22.4
15. Discuss the fossil record
-Cetaceans (whales, dolphins, porpoises) were
Once land animals
-Related to even toed ungulates
-Deer, pigs, camels, cows
-Pelvis bone
23.1
8. Discuss variations between populations
-Mus musculus separated by mountains in Madera
-Different karyotypes showing fused chromosomes
-Does not affect phenotype
Cline: Graded change in character
-mummichog fish
-Allele functioning in metabolism catalyzes better in cold water
-Enables fish to swim faster
-Seen more frequently in colder regions
9. Discuss sources of genetic variation
-Mutations
-Gene duplication
-Sexual reproduction
10. Discuss formation of new alleles
-Mutations
-Only those found in gametes can be passed
On
-Point mutations
-Most of the time harmful
-Occasionally helpful
11. Discuss altering gene number and position
-Translocation (may be helpful)
-Duplication of small pieces of DNA may not be
Harmful
-Gene duplication may persist over generations
-Mutations accumulating
-New genes may have new function
Ex: Mammalian ancestors
-Gene for detecting odors
-Duplicated many times
-Today humans have 350 olfactory receptor genes
-60% inactivated by mutations
-Mice: 1300
-20 % inactivated by mutations
12. Discuss Rapid Reproduction
-Low mutation rate in plants and animals
1/100,000 / generation
-Lower in prokaryotes
-Less time for new generation to be formed
-Mutations can quickly generate variations
-Viruses
-RNA (More mutations)
-AIDS
-Drug cocktail
13. Discuss Sexual Reproduction
-Shuffles existing alleles and deals them at random
-Crossing over
-Independent assortment
-Fertilization
23.2
4. Discuss gene pools and allele frequencies
-Gene pool: All copies of every type of allele in a population
-One allele for a particular locus (fixed)
-All homozygous
Ex: Red flowers
-Co-dominance
6. Discuss Hardy-Weinberg Equilibrium
P2 + 2pq + q2 =1
P2 = Expected frequency of RR
2pq = expected frequency of RW
Q2 = expected frequency of WW
7. What conditions must be met for Hardy-Weinberg Equilibrium to be met?
P 475
8. How would one apply the Hardy-Weinberg Principle?
-T o see whether evolution is occurring
-Medical application: Estimated % of particular inherited gene
-PKU
23.3
5. Discuss natural selection
D. Melongaster has an allele that confers resistance to insecticides
-DDT
-0% in lab strains (from those collected before DDT)
-Allele frequency now 37%
Consistently favoring some alleles: adaptive evolution
-Better fit between organism and environment
6. Discuss Genetic Drift
-Larger chance of a deviation in a small population
-Chance allele frequencies fluctuate
Fig 23.9
7. Discuss founder effect.
-A few individuals become isolated from a larger population and establish a new
population with a gene pool that differs from the source population
-Accounts for high frequency of certain inherited disorders
-Tristan da Cunah
-1814-15 British colonists
-1 had Retinitis Pigmenosa (progressive
Blindness)
-1960 out of 250 descendants 4 it
8. Discuss the bottleneck effect
-Population reduced by natural disaster (fire, flood)
-Certain genes are either over or under represented
9. Impact of Genetic Drift on the Greater Prairie Chicken
-Many disappeard due to farming
-50 left
-low genetic variation
-less than 50% of their eggs hatched
-Increase in harmful alleles
-Research revealed that some alleles were lost
-271 birds added from neighboring states over 4 years
-New alleles
-Egg hatching increased to 90%
10. Effects of Genetic Drift
1. Significant in small populations
2. Causes allele frequency to change at random
3. Can lead to loss of genetic variation
4. Can cause harmful effects to become fixed
11. Gene Flow
-Genes coming in from another population
-Bee brings pollen from white flower population
-Reduces difference between populations
-Ex. Parus major on Dutch Island
-Females born in east survive 2x as well as
Those born in central region
-Many immigrant genes (not as well adapted)
-Ex Insecticide resistance has been spread around the world by mosquitoes
23.4
11. Relative fitness
Ex: Barnacle who is more efficient at collecting food
-More energy
-Produces large # of eggs
Ex: Moth with better camouflage
-More offspring
12. Directional, Disruptive, Stabilizing Selection
-Directional
-Favors one phenotype
-Disruptive
-Favors both extremes of a phenotype
-Stabilizing
-Favors intermediate variants
13. Key Role of Natural Selection in Adaptive Evolution
-Cuttle Fish blend with background
-Snakes swallow prey larger than their head
(Imagine swallowing a watermelon)
14. Sexual Selection
-More likely to obtain mates
Sexual dimorphism: Size, color, ornamentation
Intrasexual selection: Selection within the same sex
-Top dog
-Displays but does not kill
Intersexual selection: Choosy females
-Bright plumage may attract predators
-Mate selection outweighs danger of predation
24: The Origin of the Species
24.1
11. Mystery of Mysteries
The first appearance of new beings on earth
Speciation
-DNA similarities
-Similarities with a common ancestor
Macro-evolution
-New groups of organism
Ex: Wingless Cormorant (Galapagos Islands) related to American Cormorant
-May have migrated from mainland to island
12. Biological Species concept
Species: Group of populations whose members have the potential to interbreed in nature
and to produce viable fertile offspring but do not produce viable, fertile offspring with other such
groups
-Caused by reproductive isolation
-Business woman and a dairy farmer
-Human and a chimpanzee
Ex: Eastern and Western Meadow Larks
-Different songs
13. Reproductive isolation
-Fly and frog?
1. Prezygotic barriers: block fertilization
-Impede attempt to make
-Prevent an attempted mating from being successful
-Hindering fertilization
2. Postzygotic barriers: After fertilization
-Developmental errors
-Decreases chances of survival
-Infertility
14. Limitations of Biological species concept
-Reproductive isolation can’t explain the formation of all species
-Fossils
-Asexually reproducing organisms
-Ex: Grolar Bears
15. Other definitions of species
a. Morphological species concept
-Can be applied to both sexual and asexual organisms
-Useful without info on gene flow
-Most species are distinguished this way
-Problem: Can be subjective
b. Ecological Species Concept
-Nitch interactions with abiotic factors
-Sexual and asexual
--Role of disruptive natural selection
c. Phylogenetic
-Branches on tree of life
-Morphological and molecular
-Distinguishes differences that determine species
-Problem: Degree of difference
20 others have been proposed
6. Allopatric speciation (other country)
-Gene flow is interrupted when a population is divided geographically into separate sub
populations
Ex:1 lake separated into 2 lakes
-Population of fish are separated
Ex: River divides land separating populations
Some species can overcome geographic barriers
-Birds, coyotes, pollen
Some can’t
-Small rodents
-Gene pools may diverge
-Mutations
-Natural selection
-Genetic drift
-Reproductive isolation
Ex: Mosquito fish Gambusia hobbsi
-Ponds become isolated
-One pond; high predation
-Body shape for fast swimming
-Other pond; low predation
-Body shape for endurance
-Sexual preference for speciation at the beginning
-Ex: Widely separated populations of salamanders
7. Allopatric speciation
-15 species of shrimp live on the Atlantic side of the Isthmus of Panama
-15 species live on the Pacific side
-Comparing sibling (one from A and P) species reveals that they were one species
in the past
-Before the formation of the land bridge
-Regions with highly subdivided barriers have more species
Ex: Hawaiian islands
Ex: SA divided by rivers: may butterfly species
-Experiment: Separating fruit flies and subjecting them to different environmental
conditions
-Speciation begins
9. Sympatric speciation (same country)
-Occurs in populations that live in the same geographic area
-Gene flow is reduced
A. Polyploidy: (Rare)
-Most common in plants (80%)
- Oats, cotton, wheat, potatoes, tobacco
1. Autopolyploid: More than 2 chromosome sets derived from a single species
-Failure of cell division (2n)  (4n)
-Tetraploids produce fertile offspring
-Self fertilize
-Mate with other tetraploids
-Produce (3n) reduced fertility
-2 different species breed
-Chromosomes don’t match
-Can breed asexually
-Ex: 5 new plant species since 1850
-Goat’s beard; tetraploid of 2 European species
-Ex. Chemicals induce meotic and mitotic errors
-New hybrids: Grain with the high yield of wheat and the hardiness of rye
B. Habitat differentiation
-Genetic factors enable a subpopulation to exploit a resource not used by parent
population
-NA apple maggot fly  Hawthorn tree
-200 years ago some colonized apple trees introduced by settlers
-Ripen quicker
-Cause rapid development
-Temporal isolation began (prezygotic)
-Alleles benefit flies that use one host plant but harm flies that use the other host
plant (postzygotic)
C. Sexual selection
-Ciclid fish in Lake Victoria
-600 species
-Originated from a small number of species
-Females selecting males based on color
-Red or blue