|A life-sized model of a Rafflesia plant — a leafless, stemless, rootless plant that does not use photosynthesis but bears one of the world's largest flowers — is featured in the "Tree of Life" exhibition at Yale's Peabody Museum.
Exhibit traces linkages on the ‘Tree of Life’
It may come as a surprise to learn that the fearsome Tyrannosaurus rex is closely
related to the tiny hummingbird, or that, lineage-wise, mushrooms are closer
to humans than they are to a lily.
These are among the facts visitors learn at the Yale Peabody Museum of Natural
History’s new exhibit “Travels in the Great Tree of Life.”
A “family” tree showing how all living things — from the smallest
microorganism to the largest vertebrate and redwood tree — are related
is the highlight of the exhibition, which opens on Saturday, Feb. 16, and will
be on view permanently.
Curated by Peabody Museum director and noted Yale botanist Michael J. Donoghue, “Travels
in the Great Tree of Life” explores the complex relationships that link
organisms. The idea of the “tree of life” — and the term itself — originated
with Charles Darwin, whose first sketch of a tree depicting phylogenetic relationships
was an 1837 notebook entry. In his 1859 master work “On the Origin of the
Species,” Darwin crystallized the idea that species share common ancestors
and referred to the genealogical relationships among all living things as “the
great Tree of Life.”
The Peabody exhibit reveals the history of similarities and differences among
the lineages of organisms as they have changed through time. This chronicle of
past evolutionary events is central to understanding the process of evolution
and, thus, the interpretation of all biological information, says Donaghue, noting
that this history of evolutionary events is the framework for our modern understanding
Using specially commissioned films, multimedia interactives and specimens (both
live and from the museum’s collections), the exhibition demonstrates the
full diversity of life and how one form of a species evolves into another through
evolutionary time. The exhibit also underscores an important evolutionary concept:
that the “phylogenetic relationship” refers not to similarities and
differences among organisms but to the relative times that they shared common
ancestors in the past.
Some animations in the exhibit take viewers back in time to see, for example,
what the ancestral species of a scorpion may have looked like at different points of its evolution.
A computer game invites visitors to respond to a cat’s appeal to “Help
me find my home in the Tree of Life.” Using a touch screen, museum visitors
respond to five questions about phylogenetic relationships. Each correct answer
moves the cat from the beginning of life at the base of the tree all the way
to the cat’s branch in the Tree of Life. Interesting “phylo-facts” are
learned along the way.
Also featured in the exhibit is a pair of live Black and Rufous Giant Elephant
Shrew brothers that were born on Feb. 4, 2007, at the Smithsonian’s National
Zoo in Washington, D.C. These tiny animals, the exhibit reveals, are related
to the world’s largest mammal, the elephant. Both are members of the mammal
lineage Afrotheria that includes some 80 species that are so varied that in-depth
DNA analysis is required to prove they share a unique common ancestor. This group
also includes the aardvark and manatee.
Exhibition visitors will discover how organisms that look very different can
be quite closely related and that similar-looking organisms might be only distantly
related. For instance, the body of the whale is similar to that of a fish, but
its ancestors were terrestrial and walked on four limbs. As they adapted to swimming,
their limbs were reduced and their body shape converged on the typical fish shape.
According to scientists, there are some 1,750,000 known living species, with
new ones being discovered every day. The real number may be over 10 million.
Some 100,000 species have been included in formal phylogenetic analyses so far — about
5% to 10% of the known living species and only a fraction of a percent of those
that have ever existed.
One recent phylogenetic discovery concerns Rafflesia, a group of 13 rare plant
species whose closest relatives have remained a mystery for nearly 200 years.
Leafless, stemless, rootless and non-photosynthetic, they lack almost all recognizable
structural plant features other than boasting the world’s largest flowers.
Their flowers lure pollinating flies to their blossoms by mimicking decaying
animals on the forest floor.
A breakthrough in the mystery surrounding Rafflesia came in 2007 with the finding
that they belong to the plant group Euphorbiaceae, the euphorbs. Related euphorbs
have tiny flowers, implying an astounding rate of increase in flower size along
the line to Rafflesia. A life-size model is featured in the exhibition.
In addition to the elephant shrews, the other living organisms featured in the
exhibit are carnivorous plants, succulent plants and anthropods. Representing
the latter are the scorpion and whip scorpion.
In addition to informing the world of the diversity of life on Earth, phylogenetic
research is also important in areas as diverse as human health, natural resource
management and agriculture, according to exhibition organizers. “Travels
in the Great Tree of Life” examines how knowledge of the Tree of Life is
being used to save endangered species and understand the origins of disease.
The Peabody Museum of Natural History, 170 Whitney Ave., is open 9 a.m.-5 p.m.
Monday-Saturday, and noon-5 p.m. on Sunday. Exhibits and most programs are free
with the price of admission. Admission is $7; $6 for seniors; $5 for children
ages 3-8; and free for museum members and children under age 3. Admission is
free for all on Thursdays, 2-5 p.m. For more information, visit www.peabody.yale.edu
or call the Infotape at (203) 432-5050.
T H I SW E E K ' SS T O R I E S
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Exhibit traces linkages on the ‘Tree of Life’
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Study: Older women more likely to suffer depression than older men
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Yale Rheumatic Diseases Research Center awarded $3.2 million . . .
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Conference will look at issues surrounding nuclear disarmament
Former Yale architecture dean to give Chubb Lecture
Study gives high marks to use of bypass surgery for those in their 90s
Yale Ob-Gyn researchers discussed current work . . .
Several Yale Ob-Gyn presentations are awarded honors at meeting
Judith Resnik wins prestigious honor for her ‘outstanding scholarship’ . . .
Lectures explore mythmaking in Hollywood westerns
Panel will explore ways to promote diverse faculties
‘Images 2008’ exhibition includes works by three Yale staff members
Memorial service for Dr. Barry Goldberg
Yale affiliates to be honored guests at benefit event for LEAP
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