Biological Clocks: Scale

This Pacific Chorus frog is sending out an invitation that he hopes will be irresistible to any female frog of his species. His hormones are telling him it’s the time of year to find a mate. That’s just one way biological clocks keep the wheels of life moving. I’m Jim Metzner, and this is Pulse of the Planet, presented by DuPont. Biological clocks, nature’s organic, internal timekeepers, help set the pace in everything from blue green algae to great white whales. The most obvious observed time period is the 24-hour cycle of day and night. But according to Vince Cassone, professor of biology at Texas A & M University, biological clocks come in many different sizes. Some seem to measure time in minutes, some in hours, some in years. And there are clocks within clocks.

“In addition to the daily changes that we see regulated by the biological clock, which we call the circadian clock or approximately a day clock, there are other periods that are biologically important. Probably the best example of that would be the tidal rhythms, and many organisms synchronize themselves to high tide or low tide.

There are also monthly biological clocks associated with the lunar cycle, and of course there are annual rhythms. Take, for example, autumn in North America.

“Birds begin to migrate from one part of the country to another. Many types of mammals change their types of coats of hair because its going to get cold and some animals begin their breeding season, like deer, and some animals end their breeding season.”

Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation.

Biological Clocks: Scale

Most organisms follow a 24 hour inner biological clock, but life on earth marches to the drum beat of other cyclical rhythms.
Air Date:04/06/2000
Scientist:
Transcript:

This Pacific Chorus frog is sending out an invitation that he hopes will be irresistible to any female frog of his species. His hormones are telling him it's the time of year to find a mate. That's just one way biological clocks keep the wheels of life moving. I'm Jim Metzner, and this is Pulse of the Planet, presented by DuPont. Biological clocks, nature's organic, internal timekeepers, help set the pace in everything from blue green algae to great white whales. The most obvious observed time period is the 24-hour cycle of day and night. But according to Vince Cassone, professor of biology at Texas A & M University, biological clocks come in many different sizes. Some seem to measure time in minutes, some in hours, some in years. And there are clocks within clocks.

"In addition to the daily changes that we see regulated by the biological clock, which we call the circadian clock or approximately a day clock, there are other periods that are biologically important. Probably the best example of that would be the tidal rhythms, and many organisms synchronize themselves to high tide or low tide.

There are also monthly biological clocks associated with the lunar cycle, and of course there are annual rhythms. Take, for example, autumn in North America.

"Birds begin to migrate from one part of the country to another. Many types of mammals change their types of coats of hair because its going to get cold and some animals begin their breeding season, like deer, and some animals end their breeding season."

Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation.