Autoavaliação
Em relação à disciplina, minhas expectativas foram superadas, principalmente em relação à escrita. Sobre o conteúdo específico, foi muito relevante também, e me "deu um norte" sobre o que devo dar atenção nos artigos de molecular de tubarões, e o que estudar mais afundo para compreender melhor o assunto.
Pessoalmente, acredito que o meu principal ponto fraco foi o gerenciamento de tempo. Nas duas primeiras semanas eu consegui desenvolver toda a atividade a ser entregue nos períodos entre o final das aulas e as 17h. Mas, nessa última semana, tenho dedicado todo o meu tempo para o desenvolvimento do ensaio. Além disso, eu não consegui ler, ainda que superficialmente, boa parte da bibliografia; em um ou dois assuntos percebi que não ter lido minimamente a bibliografia indicada fez com que eu me perdesse um pouco no assunto. Apesar disso participei ativamente das aulas, e me dediquei às atividades a serem entregues. Por isso, minha nota para mim mesma é 9.
Comentários Daniel sobre o texto
TExto bem bacana, seguindo os principios de escrita científica: frases título, ordem direta, referências e figuras.
Existem algumas expressões que poderiam ser melhor traduzidas para o inglês, exemplo:
Adaptationist thinking considers natural selection as the unique explanation for organisms’ adaptation (Sepúlveda & El-Hani, 2008).
"unique" tem um significado mais de "especial, diferenciado". a melhor palavra aqui seria "single".
O texto é bastante bom e aponta um problema fundamental, com exemplos reais empíricos. Sugiro que vc considere publicação deste texto em veículo apropriado da área do ensino.
Nota: 10
Ensaio Final
Is there something beyond adaptationism and Natural Selection to think and teach Evolution?
Adaptationist thinking considers natural selection as the unique explanation for organisms’ adaptation (Sepúlveda & El-Hani, 2008). The principle of natural selection states that certain traits can provide an advantage to organisms. The advantageous traits are selected by the environment and passed down to offspring. Thus, many traits of living organisms are the result of adaptations accumulated over time. Consequently, organisms with the advantageous traits are better adapted to environment; they also have a greater chance of survival and reproduction. Therefore, the perspective of adaptationist thinking recognizes natural selection as the primary mechanism driving the evolution of organisms (Meyer & El-Hani, 2005; Ridley, 2006; Sepúlveda & El-Hani, 2008). A classic example of natural selection is the camouflage of the peppered moth in the polluted areas of Manchester, England. The peppered moth (Biston betularia) from English biological collection in the XVIII century, exhibited light coloration with black spots (Figure 1). However, a variation with dark coloration (Figure 2) was documented in XIX century near Manchester.
Figure 1: Variation in the light coloring of the peppered moth (Biston betularia). Source: Google Images.
Figure 2: Variation in the dark coloring of the peppered moth (Biston betularia). Source: Google Images.
The dark variation increased in frequency, comprising 90% of population in the polluted area in the middle of XX century. In contrast, in non-polluted areas, the light variation remained predominant. One of the factors that explain the color selection of the peppered moth is bird predation. Light moths are more evident in polluted areas; on the other hand, dark moths are more visible in non-polluted areas (Figure 3). So, birds prey the evidenced color variation (Ridley, 2006). However, since the end of 1960s, the adaptacionist thinking has been criticized (Sepúlveda & El-Hani, 2007, 2008).
Figure 3: Peppered moth (Biston betularia) camouflage. Source: Google Images.
Empirical evidence and theoretical advances, such as the concept of genes and molecular genetics, shed light on the limits of natural selection (Kimura, 1991; Sepúlveda & El-Hani, 2008). Natural selection strongly influences the morphological (phenotypic) traits. However, which mechanisms, and at what level, give rise to morphological variation that can be selected? Sequential analysis of proteins and deciphering of the genetic code allow for the exploration of evolutionary mechanisms at the molecular and genetic levels. Nevertheless, evolutionary patters established at the morphological level do not necessarily apply at the molecular and genetic levels (King & Jukes, 1969). Changes in DNA (mutations) constantly occur. Intrinsic processes such as DNA replication, transcription and translation cause individual genetic variation. As a consequence, populations of the same species exhibit genetic variation (Kimura, 1991; Meyer & El-Hani, 2005). Most of mutations are random and have no effect on the survival and reproduction of organisms (neutral mutations). The increase in frequency and permanence (fixation), or extinction of neutral mutations in a population is also random. Genetic drift is the change in the genetic constitution of a population caused by stochasticity (King & Jukes, 1969; Kimura, 1991; Meyer & El-Hani, 2005). Stochasticity is understood as an important element in biological evolution at the molecular level (King & Jukes, 1969; Meyer & El-Hani, 2005). In light of new knowledge, Kimura (1968) proposed the neutral theory of molecular evolution.
The neutral theory attributes to genetic drift the predominant role in evolutionary changes at the molecular level. Meanwhile, neutral evolution does not deny natural selection. Actually, the neutral theory posits that only a very small portion of DNA changes is adaptive (Kimura, 1991). King & Jukes (1969) compared rates of amino acid substitutions in some mammalian proteins. Insulin, an important protein to mammals, for example, exhibited an elevated rate substitution. Elevated rates of substitutions in essencial proteins are not expected if only natural selection influences evolution; essencial proteins should be conserved to ensure their efficiency. The hypothesis to explain the elevated rates in essencial proteins is: substitutions that occurred should have no positive or negative effect on the individual, in other words, neutral substitutions. Thus, some substitutions accumulated over the course of mammalian evolution without any selection (King & Jukes, 1969). The situation explained in the example with mammals is valid for any other living being. Figure 4 demonstrates the difference between the types of mutations expected under selection and the neutral theory.
Figure 4: Difference between the types of mutations expected under selection and the neutral theory. Source: Google Images.
Nowadays, the process of evolution is understood as pluralistic, with distinct mechanisms involved (Gould & Lewontin, 1979; Roma, 2011). Unfortunately, the understanding of complexity of evolution is restricted to a portion of the scientific community (Roma, 2011). In Brazil, the educational content of elementary and high schools does not address the complexity of evolution. Nevertheless, according to national curricular parameters (parâmetros curriculares nacionais - PCNs), evolution is an integrating axis in the understanding and teaching of biology (Tidon & Vieira, 2009; Dalapicolla, Silva & Garcia, 2015). Formally, the content of evolution as outlined in the nacional common curriculum base (base nacional comum curricular - BNCC) is: evolutionist ideas (last year of elementary school) - Compare the evolutionary ideas of Lamarck and Darwin as presented in scientific and historical texts, identifying similarities and differences between these ideas and their significance in explaining biological diversity. Discuss the evolution and diversity of species based on the action of natural selection on variants within the same species resulting from reproductive processes; high school (all the three years) - Analyze and discuss models, theories, and laws proposed in different periods and cultures to compare different explanations about the origin and evolution of life, Earth, and the Universe with currently accepted scientific theories. Apply the principles of biological evolution to analyze human history, considering its origin, diversification, spread across the planet, and various forms of interaction with nature, while valuing and respecting human ethnic and cultural diversity (http://basenacionalcomum.mec.gov.br).
In Brazil, textbooks are an essencial teaching material. The importance of textbooks to evolution teaching is widely recognized and well-established (Roma, 2011; Zamberlan & Silva, 2012; Tomotani & Salvador, 2017). Tomotani & Salvador (2017) analyzed nine textbooks used to teach evolution in elementary school. All nine books addressed evolution superficially and do not present evolution as the fundamental and unifying theory of biology. Furthermore, the nine books discuss natural selection as the primary agent of evolution. It is not clear if genetic drift is addressed in these books. Tomotani & Salvador (2017) highlight the presence of conceptual errors in the analyzed books. Tomotani & Salvador (2017) hypothesize that these conceptual errors may result from deficiencies in the training of the textbook authors. Roma (2011) analyzed nine textbooks used to teach evolution in high school. The nine analyzed books emphasize the evolutionary theory by natural selection. All the books present Lamarck's evolutionary theory and the law of use and disuse as alternative evolutionary theories, but none of the analyzed books mention the neutral theory of evolution. In contrast, eight books cover population genetics, and seven books discuss genetic drift, topics relevant to the neutral theory.
The monopoly of adaptationist thinking in the formal teaching of life sciences is empirically demonstrated. Often, the argument that not all scientific knowledge can be accommodated in textbooks is used. However, at the same time, mandatory content to be taught is consolidated based on political, cultural, and educational interests. In the United States, for example, evolution is explicitly disqualified in textbooks in favor of the creationist hypothesis. In Brazil, although the creationist hypothesis is discussed in textbooks, there is no explicit disqualification of evolutionary thinking. Textbooks represent, albeit partially, the political and cultural interests of education. Even though there is something beyond adaptationist thinking and natural selection to consider in thinking about and teaching evolution, the analyses conducted based on textbooks make it clear that the complexities of the evolutionary process are not priorities in biology education in Brazil (Roma, 2011; Tomotani & Salvador, 2017).
References
Base Nacional Comum Curricular (BNCC) http://basenacionalcomum.mec.gov.br/
Dalapicolla, J., Silva, V. de A., Garcia, J. F. M. (2015) Evolução biológica como eixo integrados da biologia em livros didáticos do ensino médio
Gould, S. J. & Lewontin, R. C. (1979) The Spandrels of San Marco
Kimura, M. (1968) The neutral theory of molecular evolution
Kimura, M. (1991) The neutral theory of molecular evolution: a review of recent evidence
King, J. L. & Jukes, T. H. (1969) Non-Darwinian evolution
Meyer, D. & El-Hani, C. N. (2005) Evolução: o sentido da biologia
Tomotani, J. V. & Salvador, R. B. (2017) Análise do conteúdo de evolução em livros didáticos do ensino fundamental brasileiro
Ridley, M. (2006) Evolução 3ª edição
Roma, V. N. (2011) Os livros didáticos de biologia aprovados pelo programa nacional do livro didático para o ensino médio (PNLEM2007/2009): a evolução biológica em questão
Sepúlveda, C. & El-Hani, C. N. (2007) Controvérsias sobre o conceito de adaptação e suas implicações para o ensino de evolução
Sepúlveda, C. & El-Hani, C. N. (2008) Adaptacionismo versus exaptacionismo: o que este debate tem a dizer ao ensino de evolução?
Tidon, R. & Vieira, E. (2009) O ensino da evolução biológica: um desafio para o século XXI
Zamberlan, E. S. J. & Silva, M. R. (2012) O ensino de evolução biológica e sua abordagem em livros didáticos
- o ChatGPT foi utilizado para correção gramatical.