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