fossils provide an objective record of evolution fossil = a preserved or mineralized remains (bone-...
TRANSCRIPT
Fossils provide an objective record of
Evolution
Fossil = A preserved or mineralized remains (bone-petrified tree – tooth – shell) or imprint
of an organism that lived long ago.
Provide record of Earth’s past life-forms. crinoid (800 million yrs old)
pterodactyl (140 -210 million yrs old)
13:2 Evidence of Evolution
1 - Earth is about 4.5 billion years old.
2 – Organisms have inhabited Earth for most of its history.
3 – All organisms living today evolved from earlier, simpler life-forms.
3 Major Points of Scientific Agreement
Changes in a gene’s nucleotide sequence build up over
time.
PROTEINSAnalysis of amino acid sequences
Species that share a common ancestor in a more distant past (humans/frogs) have many amino acid sequence differences.
Species that share a common ancestor more recently (humans/gorillas) have few amino acid sequence differences.
Biological Molecules Contain a Record of Evolution
Nucleic Acids
Scientists can directly estimate the number of nucleotide changes that have taken place in a gene since 2 species diverged from a common ancestor by comparing the exact nucleotides sequence of genes.
VESTIGIAL STRUCTURES
Structures in different types of organisms that often reveal basic similarities in anatomy, even though the functions may be very different.
Cormorant
Anatomy and Development Suggest Common Ancestry
Structures that share a common
ancestry.
Homologous Structures
Forelimbs of vertebrates contain the same kinds of bones.