EVOLUTION. H.E.KRON-WHRHS-SCI DEPT EVOLUTION -CHANGE IN THE GENE POOL OF A POPULATION OVER TIME.
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Transcript of EVOLUTION. H.E.KRON-WHRHS-SCI DEPT EVOLUTION -CHANGE IN THE GENE POOL OF A POPULATION OVER TIME.
EVOLUTIONEVOLUTION
H.E.KRON-WHRHS-SCI DEPTH.E.KRON-WHRHS-SCI DEPT
EVOLUTIONEVOLUTION-CHANGE IN THE GENE POOL OF A
POPULATION OVER TIME
SUGGESTS THAT EXISTING SPECIES ARE DERIVED FROM PREVIOUS ONES BY DESCENT-ORGANISMS NOW ON EARTH SHARE A COMMON ANCESTRY
IS A UNIFYING THEME IN BIOLOGY & PROVIDES A FRAMEWORK FOR THE ORGANIZATION OF DIVERSE SPECIES INTO A LINKED PATTERN. A SLOW PROCESS! (AS A RULE IT OCCURRENCE CANNOT BE DEMONSTRATED DIRECTLY.)
LAMARCKLAMARCK-INHERITANCE OF ACQUIRED CHARACTERISTICS-ORGANISMS ADAPT TO THEIR ENVIRONMENT AND PASS THESE CHANGES TO THEIR OFFSPRING
USE/DISUSE: SALAMANDER-ON LAND, LEGS COULDN’T TRAMPLE THRU TALL GRASS, BEGAN USING THEIR BELLIES & LEG MUSCLES WASTED AWAY FROM DISUSE
LEGLESS SALAMANDERS EVOLVED
WHAT’S WRONG WITH THIS IDEA?
DARWIN’S THEORY OF DARWIN’S THEORY OF NATURAL SELECTIONNATURAL SELECTION: FROM HIS BOOK - ORIGIN OF SPECIES. NEW SPECIES CAME ABOUT BY NATURAL SELECTION:
OVERPRODUCTION
STRUGGLE FOR EXISTENCE
VARIATION
SURVIVAL OF FITTEST
4 COMPONENTS4 COMPONENTS:
VARIATION
COMPETITION
FITNESS
ADAPTION
VARIATION:VARIATION:INDIVIDUAL MEMBERS OF A POP. WITHIN A SPECIES HAVE HERITABLE DIFFERENCES
THESE TRAITS PASSED ON TO NEW GENERATIONS
THESE VARIATIONS ARE RANDOM
COMPETITION:COMPETITION:
RESOURCES ARE FIXED: EXP-FOOD & SHELTER
POP. GROWS TO LIMIT
REPRODUCTION EXCEEDS SURVIVAL
INDIVIDUALS MUST COMPETE
FITNESS:FITNESS:
SOME INDIVIDUALS HAVE TRAITS THAT MAKE THEM BETTER AT SURVIVAL
THE FITTEST SURVIVE TO PRODUCE & CARE FOR THEIR OFFSPRING
FITNESS IS LINKED TO THE ENVIRONMENT
ADAPTION:ADAPTION:POP. WITH BEST TRAITS OVER-POPULATE & REPLACE LESS FIT
RESULTS IN A NEW POP WITH THE BEST TRAITS
ADAPTION IS THE END RESULT OF N. SELECTION: EXP- COAT COLOR, RUNNING SPEEDS, BODY COVERINGS.
CONCERNS PHENOTYPE OCCURS WHEN GENES ARE INHERITED
MICROEVOLUTIONMICROEVOLUTION VSVS
MACROEVOLUTIONMACROEVOLUTION
DIVERSITYDIVERSITY
VSVS
COMPLEXITYCOMPLEXITY
MICROEVOLUTIONMICROEVOLUTION:
ANIMALS & PLANTS ADAPT TO CHANGING ENVIRONMENTS INVOLVES SMALL CHANGES
DOES NOT CREATE NEW SPECIES
CREATES “DIVERSITY” NOT COMPLEXITY
EXP: MICROEVMICROEV-SUPPOSE A WHITE BIRD IS BORN AMONG A POP OF BROWNS. NSNS FAVORS WHITE IN WINTER & BROWN IN SUMMER. Why? An inherited variation increases an organism’s chance of survival in a particular environment.
THE WHITE BIRD IS NO MORE COMPLEX THAN THE BROWN!
BEFORE INDUSTRIAL REVOLUTION THERE WERE PEPPERED MOTHS. AFTER, % OF BLACK MOTHS INCREASED DRAMATICALLY. WHY? Environment changes & moths adapted-black is no more complex than peppered!
MACROEVOLUTIONMACROEVOLUTION: evol. that creates a new species.
CHANGES ARE SMALL & LARGE
Difference between a wolf & dog=small
Difference between a starfish & alligator=large
EXPEXP: THAT CREATES “COMPLEXITY”
Descendants of a lizard evolved into birds with wings & feathers. Birds are more complex than reptiles.
EXPEXP: THAT CREATES “DIVERSITY”
Descendants of the wolf evolved into dogs; Huskies, Labs etc. A Lab is no more complex than a wolf.
NATURAL SELECTION DOES NOT GUIDE EVOLUTIONARY TRANSITIONS WHICH RESULT IN GREATER COMPLEXITY-THEY DEPEND ON “CHANCECHANCE”SINCE OBSERVABLE PROCESSES ONLY CREATE “DIVERSITY” THEY SHOULD NOT BE EXTENDED TO EXPLAIN THE ORIGIN OF “COMPLEXITY"
Modified Sci Method is based more on speculation than science-c/o-inability of science to test “Macroevolution”
THE EVOLUTION OF THE EVOLUTION OF COMPLEXITY REQUIRES NEW COMPLEXITY REQUIRES NEW GENES:GENES:
GENES ARE CHEMICALS
GENES DETERMINE TRAITS OF PLANTS & ANIMALS
NEW GENES ARE REQUIRED FOR THE EVOLUTION OF NEW ORGANS & STRUCTURES
NEO-DARWINISMNEO-DARWINISMSYNTHETIC THEORYSYNTHETIC THEORY
MODERN DISCOVERIES HAVE BEEN INCORPORATED INTO DARWIN’S NATURAL SELECTION
THE CELL IS THE SMALLEST UNIT OF LIFE-ALL LIFE IS COMPOSED OF CELLS
LIFE BEGINS WITH THE INFORMATION FOUND IN DNA TO MAKE PROTEINS
PROTEINS THAT GENES ENCODE ULTIMATELY DETERMINE THE
TRAITS OF AN ORGANISM
REPRODUCTION IN HIGHER LIFE REQUIRES MEIOSIS-OFFSPRING INHERIT GENES FROM BOTH PARENTS
While NSNS selects existing variations already in a pop. It does not create new varieties. The ultimate source of new variations would be:
Recombinations of existing genes
Mutations-altered genes/chr
Both of these produce genetic combinations found in earlier
generations
Recombination/crossing-overRecombination/crossing-over: homologous chrs break & reattach onto different chrs. The next generation inherits chrs with new sequences.
Sperm & ova can add even greater diversity to a pop’s gene pool!
HOW DO NEW SPECIES EVOLVEHOW DO NEW SPECIES EVOLVE
Today scientists realize that variations arise c/o random changes-MutationsMutations in existing genes.
Point mutation str. Modified irreg. #
MUTATION FACTS:MUTATION FACTS:Freq. in human sex cells=1/100,000
Humans may have as many as 100,00 genes
Most sex cells contain mutations & are common occurrences in healthy people
Causes: radiation, chemicals, viruses etc.
For mutation to be subject to NS-NS-it must be expressed in the individual’s phenotype. Selection favors mutations that result in adaptive phenotypes and eliminates non- adaptive ones. Even recessive alleles can show up in future generations
ENVIRONMENT SELECTS INDIVIDUALS WITH BEST SUITED “GENOTYPES” TO SURVIVE TO ADULTHOOD & TO REPRODUCE. FOR NS TO NS TO CAUSE EVOLUTION,CAUSE EVOLUTION, IT MUST SELECT FOR OR AGAINST ONE OF THE FOLLOWING 5 COMBINATIONS:
EITHER: AA OR aa (BUT NOT BOTH)
BOTH: AA OR aa
EITHER: AA & Aa OR aa & Aa
HETEROZYGOTE: Aa
ALL ALLELES: AA, Aa & aa
5 GENOTYPE COMBINATIONS5 GENOTYPE COMBINATIONS
SELECTION AGAINST ONE OF SELECTION AGAINST ONE OF THE HOMOZYGOTES:THE HOMOZYGOTES:
IF aaaa IS COMPLETELY SELECTED AGAINST WHILE AA & Aa ARE SELECTED FOR- THE FREQUENCY OF aaaa CHILDREN WILL DROP DRAMATICALLY. THERE WILL BE A PROGRESSIVE DECREASE IN “aa”!
EXAMPLES AGAINST “aa”:EXAMPLES AGAINST “aa”:
ALBINISMALBINISM-homozygous recessive individuals are at a slight selective disadvantage. Can live to adulthood & reproduce.
DIABETESDIABETES-inherited recessive, the selection is more severe. Prior to this century those who inherited usually died in childhood. Since insulin in 1921 it is no longer a killer of children
SELECTION AGAINST BOTH SELECTION AGAINST BOTH HOMOZYGOTESHOMOZYGOTES: only AaAa would be able to mate!
NATURE SELECTING AGAINST NATURE SELECTING AGAINST BOTH HOMOZYGOTES:BOTH HOMOZYGOTES: Malaria found in Africa c/o plasmodia-parasites that feed on RBC. People who produce norm RBC are good hosts & easily get the disease & death
In African malarial zones there is an inherited condition of the sickle-cell trait. “aaaa” have a resistance to malaria c/o deflated RBC’s are poor hosts. However these kids die in childhood from sickle cell anemia.
People who are AaAa for sickle-cell trait have good resistance to malaria c/o sickle shaped cells and rarely develop the life threatening anemia.
Those who are AA AA produce normal RBC’s which make excellent hosts for malaria. So in malarial environments - nature selects for AaAa sicklers.
It selects against “aaaa” sicklers & people who produce normal RBC’s.
EVOLUTIONEVOLUTION IS THE PROCESS BY WHICH GENE POOLS OF A SPECIES WITH TIME. ALL OF THE SPECIES MAKE UP THEIR GENE POOL. EVOLUTION CHANGES GENE POOLS AND CREATES NEW ONES.
THEREFORE NSNS ONLY PRESERVES GENES THAT
OFFER A SELECTIVE ADVANTAGE
NSNS only preserves genes that offer a selective advantage-sometimes called “competitive” advantage. These genes are responsible for beneficial variations.
EVOLUTIONEVOLUTION creates diversity by altering the gene pool. Mutations creates alleles. Alleles are not new genes, but alternate forms of the same gene. Exp: Hb-a protein for transporting O2. If mutations change the DNA encoding process, these changes may alter aa sequence. If the altered genes still encode for Hb-then they are called “alleles”.
NATURAL SELECTIONNATURAL SELECTION:PRESERVES THE BEST
ALLELES
OPTIMIZES EXISTING GENES BY SELECTING BEST ALLELES
MicroEVOL. CONCERNS ORGANISMS ADAPTING TO CHANGING ENVIRONMENTS & NS PRESERVES ALLELES MORE FIT.
ENVIRONMENTAL SELECTIONENVIRONMENTAL SELECTION:NONO EXP: LINGULA
Lamp shells found in rock strata 500 mya. Over all this time still looks the same today!
Gryphaea-coiled shell similar to oyster 180mya
Sea bed changed from rocky to mud. Flat shells only could survive in rocky areas. Curved shells could lift upper valve clear of sea bottom
ADAPTIVE LANDSCAPESADAPTIVE LANDSCAPES-VISUALIZE FITNESS OF ALLELES
Fitness= series of valleys and hills
Alleles on hill more fit
NS preserves ones on the hill
NS optimizes existing genes by sel. most favorable
ADAPTIVE LANDSCAPEADAPTIVE LANDSCAPE-APPLIES TO STR & ORGANS:
Consider a reptile evolving into a bird. Front legs are preserved by NS. Thus NS fights this transition. If the transition takes place despite NS-then only chance can guide it. Mutations away from optimized legs lower the fitness of a reptile. NS is not driving such a process.
GENETIC DRIFTGENETIC DRIFT(CHANCE)-DETERMINES WHICH GENES SURVIVE. ALLELES FREQUENCY OF A GENE POOL DUE TO CHANCE OR RANDOM EVENTS.
CAUSES GENE POOLS OF 2 ISOLATEDISOLATED POP’S TO BECOME DISSIMILARDISSIMILAR AS SOME ALLELES ARE LOST & OTHERS FIXED.
The net effect of Genetic Drift on a small pop’s gene pool can be rapid. Note the red trait increases dramatically from generation to generation
FOUNDER EFFECTFOUNDER EFFECT-case of gen. drift in which rare alleles occur in higher frequency in a pop “isolated”isolated” from general pop. Exp: Darwin’s finches
When a pop is started by one or a few who randomly separate from a larger pop-chance may dictate that allele freq. in new pop. may be different from original pop.
Island species vary from mainland species
BOTTLENECK EFFECTBOTTLENECK EFFECT-genetic drift in which a severe reduction in pop. Size results from natural disasters, predation or habitat reduction. Results in severe reduction of the total genetic diversity of the original gene pool.
Exp: Cheetah pop. Was probably reduced in the great Ice Age 10,000 ya. Separation causes infertility c/o intense inbreeding=very little gen. Variation.
WHEN ARE TWO POP’S NEW WHEN ARE TWO POP’S NEW SPECIES?SPECIES? - WHEN POP’S NO LONGER INTERBREED THEY ARE THOUGHT TO BE SEPARATE SPECIES.
GENETIC DIVERGENCE RESULTS WHEN ADAPTION,
DRIFT AND MUTATION ACT ON POPULATIONS.
Barriers to gene flow isolate pop’s & lead to formation of a new species.
ADAPTIVE RADIATIONADAPTIVE RADIATION-the diversification of a species into two or more species as groups adapt to different environments
Over time, the pop’s genetically diverge enough so that they can no longer reproduce
with each other
Models of speciation relate to geographic subdivisions:
AllopatricAllopatric-barrier
ParapatricParapatric-adj. Pop’s
SympatricSympatric-coexist
Founder EffectFounder Effect-small isolated pop on edge
VARIATION & SPECIATIONVARIATION & SPECIATION
VARIATION CAN BE MEASURED IN DIFF WAYS-HUMANS CAN BE TALL/SHORT, SKINNY/FAT ETC.(VARIATION IS A DISTRIBUTION OF AVG & EXTREMES)
NATURAL SELECTIONNATURAL SELECTION IS A PROCESS OF SURVIVAL AND REDRODUCTION THAT LEADS TO IN ALLELE FREQ. OVER TIME AS THOSE INDIVIDUALS MOST “FIT” SURVIVE AND LEAVE MORE OFFSPRING
THREE PATTERNS
STABILIZING SELECTIONSTABILIZING SELECTION-favors the intermediate phenotype. Extremes in variation are selected against. Infants weighing less that 5 lbs have higher rates of infant mortality.
DIRECTIONAL SELECTIONDIRECTIONAL SELECTION-favors one or the other of the extremes. Insecticide resistance with DDT after yrs of use lost its effectiveness on insects. Resistence to DDT is a gen. Trait only those resistant survived & reproduced.
DISRUPTIVE SELECTIONDISRUPTIVE SELECTION-favors individuals at both extremes-sel. against middle of the curve causing 2 or more distinct phenotypes. African butterflies have 2 distinct phenotypes both resemble brightly colored but distasteful butterflies of other species. Each one gains protection from predation although they are quite edible.
DISRUPTIVEDISRUPTIVE-favors both extremes
HARDY-WEINBERG THEOREMHARDY-WEINBERG THEOREM: IDEA DEVELOPED TO
DETERMINE IF A POP. WAS EVOLVING. AUTHORS SET UP A
SERIES OF PARAMETERS WHICH DO NOT EXIST DO NOT EXIST IN
NATURE TO BE FOLLOWED WHEN DETERMINING THE
ALLELE FREQUENCIES OF ANY POP.
EVOLUTION WILL NOT OCCUR IFEVOLUTION WILL NOT OCCUR IF:
NO NATURAL SELECTION
NO MUTATIONS
POP. MUST BE A LARGE SIZE
RANDOM MATINGS
POP. MUST BE ISOLATED-NO GENE FLOW
SINCE IT IS HIGHLY UNLIKELY THAT ANY OF THESE CONDITIONS WILL OCCUR IN THE REAL WORLD, EVOLUTION IS THE INEVITABLE RESULT
FFOOSSSSIILLSS
FFOOSSSSIILLSS
FOSSIL EVIDENCEFOSSIL EVIDENCE
Remains of living things that existed long ago
FFOOSSSSIILLSS
PETRIFICATION
IMPRINTS
CASTS
FREEZING
TAR PITS
AMBERBUT THERE ARE MISSING LINKS BETWEEN
EVERY MAJOR GROUP OF PLANTS AND ANIMALS
STUDY OF FOSSILFOSSIL RECORDS HELPS BUILD A HISTORICAL SEQUENCE OF BIO EVOLUTION OF COMPLEX ORGANISMS FROM SIMPLE ONES.
Sequence of snail shells oldest on left & youngest on the right dated
from 10 mya to 3 mya
Horse evolved from 5-toed browser to 1-toed grazer
FFOOSSSSIILLSS
DARWIN BELIEVED THAT OVER TIME THAT SPECIES EVOLVED C/O GRADUAL IN FREQ. OF TRAITS.
THEORY OF PUNCT. EQUILIBRIUM HAS BEEN DEVELOPED TO EXPLAIN RATES OF THAT OCCUR AT AN UNEVEN TEMPO.
PEPE IN NATURE OCCURS C/O ABRUPT IN THE WORLD’S CLIMATE & ENVIRONMENTS. SPECIATION OCCURS RAPIDLY FOLLOWED BY LITTLE OR NO
FACTS:FACTS:
Darwin recognized that the fossil record is not continuous
Most transitional forms have yet to be found
Missing links undermine the entire theory of evolution
With PE idea, the fossil record can no longer be used to disprove evolution
BIOGEOGRAPHICAL
DISTRIBUTION OF ORGANISMSDISTRIBUTION OF ORGANISMS
Animals & plants are most closely related to those in nearby regions
BIOGEOGRAPHICAL
TWO HYPOTHESESTWO HYPOTHESES:
RELATED FORMS EVOLVE IN ONE PLACE & SPREAD OUT TO OTHER REGIONS
SAME TYPE OF ADAPTION IN GEOGRAPHICAL REGIONS SEPARATES ORGANISMS
GRADUAL ISOLATIONGRADUAL ISOLATION BY NEW LAND FORMS, WATER, HIGHWAYS, VOLCANO, EQ, RIVERS.
Ice Age-one body of water & one species of fish. Dries up in diff. areas. Fish pop isolated. Fish diverged & could no longer interbreed even if brought together.
REPROD. ISOLATIONREPROD. ISOLATIONInability of formerly inter- breeding to reproduce offspring. Early and late frog breeding times have been selected against c/o predators
CONVERGENT EVOLUTIONCONVERGENT EVOLUTIONUnrelated species become similar in appearance as they adapt to same kind of environment.
COMP
ANATOMY
Bat wing Bird wing
Pterodactly wing
Human arm
MANY DIVERSE ORGANISMS SHOW ANATOMICAL SIMILARITIES
HOMOLOGY-SIMILAR STRS IN DIFFERENT SPECIES OFTEN DESPITE DIFF FUNCTIONS
COMP
ANATOMY
FORM FOLLOWS FUNCTIONFORM FOLLOWS FUNCTIONIF 2 SPECIESHAD A COMMON ANCESTOR THEYSHOULD HAVE MAINTAINED “BUT MODIFIED” THE SAME COMPONENT PARTS, BONES, MUSCLES ETC.
HOMOLOGOUS STR’S = PHYSIOLOGICAL STR’S THAT HAS BEEN ADAPTED FOR A NEW FUNCTION.
COMP
ANATOMY
VESTIGAL STR’SVESTIGAL STR’S - REMAINS OF STR’S THAT WERE FUNCTIONAL IN SOME ANCESTOR. ARE OFTEN HOMOLOGOUS TO ORGANS THAT ARE USEFUL IN OTHER SPECIES.Human tail bone is homologous to functional tails of other primates
COMP
ANATOMY
ANALOGYANALOGY-SIMILAR FUNCTION BUT DIFFERENT STRUCTURES
EXP: BIRD WINGS & INSECT WINGS=FLIGHT BUT DIFFERENT STR’S & VARIATIONS.
BIOCHEMICAL
NEARLY ALL ORGANISMS USE THE SAME BIOCHEMICAL MOLECULES-DNA, ATP & ENZYMES
COMPARISON OF BASES BETWEEN CHIMP AND HUMAN= 99.125%
SIMILARITY
EMBRYOLOGY
EARLY STAGES OF DEVELOPMENT OF EMBRYOS SHOW PECULIAR SIMILARITY
SUGGESTS COMMON ORIGIN
PURPLE-SULFUR BACTERIA
STROMATOLITES-BACT COMMUNITIES
CS
PRECAMBRIAN
TI
ME
PALEOZOIC
ERA
CAMBRIAN EXPLOSION SHOWS NUMEROUS CAMBRIAN EXPLOSION SHOWS NUMEROUS FAMILIES OF PALEOZOIC FAUNAFAMILIES OF PALEOZOIC FAUNA
BRACHIOPODS
TRILOBITE
SMALL MARINE INVERTEBRATES PLUS CORALS
ECHINODERMATAECHINODERMATA-SPINY-SKINNED &
RADIAL SYMMETRY
AGRIOCRINUSAGRIOCRINUS-FOSSIL SOFT
BODIED & UNMINERALIZED
PARTS
CAMBRIAN
OUR OWN PHYLUM WAS REPRESENTED BY A SMALL SLIVER-LIKE THING THE - PIKAIA - FOUNDER OF PHYLUM CHORDATA?
CAMBRIAN
SILURIAN
Plants evolved from algae c/o chlorophyl & starch storage- moss first land plants but still need H2O
Silurian
First vascular land plantFirst vascular land plant- cooksonia-no leaves, flowers or seeds but probably root hairs and sporangia(420mya)
DEVONIAN
PER
FIRST LAND ANIMALS-Myriapods, centepedes, millipedes
Worms with appendages
DEVONIAN PER
TETRAPOD EVOL. FROM FISH OUT OF H2O. FISH HAD SERIES OF BONES ARRANGED LIKE ARMS/LEGS.
TETRAPOD
ANTHRACOSAUR
TETRAPOD AMPHIBIANTETRAPOD AMPHIBIAN-TRANSITION FORM BETWEEN FISHES & AMPH. WITH NOTOCHORD SPINE & RIBCAGE
ICHTHOSTEGA-AMPH. BELIEVED TO BE FIRST LAND VERT. DERIVED FROM LOBE FINNED FISH
DEVONIAN DROUGHTS MAY HAVE BEEN CAUSE FOR NSNS TO FAVOR THOSE FISHES WHO VENTURED OUT TO PARCHED EARTH
LUNGFISH-EXTINCT
COELACANTH-LOBE FINNED RHIPIDISTIANS
AMPHIBIANSAMPHIBIANS
VERT. ADULTS
USE LUNGS
LARVAE-LONG TAILS USED GILLS
COLD-BLOODED & EGGS LAID IN H2O
HAVE EXISTED 350MYA
OLDEST GROUP OF TERRESTRIAL VERTEBRATES
PTERPLAX ANDRIAS
CARBONIFEROUS
PERMIAN
FERNS
GYMNOSPERMS
REPTILES
FERN-ALLOPTERIS (307MYA)
REPTILE-DIMENTRODON REPTILE-HYLONOMUS
FERN-LYGINOPTERIS 307MYA
FERN-CALAMITES-
SPORE-BEARING
FERN-GLOSSPTERIS CLUB MOSS-LEPIDODENDRON-LEAF SCARS ON TRUNK-100FT
ACROSS & 3FT DIA.
CARBONIFEROUS LAND PLANTS CARBONIFEROUS LAND PLANTS AND INSECTSAND INSECTS
POST
PERMIAN
LEBACHIA-OLDEST RELATIVE OF CONIFERS
ARISTATA CONES 2455 YRA
BRISTLECONE GHOST 4776 YRA
PONDEROSA 2455 YRA
POST PERMIAN EXTINCTIONPOST PERMIAN EXTINCTION-GYMNOSPERMS BECAME ABUNDANT. HAVE SEEDS FROM
SEEDLESS ANCESTORS - HELPED TO DISPERSE & ENCASED SPERM
EUPARKERIAEUPARKERIA-BELIEVED TO BE RELATIVES OF ARCHOSAURS
THE CROCODILES, DINOSAURS, AND BIRDS. SEEM TO BE BIPEDAL
FOR SHORT DISTANCES
MESOZOI
C
ERA
TRIASSICTRIASSIC-245-208mya-middle animals-reptile like mammals & dinosaurs
JURASSICJURASSIC-208-146mya-more dinosaurs and first mammals appear
CRETACEOUSCRETACEOUS-146-65mya-first flowering plants. Extinction of dinosaurs & modern birds appear=life as it now exists on earth.
MESOZOIC
ERA
TRIASSIC JURASSIC CRETACEOUSTRIASSIC JURASSIC CRETACEOUS
Pangaea breaks apart almost like today
Hot & dry warm/moist warm, high sea level
Seasonality no polar ice later sea levels down strong flooded plains greater extremes
Small dino’s archaeopteryx dino’s flourish ferns, cycads flying pterosaur angiosperms
Gymnosperms large dino’s ants & butterflies
Major extinction at end of this era
DINOSAURS EVOLVED FROM ARCHOSAUR REPTILES-THEIR
CLOSEST RELATIVES ARE CROCODILES
Dinos evolved upright stance & warm blooded which allowed for continuous
locomotion. Cladistically birds are dinosaurs.
Transitional fossil-mix of reptilian & avian
CRETACEOUS
TO
TERTIARY
Angiosperms evolved from gymnosperms. Closest relatives are
the Gnetophytes=outcrops of the flowering plants.
ANGIOSPERMSANGIOSPERMS ARE THE DOMINATE FLORA OF THE WORLD(3/4 OF ALL LIVING
PLANTS ARE ANGIOSPERMS)DEVELOPED FRUITS & FLOWERS FOR POLLEN AND SEED DISPERSAL
EXTINCTIONEXTINCTION-DECREASE IN BIOLOGICAL DIVERSITY.
99.9% OF ALL SPECIES THAT EVER EXISTED ARE NOW
EXTINCT!
WHY?WHY?
ENVIRONMENTAL CHANGEENVIRONMENTAL CHANGE:
LIVINGLIVING: competition, new parasites, new predators, new prey defenses.
NON-LIVINGNON-LIVING: climate, soil, pH, salinity.
Extinction occurs after a species has been reduced to a very limited distribution or has become specialized in its food, habitat or behavior patterns
EXAMPLES:EXAMPLES:
Everglades kite feeds on a certain snail who’s pop was reduced by swamp draining.
Ivory-billed woodpecker was eliminated by destruction of southern forests
Sea cows swim slowly along shorelines and were easy targets for whalers in Pacific NW-went extinct.
Will our species become extinct?Will our species become extinct?Nuclear winterNuclear winter-cooling effects of a large number of explosions results in dust or particles in the air blocking sunlight. Global nuclear war could produce temperatures of less than -40 C in 80 days-most crops and some humans would not survive.
Comets and asteroidsComets and asteroids-impacts would throw up large clouds of particulate.
Impact on other species due to:Impact on other species due to:
Habitat destruction by man
Introduction of competing & predatory species & parasites by man
Overexploited resources by humans.
ACKNOWLEDGEMENTSACKNOWLEDGEMENTSwww.axel-and-alice.com/ghbc
www.talkorigins.org
www.xs4all.nl/~steurh
//fp.bio.utk.edu/darwin
//teamwork.icdavis.edu
//depts.washington.edu/vert
www.gpc.peachnet.edu/~pgore
//geology.wr.usgs.gov
www.ucmp.berkeley.edu/vertebrates
www.life.umd.edu/classroom/bsci124
//daphne.palomar.edu/wayne/ww060/
www.zoomdinosaurs.com
www.kean.edu/~biology
//bioweb.cs.earlham.edu/9-12/evolution
www.fieldmuseum.org/exhibits
www.time-travel.com/cenozoic
www.infoplease.com
//bioserve.latrobe.edu.au/vcebiol
//ald.zen.uni-breman.de
//library.thinkquest.org/19926
//biocrs.biomed.brown.edu.Books
//darwinsmistake.com
www.sprl.umich.edu/glc
//fig.cox.miami.edu/faculty/Tom/bil160
www.sc2000.net/~czarembra
www.truman.edu/academics/ss