Figure7.24: Thisisamapofthegenesonjustoneofthe46humanchromosomes. Similarities
and differences between the genomes (the genetic makeup) of different organisms reveal the
relationships between the species. The human and chimpanzee genomes are almost identical-
just about 1.2% differences between the two genomes. The complexity of the map signifies
close evolutionary relationships when the genomes are highly similar. ( 13 )
- Geologist use a method called radiometric dating to determine the age of rocks and
fossils in each layer of rock. - Radiometric dating has been used to determine that the oldest known rocks on Earth
are between 4-5 billion years old. The oldest fossils are between 3-4 billion years old. - Body parts that do not serve any function are called vestigial structures.
- Vestigial structures indicate that two species have a recent common ancestor.
- The similarities between embryos suggests that animals are related and have common
ancestors. - The same biochemical building blocks – such as amino acids and nucleotides - are
responsible for life in all organisms, from bacteria to plants and animals. - DNA and RNA determines the development of all organisms.
- The similarities and differences between the genomes, the gene sequences of each
species, reveal patterns of evolution.
Review Questions
- What are the different kinds of evidence of evolution?
- How do geologists determine the age of rocks and fossils?
- What is an embryo?
- What is a vestigial structure?
- What is an example of a vestigial structure?