Transitional Vertebrate Fossil1

Transitional Vertebrate Fossil1 - Transitional Vertebrate...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Transitional Vertebrate Fossils Good Models, Bad Models And now we come to the main question. Which of the many theories of the origins of life on earth are consistent with the known vertebrate fossil record, and explain its major features? I'll go back to the two main models I outlined at the beginning, creationism and evolution, and break them down further into several different possibilities. I'll try to summarize what they say, and whether or not they are consistent with the major features of the fossil record. 1. Evolution alone (with no God, or with a non-interfering God) Evolution of all vertebrates by descent from a common ancestor, with change occurring both through punctuated equilibrium and gradual evolution, and with both modes of species formation (anagenesis and cladogenesis). These mechanisms and modes are consistent with (and in fact are predicted by) what is presently known about mutation, developmental biology, and population genetics According to this model, the remaining gaps in the fossil record are primarily due to the chance events of fossilization (particularly significant if evolution occurs locally or rapidly), in combination with immigration (the spreading of a new species from the site where it evolved out into different areas). 2. Evolution with a "Starting-gate God" Evolution by common descent, as above, with God having set everything in motion in the beginning -- for instance, at the initial creation of the universe, or at the initial occurrence of life on earth -- and not having affected anything since. 3. Evolution with a "Tinkering God" Evolution by common descent, as above, with God occasionally altering the direction of evolution (e.g., causing sudden extinctions of certain groups, causing certain mutations to arise). The extent of the "tinkering" could vary from almost none to constant adjustments. However, a "constant tinkering" theory may run into the problem that vertebrate history
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/22/2011 for the course GLY GLY1100 taught by Professor Jaymuza during the Spring '10 term at Broward College.

Page1 / 3

Transitional Vertebrate Fossil1 - Transitional Vertebrate...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online