Evolution Driven by Humans’ Unnatural Selections
In the film “After Earth,” the main characters return to Earth after the planet has evolved natural defenses against humans.
In real life, plants and animals are evolving in response to human action as well, although with less malicious intent than on the silver screen.
Through history, as natural selection played its part in the development of modern man, many of the useful functions and parts of the human body become unnecessary. What is most fascinating is that many of these parts of the body still remain in some form so we can see the progress of evolution. This list covers the ten most significant evolutionary changes that have taken place – leaving signs behind them.
Natural Selection is one of the main concepts found within the theory of evolution. It was discovered by Charles Darwin and Alfred Russel Wallace though Darwin championed the idea in his book “On the Origin of Species”.
Natural selection can be defined as the process by which random evolutionary changes are selected for by nature in a consistent, orderly, non-random way.
When coupled with descent with modification, Natural Selection can cause a population to evolve for fitness within a given environment over multiple generations.
Natural Selection is an observable fact. By carefully observing populations of living things with short life cycles you can actually watch it happen.
Want to learn more? Check out our notes for this video. Included are links to three examples of natural selection witnessed by researchers. There are many more as well.
Let us look at various possible stages in the emergence of consciousness.
As a possible first stage there may evolve something that acts like a centralized warning, that is, like irritation or discomfort or pain, inducing the organism to stop an inadequate movement and to adopt some alternative behavior in its stead before it is too late, before too much damage has been done. The absence of a warning like pain will lead in many cases to destruction. Thus natural selection will favor those individuals that shrink back when they receive a signal indicating an inadequate movement; which means, anticipating the inherent danger of the movement. I suggest that pain may evolve as such a signal; and perhaps also fear.
As a second stage, we may consider that natural selection will favor those organisms that try out, by some method or other, the possible movements that might be adopted before they are executed. In this way, real trial-and-error behavior may be replaced, or preceded, by imagined or vicarious trial-and-error behavior. The imagining may perhaps initially consist of incipient efferent nervous signals, serving as a kind of model, or symbolic representation of the actual behavior, and of its possible results.
Richard Dawkins has brilliantly developed some such speculations about the beginnings of mind in considerable detail.18 The main points about them are two. One is that these beginnings of mind or consciousness should be favored by natural selection, simply because they mean the substitution of imagined or symbolic or vicarious behavior for real trials which, if erroneous, may have fatal consequences. The other is that we can here apply the ideas of selection and of downward causation to what is clearly a choice situation: the open program allows for possibilities to be played through tentatively — on a screen, as it were — in order that a selection can be made from among these possibilities.
Ask most folks who came up with the theory of evolution, and they’ll tell you it was Charles Darwin.
In fact, Alfred Russel Wallace, another British naturalist, was a co-discoverer of the theory — though Darwin has gotten most of the credit. Wallace died 100 years ago this day.
Apr. 26, 2013 — Scientists have long observed that species seem to have become increasingly capable of evolving in response to changes in the environment. But computer science researchers now say that the popular explanation of competition to survive in nature may not actually be necessary for evolvability to increase.
Chris Martin has bred more than 3,000 hybrid fish in his time as a graduate student in evolution and ecology at UC Davis, a pursuit that has helped him create one of the most comprehensive snapshots of natural selection in the wild and demonstrated a key prediction in evolutionary biology.
New evidence proves humans are continuing to evolve and that significant natural and sexual selection is still taking place in our species in the modern world.
Despite advancements in medicine and technology, as well as an increased prevalence of monogamy, research reveals humans are continuing to evolve just like other species.
Scientists in an international collaboration, which includes the University of Sheffield, analysed church records of about 6,000 Finnish people born between 1760-1849 to determine whether the demographic, cultural and technological changes of the agricultural revolution affected natural and sexual selection in our species.
Project leader Dr Virpi Lummaa, of the University’s Department of Animal and Plant Sciences, said: “We have shown advances have not challenged the fact that our species is still evolving, just like all the other species ‘in the wild’. It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans.”
Dr Lummaa added: “We have shown significant selection has been taking place in very recent populations, and likely still occurs, so humans continue to be affected by both natural and sexual selection. Although the specific pressures, the factors making some individuals able to survive better, or have better success at finding partners and produce more kids, have changed across time and differ in different populations.”
As for most animal species, the authors found that men and women are not equal concerning Darwinian selection.
Principal investigator Dr Alexandre Courtiol, of the Wissenschftskolleg zu Berlin, added: “Characteristics increasing the mating success of men are likely to evolve faster than those increasing the mating success of women. This is because mating with more partners was shown to increase reproductive success more in men than in women. Surprisingly, however, selection affected wealthy and poor people in the society to the same extent.”
The experts needed detailed information on large numbers of study subjects to be able to study selection over the entire life cycle of individuals: survival to adulthood, mate access, mating success, and fertility per mate.
Genealogy is very popular in Finland and the country has some of the best available data for such research thanks to detailed church records of births, deaths, marriages and wealth status which were kept for tax purposes. Movement in the country was also very limited until the 20th century.
“Studying evolution requires large sample sizes with individual-based data covering the entire lifespan of each born person,” said Dr Lummaa. “We need unbiased datasets that report the life events for everyone born. Because natural and sexual selection acts differently on different classes of individuals and across the life cycle, we needed to study selection with respect to these characteristics in order to understand how our species evolves.”
Provided by University of Sheffield (news : web)
ScienceDaily (Apr. 1, 2012) — Picky females play a critical role in the survival and diversity of species, according to a Nature study by researchers from the University of British Columbia and the International Institute for Applied Systems Analysis (IIASA) in Austria.
To date, biodiversity theories have focused on the role played by adaptations to the environment: the species best equipped to cope with a habitat would win out, while others would gradually go extinct. The new study presents the first theoretical model demonstrating that selective mating alone can promote the long-term coexistence of species — such as frogs, crickets, grasshoppers and fish — that share the same ecological adaptations and readily interbreed.
ScienceDaily (Feb. 13, 2012) — In the wake of a mass extinction like the one that occurred 445 million years ago, a common assumption is that surviving species tend to proliferate quickly into new forms, having outlived many of their competitors.
But new research shows that tiny marine organisms called graptoloids did not begin to rapidly develop new physical traits until about 2 million years after competing species became extinct.
The discovery challenges the idea that explosive evolution quickly follows mass extinctions. In the absence of competition, the common theory goes, surviving species hurry to adapt, evolving new physical attributes to take advantage of newly opened niches in the ecosystem. But that’s not what researchers found in the fossil record of graptoloid evolution.
