The Chuckwallas and Evolutionary Research - 1627 Words

Ever since Charles Darwin’s first publication of â€Å"On the Origin of Species† in 1859, island habitats have been used by a number of scientists as the most efficient laboratories to observe the natural process of evolution taking place in modern-day organisms. Several kilometers northeast of the Galapagos Islands, where Darwin famously performed his research, is a small group of islands in the Sea of Cortà ©s, also known as the Gulf of California, between the Baja California peninsula and Mexico (see Figure 1 on page 18). Here many evolutionary biologists of the 20th and 21st century performed research on the insular organisms inhabiting these island habitats. One group of lizards in particular known by the common name chuckwallas has gained a lot of focus in evolutionary research. Chuckwallas is the name of organisms in the Sauromalus genus apart of the Iguanidae family. They are herbivorous lizards commonly found in the deserts of southwestern United States and Northern Mexico. Three species, in particular, are found on the islands off the cost of the mainland within the Sea of Cortà ©s: Sauromalus obesus (= ater), Sauromalus varius, and Sauromalus hispidus (see Figure 2 on page 20). S. obesus is a common species found on the mainland as well as few islands, while S. varius are S. hispidus are endemic to specific islands in the Sea of Cortà ©s: mainly San Esteban Island and Angel de la Guarda Island, respectively. Both of these insular species also show signs of gigantismShow MoreRelatedPredation Cost of Conspicuous Male Coloration in Collard Lizards (Crotaphytus collaris)1803 Words   |  8 Pagesxanthophores (yellow), or lecophores (white) based on the color of the pigments. The dispersal of these cells and the pigments and their orientation determin e the color patterns of the animal (Chromatophore 2013). Coloration is very critical in evolutionary biology because it can be used for protection, warning, and mate selection. Some organisms use crypsis to conceal themselves from predators and/or sneak up on prey. Other organisms may mimic others (usually a harmful species) in color and/or pattern