DAILY WARMUP Write one thing you know about

DAILY WARM-UP • Write one thing you know about Charles Darwin. • Define what you think a “seamount” is. • Rank the following pictures from youngest to oldest. A B C

RELATIVE AGE The approximate age of something determined by comparing whether it is older or younger than something similar. A B ßolder than C ßolder than

WHAT IS A SEAMOUNT? A mountain on the ocean floor that does not reach the surface.

BUILDING REEFS Ridges formed of live coral animals build-up on the skeletons of dead coral animals found in tropical oceans.

MORPHOLOGY • Morphology is the study of the origin of rocks as well as their formation and composition. • Morphology can describe the form and structure of a feature, such as a seamount or coral reef. Typical conical volcanic morphology of Mount Fuji, Japan

RELATIVE DATING Charles R. Darwin (1809 -1882) James D. Dana (1813 -1895)

CHARLES R. DARWIN Scientist aboard H. M. S Beagle voyage in 1831 and most famous for ideas on natural selection and evolution.

CHARLES R. DARWIN But … Darwin also wrote about evolution of coral reefs.

CHARLES R. DARWIN Hypothesized about the relative age progression of coral reefs in the ocean. • • • Coral reefs begin as fringing reefs. Subsidence occurs and barrier reefs form. Even more subsidence and an atoll forms.

Darwin based his hypotheses on above sea surface observations. Now we know what it looks like below the surface of the ocean, but in 1831 Darwin did not!

JAMES D. DANA Expanded on Darwin’s work on evolution of coral reefs and islands.

RELATIVE AGE DATING • Darwin and Dana were practicing relative age dating. • Rather than providing actual ages for the coral and islands they inferred that one was older than another based on appearance.

LIFE CYCLE SEAMOUNTS Hot lava erupts to make a seamount.

LIFE CYCLE SEAMOUNTS Continued eruptions and seamount becomes an island.

LIFE CYCLE SEAMOUNTS As the eruptions stop lava cools.

LIFE CYCLE SEAMOUNTS Eventually plants begin to grow on the cooled lava.

LIFE CYCLE SEAMOUNTS Soon the entire island has vegetation covering the lava.

LIFE CYCLE SEAMOUNTS Eventually the island sinks. Now it is a seamount.

CHARLES R. DARWIN The evolution of coral reefs happens at the same time.