Evolution Theory Questions and Answers

Charles Darwin

Evolution Theory

Questions and Answers

Theodore C. Goldsmith

What is an evolutionary mechanics theory?

An evolutionary mechanics theory attempts to describe the evolution process, the “how it works” aspect of evolution.

What is Darwin’s survival-of-the-fittest or natural selection evolutionary mechanics theory?

In 1859 Darwin described an evolutionary process in which evolution caused organisms to acquire evolved inheritable design characteristics (traits) that caused individual members of a species possessing the trait to produce more adult descendants than those not possessing the trait. Darwin’s concept plausibly fits the vast majority of observed traits and is widely thought to be a comprehensive explanation for the evolution process.

Why are genetics discoveries important to evolutionary mechanics theories?

Genetics discoveries have exposed issues with details of Darwin's evolutionary mechanics concept and suggest that the evolution process is more complex and time consuming than previously thought. These discoveries act to increase the feasibility of changes to Darwin's mechanics concepts.

Are there current scientific disagreements regarding evolution theory?

There is very little disagreement regarding the fact of evolution. Current species are descended from earlier and different species and the evolution of Earth life has progressively and accumulatively continued for billions of years starting from single-cell organisms. Darwin’s survival-of-the-fittest concept plausibly fits the vast majority of observations concerning organism designs. However, some observations, specifically including biological aging and animal altruism, did not fit eventually leading to multiple proposed modifications to Darwin’s evolutionary mechanics concept.

What is the main current disagreement regarding evolutionary mechanics?

The main current disagreement concerns the degree to which the growth and non-extinction of a species population affects the evolution process relative to the survival and reproduction of individuals. This issue is crucial to explaining the existance of aging because there is wide agreement that aging reduces an individual's ability to reproduce, at least in mammals. There are now multiple theories to the effect that aging increases a population’s ability to avoid extinction and grow.

What is an evolutionary theory of aging?

An evolutionary theory of aging attempts to explain how aging relates to the evolution process and more specifically, why senescence varies so much between species and otherwise resembles evolved inherited species-specific characteristics (traits) of organisms.

What is phenotypic linkage and why is it important to evolutionary mechanics theories?

Most elements of an organism’s design have a relationship with the other elements. Therefore, changing any one element (e.g. femur length) typically requires complementary “linked” changes to other design elements such as muscles, tendons, and blood supply to result in a net fitness benefit. This has implications for the nature of the evolution process, particularly regarding time-scale.

What is a genomic linkage and why is it important?

The genomic design of an organism can cause otherwise unrelated phenotypic traits to be linked to each other in such a way as to inhibit the evolution of an organism design that contains one of the traits without the other. Multiple aspects of a diploid organism’s genomic design such as pleiotropy, chromosomes, and genetic distance can result in such a genomic linkage.

Why is selective breeding not like evolution?

Selective breeding is directed at enhancing or attenuating a few organism traits that vary between individuals capable of being interbred with relatively little concern about inadvertent changes to other traits and operates on a very short time scale. Evolution is concerned with the combined net effect of all of an organism’s traits on fitness and because of many inter-trait linkage mechanisms is a much more complex and a very much longer process. Evolution can alter traits that do not vary between individual members of a population because mutations can introduce new variations.

What is pleiotropy?

Pleiotropy refers to the observation that a single gene can affect more than one phenotypic property. Single-gene genetic diseases can have multiple diverse symptoms. Pleiotropy is one form of genomic linkage.

What is the population vs. individual controversy in evolutionary mechanics?

Darwin’s evolutionary mechanics concept is very individual-oriented: The evolution process selects traits that aid an individual possessing the trait to survive and reproduce better than an individual lacking the trait. Subsequent evolutionary mechanics theories are more population-oriented and consider that the evolution process is driven by characteristics and needs of a population. Evolution operates to increase the chance that a population will avoid extinction. There are still fierce arguments as to which or which combination of theories is correct.

What is group selection?

Group selection is one of a family of post-1960 theories to the effect that a benefit to the survival of a group of individuals can offset individual disadvantage and cause the evolution of an individually adverse trait like senescence or animal altruism. Variations of this idea (e.g. kin selection, small group selection, species-level group selection) vary mainly regarding the size of the population considered. Some programmed aging theories are based on this idea.

What is evolvability theory?

Evolvability theory suggests that an organism’s ability to evolve (i.e. evolvability) can itself be affected by evolved organism design characteristics (traits), and that further, a trait that increases evolvability can be evolved and retained even if it causes some individual disadvantage. An increase in evolvability benefits a population by allowing it to adapt more rapidly or precisely to changes in its external world. Evolvability is one of the post-1960 population-oriented theories.

What was the Scopes "Monkey" Trial of evolution theory?

There has always been and still is religious opposition to evolution theory and in 1925 Tennessee passed a law prohibiting the teaching of evolution in K-12 public schools. A high school biology teacher, John Scopes, was charged and tried in 1925 for violating the law. Eventually such laws were found unconstitutional by virtue of separation of Church and State (1st Amendment) and in 1987 teaching of Creationism in U.S. public school biology classes was prohibited by the U.S Supreme Court.

How does Intelligent Design relate to evolution theory?

Intelligent Design (~1987) proponents hold that evolution theory is invalid and that the design of each Earth species is the individual result of the operation of an intelligent designer that may or may not be God. Intelligent Design is widely seen as an attempt to avoid the U.S. prohibition on the teaching of Creationism in U.S. public schools in place of or in addition to evolution theory.