Origins ANTARCTICA, Scientific Journeys from McMurdo to the Pole
People Ideas Tools Place Live Field Notes

Fish: Fresh, Not Frozen

photo of an Emperor penguin
  An emperor penguin on the Ross Ice Shelf.
Adaptation Treasure Trove
There is no shortage of examples of clever adaptations to Antarctica’s hostile environment. To protect against the cold, penguins have adapted short overlapping feathers, rounded bodies, and fat storage under the skin. Antarctica’s only two flowering plants, Antarctic grass and Antarctic pearlwort, have evolved structural changes as defense against severe ultraviolet radiation from the sun. Some Antarctic algae photosynthesize at –7°C, exceeding the photosynthetic
capability of algae from temperate regions.

Nature boasts many other instances of adaptive radiation. It occurs when birds, insects, and other species colonize new islands made by volcanoes. The mass extinction of the dinosaurs paved the way for an adaptive radiation: mammals diversified into many new species with special adaptations for running, swimming, climbing, and other types of motion.

History Hinges on the Itsy-Bitsy
The history of the Notothenioids’ rise to fame in Antarctica reveals a central characteristic of evolution: One small change can dramatically alter history. For the Notothenioids, one adaptation—the development of the antifreeze gene—paved the way for a multitude of other adaptations and new species. Like these hardy fish, each species on Earth today arose from other species through a chain of adaptations, one change making the next one possible.

It’s intriguing to ponder what the Antarctic marine ecosystem would look like today if that tiny DNA mutation in one ancestor had never happened.


page: 1 | 2 | 3 | 4 | 5
Origins Exploratorium ANTARCTICA


© Exploratorium