Cladistic Analysis and Anthropoid Origins

1997

Science, 1997

1997

2001

Cladistic analysis is a popular method for reconstructing evolutionary relationships on the human lin-eage. However, it has limitations and hidden assumptions that are often not considered by palaeoan-thropologists. Some researchers who are opposed to its use regard cladistics as the preferred method for taxonomic «splitters» and claim it has lead to a revitalisation of typology. Typology remains a part of human evolutionary studies, regardless of the acceptance or use of cladistics. The assumption/preference for «splitting» over «lumping» in cladistics (alpha) taxonomy and the general failure to evaluate (post-hoc) such taxonomies have served to reinforce this assertion. Researchers have also adopted a number of practices that are logically untenable or introduce considerable error. The evolutionary trend of human encephalisation, apparently isometric with body size, and concurrent reduction in the gut and masticatory apparatus, suggests continuous cladistic characters are biased by problems of body size. The method suffers a logical weakness, or circularity, leading to bias when characters with multiple states are used. Coding of such characters can only be done using prior criteria, and this is usually done using an existing phylogenetic scheme. Another problem with coding character states is the handling of variation within species. While this form of variation is usually ignored by palaeoanthropologists, when characters are recognised as varying, their treatment as a separate state adds considerable error to cladograms. The genetic proximity of humans, chimpanzees and gorillas has important implications for cladistic analyses. It is argued that chimpanzees and gorillas should be treated as ingroup taxa and an alternative outgroup such as orangutans should be used, or an (hypothetical) ancestral body plan developed. Making chimpanzees and gorillas ingroup taxa would considerably enhance the biological utility of anthro-pological cladograms. All published human cladograms fail to meet standard quality criteria indicating that none of them may be considered reliable. The continuing uncertainty over the number and composition of fossil human species is the largest single source of error for cladistics and human phylogenetic reconstruction.

Journal of Human Evolution, 1987

2005

Para tantos pseudo-docentes que ocultan su falta de vocación como tales a través de la pseudo-investigación. Gracias Maria José

Airlines define their business models: a content analysis, 2017

Business model is not a new concept; however, it has been recently studied in business management literature. On the other hand, business model concept has not been studied in terms of its components in airline business. The purpose of this study is to see how airlines define their business models based on business model components. In this study business model concept is introduced and business model components are discussed as they have been explained in literature. Research part aims to explore how airlines describe their business models. To clarify this, a content analysis has been done in the strategic statements and in 'about us' parts of the websites of 50 biggest airlines worldwide. Our study shows that there are four components that airlines mention in their strategic statements and in 'about us' parts of their websites. These components are: 1) the value proposition; 2) the market segmentation; 3) the value chain; 4) the profit structure.