Download Lab 12

Lab 12
Evidences for Evolution
3 types of evidence
• Fossil record
• Comparative anatomy
• Biochemical evidence
Fossil record
How are fossils dated?
First fossils were found in which era?
What type of organisms were the first fossils?
What are the 3 eras in the geologic time scale?
Lab manual exercises will look at which type of fossils
appeared in which era.
• For table 12-2 use these organisms for
examples of specimens from each era.
• Cenozoic-angiosperms
• Mesozoic-euypterids
• Paleozoic –giant club mosses
• Note which types of organisms are extinct.
Comparative Anatomy
• Comparison of homologous structures
(synapomorphies)
• Analogous structures (homoplastic features)
do not indicate evolutionary relatedness
• Compare forelimbs of several mammals to the
ancestral condition. Discuss the possible
reasons for some of the differences seen.
• Compare chimp and human skeletons and
skulls.
Comparison of embryos
• Vertebrate embryos share 3 characteristics
– post-______ tail
– ___________pouches
– Mesodermal segments called ______
– Look at chick embryo slides with a dissecting
microscope. Try to locate the features that are
found in the drawings. At what embryonic stage
can these features be seen?
Biochemical comparisons
• Comparisons of protein sequences, DNA,
ribosomal RNA.
• More similarities in sequence- more
evolutionary relatedness.
• Compare similarities of molecule cytochrome
c among species
• Work on handout which requires you to count
the difference in amino acid sequences.
Lab Report due next week
• Page 160 of lab manual “Lab Review 12”
• Questions from cytochrome c handout