Real Science

Tuesday, 10 July 2007

Giant fossil penguins

Giant prehistoric penguins in Peru? It sounds more like something out of Hollywood than real science.

But a researcher from North Carolina State University, along with colleagues in other countries, has shown that two new penguin species reached equatorial regions tens of millions of years earlier than was thought possible. What's more, this was when the earth was much warmer than it is now.

Palaeontologist Dr. Julia Clarke is assistant professor of marine, earth and atmospheric sciences at NC State. She and her colleagues studied two newly discovered extinct species of penguins. Palaeontologists from Peru had found the new penguins' sites in 2005.

Both new species lived on the south coast of Peru. The first is called Icadyptes salasi. These penguins stood 5 feet tall and lived about 36 million years ago. The second new species, Perudyptes devriesi, lived about 42 million years ago. It was roughly the same size as a living King Penguin (2.5-3 feet tall). It represents a very early stage of penguin evolution.

These new penguin fossils are among the most complete yet recovered. They call into question earlier hypotheses about penguin evolution and how penguin species moved from one part of the world to another.

Scientists believed that penguins evolved in Antarctica and New Zealand. They later moved closer to the equator. This was thought to have happened about 10 million years ago - after the Earth had gone through a period of cooling (34 million years ago).

Nowadays we think of penguins as adapted to life in cold countries, Clarke says. "But the new fossils date back to one of the warmest periods in the last 65 million years of Earth's history. The evidence indicates that penguins reached low latitude regions more than 30 million years prior to our previous estimates."

These new species are the first fossils to show that penguins were already living near the equator when the Earth's climate changed dramatically. This happened when the extremely warm Palaeocene and Eocene epochs gave way to "icehouse" Earth and permanent polar icecaps.

Penguins reached equatorial regions during this earlier warm period, these new fossils show. They also thrived there at that time: More species are now known from the new Peruvian sites than live there today.

Clarke and her colleagues estimate that the two Peruvian species are the result of two different dispersal events. They reached this conclusion by comparing evolutionary relationships with the places other fossil penguins have been found.

This showed that the ancestors of Perudyptes seem to have lived in Antarctica. Those of Icadyptes may have started out near New Zealand, say the scientists.

The new penguin specimens are among the most complete yet discovered that show what early penguins looked like. Both have long narrow pointed beaks. This is thought to be an ancestral beak shape for all penguins.

Perudyptes devriesi has a slightly longer beak than some living penguins. But the giant Icadyptes salasi has a much longer beak, with features not known in any extinct or living species.

The beak is sharply pointed, almost spear-like. The bird's neck is robustly built with strong muscle attachment sites. Icadyptes salasi is among the largest species of penguin yet found.

These fossils seem to contradict some of what we thought we knew about the relationship between penguins and climate. But Clarke warns against jumping to conclusions.

We should not assume that because prehistoric penguins were not adapted to the cold, living penguins won't be affected by climate change.

"These Peruvian species are early branches off the penguin family tree, that are comparatively distant cousins of living penguins," Clarke says. "In addition, current global warming is occurring on a significantly shorter timescale.

"The data from these new fossil species cannot be used to argue that warming wouldn't negatively impact living penguins."

More help with words













What's it all about?

  1. Where have these penguin fossils been found?
  2. How many new species have been found there?
  3. Who has been studying them?
  4. Who found the sites?
  5. How tall was Icadyptes?
  6. How long ago did it live in Peru?
  7. How tall was Perudyptes?
  8. Fossils are often simply small pieces of bone or faint impressions in rock. Are these new penguin fossils like that?
  9. What word in the story gave you the answer to the last question?
  10. These new fossils are forcing scientists to think again about what happened to penguins in the past. What five-word phrase does the writer use to say this?
  11. Before this new discovery scientists thought penguins had first appeared on Earth how many millions of years ago?
  12. In what countries did they think penguins had first appeared?
  13. Were those countries warm or cold at that time?
  14. So penguins were thought to always have been birds suited to life in ---- countries.
  15. Does this new evidence support that belief or show it was wrong?
  16. Climate is just average weather over a long time. So what was the climate like when these penguins were living near the equator?
  17. What happened to Earth's climate a long time after the penguins were living in Peru?
  18. So was it warmer or colder near the equator, when these penguins lived there, than it is now?
  19. Did the penguins do well living near the equator?
  20. What word in the story gives you the answer to the last question?
  21. "Comparing evolutionary relationships" means studying fossils and different parts of fossils to figure out which ones came first. What did this work suggest to the scientists?
  22. Are they sure about this?
  23. Find three words in the story that help give you the answer to question. Look in the paragraph that begins "Clarke and her colleagues ..." and in the next paragraph.
  24. Depending on your answer to question 15 complete one of these sentences: 1) These new fossils support the belief that penguins have always been suited to life in cold countries because ... Or 2) These new fossils show scientists were wrong to think penguins have always been suited to life in cold countries. The reason is ....
  25. With as much detail as you can find, from the whole story, describe Icadyptes salasi.
  26. The sentence that begins "We should not assume that ..." is a hard one to make sense of. In your own words what is this sentence trying to say?
  27. The very last sentence is also hard to follow. Rewrite this sentence in your own words.
  28. What two reasons does Clarke give for making her last statement?
  29. If you were these scientists what research would you like to do next?
  30. What question would that research be trying to answer?

Topic for discussion, research or pupil presentations

A) In the popular film Ice Age the intrepid heroes meet a whole army of dodos, the flightless bird that went extinct in the 17th century (not during the Ice Age at all but who's counting?).

These are portrayed as hilariously stupid, headstrong and clumsy birds, which manage to extinguish themselves at every opportunity by crashing into each other, falling off cliffs into diving into molten lava.

While this makes for entertaining episodes, it is very unfair on the poor old dodo and totally misrepresents why species do go extinct. For a start any animal as suicidally stupid as the dodos in this film wouldn't have evolved and survived in the first place.

In Ice Age 2, Manny the mammoth believes himself to be the last of his kind - until he meets a female mammoth who thinks she's a possum (don't ask - you need to watch it).

Working in groups, students should choose a bird or animal that is now extinct, such as the dodo, mammoth, sabre-toothed tiger, and explore the various possible reasons for their extinction. They should deliver a presentation on the subject to the class.

The class should then try to find the feature common to all extinctions.

B) An interesting twist on the above is an in-depth lesson from Discovery School, with extension activities and recommended websites. This lesson looks at why particular species, known as living fossils, have survived into the present, when their contemporaries have long gone the way of 99.9% of all species that ever walked, crawled, swam or flew. Extinction is normal.

A nice aspect of the lesson is the following activity that aims to make the scientific method explicit in kids' minds:

Before beginning the research, have students develop a hypothesis about why their animal did not become extinct. They should write their hypothesis on Part A of the sheet ... Students should base their hypotheses on the facts discussed during step 5, as well as the discussion about why dinosaurs became extinct. Below is a sample hypothesis explaining why coyotes might survive if conditions on Earth changed dramatically and other species were killed off.

Tips for science class discussions and groupwork

No 54

Many of our students are poor readers ... if they do not understand what they read, then school and reading simply become a source of frustration. I am teaching and coordinating our summer school program, which is primarily web based (LA and Math).

There is a ton of reading that these kids must do and many of them simply cannot do it - which is probably much of the reason they are in summer school to begin with. Being able to work one on one with these students has been an eye opening experience. This new perspective, coupled with what I am learning from the reading course [the Florida On line Reading Professional Development], is causing me to become passionate about the belief that we all (teachers) must accept the responsibility of helping all students become better readers, regardless of our particular content. Many of the students I have been working with this summer are also some of our biggest discipline problems, which may result from the overwhelming frustration they encounter every day.

Extract from an online forum of the National Science Teachers Association by Tina Annucci, Gamble Rogers Middle School, St Augustine, FL


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