Evolution

1
Evolution

• CP Chapters 10-12

2
Geological Time Scale Scientific Theory of Earth
and Lifes History

• CP Ch 10-12

3
Who studies the Earths History?

• Geologists
• Anthropologists
• Archeologists

4
Who studies the history of life?

• Paleontologists!

5
Geological Time Questionnaire

• 1. How old are you?
• 2. How old is the earth? (guess its ok!)
• 3. Can you name a species that was once here, but
  has gone extinct?
• 4. Have the conditions on earth always been the
  same?

6
How do we know about earths history?

• Geology rock patterns, tectonic plates,
  volcanic activity, chemistry of rocks
• Radiometric dating decay of radioactive
  elements begins at death and has measurable rate
  over time
• C14 dating
• Relative dating fossil location older
  deeper index fossils
• Continental Drift EX Pangea
• Types of fossils lead to speculation of climate,
  ecosystem

7
How old is old?
How old is the earth?
8
Continental Drift Miami was attached to Africa???
9
Fossils -Evidence of Lifes Past

• What can fossils tell us?
• FOSSIL TYPES
• TRACE
• CAST
• PETRIFIED
• IMPRINTS
• AMBER-PRESERVED (frozen)
• MOLDS

10
Changes on Earth

• The changes on Earth led to changes in its
  environment and the life that could live then
• The history of Earth has distinct divisions
• THE GEOLOGICAL TIME SCALE

11
The Geological Time Scale

• A calendar of the Earths history
• ERA large span of time on the scale
• Mass extinctions divide the eras
• Divisions on the scale are distinguished by the
  organisms that lived then
• Period divides up ERA based on specific life and
  conditions

12
The 4 Eras of the Timescale

• Precambrian
• 4.5 BYA 543 MYA
• Paleozoic
• 543 MYA 248 MYA
• Mesozoic
• 248 MYA 65 MYA
• Cenozoic
• 65 MYA - Present

13
What does the geological timeline have to do with
evolution?

• Earths environment has changed drastically over
  time
• ESTIMATED 99.9 OF ALL ONCE LIVING THINGS ARE
  EXTINCT!
• Organisms that are best fit (adapted) to
  changes will survive those that arent ? extinct
• Fascinating fact we are currently in the
  LARGEST MASS EXTINCTION IN HISTORY!
• Est. losing 100 species/day

14
Lab Geological Timeline

• How old is the earth?
• When did certain species arise?
• How did earths changes shape what could exist?

15
PBS Evolution Extinction!

• Permian Extinction
• How do we know what we know about this?
• What repercussions came of this?

16
Ch 15 Reading Guide

• What is Natural Selection
• Who was Charles Darwin?
• How can we know when Evolution is happening?

17
Grab a piece of Candy

• Take 1 and pass the dish
• Write down (or remember) what you took!
• Watch the video http//ed.ted.com/lessons/myths-an
  d-misconceptions-about-evolution-alex-gendler
• http//ed.ted.com/lessons/five-fingers-of-evolutio
  n

18
CH 10 Theory of Evolution

• NOT how evolution occurs ?
• History of Theory
• Who influenced Darwin
• Charles Darwins Theory of Evolution
• Evidence for Evolution

NOT how evolution occurs!
19
Charles Darwin
Charles Darwin 1809 1882 (English) Failed
medical student, theology student Naturalist for
the HMS Beagle 1831-1836 ALWAYS sea
sick Collected thousands of specimens and fossils
from around the globe Eventually developed a
Theory of Evolution by Natural Selection
20
History of Evolutionary Theory

• In 1859 Charles Darwin Published his Theory of
  Evolution after a lot of travel, research and
  thinking
• The work of many people in history helped develop
  his theory however
• Lets see who helped Darwin and how
• Linnaeus
• Malthus
• Cuvier
• Lamarck
• Lyell

21
Carl Linneaus 1707 - 1798

• Systema Naturae Classification System
• Scientific naming Canus familiaris, Canus lupus
• Dog Wolf
• Led Darwin to think life is related and may have
  had a common ancestor

22
Thomas Malthus 1766 - 1834

• Reverend and sociologist
• Said increase human population will lead to
  competition and war only the strongest survive
• Led Darwin to think organisms in nature have
  limited resources and struggle too

23
Georges Cuvier 1769 - 1832

• Geological catastrophies caused extinctions
• Fossils elephant bones distinct from modern
  elephant extinction
• Led Darwin to think earths conditions have
  changed greatly and what can live has changed too

24
Jean Baptist Lamarck 1744 - 1829

• Theory of Use Disuse
• Living things can change their traits based on
  need or want and pass them on
• Acquired traits can be passed on to offspring
• HE WAS WRONG, but
• Led Darwin to think helpful traits may be
  inherited but organisms cannot change their
  traits during their life to pass on (have or have
  not)

25
Charles Lyell 1797 - 1875

• Geologist whose Theory of Uniformatism said earth
  changes slowly too
• Earth is MUCH older than 6,000 years
• Led Darwin to think earth and its life were old
  enough to lead to BIG changes in life

26
Evidence for Evolution in Darwins Day

• Geology
• Biogeography
• Fossils
• Comparative Morphology/Anatomical studies
• What evidence is missing?
• Genetics
• Transitional Fossils

27
Darwin's Observations

• Darwin observed living organisms and collected
  fossils from all over the world
• He observed that earth and life
• Has changed greatly
• Is very adapted to local habitats

28
Darwins ObservationsOrganisms are adapted to
their different environments all over the world

• Structural internal or external structural
  changes that help an organism survive. (Bird
  beak, long legs of rabbit mimicry, camouflage)
• Physiological chemical based adaptation
  (enzymes for digestion, snake venom, metabolism)
• Behavioral response to the environment (plants
  grow toward the light, bird migration, social
  behavior, mating behavior)

29
Darwin's Observations

• Galapagos Islands
• 1000 km west of South America
• Studied many different species of land tortoises,
  iguanas, finches, insect, etc
• Different traits/adaptations were found in the
  life on different islands
• Ex Galapagos Tortoises
• Ex Galapagos Finches

30
Darwins Observations

• Resources are limited
• Organisms over reproduce offspring
• Environment puts selective force on population
• Natural inherited variation exist in any
  population
• Some inherited variations (adaptations) will be
  better for an environment at given time other
  variations wont be as successful
• Only those with the best adaptations for the
  given time and environment will survive and
  produce more offspring
• Over time if conditions stay the same, the
  population is more like those which are
  successful

31
Darwins Theory Summarized

• What was Darwins Theory?
• How did life on the Galapagos lead him to his
  theory?
• Three types of natural selection (directional,
  disruptive stabilizing) well get to later
  on.

32
Natural Selection Ex Darwins Finches

• Galapagos Finches all similar to mainland
  ancestor
• Beaks differed in size and shape
• Beak size, shape showed adaptation for food
  type/size

33
Darwins Theory of Natural Selection

• 3 Parts
• 1. Struggle for existence -competition
• 2. Survival of the fittest - those who have the
  best adaptations for the time live and have
  offspring
• 3. Descent with modification over time
  population of species will posses once novel
  beneficial traits in higher frequency (speciation)

34
On the Origin of Species

• Darwin returns from Beagle 1836
• Collaborates with Alfred Wallace Naturalist
• Wallace devised similar theory independently
• Publishes On the Origin of Species 1859
• Controversial but now highly accepted

35
Natural Selection Review

• Natural Selection acts on phenotypes, NOT
  genotypes
• Natural Selection can act on any phase of the
  life cycle
• Fitness implies reproductive success
• Populations evolve, INDIVIDUALS DO NOT!!!
• Darwins Theory of Natural Selection was lacking
• Major Transitional Fossils
• Biochemical (Genetic Evidence)

36
Candy Bowl Evolution
A B C D E
type of candy number before selection (F1) number after selection (F2) number in next generation (multiply column C by 2) (F3) did this variation increase or decrease?
   Smarties    15  2  4  decreased
    Tootsie  15  11  22  increased
     Wintergreen  15  13  26  increased
     Mint  15 8  16  increased
37
Farm Flies Case Study
At the start of every summer, a farmer sprays his
barn with pesticide X to kill the flies in his
barn. He counts the population at the start and
end of the summer. Here is the data for a 5 year
period.
Year Flies Start Flies End /-
2006 100 5 -95.0
2007 65 32 -50.1
2008 27 17 -37.0
2009 54 41 -24.1
2010 72 68 -6.0
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Farm Flies Case Study

• Why did the population of flies stop responding
  to pesticide X?
• Struggle for existence
• (variation pesticide resistant vs.
• pesticide non-resistant)
• Survival of the fittest
• (which variation best?)
• 3. Descent with modification
• (how did the population change?)

Year Flies Start Flies End /-
2006 100 5 -95.0
2007 65 32 -50.1
2008 27 17 -37.0
2009 54 41 -24.1
2010 72 68 -6.0
39
Woolybooger Natural Selection Lab

• How does this simulation show Darwins Theory?

40
Evolution Quiz 1

• 1. T/F Earths conditions have always been the
  same.
• 2. Eras tend to be separated by ____.
• a. mass extinctions
• b. evolution by need
• c. 1 billion years
• 3. Scientific evidence shows the earth is _____
  years old.
• a. 6,000 b. 4.6 million c. 4.6 billion

41

• 4. T/F Individual organisms can evolve.
• 5. Which of the following has the 3 parts of
  Darwins Theory?
• a. acquisition of traits, survival of the
  fittest, descent with modification
• b. struggle for existence, survival of the
  largest, descent with similarity
• c. struggle for existence, survival of the
  fittest, descent with modification

42

• 6. Evolution is described best as ____.
• a. change in a population over time
• b. organisms gaining traits they need
• c. one species becoming another species
• 7. Snakes produce highly toxic venom. This
  toxin venom is an example of a ____ adaptation.
• a. structural
• b. physiological
• c. behavioral

43

• 8. Which bird has the most fitness?
• a. bird with a needle-like mouth that dies off
  before reproducing
• b. bird with a fork-like mouth that survives and
  reproduces 1 offspring
• c. bird with a spoon-like mouth that survives and
  reproduces 3 offspring

44
Answers
45
Evolution Quiz 1

• 1. T/F Earths conditions have always been the
  same.
• 2. Eras tend to be separated by ____.
• a. mass extinctions
• b. evolution by need
• c. 1 billion years
• 3. Scientific evidence shows the earth is _____
  years old.
• a. 6,000 b. 4.6 million c. 4.6 billion

46

• 4. T/F Individual organisms can evolve.
• 5. Which of the following has the 3 parts of
  Darwins Theory?
• a. acquisition of traits, survival of the
  fittest, descent with modification
• b. struggle for existence, survival of the
  largest, descent with similarity
• c. struggle for existence, survival of the
  fittest, descent with modification

47

• 6. Evolution is described best as ____.
• a. change in a population over time
• b. organisms gaining traits they need
• c. one species becoming another species
• 7. Snakes produce highly toxic venom. This
  toxin venom is an example of a ____ adaptation.
• a. structural
• b. physiological
• c. behavioral

48

• 8. Which bird has the most fitness?
• a. bird with a needle-like mouth that dies off
  before reproducing
• b. bird with a fork-like mouth that survives and
  reproduces 1 offspring
• c. bird with a spoon-like mouth that survives and
  reproduces 3 offspring

49
Evidence for Evolution

• I. Geology/Biogeography
• Transitional Fossils
• Continental Drift
• II. Comparative Morphology
• Homologous structures
• Vestigial structures
• Embryology
• III. Biochemistry
• DNA
• Amino Acid Sequences
• Allele frequency changes/microevolution

50
I. Geology/Biogeography Transitional Fossils

• Shows missing links
• Ex Archeopteryx
• Imprint shows feathers, scales, teeth, beak,
  hollow bones
• Reptile/Bird transitional ancestor
• Other ex Fish with fingers Tiktaalik 383mya

51
I. Geology/Biogeography Continental Drift

• What is continental drift?
• What does it say about earths conditions and
  organisms who lived on earth?

52
I. Geology/Biogeography

• Organisms are VERY adapted to their local
  environment
• Local environments are VERY different all over
  the world
• Local environments change over time due to
  geology of the earth
• How do species become more and more fit for new
  environments?
• Evolution!

53
II. Comparative Morphology-Homologous Structures

• Similar structure, different function
• Shows evolutionary relationship, origin
• Develops in the same way, but modified

54
II. Comparative MorphologyAnalogous Structures

• Structures with similar function but different
  internal structure, development (bird wing and
  insect wings, dolphin fin and shark fin)
• Does NOT show evolutionary relationships

55
II. Comparative MorphologyVestigial Organs

• Organs and parts that had a function in
  ancestors but not now
• Ex. - tailbone/appendix in humans
• -pelvic and limb bones in snakes

56
II. Comparative MorphologyEmbryology

• Similar embryos similar patterns of development
  and relation

57
III. Biochemistry

• Genetics - mutations of the genetic code over
  time causes populations to change
• The more similar DNA sequences are the more
  recent the two shared a common ancestor
• Amino acids more similar proteome the more
  recently two organisms shared an ancestor

58
Biochemistry Comparative Morphology

• Together help us create
• Phylogenetic trees
• Cladograms

59
III. BiochemistryAllele frequency changes
(microevolution)

• Ex Antibiotic resistance
• Increase in resistance allele in bacteria
  populations
• Microevolution change in allele frequency over
  time in a population in response to a selective
  force
• What is the selective force for antibiotic
  resistance?

60
PBS Clip Why Evolution Matters (TB)

• Why has tuberculosis increased resistance to
  antibiotics?
• What have doctors done about this?
• Are antibiotics a cure or a problem?

61
Lab Fossil Lab

• What does Fossil Evidence Show Us?

62
Lab Time Evidence for Evolution

• Which type of evidence for evolution is most
  accurate comparative morphology or
  biochemistry?
• How can we compare amino acids to see how related
  organisms are?
• Which organisms are related through evolution
  most?

63
Microevolution

• Natural Selection acts on populations
• Variation is the fuel for evolution
• Phenotypes in a population often have lots
  variation (inherited) controlled by different
  alleles
• Called balanced polymorphism
• Lottery theory

64
Microevolution

• Microevolution can be measured by calculating
  allele changes in the gene pool
• A gene pool isnt a real thing, just a term for
  all the alleles for a certain trait in a
  population
• Natural selection acts on phenotypes but
  genotypes are indirectly affected

65
Genetic EquilibriumAlleles just reshuffle, so
their frequencies (percents) will not
changeAllele frequencies percents of alleles
in a population What if allele frequencies do
change?
STARTING POPULATION
490 AA butterflies Dark-blue wings
420 Aa butterflies Medium-blue wings
90 aa butterflies White wings
THE NEXT GENERATION
490 AA butterflies
420 Aa butterflies
90 aa butterflies
NO CHANGE
THE NEXT GENERATION
490 AA butterflies
420 Aa butterflies
90 aa butterflies
NO CHANGE
66
Microevolution

• A population will remain at genetic equilibrium
  as long as there is proper gene flow
• Gene flow is maintained as long as we have
• 1. large population
• 2. random mating
• 3. no mutations
• 4. no natural selection
• 5. no immigration/emigration

This is called Hardy-Weinberg Equilibrium after
two scientists who came up with an equation which
measures genetic equilibrium when these
conditions are met..
67
Microevolution

• If a population DOES NOT show genetic equilibrium
  over time we know microevolution has occurred
• What causes microevolution? Any change in allele
  frequencies from generation to generation
• This can be brought by
• Gene mutations
• Natural Selection
• Immigration/Emigration
• Small population
• Non-random mating

68
Events that Cause Microevolution

• 1. Genetic Drift change in allele frequency due
  to population size change
• Inbreeding, Bottleneck Effect Founder Effect
• 2. Artificial Selection change in allele
  frequency due to human intervention
• 3. Sexual Selection change in allele frequency
  due to mate selection
• 4. Natural Selection change in allele
  frequency due to Darwins theory

69
Genetic Drift Bottleneck Effect

• A severe reduction in population size
• Causes pronounced drift, alleles are lost

70
Genetic Drift Founder Effect

• Small number of individuals starts a new
  population
• By chance, allele frequencies of founders may not
  be same as those in original population
• Effect is pronounced on isolated islands/areas
• Polydactylism in Amish

71
Genetic Drift - Inbreeding

• Nonrandom mating between related individuals
• Leads to increased homozygosity
• Can lower fitness when rare recessive alleles are
  expressed at a higher rate
• Ex Blue people of Appalachia

72
Artificial Selection cause by humans
73
Natural Selection

• Change in allele frequencies due to Darwins
  Theory
• Struggle for Existence
• Survival of the Fittest
• Descent with Modification
• Ex http//www.biologycorner.com/worksheets/pepper
  edmoth.html

74
Lab Time Peppered Moth

• How did the allele frequencies in this population
  change due to natural selection?
• How can we measure this change?

75
Genetic EquilibriumAlleles just reshuffle, so
their frequencies (percents) will not
changeAllele frequencies percents of alleles
in a population What if allele frequencies do
change?
STARTING POPULATION
490 AA butterflies Dark-blue wings
420 Aa butterflies Medium-blue wings
90 aa butterflies White wings
THE NEXT GENERATION
490 AA butterflies
420 Aa butterflies
90 aa butterflies
NO CHANGE
THE NEXT GENERATION
490 AA butterflies
420 Aa butterflies
90 aa butterflies
NO CHANGE
76
Types of Natural Selection in a Population

• Directional
• Stabilizing
• Disruptive
• Sexual
• No graph

77
Directional Selection
Number of individuals in the population

• Allele frequencies shift in one direction
• Ex Pesticide resistance, Antibiotic resistance,
  peppered moth

Range of values for the trait at time 1
Number of individuals in the population
Range of values for the trait at time 2
Number of individuals in the population
Range of values for the trait at time 3
78
Stabilizing Selection
Number of individuals in the population

• Intermediate forms are favored and extremes are
  eliminated
• Ex Gall-making fly has two major predators
• Wasps prey on larvae in small galls
• Birds eat larvae in large galls
• Flies that cause intermediate-sized galls have
  the highest fitness

Range of values for the trait at time 1
Range of values for the trait at time 2
Range of values for the trait at time 3
79
Disruptive Selection
Number of individuals in the population

• Forms at both ends of the range of variation are
  favored
• Intermediate forms are selected against
• Ex Selection favors birds with very large or
  very small bills
• Birds with intermediate-sized bill are less
  effective feeders

Range of values for the trait at time 1
Number of individuals in the population
Range of values for the trait at time 2
Number of individuals in the population
Range of values for the trait at time 3
80
Sexual Selection No Graph!

• Selection favors certain secondary sexual
  characteristics adaptations
• Increases variation in population beneficial!
• Leads to increased sexual dimorphism

81
Sexual Selection

• Traits which attract mates
• Include behavioral, structural and physiological
• May work against natural selection or have no
  affect for that individual
• Fitness - it is the one who passes on its genes
  (mates effectively) which will create future
  generations!

82
PBS Evolution Why Sex? Clip

• How does sexual reproduction benefit a species?
• Did Darwin discover sexual selection?
• Why are females drab and males flashy in some
  animals?
• What if it were the other way around?

83
Peacock vs. Peahen

• Attractive adaptations
• Require energy
• Can be dangerous predators
• Which sex?

84
Cuttlefish mating spermatophorelike a phone
number
85
Guppies

• Drab Females vs. Colorful males!

86
Sexual Selection in Humans

• Cambridge University t-shirt study
• My, thats a nice immune system you have there!

87
Toothpick Fish lab
88
What do get when you cross a mouse with a mango?
What are the 2 types of speciation? What 7 words
summarize evolution?
89
Macroevolution Speciation Patterns

• Isabella Island finches Geospiza fortis can no
  longer interbreed with San Cristobal Island
  finches Geospiza magnirostris.
• Both share a common ancestor.
• What is a species anyway?
• What causes different species to form?

G. magnirostris
G. fortis
90
What is a species?

• How many species?
• All the same species Theridion grallator
• Common name happy face spider )
• Why?
• They can all interbreed and produce fertile
  offspring

91
Biological Species Concept

• Species are groups of interbreeding natural
  populations that are reproductively isolated from
  other such groups.
• -Ernst Mayr

92
Speciation Ex Fruit Flies

• Population of mainland fruit flies on a rotting
  banana
• Yum!
• All same species

93
Speciation Ex Fruit Flies

• DISASTER!
• A hurricane washes rotting banana and fruit flies
  out to sea
• Fruit flies and banana land on a new island 500
  miles away
• What other effect could this be as well?

94
Speciation Ex Fruit Flies

• Natural selection occurs
• Natural selection causes island fruit flies to
  become adapted to new location
• The gene pool change as a result

95
Speciation Ex Fruit Fly

• So we meet again
• No interbreeding can occur
• Different mating behaviors
• No gene flow between pops.
• Gene pool differences do not produce working eggs
• Result 2 different species

96
Speciation Ex Fruit Flies - Outcome

• Genetic changes result in different species
• Gene pools no longer overlap
• Species cannot interbreed
• New species are formed

97
Mechanisms of Speciation

• Speciation requires GENETIC DIFFERENCES
• Speciation requires ISOLATION
• When 2 populations cannot interbreed and produce
  fertile offspring speciation has occurred
• Isolation can include
• Behavioral isolation
• Geographic isolation
• Temporal isolation
• Reproductive isolation

98
Types of Speciation

• Allopatric geographic barrier prevent gene flow
• Sympatric no geographic barrier prevents gene
  flow
• Gene flow prevented by other means

99
Darwin Natural Selection Review

• Speciation in the Galapagos finches occurred by
• 1. Founding of new populations
• 2. Geographic isolation
• 3. Natural Selection
• 4. Gene pool changes
• 5. Reproductive isolation
• 6. Cont. Ecological competition

100
The 49th species of lemur in the rain forest
why so many?

• Found 2006
• Ecological competition
• Old species
• Stable climate
• Speciation is the
• outcome of evolution

101
Macroevolution

• Many speciation events over LONG periods of
  geologic time
• Major body plan transformations
• Evidence
• Transitional fossils
• Morphological
• Geologic

102
Macroevolution

• Modern Horse
• Comparative
• Morphology/
• Transitional fossils
• Changes in
• homologous structures
• Fossil C14 dating

103
Macroevolution

• Tiktaalik fish with fingers
• Comparative morphology
• Fossil C14 dating
• HOX gene mutation analysis
• Relative dating

104
How do great transformations happen?

• RANDOM mutations bring increased variation
• gene mutations alter body plan
• Natural selection increases fitness of new
  variations
• Thousands, millions, billions of years
• Over time, population descend with modification
• ie looks more like most successful variations

105
PBS Evolution Great Transformations

• What was the ancestor to modern whales?
• What evidence is there for this transformation?

106
Patterns in Macroevolution

• Punctuated Equilibrium
• Adaptive Radiation
• Gradualism

107
Punctuated Equilibrium

• Big environmental shifts bring explosion of
  speciation
• Ex Mass extinctions open up new niches
• Adaptive radiation - mammals 65 mya

108
Gradualism

• Small morphological changes build up over time
• Gene flow throughout
• Ex formation of whales from 4 legged land
  ancestor

109
Which model is correct?

• Both!
• Remember your timeline
• Periods of rapid change
• Cant see periods of gradualism slow!
• Earth stable gradualism
• Earth changing punctuated equilibrium

110
Trends in Evolution

• Convergent Evolution
• NOT closely related ancestry
• Environment shapes similarities
• Analogous structures
• Divergent Evolution
• Closely related evolutionary history
• Homologous structures

111
Co-Evolution

• Organisms drive the evolution of different
  species in their community
• Each evolve in response to one another
• Symbiosis
• Pollinators
• Parasites
• Predation
• Newt snake

• \

112
PBS Evolution Arms Race Co-Evolution Newt and
Snake

• How does the newt affect the snakes evolution
  vice versa
• Would this northeastern newt be able to
  interbreed with a newt from another nearby
  location?
• What type of speciation would this be?

113
What about Humans?

• How have humans evolved SINCE we have been on
  earth?
• What adaptations have made humans so successful?
• What natural predator most shapes humans?

114
Lab Time Human Hand Adaptations

• How does having an opposable thumb aid in
  fitness?
• What niches are opened up due to this?
• What other organisms have opposable thumbs?
• How does the immune system evolve?