Introduction to Bio Science

1. The Origin
and
Diversification
of Life
on Earth
BIOL 108
Intro to Bio Sci
Chapter 10 pt 2
Rob Swatski
Assoc Prof Biology
HACC-York1

2. 10.9 Similar structures don’t
always reveal common ancestry.
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3. 3

4. The mapping of species’ characteristics
onto phylogenetic trees
 Physical features
 DNA sequences
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5. 5

6. Convergent Evolution
 and analogous traits
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7. Analogous traits:
Features that are produced by convergent
evolution
Homologous traits:
Features that are inherited from a common
ancestor
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8. How do you know whether traits are
homologous or analogous?
DNA analysis
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9. Which structures below are
homologous?
1. Human forearm and a monkey’s forearm
2. Fish fin and whale fin
3. Butterfly wing and bat wing
4. All of the above
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10. Take-Home Message 10.9
Evolutionary trees are
best constructed by
comparing genetic
similarity among
organisms.
Convergent evolution
can cause distantly
related organisms to
appear much more
closely related.
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11. 11

12. 10.10 Macroevolution is
evolution above the species
level.
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13. 13

14. 14

15. Take-Home Message 10.10
The process of
evolution in conjunction
with reproductive
isolation…
…is sufficient to
produce speciation,
diversification, and the
rich diversity of life on
earth.
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16. 10.11 The pace of evolution is
not constant.
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17. 17

18. Take-Home Message 10.11
The pace at which evolution
occurs can be rapid or very
slow.
In some cases, the fossil
record reveals rapid periods
of evolutionary change
punctuated by longer
periods with little change.
In others cases, species may
change at a more gradual,
but consistent, pace.
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19. 10.12 Adaptive radiations are
times of extreme diversification.
When a small number of species
diversifies into a much larger
number of species
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20. 20

21.  Colonizers find a large number of
opportunities for adaptation and
diversification.
 Galapagos finches
 Hawaiian fruit flies
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22.  innovations such as the wings and rigid
skeleton that appeared in insects
 helped them to diversify into the most
successful group of animals
 more than 800,000 species today!
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23. The ability of multiple species to
evolve via adaptive radiations is due
to _______ over time.
1. Macroevolution
2. Microevolution
3. Punctuated equilibrium
4. Gradual change
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24. Take-Home Message 10.12
Adaptive
radiations tend to
be triggered by:
1) mass extinctions
of potentially
competing species
2) colonization of
new habitats
3) the appearance
of evolutionary
innovations
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25. 10.13 There have been several
mass extinctions on earth.
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26. 26

27. Background Extinction
 extinctions that occur at lower rates during
periods other than periods of mass extinctions
 occur mostly as the result of natural selection
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28. 28

29. Background and Mass Extinctions
Have Different Causes
 Mass extinctions are due to extraordinary and
sudden changes to the environment.
 Background extinctions occur mostly as the
result of natural selection.
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30. 30

31. Take-Home Message 10.13
As new species are being
created, others are lost
through extinction.
Extinction may be a
consequence of natural
selection or large, sudden
changes in the
environment.
Mass extinctions are
periods during which a large
number of species on earth
become extinct over a short
period of time.
These periods are usually
followed by periods of
unusually rapid adaptive
radiations and
diversification of the
remaining species.
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32. 32

33. 10.14 All living organisms are
divided into one of three groups.
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34. Classification Systems
The two-kingdom system
• Animal and plant
The five-kingdom system
• Monera, plant, animal, fungi, and protists
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35. Classification Takes a Leap Forward
 Carl Woese, an American biologist, and his
colleagues
 Examined nucleotide sequences
 Tracking changes
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36. 36

37. Woese’s approach is not perfect.
Are viruses alive?
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38. 38

39. Take-Home Message 10.14
All life on earth can be
divided into three
domains—bacteria, archaea,
and eukarya—which reflect
their evolutionary
relatedness to each other.
Plants and animals are just
two of the four kingdoms in
the eukarya domain,
encompassing only a small
fraction of the domain’s
diversity.
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40. 10.15 The bacteria domain has
tremendous biological diversity.
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41. 41

42. Bacteria Are a Monophyletic Group
All bacteria have a few features in common:
 single-celled organisms with no nucleus or
organelles
 one or more circular molecules of DNA
 several methods of exchanging genetic
information
 asexual organisms
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43. Which single-celled organism below is
considered to be most closely related to
the first cell to exist on our planet?
1. Plants
2. Protists
3. Bacteria
4. Archeae
5. Animals
6. Fungi
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44. Take-Home Message 10.15
Bacteria have evolved a broad diversity
of metabolic and reproductive abilities
relative to Eukarya.
The bacteria all share a common
ancestor and have a few features in
common:
• All are prokaryotic, asexual, single-celled
organisms with no nucleus or organelles.
• All have one or more circular molecules of DNA as
their genetic material.
• All have several methods of exchanging genetic
information.
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45. 10.16 The archaea domain
includes many species living in
extreme environments.
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46. 46

47. Several Physical Features Distinguish
Archeans from the Bacteria
 Archaeans’ cell walls contain polysaccharides
not found in either bacteria or eukaryotes.
 Archeans have cell membranes, ribosomes,
and some enzymes similar to those found in
eukaryotes.
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48. Take-Home Message 10.16
Archaea, many of which are
adapted to life in extreme
environments, physically
resemble bacteria but are more
closely related to eukarya.
Because they thrive in many
habitats that humans have not
yet studied well, including the
deepest seas and oceans, they
may turn out to be much more
common than currently believed.
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49. 10.17 The eukarya domain
consists of four kingdoms.
Plants, Animals, Fungi, and Protists
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51. Take-Home Message 10.17
All living organisms that
you can see with the naked
eye are eukarya, including
all plants, animals, fungi,
and protists.
The eukarya are unique
among the three domains
in that they have cells with
organelles.
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52. Humans can be classified as…
1. Homo sapiens
2. Eukarya
3. Animals
4. Vertebrates
5. All of the above
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