Evolution natural selection_and_speciation most current file
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Transcript of Evolution natural selection_and_speciation most current file
“Evolve” Means to Change Over Time
The notion that life on Earth has changed over time is quite old
To be considered science, this notion requires a great deal of evidence
The Development of Evolutionary Theory Naturalists have always wondered at the diversity of living things………Great varieties in shape, size, and ecological roleEstimated 3 million to 20 million different living speciesMuch of the natural world’s biodiversity has vanished through extinction99% of all species that ever lived are now extinctPermian-Triassic Mass ExtinctionWhat Killed the Dinosaurs?
Development of Evolutionary Theory
What could cause such great diversity, and why have so many species died out?
Charles Darwin offered an explanation based on careful observations
Who was Charles Darwin?
Development of Evolutionary Theory
Darwin Concluded:Physical traits and behaviors enable organisms to survive and reproduce (called Fitness )Fitness results from adaptations
Structural (body structures)Behavioral (protection, predation, mating, etc.)Functional (chemicals produced by the organism that perform special functions)
Darwin reasoned that adaptations result from natural selection and result in evolution
Evolution is the process by which living Evolution is the process by which living things change and diversify over timethings change and diversify over time
Development of Evolutionary Theory
Development of Evolutionary TheoryThese ideas were widely challenged
until a tremendous amount of evidence was gathered to support evolution!
Now…The Theory of Evolution is the Cornerstone of BiologyExplore the Evolution Revolution
Natural Selection and Speciation
Charles Darwin
Studied Medicine and TheologyExcelled in Geology and BiologyIn 1831 Darwin joined the H.M.S. Beagle on a trip around the world to make mapsHe was the ship’s naturalistDarwin’s Diary
Darwin Pieces Together the Puzzle
Collecting fossils and other specimens
Making detailed observations of animal behavior
Making detailed drawings of the organisms he encountered
Darwin traveled South America & Galapagos Islands
The Voyage of the Beagle: Ports of Call
Noted that populations Noted that populations of organisms were of organisms were slightly different from slightly different from place to placeplace to place
Each group was Each group was modified to their modified to their specific environmentspecific environment
The Galapagos ArchipelagoThe Galapagos Archipelago
Land Iguana
Marine Iguana
The Origin of Species Interactive Exploration
Charles Lyell
Darwin Pieces Together the Puzzle
Author of “Principles of Geology”
This book helped Darwin realize that the earth is old and changes slowly over time.
Malthus wrote “Essay on the Principles of Population”
Populations will always grow larger than the food supply, creating hunger, disease and struggle/competition. Some people live, others die.
Darwin Pieces Together the Puzzle
Thomas Malthus
18th Century Economist
Darwin coined the term Artificial Selection - the process of modification of a species through human actions which encourage the breeding of certain traits over others.
Darwin Pieces Together the Puzzle
http://www.esp.org/books/darwin/variation/facsimile/title3.html
What Darwin Learned from Artificial Selection
When chosen organisms are mated, desired characteristics are formed (Darwin didn’t know about DNA)
Individuals in the wild who possess characteristics that make it more likely for them to reproduce will pass along these characteristics to their offspring.
“Desirable" characteristics, in the wild, would be those which enhance survivability, NOT those which specifically satisfy human needs. Nature does the selecting.
Darwin Pieces Together the Puzzle
Lamarck’s View of Evolution
Stated that acquired characteristics can be passed on to offspring.
Darwin Pieces Together the Puzzle
Darwin’s View of Evolution
Darwin Pieces Together the Puzzle
Those giraffes with longer necks got more food and were better able to survive to reproduce, passing on the long-neck genes to their offspring. Over time, giraffes evolved longer necks.
4 Key Ideas of Natural Selection
“Of course, long before you mature, most of you will be eaten.”
Evolution Through Natural Selection1. Variation (genetic) is present in the
population and this variation is inherited (genetically passed to offspring).
(Praying Mantis Camouflage)
2. Living things Overproduce3. Competition for Limited Resources4. Survival of the “Fittest”
Reluctantly published On the Origin of On the Origin of Species Species in 1859in 1859Video
Natural Selection
4 Main Points of Natural Selection
1. Variation (genetic) is present in the population and this variation is inherited (genetically passed to offspring).
2. Living things Overproduce
3. Competition for Limited Resources
4. Survival of the “Fittest” Video
Natural Selection
Fitness DefinedOrganisms who better survive to produce larger numbers of offspring are considered more fit than others who do not.
The Fittest Survive
Darwin Today…Natural Selection in action…
causes a frequency
of certain alleles in a population to increase or decrease over time!
Click the Link Below to Access the Cartoon
http://evolution.berkeley.edu/evolibrary/article/0_0_0/sneakermales_01
Read the cartoon carefully and answer the discussion questions on a separate sheet of paper.
Speciation Results in Biodiversity
SpeciationNatural Selection modifies populations. Some evolutionary changes are so great that some organisms can no longer interbreed with the original populationA new species resultsSpecies
An interbreeding population of organisms that can produce healthy, fertile offspring
Reproductive Barriers and Speciation
Prezygotic: gametes never meet and fuseGeographic isolation (allopatric speciation)Ecological isolationBehavioral isolation (lacewing songs)Mechanical isolationSeasonal isolation
Postzygotic: genetic differences manifestHybrid inviabilityHybrid sterility (tigons and ligers)
Geographic Isolation
2 populations separated by geographic barriers (rivers, mountains, bodies of water)
Abert Squirrel vs. Kaibab Squirrel
Temporal Isolation (Seasonal)
Species reproduce at different times
Behavioral Isolation
Differences in courtship rituals or other types of behavior
Songs of birds
Behavioral Isolation
Mechanical Isolation
Mating/Pollination is often impossible between different animal/plant species because of the incompatible shape and size of the reproductive structures.
Size Does Matter!
Example – Black and White Sage Plants
Black sage and white sage plants invite different pollinators
White sage flowers have large landing platforms for large pollinators causing the large pollinators to brush against the stamens, but the small ones usually don’t.
Black sage flowers have small landing platform for small pollinators. Therefore, the small pollinators cannot spread pollen to the white sage flowers therefore cross pollination is no longer possible.
Land Iguana
Marine Iguana
Two populations live in different habitats and mating occurs in those habitats, thus their own gene pool.
Ecological Isolation
After Mating Genetic Differences Occur
Hybrid sterility (tigons and ligers)(Horse and a donkey = mule – sterile)
Patterns in EvolutionAdaptive Radiation (Divergence)
Development of numerous new species from a common ancestor in diverse environmentsDarwin’s Finches (Origin of Species Activity)
GradualismPunctuated Equilibrium
Pages to turn in:
63107-109 #1-31131137139
These assignments will calculate towards the 4th quarter grade.
Once these are turned in you may work on the EC assignment
Evolution Produces Biodiversity
Evolution Produces DiversityAll living things are classified by characteristics into 6 kingdoms of life
Archaebacteria
Autotrophic and heterotrophic speciesUnicellularProkaryoticCell wall w/o PeptidoglycanSome mobile
Ancient bacteriaLive in extreme environments (extremeophiles)Methanogens, Halophiles, Thermoacidophiles
Eubacteria
Autotrophic and heterotrophicUnicellularProkaryoticCell wall with PeptidoglycanSome mobile
True bacteriaE. coli, Streptococcus
Protist
Autotrophic and heterotrophicMostly unicellularEukaryoticCell wall on mostSome mobile
“Odds and ends” KingdomAmoeba, Paramecium
Fungi
Heterotrophic Mostly multicellularEukaryoticCell wall made of chitin Immobile
Mostly live on decaying organic matterFungi, yeast, mold
PlantAutotrophicMulticellularEukaryoticCell wall made of celluloseImmobile
Produce oxygen through photosynthesisTrees, shrubs, grasses, flowers
AnimalHeterotrophicMulticellularEukaryoticNo Cell WallMobile
Mammals, insects, birds, reptiles, sponges, worms
TaxonomyClassification and naming of organisms7 Taxonomic Groupings from most inclusive to most specific:
KingdomPhylumClassOrderFamily GenusSpecies
“Kings play chess on fine green silk”
Linnean TaxonomyCarolus Linnaeus (1707-1778)
Binomial nomenclature (2 name naming)Genus and species to make the scientific nameProvides a common name that can be used by all biologists regardless of their native language.
Example: human vs. chimpanzeeKingdom animalia animaliaPhylum chordata chordata Class mammalia mammaliaOrder primata primataFamily hominidaehominidaeGenus homo panSpecies sapienstroglodytes
Homo sapiens and Pan troglodytesClassification activity
Linnean Taxonomy
The Origin of LifeGeologyThe Fossil RecordComparative EmbryologyComparative BiochemistryComparative AnatomyIsn’t Evolution Just a Theory?
Scientists from many disciplines including biology, chemistry, physics, geology, and paleontology have contributed to the case for evolution!
The Origin of LifeOrigin of the UniverseBig Bang
Early EarthEvolution Starts Up: Chemical EvolutionHeterotroph Hypothesis: Molecules of life arose from inorganic building blocks
The Miller-Urey ExperimentStudied Molecules Present at Time of Early Earth
Methane, Ammonia, Carbon Dioxide, Water VaporMixed Molecules in Reaction ChamberSparked with Electricity to Simulate LightningExposed Mixture to UV Radiation to Simulate Cosmic RaysProduced Basic Amino Acids and Organic Molecules
Miller-Urey Apparatus
Biological EvolutionRNA as a information molecule and catalystEndosymbiotic Theory
Mitochondria and chloroplasts were originally free living prokaryotic cellsBoth have own DNA and ribosomesJoined together to cooperate
GeologyThe Study of the Earth and RocksEarly Ideas About Earth:
People believed Earth was only a few thousand years oldPeople believed that rocks and geological features were shaped by catastrophic events and rarely changed
Bernard Palissy 1589
GeologyIn the 18th and 19th Century Scientists Studied Geology in Great Detail
Old Earth, Ancient Life: Georges-Louis Leclerc, Comte de Buffon (1749)
Hutton (1785) and Hadrian’s Wall
Charles Lyell: The Principles of Geology
Earth is Changed by Weather and Natural Processes like Volcanoes and ErosionTakes a Very Long Time!Gradualism and Uniformitarrianism
Continental DriftOver millions of years 1 original continent Pangea drifted apart to make our modern continentsContinental drift is gradual “gradualism”
Sea Floor Spreading
Plate Tectonics
GeologyThese ideas refute the idea that the Earth is only a few thousand years oldProvides long time necessary for evolution
Backed up by radiometric dating The Earth is approximately 4.6 Billion Years Old
4,600,000,000 years is a long time!
Direct Evidence of Evolution
The Fossil RecordFossils are the preserved remains of ancient organisms
Provide information about past organismsShows that many diverse organisms lived at different times in Earth’s History
Preserved remains or traces of ancient organisms
Examples:
The Fossil The Fossil RecordRecordProvide a record of past species
Important source of information for determining ancestry and patterns of evolution
Fossil Archaeopteryx
What does the fossil record tell us?
http://www.pbs.org/wgbh/evolution/library/04/3/quicktime/l_043_01.html
•What past life looked like
•What past habitats were like and changes that have occurred
•That diverse organisms lived on earth at different times
•New species evolved
•Some species became extinct
•Earliest life forms were aquatic
•Earliest life forms were simple in structure
Missing Link?
The Fossil RecordTaphonomy: The Formation of Fossils
Fossils form in sedimentary rockDead organisms covered by sand and siltSediments are passed into bone by pressure from above (fossils form in sedimentary rock)Video
Determining the Age of FossilsRelative Dating: Technique used by scientists to determine the age of fossils relative to fossils in other layers of rock
Different layers represent different geologic periods Older fossils found in lower layers, newer fossils found in upper layersCannot determine the actual age of the fossil!
Determining the Age of FossilsRadioactive Dating: Process by which traces of radioactive elements are analyzed to calculate the actual age of a fossilMany radioactive elements can be used as geologic clocks. Each radioactive element decays at its own nearly constant rate. Once this rate is known, geologists can estimate the length of time over which decay has been occurring by measuring the amount of radioactive parent element and the amount of stable daughter elements Video
Radioactive/Radiometric Dating
How it Works:- radioactive elements (uranium,
Carbon14) break down/decay a specific rates = half life
- these rates are nearly constant
- the amount of radioactive decay that has taken place in a rock/fossil determines its age
Scientist Measure the Age of the EarthRadiometric Dating: way of estimating the age of
the Earth!
http://www.pbs.org/wgbh/evolution/library/03/3/quicktime/l_033_01.html
Carbon-14 Dating
- Determines the age of fossils of a biological origin up to approx. 50,000 years old.
- used in dating things such as bone, cloth, wood, plant fibers, etc.
5,700 year is C14 half-life
Half-life of carbon-14 is 5730 years
Half-life of carbon-14 is 5730 years
22,920 11,460
28,650 17,190
Radiometric DatingRadioactive Parent
Stable Daughter
Half life
Potassium 40 Argon 40 1.25 billion
yrs
Rubidium 87Strontium
8748.8 billion
yrs
Thorium 232 Lead 20814 billion
years
Uranium 235 Lead 207704 million
years
Uranium 238 Lead 2064.47 billion
years
Carbon 14 Nitrogen 14 5730 years
The Geologic Time ScaleBased on fossil and geologic evidenceA record of the Earth’s pastDivided into Era, Period, and EpochShows that life on Earth followed geologic change on Earth
Deep Time ActivityInteractive Time Scale
Comparative EmbryologyEmbryos are organisms at early stages of development
Comparative EmbryologyAll vertebrate embryos, including humans, share features
Eye spot • (Evolution of the Human Eye)
Gill pouchesNotochord
Shows similar genetic ancestryVideo
Comparative BiochemistryAll life is based on organic chemistry
Carbon based compounds
All life uses same molecule as blueprint DNA
Similar chemical processesBacteria, algae, and plants all do photosynthesis
Similar organisms have similar genetic codeHumans and chimpanzees share nearly identical genes (98.4% identical gene sequences) Video
Anatomy and Comparative AnatomyVestigial Organs
Organs inherited but not used by modern organismsPresent but greatly reduced in modern organismsHip bone in pythonAppendix in humanTail bone (cocyx) in human
Anatomy: Homologous StructuresSimilar parts of different organisms, often quite dissimilar in purpose, that developed from the same ancestral body parts (Video)Divergent evolution
Anatomy: Analogous StructuresSimilar in purpose, but not inherited from a recent common ancestorEnvironment selected for trait
Wings of birds and insects
Convergent evolution
Summary
There is overwhelming evidence to support the Theory of EvolutionEvidence comes from disciplines as varied as biology, geology, chemistry, physics, astronomy, and paleontologyEvolution has produced the great beauty and diversity of life on Earth over the last 4 billion years
Human Evolution
Explore Human EvolutionView the Becoming Human broadband documentary
As you view each segment, visit the related exhibits to further explore this topic
Go to the Learning Center and select the “Calculating Cousins” activityGo to the Learning Center and select the “Chromosome Connection” activityGo to the Learning Center and select the “Building Bodies” activity
The Order Primate
Characteristics of PrimatesStrong hands and opposable thumbsFree-moving shoulder jointForward facing eyes and stereoscopic visionIntelligence/larger brainSocial complexity
What Characteristics do Humans Have?All of those of primates, plus
Upright posture and bipedalUse of tools and technologyAdvanced intelligenceComplex communication and speech
The Steps to Human Evolution
TerrestrializationBipedal (Walking on all two’s)Increased Brain SizeCivilizationTake a look at the Human family tree
The Hominid Family
Each year new fossils are found to add to the Hominid family treeMost fossils of early humans are found in Africa and lower AsiaMost well understood members include genus Australopithecus (extinct) and genus HomoSolve the Riddle of the Bones
Genus AustralopithecusFirst human ancestor to live on the ground and walk on two legs
As evidenced by the Laetoli footprints
Ape-like jawSmall brainShort statureFound only in South and East Africa
The AustralopithecinesA. anamesis 4 MYAA. afarensis 3.2 MYA (Finding “Lucy”)A. africanus 2.5 MYAA. robustus 2 MYA A. boisei 2 MYA
Genus HomoMore modern hominids that exhibited major evolutionary steps
Increased brain sizeUse of toolsUse of fireUse of shelterReligionLanguage and civilization
Homo habilis “The Tool Man”Approx. 2.5 MYABrain ½ size of modern humanFirst to make and use stone tools and weapons
Homo erectus “The Upright Man”
Direct ancestor of modern humansWidespread in Africa and Asia by 1 MYAEvidence of use of shelter and fire
Homo sapiens “The Wise Man”Most likely evolved from H. erectus as early as 400,000 years agoGreatly increased brain sizeConsisted of 2 groups
NeanderthalCro-Magnon/modern H. sapiens
NeanderthalsFound in Neander Valley in GermanyFossils found throughout Europe, Middle East, and Asia from 150,000-30,000 years agoLarge bodies and brainsEvidenced painting, religion, complex social structure“Cave man”
Cro Magnons and Fully Modern HumansFirst early modern H. sapiens appear about 130,000 years agoThinner bones, smaller jaws, higher skull with little or no brow ridge, and larger brainsCave art shows complex religion and cultureLived alongside Neanderthal for several thousand years, but eventually out-competed them