EVOLUTION Many misconceptions All that it means LIVING

EVOLUTION! ü Many misconceptions ü All that it means= ü LIVING THINGS CHANGE OVER TIME

TIME ü Origin of the universe- Big Bang? ? ü Evidence? Yes- red shift, cosmic background noise ü Age of universe= 10 -20 billion years ü Geologic time ü How old is Earth? ü Approximately 4. 6 billion years old ü Many changes can occur

Has Earth Changed? ü Yes ü Observe the continents- what do you notice? ü At one point all continents were together= PANGEA- http: //geology. com/pangea. htm ü They began to split= Laurasia(north) and Gondwanaland (south) ü How did they move?

Origin of Life? ü Spontaneous Generation ü Observation- meat left out to spoil, maggots develop ü Belief- maggots spontaneously arise ü Francesco Redi said ABSOLUTELY NOT!

Redi’s Experiment- 1668 ü 2 jarsü 1 with meat left open to air ü 1 with meat that is sealed ü Results? ü Maggots only in open jars

Redi’s Exp. Step 2 ü People argued that air was necessary for spontaneous generation ü Redi seals jars with cloth to let air in but not flies

Spallanzani’s Experiment-1775 ü People were still skeptical ü Boiled broth and placed in sealed flask ü No organisms develop- people still skeptical- no air in flask

Louis Pasteur-1859 ü Uses swan neck flask ü Boils meat broth in flask and bends neck of flask into S shape ü Air can enter but airborne microorganisms cannot- they settled in the neck ü No microorganisms grew- FINALLY- no spontaneous generation- life comes from life ü BIOGENESIS

How did life begin? ü 4. 6 bya- earth was very different ü Atmosphere of methane, carbon dioxide, nitrogen, water vapor, but no free oxygen ü Intense solar radiation, lightning, volcanic activity

First living organisms ü Possibly self replicating RNA molecules ü Eventually acquired a protective lipid coating ü Becomes something resembling today’s bacteria ü But how?

Oparin’s Hypothesis ü Ancient earth’s conditions led to spontaneous formation of organic molecules (what are the main 4? ) • These accumulated in oceans and combined into cells • http: //vilenski. org/science/notebook/unit 1 /historyoflife/oparin. html

Miller-Urey Experiment ü Simulated conditions on ancient earth ü Successfully synthesized amino acids ü Confirms Oparin’s hypothesis ü Some holes in this idea

Penn State Research- very new ü Organic compounds have been located in material in space (comets, meteorites, clouds of gas) ü Membrane forming molecules have been found in some meteorites ü Comets/meteorites bombard earth and give rise to life? ? ? Problem?

Oparin’s Idea Revisited- By PSU ü More evidence shows that first organisms were thermophilic (could thrive in earth’s early state) ü Life arises at bottom of ocean as thermophilic microorganisms

So What happened next? ü Several Different Theories ü Endosymbiotic Theory ü Jean Baptiste De Lamarck- Acquired Traits ü Charles Darwin- Natural Selection ü Devries ü Gould

ENDOSYMBIOTIC THEORY

One Idea ü Organisms change over time by adapting

Adaptations ü Structures/traits that are beneficial and serve a purpose to an organism or species ü Examples? ü Let’s go outside

ACQUIRED TRAITS- Lamarck- Late 16 th century ü Adaptations are acquired throughout and organisms life and passed on. ü Adaptations are results of organisms using or not using body parts.

Acquired Traits INCORRECT!

CHARLES DARWIN ü Takes a ride on the HMS Beagle. ü Stops @ Galapagos Islands- observes Finches ü http: //worldatlas. com/webimage/countrys /samerica/galap. htm ü Comes up with theory of Natural Selection

Darwin’s Ideas ü 2 Key Points ü Species of Organisms descended from common ancestors (adaptive radiation) ü “Descent with Modification” ü Natural Selection- best suited individuals survive and leave more offspring

DARWIN-1859 ü THEORY OF NATURAL SELECTION ü established that change occurs in organisms without respect to need ü environment determines whether or not a variation improves the chance of survival ü change occurs gradually ü never said that man evolved from apes! ü infers that man and ape had a common ancestor

THEORY OF NATURAL SELECTION Key Ideas ü OVERPRODUCTION üplants and animals over produce ülimiting factors exist to balance populations and prevent extinction due to competition ü STRUGGLE FOR EXISTENCE ücompetition exists for food and other resources üfood chains become established

ü VARIATION üindividuals in a population vary- polygenic traits (humans, etc) üthey vary whether they need to or not üsome variations have an advantage in the environment ü SURVIVAL OF THE FITTEST üthose with the variations best adapted to the environment will survive üsurvivors reproduce and pass on traits to offspring

ENVIRONMENTAL INFLUENCE ON EVOLUTION ü THE ENVIRONMENT DETERMINES IF A VARIATION WILL HAVE SURVIVAL VALUE ü THE ENVIRONMENT DETERMINES WHAT DIRECTION EVOLUTION WILL TAKE

CHANGES IN ENVIRONMENT ü MIGRATION ümovement to a new environment- when 2 gene pools mix, new traits will emerge ünew mutations give offspring greater survival value ü WITHIN THE OLD ENVIRONMENT ügeologic impacts like volcanoes üresistance to antibiotics, pesticides

üINDUSTRIAL MELANISM is a change in coloration caused by industrial pollution ü ISOLATION üa split between interbreeding groups caused by geographic/physical barriers üproduces changes in behavior, color, which prevent them from breeding

DEVRIES-1901 ü MUTATION THEORY OF EVOLUTION ü sudden changes in genes results in new types of plants and animals ü accounts for the variations suggested by Darwin ü mutations can be good, bad, or have no current value ü lethal genes which leaves organism with no chance of survival (almost always recessive)

GOULD-1972? ü PUNCTUATED EQUILIBRIUM ü agrees with Mutation Theory ü disputes Darwin’s gradualism-but not natural selection ü supports idea that evolution occurs in quick spurtsseen in fossil record all the time ü mutations accumulate over time and then a new species develops when there are too many differences between them ü there are no missing links

SPECIATION ü SPECIES is a group of organisms that are similar in structure and can mate and produce fertile offspring--all have the same number of chromosomes ü CAUSES ünatural selection --mutations üchange in environment ümigration --isolation

ü EVOLUTION OF A NEW SPECIES ü each generation inherits variations that are adaptive ü each generation forms new variations ü Gene Flow, Genetic Drift (chance) ü over a period of time, accumulations of variations will result in a new species ü if variations are unfavorable, the species will become extinct

PATTERNS OF EVOLUTION ü ADAPTIVE RADIATION üdifferent species develop from a common ancestor ü CONVERGENT EVOLUTION üorganisms with different ancestors become more alike in shape, form, behavior. . . ügenerally because they share the same environment

EVIDENCE FOR EVOLUTION ü fossil record ü Homologous structures ü vestigial structures ü embryological evidence ü biochemistry

Fossil Records ü fossils at various depths show different forms of life ü lineages of fossils of a particular group are found and quite complete ü Radiometric (radiation) dating of rock layers establishes a chemical connection between fossils

Homologies ü similarities in structure and arrangement of parts ü indicates genetic relationships of common ancestor ü suggests environmental influences on adaptations selected

Vestigial Structures ü structures of modern organisms with little to no function ü structures are often degenerate in appearance ü fossil evidence suggest structures once had a function

Embryological Evidence ü similarities in development of the embryos of various organisms into differentiation of tissues ü currently, this view point is being scientifically challenged

Biochemistry ü similarity of DNA in terms of identical genes ü similarity of hormones, digestive enzymes, ATP

EXTINCTION OF THE DINOSAURS ü METEOR ü DISEASE ü CHANGE IN ENVIRONMENT ü NEW SPECIES ADDED COMPETITION

RISE OF MAMMALS ü Mammals existed for 150 million years with dinos ü LOSS OF DINOSAURS OPEN NEW NICHES ü BETTER ADAPTATIONS ü CARE FOR YOUNG ü PLACENTA ü WARM BLOOD

EVOLUTION OF MAN ü man is an animal ü man is subject to the rules of natural selection ü man changes over time

A FINAL WORD ü most reasonable people (including the pope) understand that organisms evolve ü the argument is not over “IF” it occurs, but “HOW” it occurs ü belief that things change does not challenge religious belief