Human Activities' Impact On Biological Evolution: A Topic for Evolution Educators To Think About
The important anthropogenic role humans presently play in current evolutionary processes and biosphere effect must be firmly emphasized at all levels of scientific education. This article provides a brief overview of recent human activities, as well as broad examples of how human activities have influenced biological evolution, a general overview and specific examples of incorporating human activities into evolution education, and additional online anthropogenic resources that can be used in educational settings.
It's frequently difficult for us to see ourselves as animals that interact with the world like people. "A blindness to the humanlike qualities of other animals, or the animal-like characteristics of ourselves," says Frans B. M. de Waal, who coined the term "anthropodenial." We have a different perception of a dam built by a North American beaver than we do when we construct one. However, from an evolutionary standpoint, we are both mammal species doing what we do as a result of our common evolutionary history from a period not so long ago. Throughout our lifetimes, we both engage in environmental modification activities (such as dam construction) that are compatible with our shared and different evolutionary features. While the quantity and collective activities of North American beavers have decreased due to people during the past 250 to 300 years, the number and collective activities of humans have grown dramatically over the same time span.
A Summary Of Human Activities In The Recent Past
Over the past 250 to 300 years, the number of people on the planet has increased dramatically. There were 300 million people on Earth two thousand years ago. There were 310 million people on the planet 1,000 years ago, and 790 million people on the planet 260 years ago (all values are approximate; United Nations 1999). Human population has grown by 6.1 billion individuals in the previous 260 years. On Earth, there are now 6.9 billion people, with a predicted population of 9.3 billion by 2050. (all values are approximate; U.S. Census Bureau 2010).
Humans have surpassed nature as the planet's most powerful geophysical force. We presently use over half of all available fresh water and a third to half of all available land on the planet (Lewis 2006). We've constructed reservoirs that store three to six times the amount of water found in natural rivers, and we've moved more dirt, rock, and silt than all natural processes combined. We utilize more nitrogen fertilizer than all natural terrestrial ecosystems can fix, and we create more nitric oxide than all natural sources combined.
Human energy consumption has increased sixteenfold over the previous century, resulting in "160 million tonnes of atmospheric sulphur dioxide emissions per year, more than double the amount of natural emissions." Global fossil fuel emissions surged by 41% between 1990 and 2008, and by 29% between 2000 and 2008, pushing CO2 levels into the stratosphere to their greatest levels in 15 million years and causing global warming, rising sea levels, and climate change. Humans have accelerated planetary erosion and continent devastation via building and agriculture. By an order of magnitude, erosion has now surpassed natural sediment production. In the mid to late 1980s, the worldwide human ecological footprint surpassed Earth's biocapacity, and "today surpasses the planet's regenerative capacity by around 30%," according to global human consumption rates. As a result of the global overshoot, ecosystems are deteriorating and garbage is accumulating in the air, land, and water."
Human Activities' Impact On Biological Evolution: A Few Examples
Human actions have an impact on the development of creatures like agricultural pests, weeds, and bacteria on a smaller scale. Pesticides and herbicides to manage agricultural weeds are constantly being developed and used by humans. In the year 2000, people in the United States alone used 700 million pounds of pesticide. Insects often acquire resistance to new pesticides within 10 years after their introduction. Agricultural pest species have developed resistance to so many pesticides that management is impossible in certain circumstances.
Agricultural weeds frequently gain resistance within ten to twenty-five years of the administration of a newly designed herbicide, resulting in similar evolutionary results. When inefficient antibiotic usage promotes evolution, human disease-causing microorganisms become resistant to numerous antibiotics. Overprescribing antibiotics and not finishing a course of antibiotics are two of the wasteful applications that are fueling bacterial evolution. More human-induced bacterial evolution may be seen in cattle production, where developed resistance can also be shown.
Beyond what has been seen in agricultural pests, weeds, and bacteria, significantly more severe large-scale human-induced evolutionary implications are occurring, with 65 percent of worldwide aquatic river habitat under moderate to high danger (Vörösmarty et al. 2010). More than half of the world's tropical wet forests have been lost, yet the tropics are home to around two-thirds of all creatures. The surviving tropical wet forests and the creatures that live in them are expected to be eliminated by 2060 (Pimm and Raven 2000) at their present pace of destruction, bringing an end to these species' extensive evolutionary histories.
Human activity over the past 250 to 300 years has accelerated global species extinction rates 100 to 1,000 times faster than Earth's historical geological background rate (Mace et al. 2005; Pimm et al. 1995; Rockström et al. 2009), ushering in the sixth great mass extinction in evolutionary history (Alroy 2008; Crutzen and Stoermer 2000; IUCN 2010; Jackson 2008; Lewis 2006; McDaniel and Borton 2002; Rockström et Future extinction rates are expected to be 10,000 times higher than the Earth's past geological background rate, according to computer modeling (MEA 2005). Given the rising human activity, complex key evolutionary radiations are likely to be lost in the near future.
Past mass extinctions, like the present one, have had a significant impact on the development of life on Earth. After the Ordovician-Silurian Extinction (around 439 MYA); Late Devonian Extinction (circa 364 MYA); Permian-Triassic Extinction (circa 251 MYA); End Triassic Extinction (circa 199–214 MYA); Cretaceous-Tertiary Extinction (circa 65 MYA); Cretaceous-Tertiary Extinction ( (Veron 2008). If the prior five major mass extinctions are any indication of what would happen after the present human-caused mass extinction, "evolutionary processes would not develop a replacement supply of species within fewer than several million years," according to the report (Myers et al. 2000).
Incorporating Human Activities Into Evolution Education: A Comprehensive Overview And Specific Examples
Science has shown the extent to which humans has influenced biological evolution and the ecosystem. Except for a few instances of evolutionary change in bacteria (e.g., ineffective use of antibiotics) and RNA viruses, this science is curiously absent from most scientific curricula, state science educational standards, and national science educational standards at practically every educational level (e.g., the need for new seasonal influenza vaccine every year). The important anthropogenic role humans presently play in current evolutionary processes and biosphere effect must be firmly emphasized at all levels of scientific education.
Integrating free online anthropogenic research and anthropogenic research reports from organizations like the World Wide Fund for Nature (WWF) and the Millennium Ecosystem Assessment (MEA) into existing science classroom curricula is one approach to emphasize this topic. For example, science educators can start addressing and emphasizing many specific anthropogenic evolution questions with their students by using five of the most ecologically devastating and far-reaching anthropogenic direct drivers that currently affect global biodiversity and species evolution: (1) habitat modification, fragmentation, and destruction; (2) overexploitation of species; (3) the spread of invasive species and genes; (4) pollution; and (5) climate change (MEA 2005; MEA 2005a; WWF 2008; WWF 2010).
WWF (WWF 2008; WWF 2010) and MEA (MEA 2005; MEA 2005a) reports may contain, but are not limited to, the following activity-driven questions: How does it effect a species' gene flow and genetic drift when people change, fragment, or destroy habitats? What's the link between a species' overexploitation by humans, its evolutionary fitness, and the heterogeneity of its gene pool? What effect does extinction caused by humans have on the evolutionary history of a species? What effect does pollution caused by humans have on biological evolution? What is the evolutionary significance of human-induced invasive genes? Invasive species caused by humans have an influence on coevolution. The bibliography includes other free online anthropogenic materials. These materials have the potential to be used to create a variety of question-based activities that address the present influence of human actions on biological evolution.
Pedagogy focused on inquiry-based learning (e.g., scientific inquiry [NRC 1996]; problem-based learning; 5E learning cycle, and instructional model [Bybee 1997]) that is combined with technology (e.g., TOXMAP and Google Earth) should be utilized to enable students to completely study these evolution concerns as well as to fully comprehend the complexity of the environmental challenges and problems that mankind is facing and will face in the next 50 to 100 years. Field excursions to local areas that have been affected by human activity should be done whenever feasible. Students may gather data to determine the extent of anthropogenic change and explore the effect that these activities may have had or will have on local species evolution and the ecosystem in general. Anthropogenic field visits provide authenticity to the educational experience by enabling students to see firsthand the environmental deterioration that is taking place in their communities. These encounters may then be brought back into the classroom for a more detailed discussion.
Aside from a focus on integrated science content (e.g., humanity's impact on biological evolution and the biosphere), inquiry-learning pedagogy combined with technology, and the use of local anthropogenic field trips, question-driven activities should place a special emphasis on how humanity can begin to decelerate the anthropogenic trajectory we are currently on. This problem may be explored by looking at the two primary underlying causes that are causing current global environmental degradation: the human population's expansion and the pace at which natural resources are used. These question-driven actions should also be framed by the knowledge that, on average, the more developed nations use the most natural resources per capita, while the developing countries have the fastest population increase. An emphasis should also be placed on examples of the development and implementation of more efficient and environmentally sustainable human activities, as well as an awareness that a person in a more developed country, such as the United States, consumes significantly more natural resources per capita than a person in a developing country. As a result, a person in a highly developed nation produces much more environmental destruction, either directly or indirectly, than a person in a less developed one. Finally, a focus should be made on how mankind, the class as a whole, the instructor, and the individual student may begin to morally and equitably lessen both of these underlying issues by modifying existing actions.
Human actions have clearly changed and will continue to influence the evolutionary history of numerous species in the past, present, and future. It's unclear how severe these future evolutionary shifts and extinctions will be. Education might be a method for slowing human activities that are influencing global organismal development both directly and indirectly. To that aim, evolution educators, environmental educators, and science educators in general must build curriculum that address and stress the ever-increasing influence humans have on the development of other animals and the biosphere.