evolution. word is used in many ways: –cosmic evolution of the universe –biochemical evolution...
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Evolution
Evolution
• Word is used in many ways:–Cosmic evolution of the universe
–Biochemical evolution of the 1st life
–Biological evolution of the species
Outline for Notes:
1. Definition of Evolution
2. People:a) James Huttonb) Charles Lyellc) Lamarkd) Charles Darwin
3. Natural Selection
Evolution
•Change over time
•The theory explaining how modern organisms have descended from ancient organisms
History of the Current Theory
James Hutton (1795) – Charles Lyell (1833)
• Geologists
• Proposed – earth is millions of years old– Same processes you see now are ones that
were there in the past
James Hutton• Proposed layers of rock, mountains, valleys
form slowly – so earth is very old
Charles Lyell• Processes which shape the earth now
must be the same ones that shaped the earth in the past
Providence Canyon, Georgia
How old is it?
a) 150 years b) 15,000 years c) 15 million years
Lamarck WRONG
• Inheritance of acquired traits
• Gain/lose traits through usage
Charles Darwin
• Voyaged on Beagle
• Wrote On the Origin of the Species proposing a theory where all the different species came from:
natural selection
Example: the Galapagos turtles
What kind of variations might
exist in this turtle species?
Natural Selection
–Variation exists in nature
–Struggle for existence – compete for resources
–Survival of the fittest – the strongest survive to pass their genes on
–Descent with modification – each living species has descended with changes from other species
variation: neck length
Compete for food (tall shrubs)
Long necked turtles more fit
long neck turtles survive to pass on the long neck trait
Natural Selection
– Variation
– Struggle for existence
– Survival of the fittest
Which would survive best as a seed eater?
Insect eater?
This is the part that is controversial:
Descent with modification
Outline for Notes
Fossils
a) What is a Fossil?
b) What are the Four Common Fossil Types?
c) How do Fossils Form?
d) How Are Fossils Dated? a) Absolute Age
b) Relative Age
e) What are fossil used for?
What is a Fossil?
• Remains of ancient life
4 Types of fossils
• Body fossils – actual parts (a tooth)
• Molds – hollowed out rock
• Casts – solid forms of plant/animal when mold fills up
• Prints – impressions formed in mud that harden (footprint)
How do fossils form?
• 1. Animal dies and is QUICKLY buried
• 2. Soft body dissolves leaving a mold
• 3. Minerals replace bone/shells
•
How are fossils dated?
Method 1: Relative Dating
• Compare fossils to other fossils in layers of rock
Oldest fossils are in lowest strata
Method 2: Radioactive Dating
• Absolute dating
• based on remaining radioactive isotopes
• C-14 for previously living organisms that are “young”
• Must assume that all things have remained constant over history of earth
Example
Amount Half-lives Time
Fossils show change over time…
…but they form an incomplete record of life…
Outline for Notes:
Evidences Cited for Evolution 1. Fossils
2. Homologous Structures
3. Biochemical Comparisons
4. Antibiotic Resistance
Fossils show change over time
• Controversy comes with the missing links
Homologous Structures• Perform related functions in different species
Biochemical Comparisons
• Compare amino acid sequences in proteins
• Compare nucleic acid sequences in genes
Antibiotic Resistance
• Bacteria develop the ability to “resist” antibiotics
Today:
A. Rates of Evolution
B. Geological Time Periods
C. What does Evolution Require?
Rates of Evolution
2 popular theories:(1) Gradualism: SLOW
and steady
(2) Punctuated equilibrium: long periods of no change with a sudden period of rapid change
Both take a LONG time
Geological Time Periods
• Mass extinctions often mark divisions
Evolutionary Change Requires Changes in Genetic Information
Changing the allele frequency
• 50/50
• A selecting factor
• 80/20
SPECIES evolve, not individuals
CladogramCladogramDiagram showing how organisms are related based on Diagram showing how organisms are related based on
shared, derived characteristicsshared, derived characteristics such as feathers, hair, or such as feathers, hair, or scalesscales
Michael Behe
Intelligent Design
• Bacteria flagellum• 25 different
proteins• uses an
electrochemical ion gradient to drive rotation
• speeds of up to 300 Hz.
Origin of Eukaryotic Cells
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