1. Evolutionary theory (and its history)
2. A revisionist and relevant history
3. Does evolutionary theory need a rethink?
Evolution: descent with modification, i.e., inherited change in the properties of groups of organisms over the course of generations. (Individuals do not evolve, populations do).
Natural Selection: The differential success (reproduction) of individuals in a population based on phenotypic variation. (Provides a mechanistic explanation for apparent design in nature that does not invoke the supernatural.)
Adaptation: a characteristic that varies (or varied) within a population that enhances (or enhanced) the reproductive success of individuals that bear it. Adaptations have evolved by natural selection.
Futuyma Evolution Box 1A
1831-1836: Charles Darwin serves as naturalist aboard the H.M.S Beagle charting the coast of South America. He collects fossils, specimens, and studies the diversity of local flora and fauna.
1859: Darwin publishes The Origin of Species describing descent with modification and the role of natural selection acting on hereditary variation.
1833, Charles Lyell: wrote Principles of Geology presenting geological evidence (including fossils) that the Earth is very old. Proposed uniformitarianism: that processes of small effect observable in the present (e.g., erosion) can create large-scale patterns over time.
1798, Thomas Malthus: wrote The Principle of Population arguing that populations will overgrow their capacity and cause massive starvation. At the time this thesis spurred social debates over class and government. Darwin realized the consequences of a non-random subset of individuals surviving to reproduce.
Where does variation come from? Although it was widely recognized that offspring appear similar to their parents (heredity), the prevailing understanding of the time was of Blending Inheritance, that variation should decrease towards the mean, not increase over time...
1866, Gregor Mendel wrote on a theory of Particulate Inheritance, proposing that inheritance is based on particles (i.e., genes) not blending fluids. This work was not widely known until much later. (link: an interesting book on Mendel).
By the 1930's a consensus had developed that adaptive evolution is caused by natural selection acting on particulate (Mendelian) variation.
This was spurred by the development of mathematical approaches to studying phenotypic variation in populations, primarily by Wright, Fisher, and Haldane.
The foundations of modern evolutionary biology -- the major causes of evolution within and among species -- were established as mutation, gene flow, genetic drift, selection, and recombination.
(Link: further reading on the major scientists and writers involved.)
Eugenics: The connection between the rise of evolutionary theory and eugenics cannot be ignored. Nearly every evolutionary biologist of the modern synthesis era was involved in debates on the topic. Although it has fallen from favor, the ideas persist in many systemic and outright ways today.
R.A. Fisher: one of the founding fathers of the Modern Synthesis (and also of Statistics) wrote extensively on eugenics, promoting racist doctrines and sterilization of people with disabilities.
James Watson: co-discoverer of the structure of DNA. Also famously stole information from Rosalind Franklin that aided in the discovery, without credit. Recently stripped of honors and position at Cold Spring Harbor Laboratories after years of complaints about racist attitudes and statements.
The practice of forced or coerced sterilizations as a government
sanctioned method of affecting the frequency of traits in a population
has been practiced for decades.
One of the most famous US supreme court cases, Buck v Bell (1927), ruled that the state of Virginia could sterilize women for eugenic purposes, leading to more than 70,000 sterilizations. Citing the best interests of the state, Justice Holmes wrote that to prevent the nation from "being swamped with incompetence... Three generations of imbeciles are enough."
Forced sterilization programs continue to this day, though not under the guise/term of eugenics. For example, investigative reporting recently revealed that nearly 150 Latina and African-American women were sterilised between 2006 and 2010 in the California prison system. These practices are a continuation of history that was insufficiently taught and retold. What is our responsibility as educators in evolution?
Traditional categories of race are not supported by scientific
evidence, but, humans do share different degrees of ancestry with one
another in ways that can be measured. How can we study and
use human ancestry ethically and equitably?
e.g., quantifying Native American ancestry as a test for membership has been highly controversial.
e.g., personalized medicine promises more equitable health care by taking into account ancestry. Is racial categoriation a lazy solution?
e.g., genome editing can be used to reduce genetic disease and even select specific traits, can we cure genetic diseases without slipping into eugenics
Just as the public is generally poorly educated on evolution, it is also
poorly educated on many shameful applications of evolutionary thinking.
Just consider the
2006 film "Idiocracy" by Mike Judge, the central concept
of which is a classic eugenic trope: that more highly
educated people reproduce at lower rates causing the population to
"degenerates" over time as the descendants of the less educated
increase in the population. Fisher wrote on this
exact scenario in 1930, arguing for government programs to support the
upper class to aid in their fertility.
This argument was not made in some obscure publication, it is made in his book "The Genetical Theory of Natural Selection", one of the founding texts in evolutionary biology.