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Presentation on theme: "Evolution."— Presentation transcript:

1 Evolution

2 Inherited change in organisms over time
Evolution p. 369 Inherited change in organisms over time

3 Definition: Evolution
Scientific (more accepted now): the change in the relative frequency of alleles in a population

4 Did Darwin ever use the word evolution?
NOPE He used instead “descent with modification”


6 Charles Darwin ( ), In 1831, Charles Darwin sailed to the Galapagos Islands in the HMS Beagle. “Father of Evolution” Natural Selection

7 Alexander Oparin proposed that life began in the early oceans where a rich "primordial soup" of chemical compounds could build up. He suggested that energy from UV light and lightening could form these compounds.


9 Miller-Urey Experiment
Ammonia + nitrogen + methane + hydrogen + water + Voltage …after some time amino acids and organic compounds (BUT NOT LIFE) VIDEO of Miller Explaining the Experiment

10 James Hutton: The Father of Modern Geology
The earth had to be much more than a few thousand years old (6,000) and more like millions. (ie., lava pushed up land for volcanoes)

11 Charles Lyell Principles of Geology
The processes that occurred in the earth in the past still occur today.

12 Accepted Age of the Earth
billion years old LIFE AROSE 3.5 billion years ago

13 Lamarck (1744 -1829) theory of inheritance of acquired characteristics

14 Why do Giraffes have long necks?


16 Then according to Lamarck…
Pass on longer necks. Or if you lift weights, your children will be big-muscled! BUT…

17 Passed-on-traits must be in the chromosomes in the sex cells
So…Lamarck was wrong! Passed-on-traits must be in the chromosomes in the sex cells

18 Malthus Population would outrun food supply, leading to a decrease in food per person.

19 Darwin’s 5 Year Journey Darwin observed and collected
thousands of wildlife specimen he had never before encountered.

20 Galapagos Islands H.M.S. Beagle
Galapagos islands Stock Footage and Video Clips. 39 Galapagos islands videos and movies available to search from over 20 royalty free motion brands. H.M.S. Beagle

21 Galapagos: Off S.Am. Coast

22 Did Darwin know about genes?
So what he compared were outward characteristics

23 Main Ideas of Darwin 1. The mechanism of evolutionary change was natural selection (survival of the fittest) –see Darwin’s finches

24 Darwin’s Proposed mechanism for evolution = natural selection

25 Artificial Selection Humans select the variations they find useful
Bred to produce more meat Humans select the variations they find useful

26 Natural Selection Also “Survival of the Fittest”
Individuals that are better suited to their environment survive and reproduce most successfully Orchids fool wasps into "mating" with them.

27 “Survival of the fittest”
Natural Selection “Survival of the fittest”


29 Darwin's Theory of Sexual Selection

30 Video: Evolution: Library: Evolution of Camouflage
Natural Selection nature selected the best adapted varieties to survive and to reproduce.  Video: Evolution: Library: Evolution of Camouflage

31 Why is this natural selection?
Which color beetles’ genes are more likely to be passed on?

32 Natural Selection the driving force behind the process of evolution.
“Survival of the fittest”

33 Elk Rivalry Animation Elk Rivalry
Describe how natural selection works here. Opponents lock antlers

34 One extreme phenotype is most successful
Middle phenotype is most successful Extreme phenotypes are most successful

35 English peppered moths
directional selection?

36 Does Natural Selection depend
On genotype or phenotype? PHENOTYPE

37 VIDEO Evolution: How Does Evolution Really Work? Click on Video for Students

38 Fitness Ability of an organism to survive and reproduce in its specific environment DESERT: Sleep in cool dens

39 Adaptations Inherited characteristics that increases
an organisms chance to survive Leafcutter carries 50x’s its weight Big ears dissipate heat

40 Western Grebe Courtship
Western Grebe Courtship Movie In the “rushing” display, the mating pair swim side-by-side with their wings held back, their long necks arched, and their yellow beaks angled upward.

41 Take the Blue-Footed Booby

42 Blue-Footed Booby Adaptations
1. Large webbed feet to propel in water at high speeds

43 Blue-Footed Booby Adaptations
2. Body and bill are streamlined

44 Blue-Footed Booby Adaptations
3. Large Tail to pull them out of a dive

45 Blue-Footed Booby Adaptations
4. Nostrils close so in a dive they won’t get water in their lungs

46 Blue-Footed Booby Adaptations
5. Specialized glands to manage salt intake and secrete oils

47 Chameleon: What adaptations?

48 Peacock LINK: Peacock Call

49 What adaptation did each beak allow it to eat these foods?

50 Do Beak Lab What effect does the size and shape of the bird’s beak have on the amount and type of food it can eat?

51 Darwin Agreed with: every species since the
first cells emerged from one common organism (probably some bacteria) = Common Descent

52 Tree of Life Links all living things

53 Geologic Time Scale BACTERIA Common Descent

54 Common Descent theory of universal common descent = all organisms on earth are descended from a common ancestor.

55 Darwin thought the Galapagos finches descended from finches of what country?

56 We are more different than thought!
Previous estimates of genetic similarity between humans and chimpanzees suggested they were 98.5–99% identical. However, after the sequencing of the chimpanzee genome 2005, the DNA similarity was fixed at 96%. Nature, the Chimpanzee Sequencing and Analysis Consortium, which is supported in part by the National Human Genome Research Institute (NHGRI), one of the National Institutes of Health (NIH),

57 Factors Affecting Natural Selection
Food supply Disease Unable to mate Weather natural selection Fitness of organisms

58 Most fossils are found in sedimentary rock.
Where to find fossils? Most fossils are found in sedimentary rock. Examples of sedimentary rock are limestone, shale, and sandstone.

59 Geologic Column

60 Rod Sheldon: Sedimentary Layers)

61 Historical Record of Organisms
Youngest (on top) mammals/birds Next reptiles Next amphibians Next fish Oldest (on bottom) prokaryotes

62 Assume that Sedimentary rock is laid down with the oldest rock layer on the bottom and the youngest rock layer on the top

63 Which is the most probable assumption about species A, B, and C ( In undisturbed rock layers)?
1. Species B is more abundant than species C. 2. Species C existed before species B. 3. Species A and B are genetically identical. 4. Species B descended from species A.

64 #2 Species C existed before B
ANSWER #2 Species C existed before B

65 When the industrial revolution arrived in England, the pollution had turned the bark of the trees a much darker color. Since light colored moths are much easier for birds to see on a dark background, they were preferentially eaten.

66 Some say this is not true!
1. Moths fly at night (so color would not be a factor). 2. Moths don’t land on tree trunks; they hang on upper canopy tree limbs.

67 Secondary sexual characteristics: color, size, etc
Secondary sexual characteristics: color, size, etc. different in males and females Sexual Dimorphism

68 2. descent with modification
Main Ideas of Darwin 2. descent with modification See “gradualism” and “punctuated equilibrium”

69 Descent with Modification: Hawaii honeycreepers

70 So…descent with modification
Evolution is a remodeling process Do you agree?

71 Darwin’s Ideas (cont.) 3. Living species have arisen from earlier life-forms (common descent)

72 Common Descent Theories
Phyletic Gradualism Punctuated Equilibrium

73 Phyletic Gradualism Gradual changes You would see transitional fossils (in-between forms)

74 Transitional Fossils (in-between forms)

75 Transitional Fossils The “missing link” or transitional forms may have features common to both species

76 Punctuated Equilibrium
Speciation can occur very quickly, with long periods of little change (equilibria) in between. Proposed by Niles Elderidge and Stephen Jay Gould

77 Compare These Several origins


79 How do we get “proof” of our ideas of evolution?
Fossils Biogeography Comparative Anatomy Comparative Embryology Molecular Biology

80 Fossils Imprints or remnants of organisms that lived in the past

81 Also find in Tar Pits One of best finds of Pleistocene (1.8 million to 11,000 years ago) vertebrates in La Brea (Los Angeles)

82 Imprints (shape of organism embedded in soft soil)
Fern Sycamore

83 More fossils Fish fossil Crab

84 Horseshoe Crab Often referred to as a living fossil
has remained unchanged for approximately million years.

85 Frozen Fossil

86 Australopithecus afarensis
Humans have much shorter arms compared to their legs than chimpanzees do, and Lucy falls roughly in the middle

87 Bones, teeth, shells preserve well
Leg bone of amphibian Jaw bone Horn coral shell

88 Petrified Wood Minerals dissolve in groundwater seep into the tissues of dead organisms and replace organic matter

89 Let’s Go...

90 Preserved: ice The world's oldest and best-preserved mummy (Oetzi), believed to be 5,300 years old

91 Shark tooth

92 Preserved: Amber fossil
amber is the pitch of conifer trees This is a million year old fossil insect

93 Trace Fossils 1. Tracks 2. Trails 3. Burrows Dino Foot

94 Dinosaur Tracks (Colorado)

95 My Favorite Coprolite Petrified Poop (Dung)

96 Healed Wolf Thigh Bone

97 Weathering Has Exposed Sedimentary Layers

98 Lucy: Man or Ape? Adult female - 25 yrs
About 40% of her skeleton found Her pelvis, femur (the upper leg bone) and tibia show her to have been bipedal. About 107 cm (3'6") tall (small for her species) About 28 kg (62 lbs) in weight.

99 Where did Lucy get her name?
When the bones were found, the Beatles' song "Lucy in the Sky With Diamonds" was playing over during a night of dancing and drinking.

100 Dr. Donald Johanson recollects
November 30, 1974, in Hadar, Ethiopia. "I happened to glance over my right shoulder . . .and there on the surface of the ground was a little bit of an elbow, I recognized it immediately as belonging to a human ancestor.” (good eyes?)

101 Not A Human Arguments Lucy’s DNA found she was indeed an ape (Cell magazine) -few skeletal bones which were usually fragmentary and often poorly preserved. -bones found far apart (1.5 miles away)

102 Other questions on Lucy
Present day orangutan and spider monkeys have the same angle (pelvic and knees) as humans yet are extremely adept tree climbers.

103 And... Her brain size is still small, ape-like in proportion The jaw, in particular, is distinct in that it is V-shaped, totally unlike human jaws.

104 Population Group of individuals of the same species living in the same place at the same time.

105 What is... The smallest unit that can evolve? population


107 Formation of a new species
SPECIATION Formation of a new species

108 Is a mule a new species? +

109 Did Darwin know about… Genes? No

110 Homologous Structures
Different Function but Internal Anatomy is similar means same evolutionary origin

111 Biogeography Islands of the Galapagos were geographically isolated and the species of finches on these islands were different, also.

112 Homologous Structures
Pterodactyl Bat Bird

113 Compare Evolution Theories
MODERN SYNTHESIS genes (alleles and mutations) phenotypes populations (and genetic drift) DARWINISM Organisms Speciation Individuals.

114 Homologous Structures

115 Bat Mouse Human wing forelimb arm

116 Embryology Compared

117 Haeckel’s Hoax "ontogeny recapitulates phylogeny".

118 Real Embryos Compared With Haeckel’s

119 Gills? In fact embryos never have true gills, and calling features of human embryos 'gill slits' is merely to read Darwinian theory into the evidence.

120 Comparative Molecular Biology: Number of Amino Acid Differences with humans
Gorilla 1 Gibbon 2 Rhesus monkey 8 Dog 15 Horse, cow 25 Mouse 27

121 DNA Cladistic Diagram

122 Molecular Biology Homologies:
Similarities in blood, proteins and DNA and RNA sequences that indicate species relatedness; the greater the similarities, the more closely related two organisms are thought to be

123 Comparative Molecular Biology: Number of Amino Acid Differences with humans
Gorilla 1 Gibbon 2 Rhesus monkey 8 Dog 15 Horse, cow 25 Mouse 27 So organisms with similar DNA or proteins would be more closely related

124 Darwinian Fitness Contribution an individual makes to the gene pool of the next generation relative to the contribution of other individuals

125 The total collection of all genes in a population at one time.
Gene Pool The total collection of all genes in a population at one time.

126 Changes within a species
Contrast Microevolution Changes within a species EXAMPLE: humans are getting taller Macroevolution Species change into other species EXAMPLE: reptile into a bird

127 Microevolution Darwin did in fact observe small changes, such as changes in the size and shape of finch beaks etc.

128 Macroevolution? Darwin never did see a finch turn into an iguana or visa versa (or any other such major change). Major changes are theorized to take millions of years.

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