238 Appendix 3: The Next 40
Global warming
Many
First cloning
Laetoli footprints (3.5 million
years old)
”Lucy” (3.2 million-year-old
skull)
Non-oxygen-based deep sea life
Dinosaur extinction (K-T
asteroid)
Human retrovirus HIV
Toumai skull (6 to 7 million years
old)
Gurden
Mary Leakey
late twentieth
century
1967
1973
Donald Johnson
1974
Ballard
Alvarez
1977
1979
Gallo and Montagnier
Michel Brunet
1982
2002