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Evolution
Genetic change in a population over time
What are the 3 necessary ingredients for evolution?
• Evolution is a natural phenomenon that will occur wherever suitable conditions exist
• It’s a genetic change in a population over time• Is the example below macroevolution or microevolution?
Evidences for Evolution
• Fossils: What is a fossil?
• Comparative Embryology
• Comparative Biochemistry
• Comparative Anatomy
Fossil Evidence
• Preservation in ice and acid
• Preservation in amber
• Preserved hard parts
• Petrification
• Molds and casts
• Imprints
Preservation in Ice & Acid• Organisms are kept from decaying
in ice or strongly acidic conditions.• Why are bogs conducive to preservation
and not decomposition?
Preservation in Amber
• Fossilized tree sap
Preserved Hard Parts
• Organic materials in hard parts of living things leech out and are replaced by minerals in the surrounding rock
Petrification
• Organic materials in tree tissue leech out and are replaced by minerals in the surrounding rock
Molds & Casts• Molds impressions
• Casts 3-D
• Identify the 3 pictures as molds or casts.
Imprints
• Impressions or indentations in rock
Stratificationstrata
• What does the root word “strata”mean?
• How fossils are formed• Becoming a Fossil
Relative Datingestimating the age of something compared to something else
Absolute Dating
RadioMetric Dating Video: http://www.pbs.org/wgbh/evolution/library/03/3/l_033_01.html
• radioactive: decay of nuclei of unstable atoms half-life
• uranium 238 = 4.5billion yrs uraniumlead
• C14 up to 40,000yrs• C14C12 half life 5700
• If a piece of rock is found with a Lead:Uranium ratio of 7:1, how old is the rock?
Comparative Embryology• "ontogeny
recapitulates phylogeny"
• each embryo has to repeat the adult stages of its biological predecessors
• Haeckel was a fraud!
Comparative Biochemistry
• DNA sequence and protein molecules
• What is the adjacent picture called?
• What is the name of the process which generates it?
Comparative Anatomy
• Homologous structures
• Analogous structures
• Vestigial structures
Homologous Structures• Similar in design, different in function
• Divergent Evolution offspring of a common (similar) ancestor diverge b/c they are adapted by different environments
Adaptive Radiation process by which ancestral species evolve into a number of diff species
Analogous Structuressimilar in function different in design
• offspring nonrelated (different) ancestors converge b/c they are adapted by similar environments
• Speed and stealth in the water
• Rolling for defense
What is the name of this animal?
• Echolocation for feeding in darkness (Oil bird and bat)
• Convergent Evol.• result of geographic
isolation and niches to be filled
• process by which different species evolve similar structures or adaptations to similar (but diff) environments
Parallel Evolution
Divergent, Convergent & Parallel Evolution
Make a Venn comparing the 3 types of evolution. 3 facts per group.
• Hummingbird flowers• What kind of evolution
do these flowers exhibit? Why?
Co-Evolution• When two different
organisms change in response to each other
• How many bees are on the screen? Write your answer and then watch the videos.
Evolution of Camouflage:
Orchard Wasps
MimicryWill the REAL stinging insect please stand up!How many stinging insects on the screen?
Mimicry only works if there are more _____________
Vestigial structures• a structure or organ
that has no apparent use
• if organisms use the minimal amount of E to survive,why would they use E to form a structure that has no use?
Theories of Evolution• Empedocles• Aristotle• Linnaeus• Lamarck• Cuvier• Lyell• Wallace/Darwin• Stanley/Gould• Write at least 1 fact
about each theorist.
Lamarck & Acquired Characteristics
• Acquired characteristics traits acquired during life can be passed to offspring
• Theory of Use & Disuse what we use gets larger and what we don’t gradually disappears
Natural Selection (Darwin & Wallace)
• Overproduction
• Struggle for existence/ Competition
• Variation within a species
• Survival of the fittestproblem: how did variations arise?
How does Evolution Really Work
Overproduction
• Thomas Malthus "Essay on Principles of Population"
• geometric/exponential progression (vs arithmetic)
Gradualism vs Punctuated Equilibrium
Permian Extinction Cambrian Explosion
Speciation
Formation of a new species (group of organisms that can reproduce fertile offspring) needs:
1. Available niche
2. Genetic Isolation
3. Time
Genetic Isolation
Geographic/allopatric Isolation results from physical separation
Ecological/sympatric Isolation:• Mechanical (post/pre zygotic)• Temporal• Ethological (behavioral)• Isolating Lacewing songs
Directional Selection
• Selection against one extreme
• Fit to be ONE extreme
Stabilizing Selection• Selection against
both extremes
• Fit to be AVERAGE
Disruptive Selection
• Selection against the average
• It is fit to be BOTH extremes
• Give a plausible example of each of the 2 types of speciation.
• Give a plausible example of each of the 3 types of selection.
• Making a Cladistic: Try the following activity: http://www.pbs.org/wgbh/evolution/change/family/
Why Does Evolution Matter Now?
• Evolution of Antibiotic Resistance
• Biological Invaders
References
• Absolute Dating: dig.anthro.niu.edu/anth102/ 01intro/1dating.html
• PBS Evolution Library: http://www.pbs.org/wgbh/evolution/library/index.html
• Mimicry: http://www.morning-earth.org/Graphic-E/Transf-Mimic.html