Literature Sources and Their Relevance
Most studies existing nowadays were conducted about real research and exploration of commonplaces of living, ways of behavior, and other peculiarities that can be inferred from palaeontological excavations and laboratory research that allows scientists to assume possible appearance and way of living of extinct vertebrates and other species known to modern people only from the history of our planet. It is necessary to mention that there are a great number of literature sources that are truly substantial and based on profound research, though leave efficient space for new coming scientists on paleontology to conduct further researches and complete successive literature works on this topic.
Limitations and Inferring
The current article contains information on different works of literature that present a discussion of fossil taxa and possible variants of investigating limitations on inferring behavior in fossil taxa. Naturally, science does not stop on the results achieved, though as in fashion, the are certain trends in certain eras because “… there has been renewed interest in viewing fossils not just as collections of bones but rather as living, functioning animals.” (Witmer, 1995:19) these trends can be observed in the current era as numerous studies are dedicated to the analysis and discussion of fossil taxa in terms of different approaches that can be used to restore the appearance, way of behavior, especially certain aspects of behavior, suchlike reproduction, defense, feeding, locomotion, communication, and group dynamics, and other peculiarities of extinct species. The restored information can contribute greatly to the overall knowledge of paleontologists on preceding living beings that inhabited our planet in different centuries.
Discussion of Fossil Taxa and Vertebral Column
The Body Posture of Extinct Large Vertebrates
As suggested by the authors of the relation between body posture and the shape of the vertebral column, Christian and Preuschoft (1996), “even if complete skeletons of an extinct species are preserved, the possible arrangements of the fossilized bones usually leave open some questions about body and limb posture” (801). It is necessary to analyze a way that would leave fewer questions for further consideration. As it comes from the researches conducted by Joseph Leidy who had introduced taxa analyzed from nine lithographic plates (Anon., n.d.:1), it is possible to attribute certain features of the bodily posture to species that existed in certain periods of history about their behavioral aspects.
Methods Used to Investigate on Extinct Taxa
Some researchers try to introduce the method of using DNA as a way to trace all possible changes that the species might have faced (Austin and Arnold, 2001); others present the most disputable issues that appear in the area of paleontology concerning the relevance of the revolutionary approach to the discussion of the ancient species (Tasi, 2008:12). The irrelevance of the evolutionary approach has been argued by Donoghue and Purnell (2005:312), “A fundamental problem with the hypothesis linking gen(om)e duplication events in vertebrates with evolutionary jumps is that extinct lineages are ignored.” This brings us to the discussion of the most appropriate methods of analyzing extinct vertebrates and fossil taxa in general that can be introduced to investigate limitations on inferring behavior in fossil taxa and some possible variants of learning about the behavior of different taxa with the help of research.
Teeth are another disputable issue that may contribute greatly to the salvation of the problem about the way of defense and feeding; as discussed by Smith and Johanson (2003); Purnell (2002), “The origins and evolution of the dentition of jawed vertebrates have come under recent scrutiny. New research has questioned the classic concept of evolution of teeth by co-option of external skin denticles at the margins of the jaws and the obligatory evolution of ‘teeth with jaws’.” (Smith and Johanson, 2003:1235) As you can see, different approaches to the exploration of genuine aspects of the behavior of extinct vertebrates open a new chapter in consideration of the limitation of inferring on the behavior of fossil taxa.
Though the current article is aimed at considering the aspects of the behavior of extinct taxa, it is necessary to mention that “… contemporary evolutionists themselves admit that even today valuable, logically consistent, detailed explanations of the beginnings of instinctive animal action are practically nonexistent” (Tasi, 2008:14). Sometimes it seems relevant to introduce a certain hierarchy of methods evaluating aspects of the behavior of extinct vertebrates about their effectiveness and reasonability in terms of using the technologically advanced methods.
The authors of the article on the evolution, teeth, and evolutionary origins claim that “teeth, as part of a statodont dentition, are present only within the derived placoderm group Arthrodira and are absent in more basal groups in the phylogeny.” (Smith and Johanson, 2003:1236) Sometimes teeth and other parts of the skeleton of extinct vertebrates can not necessarily be traced in the process of evolution that is why the analysis of actually existing species cannot give answers to all questions arising from discussion of ancestors of modern species. Though the evolutionary approach seems to be irrelevant to the current investigation, it is possible to take into account an integrated approach, though it, “… combining morphological and molecular characters, has not been utilized to infer deuterostome phylogeny.” (Turbeville, et al., 1994:648)
Extinct Vertebrate Taxa
The most important is the soft-tissue approach to the analysis of different species and possible aspects of their behavior about the posture of their vertebral axis and a skeleton in general. As suggested by Witmer (1995:20), the knowledge about soft tissues can contribute greatly to the overall knowledge about the possible construction of the skeleton and, consequently, about aspects of the behavior of extinct vertebrate taxa as “… soft tissues largely are responsible for the existence, maintenance, and form of bones; judgments about the form and actions of soft tissues are … the basis for a host of paleobiological inferences; and … soft-tissue relationships may provide testable hypotheses on independence or nonindependence of phylogenetic characters.”
This idea brings us to the discussion of a certain extinct vertebrate taxon. The history of the research conducted on the topic of vertebrate taxa and possible variants of aspects of their behavior can be considered good assistance in analyzing theoretical options of animal behavior: “… the primary evidence of the evolutionary history of back-boned animals is based on a rich record of preserved hard skeletons, making it readily available for detailed anatomical, systematic and phylogenetic studies.” (Reisz and Muller, 2004:237) So, the current article concerns dinosaurs “or any other terrestrial vertebrate” (Christian and Preuschoft, 1996:801).
As far as the methods established by other scientists allow us, we can judge upon the posture of a dinosaur about the vertebral column even without knowing a theoretical distribution of the body mass of this extinct vertebrate. The posture can tell us about the aspects of behavior in terms of feeding and defense, as the animal units with a certain distribution of body mass were able of feeding on plants that grew short because their skeleton did not allow them to stretch their body to the plants that grew tall. As the construction of the skeleton can be considered the [primary aspect of the behavior in general and different peculiarities, it is necessary to take into account the essence of posture about the soft tissues and distribution of mass.
Conclusion
The essence of paleontology is the theoretical possibility to analyze and assume the hypothetical construction of different extinct organisms. It is necessary to consider extinct vertebrates as their posture and skeleton are closely connected and exploration of this aspect can contribute greatly to the overall knowledge on the lineage evolution gaps. The discussion of teeth and phonological aspects are of great importance for the analysis of aspects of behavior such as feeding and defense. Predators had a stronger skeleton which was more stable and allowed the animal unit to hunt on those that were not able to stretch their bodies and to turn aside from their bites. The current article also contain a discussion of the DNA which can be considered as another approach to the exploration on extinct species.
Literature Cited
Austin, J. J., and E. N. Arnold. 2001. Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of Indian Ocean giant tortoises (Cylindraspis). Proc. R. Soc. Lond. B 268:2515–2523.
Anon. n.d. Extinct Western vertebrates. Academy of Natural Sciences. 2010. Web.
Christian, A., and H. Preuschoft. 1996. Deducing the body posture of extinct large vertebrates from the shape of the vertebral column. University of Ruhr. Web.
Donoghue, P. C. J., and M. A. Purnell. 2005. Genome duplication, extinction and vertebrate evolution. Trends in Ecology and Evolution 20(6):312–319.
Purnell, M. A. 2002. Feeding in extinct jawless heterostracan fishes and testing scenarios of early vertebrate evolution. Proc. R. Soc. Lond. B 269:83–88.
Reisz, R. R., and J. Muller. 2004. Molecular timescales and the fossil record: a paleontological perspective. Trends in Genetics 20(5):237–241.
Smith, M. M., and Z. Johanson. 2003. Separate evolutionary origins of teeth from evidence in fossil jawed vertebrates. Science 299:1235–1236.
Tasi, I. 2008. Programmes of the living world: extraordinary animal behaviours that defy evolution. Science and Spiritual Quest 11-25.
Turbeville, J. M., J. R. Schulz, and R. A. Raff. 1994. Deuterostome phylogeny and the sister group of the chordates: evidence from molecules and morphology. Mol. Bid. Evol. 11(4):648–655.
Witmer, L. M. 1995. The extant phylogenetic bracket and the importance of reconstructing soft tissues in fossils. Cambridge University Press. Web.