Theory of Evolution

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Chapter 15

• Theory of Evolution

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Objectives

• CLE 3210.5.3 Explain how genetic variation in a
  population and changing environmental conditions
  are associated with adaptation and the emergence
  of new species.
• SPI 3210.5.3 Recognize the relationships among
  environmental change, genetic variation, natural
  selection, and the emergence of a new species.
  ?3210.5.2 Explain how natural selection operates
  in the development of a new species

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Objectives

• CLE 3210.5.4 Summarize the supporting evidence
  for the theory of evolution.
• SPI 3210.5.5 Apply evidence from the fossil
  record, comparative anatomy, amino acid
  sequences, and DNA structure that support modern
  classification systems.
• ?3210.5.3 Associate fossil data with biological
  and geological changes in the environment.

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Evolution

• The process of change in the inherited
  characteristics within populations over
  generations such that new types of organisms
  develop from preexisting types.
• The processes that have transformed life on earth
  from its earliest forms to the vast diversity
  that characterizes it today.
• A change in the genes!!!!!!!!

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The inheritance of acquired characteristics

• Proposed by Jean Baptiste Lamarck (early 1800s)
• by using or not using its body parts, an
  individual tends to develop certain
  characteristics, which it passes on to its
  offspring.

http//kentsimmons.uwinnipeg.ca/16cm05/1116/lamark
.jpg
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The inheritance of acquired characteristics
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Catastrophism

• George Cuvier
• Geologist
• Noted that fossilized organisms differed greatly
  than current
• Sudden catastrophes had caused the extinction of
  groups

diogenesii.wordpress.com/ tag/geology/
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Uniformitarianism

• Charles Lyell
• natural forces gradually change Earths surface
  and that the forces of the past are still
  operating in modern times
• Influenced Darwins ideas

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Darwins Voyage
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Charles Darwin

• Darwin set sail on the H.M.S. Beagle (1831-1836)
  to survey the south seas (mainly South America
  and the Galapagos Islands) to collect plants and
  animals.
• On the Galapagos Islands, Darwin observed species
  that lived no where else in the world.
• These observations led Darwin to write a book.

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On the Origin of Species by means of Natural
Selection

• Published 1859
• Two main points
• 1. Species were not created in their present
  form, but evolved from ancestral species.
• 2. Proposed a mechanism for evolution
  NATURAL SELECTION

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Natural Selection

• Individuals with favorable traits are more likely
  to leave more offspring better suited for their
  environment.
• Also known as Differential Reproduction
• Example
• English peppered moth (Biston betularia)
• - light and dark phases

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Natural Selection

• Organisms in a population adapt to their
  environment as the proportion of individuals with
  genes for favorable traits increases.
• Those individuals that pass on more genes are
  considered to have greater fitness.

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Natural Selection
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Artificial Selection

• The selective breeding of domesticated plants and
  animals by man.

http//toolbox-4-websites.com/2011/which-breed-of-
humans-are-you/
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Artificial Selection
http//alyannas-bioblog.blogspot.com/2010/04/artif
icial-selection-is-it-good-or-bad.html
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Evidence of Evolution

• 1. Biogeography
• Geographical distribution of species.
• the study of the locations of organisms around
  the world, provides evidence of descent with
  modification.

http//faculty.scf.edu/odaffej/WasDarwinWrong.3/bi
ogeography.jpg
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Evidence of Evolution

• 2. Fossil Record
• Fossils and the order in which they appear in
  layers of sedimentary rock (strongest evidence).
• The fossil record shows that the types and
  distribution of organisms on Earth have changed
  over time.
• Fossils of transitional species show
  evidence of descent with modification.

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Fossil Record
http//www.fossilmuseum.net/fossilpictures-wpd/Arc
haeopteryx/Archaeopteryx.htm
http//faculty.weber.edu/bdattilo/images/campsogna
thus.jpg
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Fossil Record

• Transitional Species
• Fossils of transitional species show evidence of
  descent with modification.

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Evidence of Evolution

• 3. Homologous
• structures
• Structures that are similar because of common
  ancestry (comparative anatomy)

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Evidence of Evolution

• 4. Comparative embryology
• Study of structures that appear during
  embryonic development.

http//bealbio.wikispaces.com/file/view/compembryo
logy_pic.jpg/89605487/compembryology_pic.jpg
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Evidence of Evolution

• 5. Vestigial structures
• Structures that are not used in current form

http//www.kirksville.k12.mo.us/khs/teacher_web/al
ternative/whale-vestigial-structure.jpg
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Evidence of Evolution

• 6. Molecular biology
• DNA and proteins (amino acids)
• - the subunit sequences of biological molecules
  such as RNA, DNA, and proteins indicates a common
  evolutionary history.

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Molecular biology Hemoglobin
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Case Study Caribbean Anole Lizards

• Ongoing examples of evolution among living
  organisms can be observed, recorded, and tested.
• In convergent evolution, organisms that are not
  closely related resemble each other because they
  have responded to similar environments.

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Case Study Caribbean Anole Lizards

• Divergence and Radiation
• In divergent evolution, related populations
  become less similar as they respond to different
  environments.
• Adaptive radiation is the divergent evolution of
  a single group of organisms in a new environment.

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Natural Selection of Anole Lizard Species
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Convergent Evolution

• Species from different evolutionary branches may
  come to resemble one another if they live in very
  similar environments.
• Example
• 1. Ostrich (Africa) and Emu (Australia).
• 2. Sidewinder (Mojave Desert) and
• Horned Viper (Middle East Desert)

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Coevolution

• Evolutionary change, in which one species act as
  a selective force on a second species, inducing
  adaptations that in turn act as selective force
  on the first species.
• Example
• 1. Acacia ants and acacia trees
• 2. Humming birds and plants with flowers with
  long tubes
• 3. Antibiotic resistance among bacteria