Slides from the isotopes discussion in AP Biology.

1. Isotopes
What good are they?

2. Isotopes
•forms of an atom with varying numbers of neutrons
•can be identified by their weight

3. Some are radioactive and some are stable.

4. •neutrons “fall off”
•emission can be
detected and traced
•molecules “decay”
into another kind of
molecule
Some are radioactive and some are stable.

5. •neutrons “fall off”
•emission can be
detected and traced
•molecules “decay”
into another kind of
molecule
•neutrons stay put
•remain as they are
over time
Some are radioactive and some are stable.

8. Monarch Migration video (NOVA)
http://www.pbs.org/wgbh/nova/nature/journey-butterflies.html

9. Until now, there's never been a good way to find out exactly where the Mexican
monarchs spend their summers and reproduce. Butterfly tagging programs are
popular. But only a few tagged butterflies are found among the millions of
monarchs in the wintering grounds. Butterflies are too small to track with radios or
satellites.

11. In nature, an element occurs as a mixture of isotopes
which can vary according to geography and other
environmental factors

12. How can isotopes be used to study monarch migration?

13. How can isotopes be used to study monarch migration?
Researchers analyze wing membranes because their isotopic
composition does not change after they are formed at the
breeding site.

14. radioactive isotopes
can be used to:
•trace atoms in
metabolism
•diagnose medical
disorders
•monitor chemical
processes in the
body

15. date fossils

16. Anthropological and forensic problems?

18. As well as in determining past climates from oxygen isotopes in ice
and ocean organisms

19. Which oxygen isotope gets trapped
in ice (as a result of precipitation)
and in the shells of ocean
organisms is temperature
dependent so . . .

20. Which oxygen isotope gets trapped
in ice (as a result of precipitation)
and in the shells of ocean
organisms is temperature
dependent so . . .
ratios can be used to
determine past temperatures
ratios can be used to
determine past temperatures

21. ice core sampling

22. ice core storage facility

23. Uses for isotopes:
•tracking migration
•medical uses
•forensic uses
•environmental changes (like
climate changes and pollution
movement)
•radioactive isotopes can be used
for aging things

24. the end