BIOL 1010 Lecture Notes - Lecture 19: Paleogene, Neogene, Phanerozoic
Macroevolution
November 27, 2014
Fossils
• Preserved remnants (or traces) of past life
o Mineral components
o Petrified organic material
o Casts
o Trace fossils (ex. Footprints)
• Provide a more direct view of evolutionary history than from living organisms
• Infer past ecosystems, climate, sea levels, etc.
• Most fossils are found in sedimentary rock
Dating the Fossil Record
• Relative dating
o Order of appearance in strata
o Index fossils to compare locations
• Absolute dating
o Mostly for volcanic rock, not sedimentary
o Ex. Radiometric methods (isotopic decay)
o Place a absolute value on the age of a fossil
Geological Record
• Earth is ~4.6 billion years old
• Microbial life arose relatively early
• Fossils of animals and plants common in the last ~550 million years (Phanerozoic Era)
• Phanerozoic divided into three eras which are subdivided into several periods
Mass Extinctions – many species extinct in a short time caused by large environmental
changes. These causes may include massive volcanic activity, changes in ocean circulation
patterns and impact by an asteroid/comet.
Geological record (last 300 million years)
Era Period
Cretaceous *
Jurassic
Triassic
Cenozoic
Mesozoic
Paleozoic
(last part)
Neogene
Paleogene
Permian *
Quaternary
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Document Summary
Fossils: preserved remnants (or traces) of past life, mineral components, petrified organic material, casts, trace fossils (ex. Footprints: provide a more direct view of evolutionary history than from living organisms, most fossils are found in sedimentary rock. Dating the fossil record: relative dating, absolute dating, order of appearance in strata (cid:494)index fossils(cid:495) to compare locations, mostly for volcanic rock, not sedimentary, ex. Radiometric methods (isotopic decay: place a absolute value on the age of a fossil. Geological record: earth is ~4. 6 billion years old, microbial life arose relatively early, fossils of animals and plants common in the last ~550 million years (phanerozoic era, phanerozoic divided into three eras which are subdivided into several periods. Mass extinctions many species extinct in a short time caused by large environmental changes. These causes may include massive volcanic activity, changes in ocean circulation patterns and impact by an asteroid/comet.
