evolution i. definitions a. evolution = change through time 1. examples a) surface of earth ~...
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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
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
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
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
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
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
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D. Co-evolution
1. Two unrelated species develop adaptations towards each other
Example: Insects and Flowers
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