AP Biology

I. Evolution and Evolutionary
A.
Evolution—change in gene frequency in a population over time i.
Change must be genetic ii.
Occurs in a population—not individuals iii.
Time depends on how fast environment changes and how fast organisms reproduce
B.
Evolutionary Theory—diversity of organisms on earth is due to evolution from simple to complex

II. Hypotheses about Origins of Life
Resources for these notes
 Bozeman Video—Abiogenesis http://www.bozemanscience.com/010-abiogenesis
 Campbell Textbook—
 Ch. 25.1
 Ch. 25.3

II. Hypotheses about Origins of Life
A.
Spontaneous Generation—thought that life could form from non-living things
 1862—Pasteur disproved this idea through is experiments

II. Hypotheses about Origins of Life
B.
Organic Molecules—Building
Blocks of Life i.
1 st Organic Molecules made in lab—Miller-Urey 1953
 Early earth—reducing environment
 Energy—from lightning, UV,…(no ozone yet)
 Experiments with these conditions created amino acids
(abundantly)…also sugars, lipids,
& nitrogenous bases

II. Hypotheses about Origins of Life ii.
Polymerization—putting pieces together to make macromolecules!
 Researchers have made polypeptides without enzymes.
 Dehydration by vaporization—drip amino acids on hot sand, clay or rock

II. Hypotheses about Origins of Life iii.
Membranes—lipids spontaneously form spheres—enclose liquids and form a membrane (Protobionts / Protocells)

II. Hypotheses about Origins of
Life iv.
1 st Genetic Material
 Life needs replication and replicating molecules
 1 st genes were RNA—which can replicate
(“RNA World”)
 Ribozymes—RNA catalysts—assembled amino acids and replicated RNA (no enzymes or ribosomes yet)

II. Origins of Life
C.
Prokaryotic Cells—First Fossils are apprx.
3.5 billion years old
 2 Domains—Archaea and Bacteria
 2 Hypothesis about how they got their energy
 Took ATP from environment
 Made ATP from sulfur and iron

II. Origins of Life
 First fossils are apprx. 2.1 billion years old
 Membrane enfolding and
Endosymbiosis (Review!)

III. Developing Ideas about Evolution
Resources
 Campbell Textbook
 Ch. 22

III. Developing Ideas about Evolution
A.
i.
Anaximander– Greek; 500BC; thought perhaps simple things developed into more complex forms ii.
Aristotle—Greek; 384-322BC; believed that species are “fixed”; created separately and could not be changed iii.
Other cultures—each culture had an explanation (varied)

III. Developing Ideas about Evolution
B. Mid-1700’s– Geology presented several big ideas…
 Earth is older than 6000 years old
 Early 1800—Lyell—Principals of
Geology—gradual forces shape the earth rather than catastrophes
 Collections of fossils—found ocean fossils on mountain tops— perplexed scientists…
Sir Charles Lyell

III. Developing Ideas about Evolution
C.
Lamarck/Wallace
 Lamarck-Published essay in 1809
 “Inheritance of Acquired Characteristics”changed due to use/disuse and developed traits could be passed on…
 Wallace-Published essay in 1858
 Natural selectionslow modificationdidn’t apply to humans
Jean Baptiste-
Lamarck
Alfred Wallace

III. Developing Ideas about Evolution
i.
Darwin’s Voyage—HMS Beagle 1831-1836—
Some observations made on the voyage
1.
Similar adaptations occurred in similar environments
2.
Great diversity within the same environment
(ex. Galapagos finches)
3.
Fossils—Darwin developed a large collection

III. Developing Ideas about Evolution
Charles Darwin and HMS Beagle Voyage

III. Developing Ideas about Evolution ii.
Darwin’s Explanation—Decent with
Modification
1.
Did not use the term evolution
2.
No supernatural—all based upon what was seen in the natural world
3.
Developed ideas while on HMS Beagle— highly influenced by Malthus, Lyell, and other scientists
4.
Basic idea was that organisms change over time…main mechanism is natural selection…particularly for adaptive change

III. Developing Ideas about Evolution
Timeline of Scientific Ideas about Geology,
Inheritance, Evolution, and Population Limits

IV. Natural Selection and Artificial Selection
Resources
 Bozeman—Natural Selection
 http://www.bozemanscience.com/001-natural-selection
 Campbell Textbook
 Ch. 23
 Learn Genetics
 http://learn.genetics.utah.edu/content/selection/artificial/

IV. Natural Selection and Artificial Selection
A.
Natural Selection–organisms with certain inherited traits tend to survive and reproduce at higher rates in their environment than other individuals because of those traits.
1.
Differential Reproduction—organisms overproduce
-> not all survive -> those better suited for environment survive -> Reproduce more
 Reproduction is what matters—ensures passing on of genes
 “Better suited” to survive, not “best”… really survival of the good enough… 
 Conditions of environment determine if fit enough

IV. Natural Selection and Artificial Selection
2.
Adaptation—genetic trait that helps an organism reproduce
(variations sometimes turn into adaptations, but not always)
3.
Relative Fitness—the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals
**Likelihood of reproducing and passing on genes

IV. Natural Selection and Artificial Selection

IV. Natural Selection and Artificial Selection
B.
Artificial Selection– humans determine who reproduces
 Can create more change in short period of time
 May create artificial environment for artificially selected organisms to survive