Transcript Chapter 13 Notes Continued Evidence of Evolution

Chapter 13
Notes Continued
Evidence of Evolution
There are five modern day
evidences that support the work of
Darwin
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Age of the Earth
Fossil evidence
Anatomical evidence
Biochemical evidence
Embryological evidence
1. Age of the Earth
• While many bible scholars estimated the
earth to be 30,000-40,000 years old,
Darwin predicted the Earth to be Millions
of years old. (Deep Time)
• Modern evidence suggests the earth to be
4.6 Billion years old
2. Fossils
• Fossils are the remains or traces of
remains of organisms that lived long ago
• Typically are the bones, teeth or shells of
past animals
• Imprints and casts are other types of
Fossils
• Most fossils are formed in sedimentary
rock
Fossils
• Age is important! Fossils can be “dated” by
radioisotopes of Carbon-14, Uranium-238
or Potassium-40.
• The half-life of these chemicals is the
amount of time it takes for that chemical to
decay by 50%
• Half-life for Carbon-14 is 5,730 years
Fossils
• Age of the rock a fossil is found in, can
also be tested.
• Law of Superposition- fossils found
deepest in the rock strata are older than
the strata at the top. Is useful for following
evolution progression
• Study of Fossils is called Paleontology
Law of Superposition
3. Biochemical Evidence
• Chemicals such as Proteins, Amino Acids
and Nucleic Acids (DNA and RNA) can be
studied to compare organisms.
• examples: chimpanzees and Humans are
96% the same by chemical composition
• Horseshoe Crabs are more related to
Arachinids than Crusteaceans.
4. Anatomical Evidence
• Vestigial Organs or Structures- have no
apparent use or function.
• May be clues to a distant past
• Examples: wings of flightless birds, pelvic
bones in Whales and some Snakes
Vestigial organs continued
• Human Vestigial organs- Appendix,
Wisdom and Canine teeth, Male nipples,
Human Tailbone and Muscles to move
ears
• Homologous Structures- Body parts that
differ in use but are similar in structure.
• A Man’s arm and a Whale flipper would be
considered Homologous.
• Analogous Structures- Body parts that
are different in structure but perform a
similar task.
• Ex. Bats wing, Butterfly’s wing and Birds
wing are analogous
5. Embryological Evidence
• In early embryos, Organisms that are
related develop in a similar way. All
vertebrates develop alike until late stages.
• Under this concept, all vertebrates are
more closely related to Echinoderms
(starfish) than other invertebrates
• See next slide.