| 2004-present. | Associate Curator, Dept. of Invertebrate Zoology & Geology, California Academy of Sciences. |
| 2001-2004. | Department Chair, Dept. of Inverterbrate Zoology & Geology, California Academy of Sciences. |
| 1999-2003. | Assistant Curator, Dept. of Invertebrate Zoology & Geology, California Academy of Sciences. |
| 1997-1998. | Research Associate, Dept. of Geosciences, University of Arizona. |
| 1994-1998. | Assistant Professor, Dept. of Biology, Southeast Missouri State University. |
| 1994. | Lecturer, Biological Oceanography, UC Davis. |
| 1994. | Post-doctoral Researcher, Dept. of Geology, UC Davis. |
| 1992. | Research Assistant, UC Davis Museum of Nematology. |
| 1991-1992. | Vertebrate Collections Manager, UC Davis Museum of Zoology. |
| 1991. | Research Assistant, UC Davis and NOAA, NITROX Open Water Diver. |
| 1989. | Research Assistant, Paleontology, Dept. of Geology, UC Davis. |
| 1989-1993. | Teaching Assistant, UC Davis. |
| 1988. | Teaching Assistant, Dept. of Zoology, University of Maryland. |
| 1985-1986. | High School Teacher, General Science, Biology and Oceanography, Nowlin Oceanview Private School, Florida. |