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