13.4-13.5 notes

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13.4

1. The fossil record and existence of homologous structures in living organisms have been used to argue that all living things have evolved from a common ancestor.

2. Geologists in the seventeenth century described and began interpreting the origin of sedimentary rocks and index fossils within them.

3. Darwin's followers have assumed that most fossils are related genetically to fossils above and below them in the sedimentary rock starta.

4. In evolutionary thinking, a fossil that is intermediate in structure between two other fossils is termed a transitional form.

5. The Cambrian formation of rocks begins with an explosive array of basic, new animal body plans that represent about hall of all modern animal phyla.

6. Darwin and his followers have found the Cambrian explosion difficult to explain because of the high level of diversity that appears in short period of time.

7. Evolutionists argue that these diverse phyla existed in pre-Cambrian rocks but were not fossiliz-able at the point in time.

8. Current design theorists argue that it is highly improbable that 20 phyla of animals would all become fossiliz-able in the short time indicated.

1. Homeobox gene is a control protein, not a structural protein.

2. Homeobox genes have sequence similarities across the entire animal kingdom and a such are widely assumed to be homologous to be homologous in a Darwinist sense.

3. Homeo gene products combine with regulatory proteins from other loci to determine where in an animals body its various structures will be located spatially.

4. Homeobox genes do this by sensing their location within chemical gradients setup by maternal gens in the early embryo.

5. At present, detectable mutational changes to homeobox genes have been without exception deteriorative of existing animal body plan.

6. Natural selection is required to create a forelimb for an animal at the same that it is altering homeobox genes to determine where the limb will be located.

7. When the Cambrian explosion occurred..natural selection had to find about 200 new homeobox genes and assign them roles within 20 or so different basic animal body plans.

8. Large populations of early animal populations would have to die by natural selection for this large number of changes to occur suddenly within the early Cambrian period.

9. The Darwinian explanation of homology in vertebrate forelimbs is both simple and elegant, but it fails to explain the extreme information content required to generate a forelimb and position it temporally..and spatially within the development of an animal.

10. Darwinists argue that homologous structures exist because the two organisms containing them derive by mutation and selection from a common ancestor.

11. Since some structures assumed to be homologous turn out not to be when studied in detail, it is safer to search for homology among genes, the actual sites of mutation.

13.5

1. Mutation and natural selection do not appear to have the power to create new kinds of organisms or fundamentally new structures within organisms.

2. Most mutations are slightly harmful to modern organisms because they have a high level of either design or adaption depending on view of origins.

3. Very small changes in DNA sequences can cause profoundly detrimental effects in the organism in which they occur.

4. Some mutations are selectively neutral; they do not alter the phenotype of the organism, or they do so in a way that gives the resulting organism no selective advantage.

5. Neither harmful nor neutral mutations contribute positively to evolutionary change.

6. A helpful mutation is any change in the genome that allows its bearer to leave more healthy offspring for the next generation compared to rival organisms of the same population.

7. Beneficial mutations depend on the environmental variables. What is optimal in one set of conditions may be harmful in a different set of conditions.

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