EVOLUTION CONTINUED

1
EVOLUTION CONTINUEDWheres the Evidence?!

• Chap. 13 The Macroevolutionary Puzzle

2
VocabularyRead (282-292)(740)(327)

• 109 paleontologist
• vestigial structure
• homologous structure
• gradualism
• punctuated equilibrium
• continental drift
• analogous character
• isotope
• 117 radioisotope

3
Radiometric Dating or Radioactive Dating

• Isotope- 1 form that an element can have. Number
  of neutrons is variable between isotopes of the
  same element. (number of electrons and protons
  stays the same)
• Minerals possess radioactive isotopes (give off
  energy and subatomic particles) that decay
  (breakdown) into smaller isotopes.

4

• Formed in igneous rock, the minerals grow as the
  liquid rock cools.
• Amounts of the parent (or original) and
  daughter isotopes can be measured in a sample
  collected today.
• The rate of decay can be calculated
  experimentally.
• Half Life is a common unit of measure of the
  rate of break down.

5
Radioactive parent nucleus
Decay process
Daughter nucleus
p
p
p
p
Atomic mass decreases by 4 atomic
number decreases by 2
p
p
p
p
p
p
p
p
p
p
Proton
Neutron

p
Alpha particle
Emission of 2 protons and 2 neutrons (alpha
particle)
(a)
Alpha decay

p
p
p
p
p
p
Atomic mass not changed much atomic
number increases by 1 because Neutron becomes
proton
p
p
p
p
p
p
p
p
p
p
p
p
p
Beta particle
(b)
An electron (beta particle) is ejected from the
nucleus
Beta decay

p
p
p
Atomic mass not changed much atomic
number decreases by 1
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
electron combines with a proton to form a neutron
Beta particle
(c)
Electron capture

6
(No Transcript)
7
(No Transcript)
8
Sample Problems

• The half-life of Potassium 40 is 1.3 million
  years. It breaks down into Argon 40
• 1) If an original rock sample contains 200
  micrograms of Potassium 40, how much would remain
  after two half-lives?

9
Uranium 238 has a half-life of 4.51 billion years
and decays into Lead 206

• 2) A newly discovered rock sample has 15
  micrograms of Uranium 238 and 105 micrograms of
  the daughter material Lead 206. How old is this
  rock?

10
Homework 2 sides in binder

• The next 2 slides are more practice problems to
  work on later.

11

• U238 decays into Pb206 in 4.51 billion years
  (HALF LIFE)
• How much U238 and Pb206 are present in a sample
  after 2 HALF LIVES?
• (original sample is 300 grams)
• U238 75 grams Pb206 225 grams
• How long would 2 half lives be?
• 9.02 billion years

12

• How old is an igneous rock sample containing 275g
  U238 and 1925g Pb206?
• 3 x 4.51 13.53 billion years

13
V. EVIDENCE OF EVOLUTION FROM FOSSILS

• any evidence of once living creatures
• Where are fossils most likely to be found?

14
A. 4 Types of Fossils

• 1. Compression- organic material between layers
  of sediment, Some details can be observed . ex.
  fern frond, fish
• 2. Impression- external shape and form, no
  organic matter ex. foot print, limb print
• 3. Mold and cast- external features in one layer,
  then the item itself is replaced by other
  sediments ex. Egg, shark tooth
• 4. Petrifaction- tissues are gradually
  infiltrated by minerals. No organic material
  remains ex. petrified wood

15
8_10
How impression fossils form (the most common type)
Shells settle on ocean floor
Cast forms when mold is filled in with
mineral water
Rock broken to reveal fossil cast
Rock broken to reveal external mold of shell
Shells buried in sediment
Mold, or cavity, forms when original shell
material is dissolved
16
BOG people

• Bogs filled with danger where you could easily
  get lost and drown. It's not hard to understand
  why tribes of long ago used to believe that gods
  and ghosts inhabited the swamps. Gifts and
  sacrifices were thought to win their good graces.
  Prehistoric man offered all kinds of objects to
  the bogs. So it was that bogs became gigantic
  offering locations.

17

• Never before had there been so many bog bodies
  and offering all in one place. Schatten uit het
  veen provides an impressive picture of the
  beliefs and rituals of our ancestors in
  North-western Europe.

18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
B. Distribution of fossils in layers of rocks?

• many varieties
• and great complexity
  
  
• first fossils were
• aquatic and some
  
  are extinct
• few varieties
• and little complexity

YOUNGEST
Fossils in every layer
OLDEST
STRATIFICATION
25
Each geologic time period is characterized by
certain fossils (remember the GEO TIME TABLE?)
26
Why do organisms disappear from the fossil record?

• 1. unable to adapt to a changing environment
• Ex. lake drying, cooling climate ,glaciers
• 2. out competed by organisms more suitable to the
  new environment
• Ex. reptiles competing with early mammals
• Or fish vs. amminoids

27
Diagram of species abundance over time

• Flowering plants and ferns

28
Diagram of species abundance over time

• Bony fish and amminoids

29
Notes in student binder

• GREAT! Less writing

30
VI CONTINENTAL DRIFT or PLATE
TECTONICS

• Alfred Wegener early 20th century
• initially incorrect explanation but modified
  theory is widely accepted (seafloor stationary
• and continents
• move WRONG!!!!)

31

• 10 MAJOR PLATES AND MANY MINOR PLATES UP TO 100
  KM THICK
• Continents ride on the moving crustal plates
  (less dense material )

32
(No Transcript)
33
These are the possible events at the boundary of
plates

• Slide
• Spread

34
(No Transcript)
35
These are the possible events at the boundary of
plates

• Subduction
• Subduction w/continents

36
(No Transcript)
37
(No Transcript)
38
1. Theory and Evidence

• OLD
• 1. puzzle pieces
• 2. fossil distribution
• 3. sediment layers "Gandwanan Sequence" similar
  geology on the 4 southern continents
• sandstone with
  coal
• black shale
• glacial till

39
(No Transcript)
40
NEW

• 1. earthquake distribution
• shallow quakes at ridges Mid Atlantic
• shallow and deep quakes at trenches
  subduction
• distribution of the RING OF FIRE pg 303
• 2. Movement of plates can be measured from space
• 3. Dating rocks on opposite sides of ridges

Draw ring of fire on map
41
(No Transcript)
42
End of geological evidence

• the earth is old and has changed (volcanoes,
  glaciers, earthquakes)
• organisms that lived in the past are now gone
• different organism appear in later rocks than
  in early ones
• therefore new organisms must be developing from
  old EVOLUTION

43
VII EVIDENCE OF EVOLUTION FROM LIVING CREATURES

• Common Ancestry through comparative anatomy
• Georges Buffon 1760 French Naturalist
• - observed the feet and legs of many animals
• - concluded that they were but variations on a
  single theme

44
(No Transcript)
45
(No Transcript)
46
(No Transcript)
47

• "The ancestors of backboned animals must have had
  the same limb structure but has been modified for
  the life of the individual"
• This suggests that organisms have changed with
  time and had a distant common ancestor

48
What similarities must exist for organisms to
have a common ancestor?

• 1. anatomy (talons, bones, coloration)
• 2. physiology (DNA, hemoglobin, digestion)
• 3. behavior ( instinct, learning)

49
Evidence of Evolution from living creatures
continued

• HOMOLOGOUS STRUCTURES- organs or parts that are
  structurally similar but may have different
  functions (Indicates common ancestry or origin)
  SEE HANDOUT

50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53

• ANALOGOUS STRUCTURES- same function but
  structurally different (bird and moth wing)
  Does not indicate any relatedness SEE HANDOUT

54
(No Transcript)
55

• VESTIGIAL ORGANS- remnants of organs or parts
  that are believed to have been well developed in
  ancestors but have little function now. (genes
  are still present)
• (tailbone, appendix, pelvic bones, ) SEE
  HANDOUT

56
(No Transcript)
57
Vestigial organs

• Modern animals may have structures that serve
  little or no function
• remnants of structures that were functional in
  ancestral species
• evidence of change over time
• some snakes whales show remains of the pelvis
  leg bones of walking ancestors
• eyes on blind cave fish
• human tail bone

58
Vestigial organs

• Hind leg bones on whale fossils

Why would whales have pelvis leg bones if they
were always sea creatures?
59

• BIOCHEMICAL- organic compounds that are
  essential to certain processes
• (blood proteins, cytochrome C universal and
  essential to aerobic respiration, DNA ,
  ribosomes) SEE LAB ACTIVITY

60
Molecular biology

• Comparing DNA protein structure
• universal genetic code!
• DNA RNA
• cytochrome C (respiration)
• protein structure
• hemoglobin (gas exchange)
• protein structure

Evolutionary relationships among species are
documented in their DNA proteins. Closely
related species have sequences that are more
similar than distantly related species.
61
(No Transcript)
62
(No Transcript)
63
Before comparing the amino acidsHypothesize on
closely related pairs

• Pair Reason
• 1.
• 2.
• 3.

64
Before comparing the amino acidsHypothesize on
unrelated pairs

• Pair Reason
• 1.
• 2.
• 3.

65

• EMBRYOLOGICAL- the study of early developmental
  forms between organisms can suggest relatedness.
  (ex. larva forms may look similar though the
  adults do not) SEE HANDOUT

66
Comparative embryology

• Similar embryological development in closely
  related species
• all vertebrate embryos have a gill pouch at one
  stage of development
• fish, frog, snake, birds, human, etc.

67
Building family trees

• Closely related species (twigs of tree) share
  same line of descent until their recent
  divergence from a common ancestor

68
PATTERNS OF EVOLUTION

• MORPOLOGICAL DIVERGENCE related organisms
  become less similar due to different
  environmental circumstances . Develop features to
  suit their habitat
• MORPHOLOGICAL CONVERGENCE organisms may have
  similar features but are unrelated. This
  results from being exposed to similar
  environmental conditions
• (ex. wombat vs. ground hog )

69
The Rate of Evolution

• Gradualism-(Darwin) small changes accumulate over
  a long period of time. (Transitional fossils
  would be expected)
• Punctuated Equilibrium- (Stephen J. Gould) long
  periods of uneventful time passes until a
  catastrophe creates opportunities for new species
  to flourish. Little change is punctuated by
  rapid evolution of new species.

70
(No Transcript)
71
Evidence of relatedness

• Example Transitional forms in the fossil record

Hypothesis If terrestrial vertebrates
(tetrapods) evolved from lobe-finned fish
(sarcopterygians), then there should be
transitional forms that possess traits that are
intermediate.
72
Previously identified transitional forms
From Ahlberg and Clack, Nature 2006
73
General Methods

• Scientists looked specifically for the
  transitional form of interest by sampling
• Appropriate habitats (stream system)
• Appropriate geologic time (early Late Devonian
  385-376mya)

From Daeschler et al., 2006
http//tiktaalik.uchicago.edu/photos.html
74
They found Tiktaalik roseae!
http//tiktaalik.uchicago.edu/photos.html
From Ahlberg and Clack, Nature 2006
From Daeschler et al., Nature 2006
75
http//tiktaalik.uchicago.edu/photos.html
From Shubin et al., Nature 2006
76
Summary

• The study of and the evidence for evolution
  clearly fits within the scientific framework.
• We use current evolutionary theory to make and
  test hypotheses
• There are many thousands of examples of evidence
  for evolution

77
What about man?

• Where is the evidence of human ancestry?

78
What data from whole genome sequencing can tell
us about evolution of humans
79
Example the Evolutionary Hypothesis of Common
Ancestry Chromosome Numbers in the great
apes human (Homo) 46chimpanzee
(Pan) 48gorilla (Gorilla) 48orangutan (Pogo) 48
Testable prediction If these organisms share a
common ancestor, that ancestor had either 48
chromosomes (24 pairs) or 46 (23 pairs).
80
Ancestral Chromosomes
Chromosome Numbers in the great apes
(Hominidae) human (Homo) 46chimpanzee
(Pan) 48gorilla (Gorilla) 48orangutan (Pogo) 48
Centromere
Telomere
Testable prediction Common ancestor had 48
chromosomes (24 pairs) and humans carry a fused
chromosome or ancestor had 23 pairs, and apes
carry a split chromosome.
81
Human Chromosome 2 shows the exact point at
which this fusion took place
Chromosome 2 is unique to the human lineage of
evolution, having emerged as a result of
head-to-head fusion of two acrocentric
chromosomes that remained separate in other
primates. The precise fusion site has been
located in 2q132q14.1 (ref. 2 hg 16114455823
114455838), where our analysis confirmed the
presence of multiple subtelomeric duplications to
chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22
(Fig. 3 Supplementary Fig. 3a, region A). During
the formation of human chromosome 2, one of the
two centromeres became inactivated (2q21, which
corresponds to the centromere from chimp
chromosome 13) and the centromeric structure
quickly deterioriated (42).
Homo sapiens
Inactivated centromere
Telomere sequences
Chr 2
Hillier et al (2005) Generation and Annotation
of the DNA sequences of human chromosomes 2 and
4, Nature 434 724 731.
82

• Test topics evidence of evolution
• EVOLUTION TEST 2
• Notes over
• Geological evidence of evolution
• Biological Evidence of Evolution
• Amino Acid Lab
• Radiometric Dating
• Text (282-292, 740, 327)
• Vocabulary (105-113)
• Worksheets x2 (History of Life and Evolution)
• Plate tectonics Map Know the continents
• Homologous vs. analogous
• Gradualism vs. Punctuated Equilibrium
• Comparative Anatomy Buffon (1-2-5)

83
(No Transcript)
84
(No Transcript)
85
(No Transcript)