User:Ryguasu/Evolution

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[edit] comlexity

Gould: first, there isn't an increasing trend (eukaryotes are everywhere), and second, it is to be expected, given there's a lower bound but no upper bound on complexity.

Wolfram: complexity needn't be explained by natural selection. complexity is EASY. in fact, natural selection probably creates simplicity - it makes rougly separate components, like a good engineer; doing otherwise makes "small" mutations have disasterous consequences.


species

see gradualism missing link speciation the origin of species


logical fallacy

Is there a standard name for arguments of the form

Not P is very unlikely. Therefore P.

or, alternatively

Not P seems very unlikely. Therefore P.

Would these commonly be called "logical fallacies"?

gambler's fallacy

"chance has no memory" (D p. 54)

algorithm

is it really common to use algorithm for only what can be proven to terminate??

evolution

evolution is FOR making us (D p. 56). Does anyone coherently argue this?

"Evolution is not a process that was designed to produce us, but it does not follow from this that evolution is not an algorithmic process that has in fact produced us."


-============

- Does anyone know the history of the phrase "argument from design", or when "design" came to be used in this sense? Was "design" the word used in watchmaker arguments before Neo-Darwinists like Daniel Dennett came along?

Dennett (pp. 28-9) shows that Paley cannot claim primary for the idea:

  1. Cicero
  2. attributes the logic to Hume's Cleanthes (1779: Dialogues Concerning Natural Religion)


design

OED: design (used by hume: "design, thought, wisdom, and intelligence")

This shows that classification did NOT begin with Linneus (or whatever hsi name is)

"by Darwin's time the work of the great taxonomists (who began by adopting and correcting Aristotle's ancient classifications) had created a detailed hierachy of two kingdoms (plants and animals), divided into phyla ... which divided into species. Species also could be subdivided, of course, into subspecies or varieties." (Dennett, p. 36)


For plato, each Earthly eagle was an imperfect copy of the Form called eagle, just as each Earthly triangle was an imperfect triangle of the Form called triangle. (Dennett, p. 36)

For Aristotle, each animal had a timeless, unchanging essense which defined which it was. (ibid)

For both, species were immutible and every animal could be correctly classified as belonging to one and only one species. (ibid)

(this doesn't imply that organisms were identical, just that they shared the same "essential" properties)


Darwin was NOT the first to suggest descend with modification:

"species had births in time, could change over time, and could give birth to new species in turn. The idea itself was not new; many versions of it had been seriously discussed, going back tot he ancient Greeks. But there was a powerful Platonic bias against it." (p. 38)

Before that time, Aristotle(4th century BC) speculated that the relative contributions of the female and the male <article?idxref=502758> parents were very unequal—the female was thought to supply what he called the “matter” and the male the “motion.” [Britanica, Heredity, Early conceptions of heredity]

Although Aristotle recognized that species are not stable and unalterable and although he attempted to classify the animals he observed . [Britanica, the history of biology]

, Aristotle was the first to attempt a system of animal classification, in which he contrasted animals containing blood with those that were bloodless. [Britanica, the history of biology]

Further, Aristotle also believed that the entire living world could be described as a unified organization rather than as a collection of diverse groups. [Britanica, the history of biology] [what does this mean??]


Qs:

  • is species more important than other levels, e.g. animals vs. plans, or subspecies?
  • what is a species?
  • are species connected somehow?
  • can species change?
  • can speciation occur?

This article should be shorter! It might not have to cover how the species all relate...

You could move this to "History of 'species'". Or even "History of biology"

Organization(?):

  1. species in the ancient world (was breeding of animals known in the ancient world?)
  2. species before Darwin (et al?)
  3. species after Darwin: Dennett vs. creationists?

In biology, a species is a group of organisms that have been classified together, either for having key properties in common, or for being part of the same "extended family" of organisms. Species is 7akin to the more narrow classifications commonly used by non-scientists, more along the lines of "dog" than "animal".

[oops: or for being part of the same family tree]

["species" is a particularly important concept only to some....]

(There is also an article on the mathematical concept of a combinatorial species.) Species is a biological concept that refers to a population of organisms that are in some important ways similar. What constitutes an "important similarity" is a matter of debate. In the earliest works of science, a species was simply an individual organism that represented a group of similar or nearly identical organisms. No other relationships beyond that group were implied. When early observers began to develop systems of organization for living things, they began to place the formerly isolated species into a context. To the modern mind, many of the schemes delineated are whimsical at best, such as those that determined consanguinity based on color (all plants with yellow flowers) or behavior (snakes, scorpions and certain biting ants).

In the 18th century Carolus Linnaeus classified organisms according to differences in the form of reproductive apparatus. Although his system of classification sorts organisms according to degrees of similarity, it made no claims about the relationship between similar species. At the time some believed that there is no organic connection between species no matter how similar they appear; every species was created by God, a view today called creationism. This approach also suggests a type of idealism, in other words, that each species exists as an ideal form. In fact, there are always differences (although sometimes minute) between individual organisms. Linnaeus considered such variation problematic. He strove to identify individual organisms that were exemplary of the species, and considered other non-exemplary organisms to be deviant and imperfect.

By the 19th century most naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. As such, the new emphasis was on determining how a species could change over time. Lamarck suggested that an organism could pass on an acquired trait to its offspring. This theory is sometimes explained by positing a situation wherein an animal that repeatedly stretched its neck in order to reach the treetops would then pass on to its offspring a longer neck; such an example is, however, an oversimplification of Lamarck's ideas. Lamarck's most important insight may have been that species are at best magnificently fluid; his 1809 Zoological Philosophy contained one of the first logical refutations of creationism. With the advent of Darwin, Lamarck's reputation suffered gravely. In the late 20th century, though, his work began to be rexamined, and Lamarck's work is fundamental to the modern theory of adaptive mutation. His long-discarded ideas of the goal-oriented evolution of species, also known the teleological process, have also received renewed attention, particularly by proponents of artificial selection.

Charles Darwin and Alfred Wallace provided what scientists now consider the most powerful and compelling theory of evolution. Basically, Darwin argued that it is populations that evolve, not individuals. His argument relies on a radical shift in perspective from Linnaeus: rather than defining species in ideal terms (and searching for an ideal representative and rejecting deviations), Darwin considered variation among individuals to be natural. He further argued that such variation, far from being problematic, is actually a good thing.

Following Thomas Malthus, he suggested that population would often exceed the amount of food available, and that some organisms would die. Darwin suggested that those organisms that would die would be those less adapted to their environment, and that those that survived -- and reproduced -- would be those best adapted to their environment. Variation among members of a species is important because different and changing environments favor different traits (i.e. there is no ideal trait; whether a trait is beneficial or not depends on the environment).

These survivors would not pass acquired traits on to their offspring; they would pass their inherited traits on to their offspring. But since the environment effectively selected which organisms would live to reproduce, the environment would select which traits would be passed on. This is the theory of evolution by "natural selection." For example, among a group of animals some have longer necks, others have shorter necks. If all the leaves are high up, those with shorter necks will die; those with longer necks will thrive. This process is evident today as resistant strains of bacteria evolve.

The development of the field of genetics (many years after Darwin) has revealed the mechanisms that generate variation as well as those through which traits are passed on from generation to generation.

The theory of the evolution of species through natural selection has two important implications for discussions of species -- consequences that fundamentally challenge the assumptions behind Linnaeus' taxonomy. First, it suggests that species are not just similar, they may actually be related. Some students of Darwin argue that all species are descended from a common ancestor. Second, it supposes that "species" are not homogeneous, fixed, permanent things; members of a species are all different, and over time species change. This suggests that species do not have any clear boundaries but are rather momentary statistical effects of constantly changing gene-frequencies. One may still use Linnaeus' taxonomy to identify individual plants and animals. But one can no longer think of species as independent and immutable.

The rise of a new species from a parental line is called speciation. There is no clear line demarcating the ancestral species from the descendant species.

The modern biological species concept defines a species in terms of reproductive isolation. This definition is not considered adequate by all parties - for example, it does not work so well in describing plant species as animal species. It is also problematic when dealing with extinct species.

Whether species is a concept, or whether it has reality independent of our classification systems, is also subject to debate. Answers to this question may hinge on one's understanding of epistemology as much as of biology.

The classification of species has been profoundly affected by technological advances that have allowed researchers to determine relatedness based on genetic markers. The results have been nothing short of revolutionary, resulting in the reordering of vast expanses of the phylogenetic tree (see also molecular phylogeny).

A species name can be:

There are several common species names. Most of these are adjectives.

Linnaean taxonomy discusses how the category "species" meshes with other classification categories, such as "kingdom" and "genus".

Compare with race.

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