Scientific Methodology For Determining Human Existence

"How do scientists know how old humans are?"

1. Provide a rationale for this investigative question. E.g., Why do we need to know this?

2. Describe the investigative processes for collecting, organising, analysing and interpreting the data e.g., What are the scientific processes involved in exploring this question? 

3. Describe the data that you source and represent it using a variety of forms of evidence e.g., timelines, photographs 

4. Discuss your findings in relation to the question and its application to current scientific investigations 

5. What are the implications for teaching students scientific reasoning? 

Obtaining and Dating Human Fossils

This information report is intended to provide comprehensive reference and background information in regard to discerning the scientific methodology behind answering of the question ‘how long have the humans existed?’. Knowing this helps in understanding various scientific ways of research involved in proving of human existence over the years, that help in creating and preserving human history. It is important to study this topic since it helps in understanding the applicable scientific ways of discerning the period that the humans have existed. The information proves its importance when it comes down to proving of other scientific areas like evolution of human beings.

Data for the investigation involves obtaining of human fossils considered to be the primary source for dating human existence. This can be obtained from museums or archaeological sites containing human fossils. This is mainly sourced by excavating the human remains considered to be dating years back keeping in mind the type of sediment holding the fossils to avoid ruining the fossils (Smith et al 2009). The fossils are cleaned by use of agents like weak acetic acid or lightweight hammers to scrap off soil deposits covering fossils (Katzenberg et al 2018, p. 468). Obtained specimens are classified and catalogued with reference to their position vertically and horizontally in a site. This arrangement helps in identifying the organism size, the shape and structures of the bones Smith et al. (2009). This will involve taking pictures of the obtained samples. In the laboratory the fossils are examined by binocular used to view the features on the surface of the bones and scanning electron microscope is used for detailed analysis of the bones’ structure and its makeup composition (Li, & Durbin, 2011). Isotope analysis is also done on sourced soil and tooth enamel which give detailed information on the environment and diets of the human. Li et al. (2011) DNA analysis also helps in understanding the relationship between obtained particles. J. M. (2009). A rough time frame for the fossils can be obtained by relating them to rock layers that they were found in. Knowing this helps in understanding various scientific ways of research involved in proving of human existence over the years, that help in creating and preserving human history. It is important to study this topic since it helps in understanding the applicable scientific ways of discerning the period that the humans have existed. Where human fossils are found in volcanic ash, they are dated by use of potassium-argon dating. Reiches et al. (2009) Decay of radioactive isotopes can be used in uranium series dating by measuring the ratio of uranium to lead in an ancient sample. Kang. (2012). Radiocarbon dating is applicable to human fossils dating basing on the facts that humans have a mixture of stable 12C and 14C radioactive isotopes. Absorption of 14C radioactive isotopes stops after death of an organism and the remaining isotopes decay at a precise rate (Katzenberg et al 2018, p. 467). Measuring the ratio of the two helps in calculating the age of the fossil. The dating can be able to give the exact era the human fossils were considered dead (Katzenberg & Waters?Rist, 2018). The drawback is that the dating process can not give a precise calendar date but help in providing applicable calendar calibrations (Katzenberg et al 2018, p. 468). In cases where calibrations were not included with provided research results then the samples were considered as too young or too old or inappropriate for the dating process (Katzenberg et al 2018, p. 469). The interpretation of data is based on predefined databases in relation to calibration of radiocarbon age. Tennessen et al. (2012) Dating of human fossils is the clearest method of identifying the exact existence period of humans (Tennessen et al 2012).

The History of Humans

The sourced data mainly constitutes the fossils. Fossils are in most cases preserved by being compressed into different forms of soil compositions. Other data sourced are DNA of the human fossils, bone compositions like the amount of carbon or calcium and the structural appearance of the bones (Hochberg, 2009). Fossils that have the same age dating are grouped together to help in understanding more about the particular time they were in existence. Sourced information can be presented in form of timelines. This is a representation of the findings from the investigative process in an event list, identifying the sequential arrangement of the findings. The succession for this situation will be founded on the age information got from the dating of the fossils. Timelines guarantee that a sequential game plan of occasions is pursued. The age information depends on a predefined logical database for dating of fossils. The predefined database is for the most part utilized in referencing of cell-based dating with the end goal to allocate an appropriate date (Previc, 2009).

The picture displayed is a good examples of fossil extraction. Basing on the picture we can deduce that fossils can be based on anything prehistoric and it’s not entirely based on human bones. The timeline is used to present the pre-existing discovered human lifeforms before the humans came into existence (Langergraber et al 2012). The spoke to information depends on the ages and the connection between the occasions is plainly illustrated. Portrayal of sourced information on timetables can in itself go about as an optional wellspring of information in understanding the historical backdrop of people. Information portrayal in course of events shape helps in arranging of substantial data on human presence over a significant lot of time sequentially.

According to the scientific data sourced, the humans have been in existence for quite a long time. The research estimates that the current form of humans have been in existence for over 200,000 years (Bogin, 2009, p. 567). The collected data also shows that humans have been able to survive in different environmental conditions over a long period of time. The main substantial connects to humankind began around six million years back with a primate aggregate called Ardipithecus (Bogin, 2009). This is generally viewed as critical in light of the fact that it took into consideration all the freer utilization of the hands for toolmaking, weaponry and other survival needs. Next came Paranthropus, which existed between around one million and three million years back. They are recognized by their larger teeth, giving a more extensive eating routine (Bogin, 2009, p. 568). Our group the homo sapiens began existing more than two million years ago. This specie was distinguished by their bigger brains, improved tool making and the overall ability of being able to traverse on the planet. Migrations of the human species resulted to different environmental exposures thus resulting to varying of colour between the specie. According to scientific investigation, human origin is based in Africa. (Bogin, 2009, p. 569). Over time this specie experienced further evolution in relation to the morphological structures resulting to the present-day humans. It is important to note that at some given instances there were times where more than one relative species to the humans existed suggesting that evolution was a gradual process that lasted for years. This scientific finding was based on a vast range of data like the DNA, morphological structure and brain size, in order to distinguish the human species from the other species (Reiches et al 2009). It is evident from the research that humans were able to outlive the other existing species and became a dominant specie on the planet by reproduction (Reiches et al 2009, p. 421).

The Benefits of Teaching Scientific Reasoning to Students

Teaching students scientific reasoning has advanced their development of knowledge understanding. Unlike other subjects, science needs to be hands on experience in order to guarantee that the students benefit. The teaching is based on the fact that students have different understanding level regardless of the fact that the development process is the same (Halpern et al 2012). This prompts teachers to use various methods of teaching and allowing for a range of learning experiences. Scientific reasoning is beneficial to students since it uses environmental knowledge for students’ better understanding. It helps in the educators with a challenging but clear vision of the goals of elementary science education. Pragmatic thinking is a principal capability required for regular basic leadership and also for the generation of logical learning. Be that as it may, almost no consideration is given to building up this ability in school science classrooms or in instructive research programs. It is important to clarify the custom of practical thinking and its pertinence to science and science training (Wilson, 2017). Suggesting ways in which pragmatic reasoning may be developed in students such that they are enabled to better understand how scientific knowledge is produced and how they may be better able to contribute to improving scientific practices.

References

Bogin, B. (2009). Childhood, adolescence, and longevity: a multilevel model of the evolution of reserve capacity in human life history. American Journal of Human Biology: The Official Journal of the Human Biology Association, 21(4), 567-577.

Halpern, D. F., Millis, K., Graesser, A. C., Butler, H., Forsyth, C., & Cai, Z. (2012). Operation ARA: A computerized learning game that teaches critical thinking and scientific reasoning. Thinking Skills and Creativity, 7(2), 93-100.

Hochberg, Z. E. (2009). Evo–devo of child growth II: human life history and transition between its phases. European journal of endocrinology, 160(2), 135-141.

Katzenberg, M. A., & Waters?Rist, A. L. (2018). Stable isotope analysis: a tool for studying past diet, demography, and life history. Biological anthropology of the human skeleton, 467-504.

Langergraber, K. E., Prüfer, K., Rowney, C., Boesch, C., Crockford, C., Fawcett, K., ... & Robbins, M. M. (2012). Generation times in wild chimpanzees and gorillas suggest earlier divergence times in great ape and human evolution. Proceedings of the National Academy of Sciences, 109(39), 15716-15721.

Li, H., & Durbin, R. (2011). Inference of human population history from individual whole-genome sequences. Nature, 475(7357), 493.

Smith, G. J., Vijaykrishna, D., Bahl, J., Lycett, S. J., Worobey, M., Pybus, O. G., ... & Peiris, J. M. (2009). Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic. Nature, 459(7250), 1122.

Stewart, J. R., & Stringer, C. B. (2012). Human evolution out of Africa: the role of refugia and climate change. Science, 335(6074), 1317-1321.

Previc, F. H. (2009). The dopaminergic mind in human evolution and history. Cambridge University Press.

Reiches, M. W., Ellison, P. T., Lipson, S. F., Sharrock, K. C., Gardiner, E., & Duncan, L. G. (2009). Pooled energy budget and human life history. American Journal of Human Biology: The Official Journal of the Human Biology Association, 21(4), 421-429.

Tennessen, J. A., Bigham, A. W., O’connor, T. D., Fu, W., Kenny, E. E., Gravel, S., ... & Kang, H. M. (2012). Evolution and functional impact of rare coding variation from deep sequencing of human exomes. science, 337(6090), 64-69.

Wilson, E. O. (2017). Biophilia and the conservation ethic. In Evolutionary perspectives on environmental problems (pp. 263-272). Routledge.