This document provides information about evolution including:
- Natural selection causes evolution by favoring traits that increase survival and reproduction.
- Domestic plants like cabbage, broccoli and kale evolved from a common wild ancestor through artificial selection on different traits.
- There is direct evidence for evolution from observations of antibiotic resistant bacteria and other examples of adaptive evolution.
- Classification systems reflect evolutionary relationships as organisms with shared ancestry have similar characteristics.
- Homologous structures and vestigial traits provide evidence that organisms share a common ancestor.
- Transition fossils provide evidence of gradual evolution from one form to another over generations.
13. FACT Individuals within populations
vary.
FACT Some of the variation among
individuals is passed on to
offspring.
FACT Populations produce more
offspring than can survive.
FACT Survival and reproduction are not
random.
INFERENCE Natural selection
causes evolution.
19. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
– Antibiotic resistant bacteria
– Drug resistant germs
– Insecticide resistant insects
– Herbicide resistant weeds
– Galapagos finch beaks
– Cichlid fish in Lake Victoria
– Many, many other examples
20. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
– What explains why different organisms or
species share the same traits?
– Taxonomic groups are determined by shared
similar characteristics.
21. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
22.
23. It is not the strongest of the
species that survive, nor the
most intelligent, but the one
most responsive to change.
- Charles Darwin
31. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
– Homologous structures
• Vertebrate limbs, vertebrae, skulls, exoskeletons
• Lab: Hominid skull comparisons
– Vestigial traits
32. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
– Homologous structures
– Vestigial structures
• Appendix, wisdom teeth, human body hair, snake
“claws”, whale leg bones, micropterous insects
33.
34. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
• Homology in development
35.
36.
37.
38. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
• Homology in development
• Homology in biochemistry
– The more similar DNA, proteins, and other
biochemistry is, the more closely related
organisms are.
39.
40. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
• Homology in development
• Homology in biochemistry
• Transition fossils
41.
42.
43.
44.
45.
46.
47. Evaluating the Evidence for
Evolution (by common descent)
• Direct observations
• Biological classification
• Homology in comparative anatomy
• Homology in development
• Homology in biochemistry
• Transition fossils
• Biogeography
48. Hypotheses to account for
distribution of organisms
• Separate origins
– penguins & auks, gazelle & deer
• Migration
– weeds, starlings, rabbits in Australia
• Vicariance
– Lednia stoneflies, meadowlarks
• Continental drift
– Cichlid fish in Africa & S. America
– Drumming stoneflies in N. hemisphere
49.
50. “It is not the strongest of the
species that survive, but those
most responsive to change.”
- Charles Darwin
54. What is a species?
• Species = a group of potentially
interbreeding organisms.
55.
56. What is a species?
• Species = a group of potentially
interbreeding organisms that produce fertile
offspring.
57.
58. What is a species?
• Species = a group of potentially
interbreeding organisms that produce fertile
offspring, regularly in nature.
59. How do we decide if an organism is
an undescribed species?
• Biological species = a population of
potentially interbreeding organisms that
produce fertile offspring in nature
– Limitations? Advantages?
• Morphological species = a population of
organisms that look similar
– Limitations? Advantages?
68. Evolution of Jelly bellicus
0
1
2
3
4
5
6
7
8
breakfast lunch dinner
numberofsurvivors
green
green spots
orange
yellow spots
red
red spots
dk brown spots
tan spots
69. Evolution of Jelly bellicus
0
2
4
6
8
10
12
breakfast lunch dinner
numberofsurvivors
green
green spots
orange
yellow spots
red
red spots
dk brown spots
tan spots
70. Evolution of Jelly bellicus population shift
0
2
4
6
8
10
12
14
beginning after 1st meal after 2nd meal after 3rd meal
numberinpopulation
green
green spots
orange
yellow spots
red
red spots
dk brown spots
tan spots
71.
72.
73. How do we define evolution?
• Change in allele frequency of a
population’s gene pool,
• leading to change in organisms over time.
• Measure allele frequencies
How do we measure evolution?
74. Population Genetics Lab
• Question: How do selective pressure,
heterozygote advantage, and population size
affect allele frequencies and evolution?
• Hypotheses:
selective pressure against an allele’s phenotype
will _______ the allele’s frequency.
Heterozygote advantage will ________ the
frequency of a dominant allele.
Allele frequencies will fluctuate more in ______
size populations.
75. Population Genetics Lab
• Methods
1.Begin each simulation by holding 1 dime
(representing a dominant allele) and 1 penny
(representing a recessive allele) in opposite
hands.
2.Each person selects a “mate” randomly in a
“hermaphroditic” population like slugs. Each
person holds a penny in one hand and a
dime in the other hand.
76.
77.
78. Population Genetics Lab Methods
3. Person 1 selects a partner’s hidden coin,
then person 2 selects a hidden coin.
4. The offspring is considered person 1’s
offspring and the genotype is determined by
what coins were selected.
5. Repeat the process for person 2’s offspring.
6. Record the genotpyes.
7. Exchange coins, if needed, from the class
gene pool.
79. Population Genetics Lab Methods
8. Record class data for numbers of
homo. dom., heterozygous, homo. recessive
frequencies of dominant & recessive alleles
8. Repeat for a total of 5 generations.
9. Repeat all steps for Case 2, 3, & 4
For Case 2 – selection:
• Homozygous recessive offspring die and
another mating must occur.
80. Population Genetics Lab Methods
For Case 3 – heterozygote advantage:
•Homozygous recessive offspring die and
•Homozygous dominant offspring must toss a
coin to see if the offspring lives or not. Head it
lives, tails it dies and must choose again.
For Case 4 – genetic drift:
•Class divides into 3 small groups,
reproductively isolated from each other.
81.
82. Hardy-Weinberg Equilibrium
• p = % of dominant alleles in a population
• q = % of recessive alleles in a population
• % of homozygous dominant individuals =
• % of homozygous recessive individuals =
• % of heterozygous individuals =
• p + q = 1
• p2
+ 2pq + q2
= 1
83. Hardy-Weinberg Equilibrium
• Out of 1000 stoneflies collected, 160 are
apterous (no wings), a Mendelian recessive
trait.
• What are the percentages of homozygous
dominant stoneflies and heterozygous
stoneflies in the population?
• What percentage of each genotype will exist
in the next generation?
• Allele frequencies never change!
84. Conditions necessary for
Hardy-Weinberg Equilibrium
• No mutations
• No migration in or out of population
• No advantage of any phenotype over others
• Random mating
• Large population size
85. Forces that cause evolution
• Natural selection
• Mutation
• Gene flow
• Genetic drift
86.
87.
88.
89.
90.
91.
92.
93.
94.
95. Forces that cause evolution
• Natural selection
• Mutation
• Gene flow
• Genetic drift
• Non-random mating
100. • If humans evolved from other animals,
what type of animals would they most
likely have evolved from?
– Apes
• If humans evolved from some type of
apes, what evidence should exist?
– Transition fossils
– Anatomical & embryological homologies
– Molecular & biochemical homologies
– Behavioral similarities?
106. Avoid these misconceptions
• Individuals evolve.
• Changes in environment cause beneficial
mutations and natural selection.
• Natural selection causes perfection.
• Natural selection works toward reaching a
predetermined goal.
– Were Alloperla sp. stoneflies supposed to
evolve to become a brilliant green color?
– Were humans supposed to become the way
they are?
107.
108.
109. “It would disturb me more to
find out that life couldn’t be
started in a laboratory. If life
can’t be started somehow in
this physical world, then how
did I get here?”
- Dr. Henry Eyring
Notas del editor
Figure 22.9 Artificial selection.
Figure 24.2 The biological species concept is based on the potential to interbreed rather than on physical similarity.
