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Smithsonian National Zoological Park l Friends of the National Zoo

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Pitohui; Jack Dumbacher
Pitohuis are brightly colored to warn predators of their toxicity. CCEG scientists have determined the evolutionary relationships of this group of birds in relation to their toxicity level and coloration to show that elaborate mimicry is involved.
Photo credit: Jack Dumbacher

Systematics and Definition of Conservation Units

Conservation strategies require knowing what taxonomic units (species, subspecies, or populations, for example) need to be preserved and how unique they are. How much gene flow is there between two geographically isolated populations? How unique are populations or species and which one’s extinction would most affect genetic diversity? DNA analyses can be extremely useful for answering these types of questions.

South American deer; Jesus Maldonado
CCEG scientists study the genetics and systematics of South American deer.
Photo credit: Jesus Maldonado

CCEG scientists have been involved in a large number of such studies, most with conservation implications. They have conducted systematic and phylogeographic analyses on: Hawaiian honeycreepers, Indian wolves, California shrews, yellow-billed cuckoos, fox squirrels, American jays, Brazilian lion-tamarins, clapper rails, Caribbean racoons, owlet-nightjars, African forest robins, Micronesian white-eyes, frigatebirds, gray whales, ivory-billed woodpeckers, Asian elephants, South American deer, olingos, Mariana crows, fur seals, pitohuis, bowerbirds, quaggas, swamp sparrows, giant kangaroo rats, brown boobies, Hawaiian ohia trees, parrots, millerbirds, black-footed ferrets, quolls, Spheniscus penguins, mountain coatis, and common ravens.

In addition, DNA-based phylogenies (evolutionary trees for a group of individuals or species), are very powerful devices for learning how species evolve and adapt. A well-resolved phylogenetic tree based on DNA sequences can tell us a lot about evolution. It can tell us what species or groups of species are most closely related, how their adaptive traits evolved, how moved about the Earth, and, with fossil- or geology-based ages to calibrate part of a tree, how rapidly evolution occurred. CCEG scientists are especially interested in adaptive radiation—the process of speciation from a single ancestral species while evolving traits in response to environmental variables. Some key examples of this process include our work on Hawaiian birds and South American mammals.