EVOLUTION

I. DefinitionsA. Evolution = Change Through Time

1. Examplesa) Surface of earth ~ 6billion years old

i. Much evidence to indicate changeii. Acted on by force of nature

b) Baseballi. Rulesii. Uniforms

c) Social Structure of Societyi. Dating age

Evolutiond) Dress

e) Automobile designs

f) DNA

i. Random mutations

ii. Good ones can be passed on

g) Living species

i. Many species have ancestors that look very different ie: horses

ii. Many species are extinct(prior to man)

iii. Many species show signs of change now ie: bacteria exposed to antibiotics

Evolution

E. Scientific Theory1. Hypothesis which has been proven to be

correct many, many times

F. Popular Theory 1. hypothesis that has been untested

G. Belief1. Idea untested w/I framework of science

a) Is not based on scienceb) May be right or wrong

2. Often based on philosophy

Evolutiona) Science cannot be used to prove or disprove

philosophical ideasb) Philosophy cannot be used to prove or disprove

scientific theoriesc) Each discipline is valid within it’s own framework

III. Evolution according to LamarckA. Theory of acquired characteristics

1. Individuals change during lifetime2. According to Lamarck these changes could be

passed ona) Giraffe stretching to reach branch

Evolution

3. Ability to run faster

4. Results of weight training

5. Knowledge of biology

6. Lamarck’s ideas were Never Proven

7. Accepted for 50 yrs. as fact

Evolution

IV. DarwinA. Son of Doctor

B. Well educated

C. Excellent naturalist

D. Completed Theology Degree

E. Set sail on Beagle - World tour 1831

F. Took Charles Lyle’s book on geology1. Started that shape of the earth was due to

Evolution2. Small and constant forces and not

catastrophes - ie: erosion, wind, water

G. Made many observations on the voyage that led to hypothesies

H. Returned from voyage with ideas on evolution formed

1. Spent 20 years refining ideas and writing “Origin of Species”

2. Published when Wallace came to same conclusions

Charles Darwin

I. Charles before voyage

II. Charles late in life

HMS Beagle

Fitzroy

Wedgewood China

Alfred Russell Wallace

Evolution

V. Theory of Evolution by Natural Selection

(Darwin and Wallace)A. All species have the ability to produce more

offspring than can actually survive1. From any pair only 2 offspring will survive and reproduce

in stable population

2. Salmon

3. Grasshoppers

B. Supply of resources is limited

Evolution

1. Food

2. Nest space

C. Since resources are limited competition exists

1. Food

2. Nest space

3. Mates

D. All populations show variability1. Due to random mutations

Evolution

2. Some are favorable

3. Some are not favorable

E. Those individuals w/ favorable variations will survive and reproduce

1. Genes for favorable variations are passed on

2. Those w/o favorable variation do not survive

3. = SURVIVAL OF THE FITTEST

VI. Evidence for Evolution

A. Fossil Record

1. Extinct species

a) over 99% of all species that ever lived are now extinct

b) earth only has so much room

Archaeopteryx

Small Dinosaur•Teeth

•Wings with Feathers

•Reptile?

•Bird?

2. Radiometric Datinga) 1/2 life of elements in

rocks where fossils are found tells age of fossil

b) different elements have different 1/2 lives

Half Lives of Elements

B. Embryology 1. Organisms pattern of

development reflects prior ancestors (generally)

a) all vertebrates have tails & gill slits at some point in

development2. Closely related species show

similar development patterns

C. Selective breeding shows genetic diversity

1. People have been selectively breeding animals & plants for centuries

Selective Breeding

D. anatomy1. Closely related species have similar

structures2. Homologous structures= structures with same origin

3. Closely related species have very similar homologus structures

homologous structures4. Analogous structures= structures with same function but different origin

ie: Bird wings and insect wings

5. Vestigial Structures ie: appendix

E. Biochemical Evidence

1. DNA

a. closely related species have similar DNA codes

2. Amino Acid sequences

vii. Patterns of Evolution

A. Divergent Evolution

1. Related species become different over time due to isolation

a) random mutations in both

B. Adaptive Radiation

1. One species gives rise to several

2. Often seen on islands 3. New islands have many open niches

4. Competition is reduced

Example: Galapagos Finches

Darwin’s Finches

C. Convergent Evolution1. Unrelated species living in same type of habitat end up looking alike2. Random mutations occur in both places and the good ones are passed on3. The same adaptations are favorable in both locations

Examples: North American Placentals and Australian Marsupials

Convergent Evolution

Convergent Evolution

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Convergent Evolution

http://www.museum.vic.gov.au/waypoint1/converge.htm

Convergent Evolution

Convergent Evolution

D. Co-evolution

1. Two unrelated species develop adaptations towards each other

Example: Insects and Flowers

Coevolution