San Francisco State University
Geography 316: Biogeography
The Biogeography of King Penguin (Aptenodytes patagonica)
by Cid Chiu, student in Geography 316, Fall 1999
Kingdom: Animalia
Phylum: Chordata
Class: Birds
Order:
Family:
Genus: Aptenodytes
Species: Aptenodytes patagonica
Description of Species
Penguins are common name for flightless aquatic birds. They are
grouped into 18 species and 6 genera. The largest species are the king penguin,
ranging in size from 91 to 97 cm (36 to 38 in), Most penguins have a white breast and a
black back and head, but the king penguins have blue-gray backs, bright reddish on the
sides of their mandibles and large orange patches on the sides of their necks.
Habitat
Today, Penguins range from the Galapagos Islands, simmering in the
glare and swelter of the equatorial sun, south to Cape Royds, an Adelie colony in the Ross
Sea at 77 degrees 33 minutes south latitude, deep inside the Antarctic Circle and the most
southerly penguin colony of any species (Wayne, Lynch 1997). King penguins are not
evenly distributed over the Southern hemisphere; they only live where there is an adequate
of food supply. King Penguins are found on the Antarctic ice barrier, Tierra
del Fuego and on eight islands in the Southern hemisphere (Microsoft Encarta Encyclopedia
99. 1993-1998).
Natural History
Penguins are an ancient order of birds dating back in time of the
dinosaurs. By 55 million years ago, penguins were already flightless and were
completely adapted to a life in the ocean. As noted by Wayne (1997), when the
dinosaurs disappeared, many marine reptiles also became extinct. The time was right
for penguins, and they diversified rapidly to exploit the ocean vacancies left by the
extinction of these reptiles. In fact, from 40 to 25 million years ago, penguins
were the dominant warm-blooded predators of fish, krill and squid. The penguin
family was very different then. To begin with, there were at least 40 species
compared with the 17 living today. The good life for the penguin clan did not last
very long. The birds eventually found themselves with some very serious competition
for the edible bounties of the sea. The first were small toothed whales, and they
were followed by seals and sea lions. In the end, only a few types of penguin
survived, and it is these that are with us today.
Evolution
According to Charles Darwin’s Natural Selection theory, the
surrounding environments effect the change of evolution in species. For example, the
evolution of penguins, many people believe the natural environments selected them to be a
flightless bird. Penguins lives in oceanic islands, or large isolated cold
continents that are free from many predators that has no need to fly, therefore they have
lost the ability to fly. John Sparks and Tony Soper (1987) points out that the
evolutionary history of penguins can be seen as an account of the gradual perfection of
flight beneath the surface. Some 100 millions years ago, the ancestors of
today’s penguins were shearwater-like birds, traversing the oceans. During the
next 30 million years, they lost their ability to fly and emerged as penguins- a little
different in structure from modern ones (Sparks And Soper 1987).
There may have been overcrowding and competition for living space both
on the ground and in the air. So, penguins may have abandoned flight to adopt a
swimming way of life. The origin of penguins has always been connected with their
inability to fly. One piece of evidence is that there is no fossil
penguin that is more than 45 million years old has yet been unearthed. By then,
flying birds to those we know today were already well established (Penguins 1987).
It is very likely penguins were descended from flying ancestors.
Additional evidence that points to why penguins are descended from
birds is their bone structure. Their flippers are constructed as a paddle-like
modification of a flying wing. This is a modification to strengthen the wings for
the attachment of gills-so necessary for supporting flight. Also, their breastbone
is strongly keeled for anchoring the powerful pectoral and supracoracoideus muscles
developed initially for flying (Sparks And Soper. 1987). Perhaps the most convincing
evidence of aerial ancestry is the presence of a small bony structure called the
pygostyle, which supports the tail feathers. In the interests of aerodynamic
efficiency and maneuverability the terminal series of tailbones became abbreviated, and
some fused into a small knob of bone – the pygostyle. This adaptation to flight
came to support a fan-like arrangement of tail feathers, and is found in all modern birds;
for penguins, it must be an evolutionary hangover from flying ancestors (Sparks and Soper
1987).
Distribution
King penguins are not evenly distributed over the Southern hemisphere;
they only live where there is an adequate of food supply. King Penguins are
found on the Antarctic ice barrier, Tierra del Fuego and on eight islands in the Southern
hemisphere (Microsoft Encarta Encyclopedia 99. 1993-1998).
Map of Distribution:
locations of the two sub-species of King Penguins. Pale yellow dots
represent A. p. patagonicus and orange dots indicate A. p. halli.
http://ourworld.compuserve.com/homepages/Peter_and_Barbara_Barham/frame_ndx.html
Other interesting issues
Penguins do not live at the North Pole.
Penguins are not Fish
Penguins are not Mammals
Penguins do not have fur
Penguins did not come from Alaska
Polar Bears do not eat Penguins
References
Wayne, Lynch 1997. Penguins of The World. Buffalo,
NY. Firefly Books Inc.
"Penguin," Microsoft® Encarta® Encyclopedia 99. © 1993-1998 Microsoft Corporation. All rights reserved.
Sparks, John. and Soper, Tony. 1987. “The Evolution of Penguins.” Pp 141-159. Penguins – 2nd ed. Newton Abbot, London. David & Charles Publishers Plc.
Stonehouse, Nernard. 1975. The Biology Of Penguins. Baltimore, Ml. University Park Press.
Pete & Barb's Penguin Pages 06/29/1996 http://ourworld.compuserve.com/homepages/Peter_and_Barbara_Barham/frame_ndx.html
send comments to bholzman@sfsu.edu
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