building and erosion
  suggested an Earth that must be very cold
• These slow and gradual processes occurring over
  vast spans of time could cause enormous change on
  Earth

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Darwin (cont.)

• Darwin was at sea for 5 years
• Over this time he sent letters and specimens back
  to England
• This established his reputation with other
  scientists
• Left as young graduate
• Returned as a famous naturalist
• After analysis of his data, he became convinced
  that Earth was ancient and that species change
  through time.

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Darwin (cont.)

• Thomas Malthus (wrote essay few decades before
  Darwin)
• Contended that much of human suffering was due to
  the human populations potential to grow
• Populations grow IF food supplies and other
  resources can be produced
• If this does not happen it is a struggle for
  existence
• This helped Darwin to propose a mechanism of
  evolutionary change.

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Darwin (cont.)

• Darwins essay (1844)
• 200 pages
• Didnt release it to the public
• Colleagues urged Darwin to publish before someone
  else did
• Alfred Wallace (1858) came to same conclusion and
  wrote to Darwin explaining his findings
• Within a month, both had findings presented to
  public together
• Darwin published The Origin of Species about a
  year later

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Darwins 2 Points

• Darwin made 2 main points in his book
• He argued from evidence that the species of
  organisms living on Earth today descended from
  ancestral species
• Life has a history of change
• Descendants of the earliest organisms spread into
  various habitats over millions of years
• Accumulated different modifications Descent
  with Modification
• Accounts for diversity of life

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Darwins 2 Points (cont.)

• Darwins 2nd point
• His argument for natural selection was the
  mechanism for evolution
• Natural selection can cause a population to
  change over time
• Result adaptation

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Evolution in Process

• Homologous vs. Analogous Structures (evidence of
  evolution)
• Homologous similar features that originated in
  a shared ancestor (see page 289 in your
  text)-or-complete online activity 14.2 in
  Exploring Life
• Look different but have similar skeletal
  structure
• Derive from same structures in embryo
• Analogous serve identical functions and look
  somewhat alike
• Very different embryological development

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Look at t his picture
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Other Evidence of Evolution

• Vestigial Structures features seem to serve no
  useful function now (humans tailbone) but may
  have done so historically
• Similarities in Embryology See page 291, Figure
  15-9
• Ernst Haeckel embryological development repeats
  evolutionary history! (slightly exaggerated
  similarities fade as development proceeds)
• Similarities in Macromolecules - homologous
  proteins RNA and DNA amino acid sequence is
  similar between different species

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Patterns of Evolution

• Coevolution change of 2 or more species in
  close association with each other
• Predators and their prey parasites and hosts
  plant-eating animals and their chosen plant
• Convergent Evolution Organisms appear to be
  similar but are not closely related at all
  analogous structures are similar adaptations that
  result from this
• Divergent Evolution 2 or more related
  populations become more and more dissimilar
• Adaptive radiation
• Artificial selection

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Adaptive Radiation
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Artificial selection