1. Evolution
Chapter 15

2. Darwin Charles Darwin – father of evolution
The Origin of Species – Darwin’s book
Darwin's book only uses the word evolution on the last page
Evolution - cumulative changes in groups of organisms through time
Natural Selection is a means to explain how Evolution works

3. Darwin’s Theory
Survival of the fittest – the species that is best fit to survive will reproduce more, making their genetics more dominant.
The weak animals die off and never reproduce, so those genes are not passed down to the next generation

4. Darwin’s Theory Natural Selection does NOT equal Evolution
It is only a means to explain evolution

5. Darwin’s Theory
Artificial Selection - hand selecting certain characteristics for breeding purposes
ex. domesticated dogs
Variation - individuals in a population differ from one another
ex. height of the sunflowers
Heritability - Variations are inherited from parents
ex. Tall sunflowers produce tall sunflowers, and short produce short

6. Sunflower expamle
Overproduction - Populations produce more offspring than can survive
ex. Each sunflower has hundreds of seeds, however only a few will germinate
Reproductive Advantage - Some variations allow the organism that possesses them to have more offspring than the organism that does not possess them
ex. In this habitat shorter sunflowers reproduce more successfully
Overtime - the average height of the sunflower population is short, because the shorter ones reproduce more successfully and the taller ones die off

7. Sunflowers con’t
Overtime - the short sunflowers may become a new species if they are unable to breed with the original sunflowers
Natural Selection - through time nature modifies a population to produce new species

8. Evidence of Evolution
Fossil Record - a history of fossils displaying evolutionary changes
Derived Traits - newly evolved features that do not appear in the fossils of common ancestors
ex. Feathers
Ancestral Traits - primitive features that appear in the fossils of common ancestors
ex. Teeth, tails
Transitional fossils - provide detailed patterns of evolutionary change, display both derived and ancestral traits

9. Evidence of Evolution
Homologous Structures - anatomically similar structures inherited from a common ancestor
Predicts that body parts are modifications of ancestors rather than new body parts
Vestigial Structures - structures that are the reduced forms of functional structures in other organisms
ex. molars, appendix, hairy bodies, etc

10. Evidence of Evolution
Analogous structures - structures used for the same purpose and look similar, however they are not inherited from a common ancestor
ex. an eagle wing, and a beetle wing
Comparative embryology - comparing vertebrate embryos, they are very similar during different stages of development, they display homologous structures
Embryo - early, pre-birth stage of an organism's development

11. Evidence of Evolution
Geographic Distrubution - South America mainland vs. Galapagos Islands
Migration patterns explained plant diversity on islands (seeds, wind, bird droppings)
Biogeography - study of the distribution of plants and animals around the world

12. Evolution
Adaptation - a trait shaped by natural selection that increases an organism’s reproductive success
Fitness - a measure of the relative contribution an individual trait makes to the next generation
ex. the number of reproductively viable offspring that an organism produces in the next generation
Camouflage - adaptations that allow them to blend in with their environment
Mimicry - one species evolves to resemble another species

13. Evolution terms
Hardy-Weinberg Principle - when allelic frequencies remain constant, a population is in genetic equilibrium, so even if populations grow they will grow in the same ratio.
Genetic Drift - any change in the allelic frequencies in a population that is due to chance
founder effect - when a small sample of a population settles in a location separated from the rest of the population (alleles that were common in one place may now be very uncommon in the new place)
Bottleneck - when a population declines to a very low number and then rebounds. The gene pool is greatly reduced and reduces diversity

14. Darwin’s Finches

15. Types of Natural Selection
Stabilizing selection - eliminates extreme expressions of a trait
ex. human babies born with either above or below normal weights have a smaller chance of survival than average weight babies, as a result the average baby weight for humans is a small range
Directional selection - when an extreme version of a trait makes an organism more fit
ex. peppered moths
Disruptive Selection - splits a population into two groups, removes individuals with average traits
Sexual Selection - when males and females differ significantly in appearance
ex. peacocks

16. Peppered Moths
Moths.swf </exchweb/bin/redir.asp?URL= echapps.net/interactives/pepperMoths.swf>

17. Reproductive Isolation
Prezygotic isolation - when reproduction is prevented by making fertilization unlikely
ex. Eastern and Western Meadowlarks look the exact same, but they have different mating songs
Postzygotic isolation - when fertilization has occurred but offspring cannot develop or reproduce
ex. Ligers, donkeys

19. Speciation
Allopatric - a physical barrier divides one population into two or more populations
ex. mountain ranges, rivers, canyons
Sympatric - when a species evolves into a new species without a physical barrier
ex. mutations

20. Patterns of Evolution
Adaptive Radiation - divergent evolution, many species evolve from one common ancestor in a short amount of time, happens when there are new niches
ex. Cichlids species evolved from 1 in the past 14,000 years
Convergent evolution - when unrelated species evolve similarly even though they live in different parts of the world, happens because of similar ecology and climate
Gradualism - evolution proceeds in small, gradual steps
Punctuated equilibrium - rapid spurts of genetic change cause species to diverge quickly causing abrupt changes

21. Chapter 14/15 Test 19 short answer questions Types of fossils
Relative and Radiometric Dating
Geological time scale
Theories of early life (spontaneous generation, biogenesis, etc)
Micro vs Macro Evolution
Darwin and the Galapagos Islands
Artificial and Natural Selection
Homologous Structure, Analogous Structures
Finches
Postzygotic Isolation
Peppered moth's
Process of Evolution

22. Chapter 15 Review p 445 - 1-7, 10-13 p 446 - 14-17, 19-20, 23-26