EVOLUTION!

Many misconceptions

All that it means=

LIVING THINGS CHANGE OVER TIME

TIME

Origin of the universe- Big Bang?? Evidence? Yes- red shift, cosmic background

noise Age of universe= 10-20 billion years Geologic time How old is Earth? Approximately 4.6 billion years old Many changes can occur

Has Earth Changed?

Yes Observe the continents- what do you notice? At one point all continents were together=

PANGEA- http://geology.com/pangea.htm They began to split= Laurasia(north) and

Gondwanaland (south) How did they move?

Origin of Life?

Spontaneous Generation

Observation- meat left out to spoil, maggots develop

Belief- maggots spontaneously arise

Francesco Redi said ABSOLUTELY NOT!

Redi’s Experiment- 1668

2 jars- 1 with meat left open to air1 with meat that is sealed

Results?

Maggots only in open jars

Redi’s Exp. Step 2

People argued that air was necessary for spontaneous generation

Redi seals jars with cloth to let air in but not flies

Spallanzani’s Experiment-1775

People were still skeptical

Boiled broth and placed in sealed flask

No organisms develop- people still skeptical- no air in flask

Louis Pasteur-1859

Uses swan neck flask Boils meat broth in flask and bends neck of

flask into S shape Air can enter but airborne microorganisms

cannot- they settled in the neck No microorganisms grew- FINALLY- no

spontaneous generation- life comes from life BIOGENESIS

How did life begin?

4.6 bya- earth was very differentAtmosphere of methane, carbon dioxide,

nitrogen, water vapor, but no free oxygen Intense solar radiation, lightning, volcanic

activity

First living organisms

Possibly self replicating RNA molecules

Eventually acquired a protective lipid coating

Becomes something resembling today’s bacteria

But how?

Oparin’s Hypothesis

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/unit1/historyoflife/oparin.html

Miller-Urey Experiment

Simulated conditions on ancient earth

Successfully synthesized amino acids

Confirms Oparin’s hypothesis

Some holes in this idea

Penn State Research- very new

Organic compounds have been located in material in space (comets, meteorites, clouds of gas)

Membrane forming molecules have been found in some meteorites

Comets/meteorites bombard earth and give rise to life????? Problem?

Oparin’s Idea Revisited- By PSU

More evidence shows that first organisms were thermophilic (could thrive in earth’s early state)

Life arises at bottom of ocean as thermophilic microorganisms

So What happened next?

Several Different Theories

Endosymbiotic Theory

Jean Baptiste De Lamarck- Acquired Traits

Charles Darwin- Natural Selection

Devries

Gould

ENDOSYMBIOTIC THEORY

One Idea

Organisms change over time by adapting

Adaptations

Structures/traits that are beneficial and serve a purpose to an organism or species

Examples?

Let’s go outside

ACQUIRED TRAITS- Lamarck- Late 16th century

Adaptations are acquired throughout and organisms life and passed on.

Adaptations are results of organisms using or not using body parts.

Acquired Traits

INCORRECT!

CHARLES DARWIN

Takes a ride on the HMS Beagle.Stops @ Galapagos Islands- observes

Fincheshttp://worldatlas.com/webimage/countrys

/samerica/galap.htmComes up with theory of Natural

Selection

Darwin’s Ideas

2 Key Points

Species of Organisms descended from common ancestors (adaptive radiation) “Descent with Modification”

Natural Selection- best suited individuals survive and leave more offspring

DARWIN-1859

THEORY OF NATURAL SELECTION

established that change occurs in organisms without respect to need

environment determines whether or not a variation improves the chance of survival

change occurs gradually

never said that man evolved from apes! infers that man and ape had a common ancestor

THEORY OF NATURAL SELECTIONKey Ideas

OVERPRODUCTIONplants and animals over producelimiting factors exist to balance populations and

prevent extinction due to competition

STRUGGLE FOR EXISTENCEcompetition exists for food and other resourcesfood chains become established

VARIATIONindividuals in a population vary- polygenic traits

(humans, etc)they vary whether they need to or notsome variations have an advantage in the

environment

SURVIVAL OF THE FITTESTthose with the variations best adapted to the

environment will survivesurvivors reproduce and pass on traits to

offspring

ENVIRONMENTAL INFLUENCE ON EVOLUTION

THE ENVIRONMENT DETERMINES IF A VARIATION WILL HAVE SURVIVAL VALUE

THE ENVIRONMENT DETERMINES WHAT DIRECTION EVOLUTION WILL TAKE

CHANGES IN ENVIRONMENTMIGRATION

movement to a new environment- when 2 gene pools mix, new traits will emerge

new mutations give offspring greater survival value

WITHIN THE OLD ENVIRONMENTgeologic impacts like volcanoesresistance to antibiotics, pesticides

INDUSTRIAL MELANISM is a change in coloration caused by industrial pollution

ISOLATIONa split between interbreeding groups

caused by geographic/physical barriersproduces changes in behavior, color, which

prevent them from breeding

DEVRIES-1901

MUTATION THEORY OF EVOLUTION

sudden changes in genes results in new types of plants and animals

accounts for the variations suggested by Darwin

mutations can be good, bad, or have no current value

lethal genes which leaves organism with no chance of survival (almost always recessive)

GOULD-1972?

PUNCTUATED EQUILIBRIUM agrees with Mutation Theory disputes Darwin’s gradualism-but not natural

selection supports idea that evolution occurs in quick spurts-

seen in fossil record all the time mutations accumulate over time and then a new

species develops when there are too many differences between them

there are no missing links

SPECIATION

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

CAUSESnatural selection --mutationschange in environmentmigration --isolation

EVOLUTION OF A NEW SPECIESeach generation inherits variations that are

adaptiveeach generation forms new variations

Gene Flow, Genetic Drift (chance)

over a period of time, accumulations of variations will result in a new species

if variations are unfavorable, the species will become extinct

ADAPTIVE RADIATIONdifferent species develop from a common

ancestor

CONVERGENT EVOLUTIONorganisms with different ancestors become

more alike in shape, form, behavior...generally because they share the same

environment

PATTERNS OF EVOLUTION

fossil record

Homologous structures

vestigial structures

embryological evidence

biochemistry

EVIDENCE FOR EVOLUTION

fossils at various depths show different forms of life

lineages of fossils of a particular group are found and quite complete

Radiometric (radiation) dating of rock layers establishes a chemical connection between fossils

Fossil Records

similarities in structure and arrangement of parts

indicates genetic relationships of common ancestor

suggests environmental influences on adaptations selected

Homologies

structures of modern organisms with little to no function

structures are often degenerate in appearance

fossil evidence suggest structures once had a function

Vestigial Structures

Embryological Evidence

similarities in development of the embryos of various organisms into differentiation of tissues

currently, this view point is being scientifically challenged

similarity of DNA in terms of identical genes

similarity of hormones, digestive enzymes, ATP

Biochemistry

EXTINCTION OF THE DINOSAURS

METEOR

DISEASE

CHANGE IN ENVIRONMENT

NEW SPECIES ADDED COMPETITION

RISE OF MAMMALS

Mammals existed for 150 million years with dinos

LOSS OF DINOSAURS OPEN NEW NICHES

BETTER ADAPTATIONSCARE FOR YOUNGPLACENTAWARM BLOOD

EVOLUTION OF MAN

man is an animal

man is subject to the rules of natural selection

man changes over time

A FINAL WORD

most reasonable people (including the pope) understand that organisms evolve

the argument is not over “IF” it occurs, but “HOW” it occurs

belief that things change does not challenge religious belief