a. The age of the earth is 4.5 billion years old.

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EVOLUTION Geological Time Scale

• a. The age of the earth is 4.5 billion years old.
• b. Geological history of the earth is divided
  into eras, periods, and epochs.
• c. Fossil record provides relative dating of rock
  layers top layers of rock are younger than lower
  layers.

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EVOLUTION Geological Time Scale

• d. Absolute dating method uses radioactive
  isotopes.
• (1). Isotopes each have a particular half-life
  or time it takes for half of the
  isotope to decay and become nonradioactive.
• (2). Carbon-14 is used to date organic
  matter half decays to Nitrogen-14 each
  5,770 years.

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EVOLUTION Geological Time Scale

• Absolute dating continued
• (3). Half of potassium-40 decays to argon- 40
  each 1.3 billion years it is used to estimate
  the age of younger rocks.
• (4). Half of Uranium-238 decays to lead 206
• every 4.5 billion years it is used to
  estimate the age of older rocks.

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EVOLUTION Fossil Evidence

• a. Fossils are remains, traces or other direct
  evidence of past life forms.
• b. Most fossils form from burial of plants and
  animals in sediment soft parts are more often
  consumed or decomposed but may leave imprints if
  buried rapidly.
• c. Most fossils are embedded in sedimentary rock
  . Which are weathered particles that provide
  strata from lower older layers to upper newer
  layers.

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EVOLUTION Fossil Evidence

• d. Paleontologists study the fossil record
  based on boundaries between
  strata, where one mix of fossils gives way to
  another.
• e. Transitional links are intermediate between
  major groups.
• Example Archeopteryx has features intermediate
  between primitive reptiles and birds.

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Archeopteryx fossil
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Archeopteryx drawing
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EVOLUTION Anatomical Evidence

• a. Many organisms share a unity of plan
  for example, vertebrate forelimbs contain
  the same sets of bones used for different
  functions in bat wings, whale fins, etc.
• b. The simplest explanation is having a common
  ancestor whose basic forelimb plan was modified
  in succeeding groups as each continued along its
  own evolutionary pathway.

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EVOLUTION Anatomical Evidence

• c. Homologous structures are similar structures
  derived through descent from a common ancestor.
• d. Analogous structures have similar functions
  but differ in anatomy and did not derive from
  the same ancestral structure for instance, an
  insect wing and a bird wing.

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EVOLUTION Anatomical Evidence

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EVOLUTION Anatomical Evidence

• e. Vestigial structures are reduced and
  functionless anatomical features that are fully
  developed and functional in other ancestral
  groups.
• Vestigial structures are evidence of an
  organism's evolutionary history.
• (1). Flightless birds have vestigial wings.
• (2). Snakes have remnants of a pelvic
  girdle.
• (3). Humans have a tail bone but no tail.