“Education is the most powerful path to sustainability. Economic and technological solutions, political regulations or financial incentives are not enough. We need a fundamental change in the way we think and act.” (Bokova, 2012)
Ethics is, according Savater (1995) , the art of living well, of knowing how to live. To have, practice, and manage the art of living well is ought to provide a good life. A good life implies choosing, which for those with less academic resources is more difficult (see IDSN , http://idsn.org/key-issues/education/). Our well-being depends on the existent biodiversity and on ecosystems’ prosperity (MEA, 2005) . However, people still choose to deplete natural resources, affecting other species, hence reducing biodiversity (Rands et al., 2010) , and even annihilating it (see Ceballos et al., 2017 ).
The 2000-2010 decade was productive in ideas, congresses and documents about how the loss of biodiversity jeopardizes our future. It is the decade of the Millennium Development Goals (MDGs), and of the Millennium Ecosystems Assessment (MEA). The MEA (2005) highlights the fact that society does not understand completely how biodiversity and well-being are linked. Most people recognize that their lives depend on natural functions, which provide fresh water, food, shelter, fibers; but people take the benefits they take from Nature for granted (MEA, 2005) .
In developed countries, schools teach how important it is to preserve biodiversity. Of course, in these countries, native biodiversity has been deeply affected by the development of societies through centuries (Despommier, 2010) . We became aware of the importance of preserving forests, dealing with waste, and purifying water to drink (Despommier, 2010) . Schools in developed countries have projects like ECO-SCHOOLS , http://www.ecoschools.global/, and most (if not all) subjects (English, Geography, History, Informatics, Mathematics, Natural Sciences, etc.) incorporate themes related with the Brundtland Report (1987) and the Agenda 21 (1992) themes. Whereas developed countries have been improving their school systems and acquiring experience in teaching and creating experiences related with biodiversity and sustainability, debating about science and ecology, which are complex issues for kids, teenagers and even adults (Vale, 2013; Nordlund, 2016) , developing countries are struggling to bring more children to school, to build better schools, to train more teachers and to improve subjects’ curricula (see “progress of goal 4 in 2017” at SDG 4 (2015) https://sustainabledevelopment.un.org/sdg4). Because people’s future will depend on how they relate to ecosystems, it is urgent to provide strategies to empower teachers and learners on a global basis.
“Biodiversity change is (…) inextricably linked to poverty, the largest threat to the future of humanity identified by the United Nations (Díaz et al., 2006) .”
The contribution done here addresses the concern of empowering society to understand the link between biodiversity and human well-being in such a way that almost every aspect of people’s lives could be conducted by a better philosophy of choosing healthier ways of relating to ecosystems’ functions, services and species. Our way of living is not yet oriented towards sustainability, and the only way to improve it is by reaching as many people as possible through education.
“(…) education is a public good, a fundamental human right and a basis for guaranteeing the realization of other rights. It is essential for peace, tolerance, human fulfillment and sustainable development.” (UNESCO, 2015)
Science, as an institution, has been concerned with these issues and debates a way to “translate economic and socio-cultural values of ecosystems services into monetary values” (de Groot et al., 2010) to make people understand better its importance (Costanza et al., 1997) . Science is still deciphering how biodiversity is linked to ecosystem services (Díaz et al., 2006; Rands et al., 2010) , while the United Nations (UN) assesses governments on their efforts to reach Sustainable Development targets related to climate (SDG 13), biodiversity on land (SDG 15) and sea (SDG 14) goals, among others (https://sustainabledevelopment.un.org/?menu=1300).
Planetary citizenship is also a well-known concept that emerged from a post-globalization world (Bindé, 2004) that is still being developed (by the SDGs ). UNESCO established the creation of four contracts to build planetary citizenship values: The social contract, in which education should be viewed as a priority through life; The natural contract, which aimed at serving the human development, respecting ecosystems and species; The cultural contract, which debated cultural impacts; and The ethical contract, that aimed for the emergence of a global philosophy, in what concerns human well-being and sustainable development (Odhiambo in Bindé, 2004) . Philosophers like Popper (1999) , years before, struggled to build a global framework to end poverty and violence. Many (UN, UNESCO, UNICEF) believe that education is a strong tool to make a difference in building up a better planetary citizenship (UNESCO, 2015) .
In this paper, it is aimed to make a specific contribution of a basic science global curriculum for seven years of school (from primary 3 to the ninth grade). It is also intended to debate the importance of providing a basic framework to guide science teaching from the third grade to the ninth grade; sometimes, instead of establishing an unachievable goal, to begin with a simpler solution can be better.
Education through life is also an ambitious goal, and, perhaps, still far from reach in many parts of our world. But, the effort of providing information to adults will help people ask more questions and search for answers. A basic curriculum for children can be used and adapted to adult’s need of learning more about science.
“Education transforms lives and is at the heart of UNESCO’s (2017) mission to build peace, eradicate poverty and drive sustainable development” http://en.unesco.org/themes/education-21st-century
2. A Global Science Curriculum: A Framework for the First Nine Years of School
The Incheon Declaration (UNESCO, 2015) emphasizes the need for “relevant teaching and learning methods and content that meet the needs of all learners, (…) using appropriate pedagogical approaches and supported by appropriate information and communication technology (ICT)”, among other important issues. ICT, for example, are not available in every school, but education systems can deliver information to remote schools. Because of the urgency of providing “relevant content that meet the needs of all learners”, we believe that a basic framework to teach and engage children, teenagers and adults (people are never too old to learn) in Science learning is fundamental. This curriculum, proposed here as a non-closed document, i.e. open to discussion, is ought to be translated and downloaded by any country that desires to use it. Also, the pedagogical approaches and materials derived from the curriculum should be available and translated for free in every language. This is the perspective we advocate.
We are mostly concerned with an “education for sustainable development” (ESD) that prepares children for problem solving, critical thinking and reflecting about issues that condition their lives (Vale, 2013) . We want them to be aware of the fact that human beings are connected and depend on ecosystems and other species. We want them to be able to criticize and predict the consequences of human actions for the environment.
The framework shown here tried to intertwine information from several fields of Science, especially for the 7th, 8th and 9th grades of the curriculum. Repetition of information was avoided, thinking on the importance of providing a basic set of information to children that face the risk of quitting school earlier. We strongly recommend teachers to see this curriculum not as a “list of required topics and information” to pack in each school year (Vale, 2013) , but as a guide to adapt to the context of each situation. We also emphasize the importance of the views shown in Vale’s (2013) perspective, since allowing children to ask questions is allowing them “to promote independent learning”.
The framework for the first years of school is shown in Table 1. We consider that Natural Sciences should be introduced as soon as possible. In fact, primary education in Singapore comprises Science as one of the core subjects for primary education, and they introduce it in primary 3 (Tan et al., 2016) . The recommendation of starting with 8 years old is just because many schools do not have the means to keep young children for many hours learning, so they engage in teaching first native languages and mathematics. However, Science can be introduced even earlier (i.e. pre-school education). A connection between the themes and some of the SDGs was also taken in concern, and is pointed out in Table 1 and Appendix A.
For the 5th and 6th grades the complexity increases. The curriculum we propose is focused on understanding how science works and how ecosystems function. Conservation biology topics are explored (see Table A1 and Table A2. in Appendix A).
For the 7th, 8th and 9th grades abstract notions are added like: what were dinosaurs, how mountains are built, what is matter and energy, etc. Evolution, cell structure and metabolism, are examples of themes that should be developed (see Tables A3-A5 in Appendix A).
Table 1. Natural Sciences curriculum themes for the first four years of school; Themes were distributed for the third and fourth years of primary school, but they can be distributed in other ways.
To develop materials for or derivations of this (or other) curriculum, we emphasize the importance of learning in a “safe, healthy, gender-responsive, inclusive and adequately resourced environment” (UNESCO, 2015) , as much as possible. What is encouraged is a state of mind of “Teach Less, Learn More”, following Singaporean ideology (Tan et al., 2016) .
Education about conservation ecology is important to improve human relation with natural goods and benefits. Only through education will it be possible to improve the human relationship with ecosystems. The public and governments’ interest in reverting the pressures on wild species is increasing, as Rands et al. (2010) emphasize, but not effectively to halt biodiversity loss (Ceballos et al., 2015, 2017) . Perhaps due to the fact that, like climate change, ecology’s complexity demands more understanding and compliance from governance and policy, sponsors, markets, education systems, and from common people.
“Education systems must be relevant and respond to rapidly changing labour markets, technological advances, urbanization, migration, political instability, environmental degradation, natural hazards and disasters, competition for natural resources, demographic challenges, increasing global unemployment, persistent poverty, widening inequality and expanding threats to peace and safety.” (UNESCO, 2015) .
Marine turtles, for example, subjects of many conservation projects have a strong impact on tourists and local people, especially children. But the local children are confronted with mixed feelings: turtles must be protected to ensure monetary revenue by tourism (upon which many families rely), but turtles are also explored and pressured by being advertised by locals. This is what happens, for example in Quintana Roo, México despite the efforts of non-governmental organizations like “ Centro Ecológico Akumal ” (http://www.ceakumal.org/), that develop environmental education activities for children. And this is only an example that involves emblematic species and their delicate habitats and niches (the nesting beaches used by females, the sea grass beds and the corals explored by the juveniles in the coast).
Human-wildlife conflicts―another example―show the complexity of the human need to use ecosystems and compete with other species. For humans, other species have different value. Some are just to contemplate, while others provide material goods (many of which have been prohibited to collect).
Elephants are poached because of their ivory (Goldenberg et al., 2016) , and though it is prohibited to hunt them, many poachers still take the risk, because of the profit generated in the market (Goldenberg et al., 2016) . Many elephants are also killed because they are feared and destroy goods (Taruvinga & Mushunje, 2014; Anastácio et al., 2014) . But in all cultures they are seen as symbols of nature, used as flagship species (Lee & Graham, 2006) . Beyond the problems they cause, elephant’s species are gardeners of the ecosystems (Douglas-Hamilton et al., 2005) , and they are classified as keystone species (Meffe & Carroll, 1997; Thouless et al., 2016) , hence, they play an important role in the ecosystems, which humans cannot afford to lose. The example of elephants’ relation with humans poses a great challenge to all of us. How can poor people live and share resources with these big and charismatic creatures? Elephants’ spots and home ranges are being invaded by people in worryingly increasing numbers, and conflicts happen frequently, ending in people or elephant deaths (Douglas-Hamilton et al., 2005; Pinter-Wollman, 2012; Taruvinga & Mushunje, 2014) , even inside protected areas (Craig, 2013) . So, how can this problem be dealt with from an educational perspective? Can it be separated from an ecological/conservation perspective? Can the biological perspective be separated from the social point of view? It seems like it cannot (Bradshaw & Bekoff, 2001) . Conservation ecology is a multidisciplinary field that depends on understanding peoples’ beliefs and needs (sociology, anthropology), how ecosystems function (ecology, biology), and how society experiences their time and space (economics, political science, communication science, education science) (Meffe & Carroll, 1997) .
What can we do, as a global society, to help preserve species like elephants, and people? What can we teach and inform people about that would make a difference? We can prepare people to debate the dilemma by going to school. The Incheon Declaration (UNESCO, 2015) has the ambition of ensuring “the provision of 12 years of free, publicly funded, equitable quality primary and secondary education, of which at least nine years are compulsory, leading to relevant learning outcomes.” A general science curriculum for the first nine years of school that emphasizes themes related with human well-being and ecosystems conservation, that enables the debate of complex questions like “what can we do to mitigate ivory poaching?” is, in our belief, a strong strategy. It is expected to be available online, but also in the form of didactic materials, for teachers to use them. Instead of waiting for each country to define standards and review curricula, UNESCO can provide, for each subject, a basic curricula for each grade, and from it, each country can adapt it to “ensure quality and relevance to the context, including skills, competencies, values, culture, knowledge and gender responsiveness” (UNESCO, 2015) . For example, in the absence of a solution, the Ministry of Education of each country can start to translate and adapt the basic science curriculum, for every language spoken in the country, and upload their versions in the web. Only by sharing educational resources and experiences is it possible to transform lives in an effective way. And the attitude of sharing freely and offering pedagogical materials can help achieve a holistic development of competencies, like critical thinking, creativity and divergent thinking, communication, collaboration, independent learning, lifelong learning, and the most important of all, active citizenship (Tan et al., 2016) , and global citizenship, and critical questioning (Vale, 2013) .
Singapore, one of the most successful stories of growth, invested in its educational system in such a way that it constitutes an example that is still seeking, today, ways of improving and of breaking with a homogeneous rigid system (though effective) to become more heterogeneous, enabling their students to discover themselves by also developing soft skills (OECD, 2010; Gopinathan, 2011; Tan et al., 2016) .
UNESCO has started the “sharing” effort with the “ Open Educational Resources ” (UNESCO-OER, 2017) , or by creating the International Bureau of Education (IBE) (a global center of excellence in curriculum, at http://www.ibe.unesco.org/en/who-we-are). Also, initiatives like PISA4U (https://www.pisa4u.org/), which started in 2017, and even sites like https://www.oercommons.org/, or BBC Bitesize http://www.bbc.co.uk/education/subjects/zng4d2p constitute solid examples of what is intended. We believe that these platforms and projects would benefit from more simplicity (pages are a bit confusing, with immense information). Sharing what we know and how we know it for free is one of the most valuable gestures for the future of all living things.
Other aspects are needed, like improving the preparation of teachers, or supervising pair work, choosing the most gifted for the job. However, considering that a country does not have enough teachers, at least every person with university or even secondary graduations can, if guided, help in the first years of education to expand the network of schools and achieve the SDGs 4, 5, and 10. In Portugal many engineers started to teach Mathematics, Physics or Chemistry in public schools after the 1974 Revolution, and many found a passion for teaching. It also happened with Biologists, who became great Biology teachers. Later, these “teachers” had to become specialized in education, and they embraced the teaching career, instead of the technical and industrial purpose for which they were prepared. If people have the proper orientation (e.g. clear curricula and materials), and the values that guide a teacher’s activity, many can transform themselves into marvelous teachers. How many retired engineers, industry leaders, attorneys, investigators etc. in many countries can help teaching children as volunteer work? We comprehend that a country without enough teachers has to make a plan. Other measures have to be taken: if there is no money to train teachers, is it possible to train people in a specific area, whilst providing knowledge for that same person to be able to teach in a public school? Is it possible to have more than one profession in our lives? Is it possible to invest more in education and train more teachers? Is it possible to, after that, take the step of increasing teachers’ pay? Poor countries need to be creative in finding solutions. Rich countries need to be supportive and share know-how. For now, our concern is delivering a curriculum for seven years of schooling that conjugates Physics, Chemistry, Biology and Geology in one single subject: Natural Sciences.
To make a difference in a child’s life is to empower that child to become free to choose and act, feel and seek security in the environment, have access to basic materials, healthcare and information in a society that enables good social relations among people and that respects ecosystems and other species (MEA, 2005) . Educating children from an early age in Science themes will increase their capacity to ask important questions, and to seek answers through their adult life. The Incheon Declaration has the goal of providing nine years of quality education to every child in the World. Whereas some countries have the means and the experience of good practices, underdeveloped countries struggle with many problems, including having a task force which is either unprepared or not large enough to guarantee nine years of studying for every girl and boy.
The global Natural Sciences Curriculum is open to discussion and it is not a perfect scheme. It intends to conjugate Biology, Geology, Physics and Chemistry in a single framework. This framework was built having in consideration the SDG 4, through which it is possible to achieve the SDG 1.
To build up the following curricula the authors studied the science curricula from Portugal (RA applied the Portuguese Natural Sciences Curriculum several years, as a teacher―5th to 9th grades and 10th - 12th grades biology/geology curriculum), Mozambique (to which the authors had access), United States and U.K. (K-12)―available in the internet.
Several recent Biology, Geology, Chemistry and Physic books were used, to prepare a logical perspective of the themes.
Table A1. Proposal for fifth grade natural science curriculum.
Table A2. Proposal for sixth grade natural science curriculum.
Table A3. Proposal for seventh grade natural science curriculum.
Table A4. Proposal for eighth grade natural science curriculum.
Table A5. Proposal for ninth grade natural science curriculum.