1. February 13 B Day Test: Chapters 18, 19, 20 Coming up……………
Parade of Kingdoms due 2/23
- Don’t wait until the last minute, study each chapter – there will be multiple quizzes and a test at the end.
Be ready for the Drosophila lab and the Transformation lab so we can start as soon as the live materials are in - highlight important points.

2. EVOLUTION & SPECIATION

3. Population: a localized group of individuals belonging to the same species
Species: a group of populations whose individuals have the potential to interbreed and produce fertile offspring
Gene pool: the total aggregate of genes in a population at any one time
Population genetics: the study of genetic changes in populations
Modern synthesis/neo-Darwinism
“Individuals are selected, but populations evolve.”

4. Gene Pool Combined genetic info. of all members
Allele frequency is # of times alleles occur

5. Variation in Populations
2 processes can
lead to this:
Mutations -
change in DNA
sequence
Gene Shuffling –
from sexual
reproduction

6. Genetic Drift changes populations…….
Random change in allele frequency causes an allele to become common

7. Microevolution
The Bottleneck Effect: type of genetic drift resulting from a reduction in population (natural disaster) such that the surviving population is no longer genetically representative of the original population

8. Microevolution
Founder Effect: a cause of genetic drift attributable to colonization by a limited number of individuals from a parent population

9. Microevolution
Gene Flow: genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations

10. Microevolution
Nonrandom mating: inbreeding and assortive mating (both shift frequencies of different genotypes)

11. Microevolution
Natural Selection: differential success in reproduction; only form of microevolution that adapts a population to its environment

12. SPECIATION - formation new species
- Anagenesis (phyletic evolution): accumulation of heritable changes
- Cladogenesis (branching evolution): budding of new species from a parent species that continues to exist (basis of biological diversity))

13. Evolution of Populations
Occurs when there is a change in relative frequency of alleles

14. Punctuated equilibrium
Tempo of speciation: gradual vs. divergence in rapid bursts; Niles Eldredge and Stephen Jay Gould (1972); helped explain the non-gradual appearance of species in the fossil record

15. Population variation
Polymorphism: coexistence of 2 or more distinct forms of individuals (morphs) within the same population
Geographical variation: differences in genetic structure between populations (cline)

16. Variation Preservation
Prevention of natural selection’s reduction of variation
Diploidy 2nd set of chromosomes hides variation in the heterozygote
Balanced polymorphism heterozygote advantage (hybrid vigor; i.e., malaria/sickle-cell anemia); frequency dependent selection (survival & reproduction of any 1 morph declines if it becomes too common; i.e., parasite/host)

17. Sexual selection
Sexual dimorphism: secondary sex characteristic distinction
Sexual selection: selection towards secondary sex characteristics that leads to sexual dimorphism

18. Natural Selection
Shifts to
middle range
2 extremes
1 extreme

19. Fitness: contribution an individual makes to the gene pool of the next generation

20. Conditions needed for Genetic Equilibrium

21. Hardy-Weinberg Equation
p=frequency of one allele (A); q=frequency of the other allele (a); p+q= (p=1-q & q=1-p)
P2=frequency of AA genotype; 2pq=frequency of Aa plus aA genotype; q2=frequency of aa genotype; p2 + 2pq + q2 = 1.0

22. AS NEW SPECIES EVOLVE, POPULATIONS BECOME REPRODUCTIVELY ISOLATED (gene pools are isolated)
REPRODUCTIVE ISOLATION – MEMEBERS OF 2 POPULATIONS CANNOT INTERBREED & PRODUCE FERTILE OFFSPRING.

23. Table 23.1a

24. Table 23.1b

25. Tigon
Result of male tiger and female lion mating incaptivity. Offspring are infertile.
Separated both geographically and ecologically.

26. Liger
Result of male lion and female tiger mating in captivity. Offspring are infertile.

31. Fig. 23.6
Four species of leopard frogs: differ in their mating calls. Hybrids are inviable.

32. These squirrels living on opposite sides of the Grand Canyon demonstrate allopatric speciation.

33. Sympatric: reproductively isolated subpopulation in the midst of its parent population (change in genome); polyploidy in plants; cichlid fishes

35. Evidence of Evolution Fossil Record
Geographic Distribution of Living Species
Homologous Body structures
Similarities in Embryology

36. Evidence of
Evolution
Fossil Record provides evidence that living things have evolved
Fossils show the history of life on earth and how different groups of organisms have changed over time

40. Marsupial Mammals Convergent Evolution Placental mammals and
Flying Squirrel
Sugar Glider
Marsupial Mammals
Convergent Evolution
and
Analogous Structures
Placental mammals
Mammalia
Rat like common ancestor

41. Big Question!!! How did life arise on the big blue planet??
Scientists attempt to answer this question scientifically.

42. Relative Dating versus Absolute Dating

43. Relative Dating Can determine a fossil’s relative age
Performed by estimating fossil age compared with that of other fossils
Drawbacks – provides no info about age in years

44. Absolute dating Can determine the absolute age in numbers
Is performed by radioactive dating – based on the amount of remaining radioactive isotopes remain
Drawbacks - part of the fossil is destroyed during the test

45. Carbon-14 Dating

46. Fossil Formation

47. Big Bang Theory
A cosmic explosion that hurled matter and in all directions created the universe billion years ago
Evidence
it explains why distant galaxies are traveling away from us at great speeds
Cosmic radiation from the explosion can be observed
The Big Bang theory probably will never be proven; consequentially, leaving a number of tough, unanswered questions.

48. What was early earth like?
Earth was Hot!!
Little or no oxygen
Gasses in atmosphere:
Hydrogen cyanide (poison to you!)
Hydrogen sulfide
Carbon dioxide
Carbon monoxide
Nitrogen
water

49. So how did the earth get oxygen?
Some of that oxygen was generated by photosynthetic cyanobacteria
Some came from the chemical separation of water molecules into oxygen and hydrogen.

50. Others evolved ways of using oxygen for respiration
Oxygen drove some life forms to extinction
Others evolved ways of using oxygen for respiration

51. How did life begin? Miller and Urey’s Experiment
Passed sparks through a mixture of hydrogen methane ammonia and water
This produced amino acids – the building blocks of life

52. Miller’s experiment suggests that lightning could have produced amino acids

53. How can simple amino acids result in life? There are 3 theories
1. Formation of microspheres
Large organic molecules can sometimes form tiny proteinoid microspheres
Store and release energy, selectively permeable membranes, may have acquired more characteristics of living cells

54. 2nd Hypothesis for Life Evolution of RNA to DNA
RNA was assembled from simple organic molecules in a primordial soup
RNA was able to replicate itself and eventually form DNA
Not scientifically proven to be possible

55. 3rd Theory of Life Endosymbiotic theory
eukaryotic cells arose from living communities formed by prokaryotic organisms
Ancient prokaryotes entered primitive eukaryotic cells and remained there as organelles