Carolin Bags Research Paper

Adaptive radiation of different organisms have occurred throughout geological time through the filling of ecological niches. Organisms different from one another are capable of radiating greatly, as they evolve traits that allow them to thrive better in their environment. The Anolis lizards of the Caribbean islands are a great example of a single genus to have radiated not once, but multiple times through very similar mechanisms. Different populations of the Anolis phenotypically vary in their morphological traits to facilitate adaptation to particular niches. These phenotypic variations have evolved in convergence in more than one occasion, as recently discovered fossil specimens show similar patterns in morphology to modern Anolis.

In the beginning, the author introduces the nutria rat also known as coypu, it was first brought into the U.S. in 1899 in California for the fur industry. These creatures now live in 15 other states including Louisiana. They were released into “Louisiana wild by state and federal agencies to provide a new fur resource and to control problem plants such as the water hyacinth (Eichhornia crassipes) and alligator weed (Alternanthera philoxeroides)” ( 1). It did not take long for them

With nearly 84% of its natural habitat gone, it is no wonder Reithrodontyms Raviventris finds itself on the endangered species

The New Caledonian Crested Gecko is one of the most sought out reptiles in the herptoculture hobby today. This medium-sized gecko has all the qualities of what to expect of a pet lizard. They combine their sheer beauty and low maintenance and docile tempers, making it an all around great pet to own (Rhacodactylus, p. 16). In the herpetological society, the crested gecko’s popularity has grown above hobbyist, into the hands of many first time pet owners, giving a first time experience made easy. According to Fester, (2007) “the rare Crested Gecko thought to be extinct but rediscovered in New Caledonia in 1994” (fester’ at Ireland

Population bottlenecks occur when a population undergoes a large reduction in size as a result of environmental events or human activities. As a result, genetic variation may decrease as certain alleles may be over presented, under presented, or completely absent. Consequently, the genetic variation may continue to decline throughout subsequent generations as smaller populations, with less genetic diversity, sexually reproduce, passing on a limited amount of genes to future offspring. Furthermore, heterozygosity in these populations may decrease as a result of inbreeding. Inbreeding occurs when two closely related individuals reproduce; inbreeding may cause the accumulation of homozygous recessive genes and a decrease in genetic variation. Additionally, infrequently occurring alleles, rather than common alleles, may face a greater chance of being lost, which may further decrease the level of genetic diversity. As the population continues to decline, the genetic drift may be intensified as a result of increasing genetic limitations. Similarly, Rubin et al. (2001) compared smaller, isolated populations of Blanding’s turtles found in the Greater Chicago area to larger populations found in Michigan, Nova Scotia and Wisconsin, and determined, by using amplified polymorphic DNA, that the smaller populations had a loss of genetic variation in comparison to the

The focus of regenerative medicine is to the combine effects of a cell source, scaffold support, and anabolic stimulus to enable healing to the damaged tissue. One of the options for a cell source would be tenocytes; however, this would leave a lesion at the donor site from a biopsy, which cannot be done to a horse’s flexor tendon without additional consequences. Also, cells derived from different tendons show different characteristics compromising their effectiveness. Another option for differentiated fibroblasts includes dermal and ligament fibroblasts, but they have different cell characteristics that may not be useful in tendon repair. Therefore, stem cells are being seen as the greatest option for soft tissue repairing and healing (Herthel

Among a substantially diverse quantity of mammals, particularly those found in Texas, from which one can choose, the Virginia Opossum is probably among the least appealing. However, when researched, this particular animal is surprisingly notable for the vast amount of peculiarities it possesses. Among those peculiarities, the most evident one is their classification. Indeed, although for the average public the Virginia opossum is often considered a rodent, the reality could not be further from that. Instead, the Virginia Opossum classifies as a marsupial. However, these mammals are not to be confused with kangaroos or koalas. What makes the Virginia opossum part of the Marsupialia infraclass is the pouch in which they finalize the growth of

A member of the chelonian family Chelydridae, the common snapping turtle was formally described in 1758 by the Swedish botanist and zoologist Carolus Linnaeus. Currently regarded as having stable population levels, the species is, nevertheless, heavily exploited with documented population declines in some portions of its range.

The article focuses on the description and biology of the Pygmy Short-horned Lizard, and why they differ from an ordinary lizard. The Pygmy Short-horned Lizard is the smallest of the horned lizards and it hardly exceeds 6 cm from snout to tail. Compared to other armoured horned lizards, the Pygmy Short-horned Lizard has relatively small horns on its head and body. The colour and pattern vary within the species; however, the colour typically blends with its environment, making it extremely difficult to detect when it is motionless. This is a type of protection it uses to protect from its preys. The tail of the Pygmy Short-horned Lizard is short and is incapable of regrowth if lost, unlike the tails of many other lizards. Also unlike some other lizards that lay eggs, the Pygmy Short-horned Lizard is viviparous. This means it gives birth to fully developed live young, and the newborns resemble adult lizards that are smaller and not fully developed horns (Hong 2009). Question: What are possible explanations for the eradication of the Pygmy Short-horned Lizard in Canada?

In the early 20th century a Russian American named Alexander A. Maximow, established the theory that every cell comes from a precursor cell. Maximow was deeply involved in histology, the study of plant and animal tissue. Being the first to show that blood cells come from a common precursor cell, he is given the most credit in discovering what is known as stem cells (source #7). Stem cells have the ability to change into other cells such as blood, bone, tissue, and muscle cells. Researchers are trying to better understand these foundation cells to create cures and treatments for diseases and injuries. The report will be based on two articles. The next point will evaluate each source. Afterwards, the following information will

Significant progress has been made in identifying the molecular players that help in formation of the regenerating limb, as well as how they operate. Researchers have identified a particular player which controls proximal and distal properties. They did so by experimenting with retinoic acid (RA), which has control over cells. RA signaling, however, can only be done experimentally because blastema cells originating from cartilage follow the aforementioned distal transformation rule during normal limb regeneration. Additionally, as mentioned earlier, researchers have examined a number transcription factors that have been determined to be used in both embryonic development and limb regeneration, discovering a number of new ones. One of them, the MEIS family, is critical for upper limb development. Besides transcription factors, gradients also play a critical role in regeneration. The recently discovered newt anterior gradient (NAG) is a factor that encourages blastema cell growth and may also affect patterning of the Px/Ds axes. All of these are unique components in regeneration and would be interesting models for future

Ever since Charles Darwin’s first publication of “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 Cortés, 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.

Many animals have the ability to restore their tissue after injury. Among the most fascinating vertebrate models are newts and axololts, which can regenerate their entire appendages. This intricately regulated process is mediated by the formation of the blastema. While much has been learned about limb regeneration in the past decades, several underlying mechanisms remain to be elucidated. A recent study by Sandoval-Guzman and colleagues has shed light on the regeneration of muscle in such salamander species. This review will briefly discuss the findings of the paper and compare the strengths and limitations of each research model.

First finding: “Msx genes are essential in ectomesodermal interactions to mediate cellular proliferation and differentiation during limb formation, AEC formation, and limb patterning. Second finding, “overexpressed Msx1 (Hox7) in hindlimb regeneration in a transgenic Xenopus model (M1) resulted in higher proliferation rate in both BCs and AEC, thickened wound epithelium, and more regenerated toes in M1 compared with WT animals in stage 54”(5).

The concept of live birth in groups other than mammals has fascinated scientists for decades. One particularly interesting group that has captured the attention of the scientific community is the order Squamata, which includes all lizards and snakes. This group displays a variety of reproduction modes ranging from oviparity to oviparity with egg guarding to viviparity. Of the many squamate species, approximately 20% exhibit viviparous reproduction. Interestingly, the viviparous species of the lizard families Iguandiae and Scincidae and the snake families Colubridae and Viperidae comprise 71% of all viviparous species present on earth today (Andrews and Mathies 2000). Such irregular distribution has led to many questions regarding the evolution of viviparity in this group, with lizard species being an especially examined sub-group.