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1.
Ian Tattersall 《Evolution》2009,2(4):584-589
Human beings are unusual in many ways but perhaps most strikingly in their unique symbolic form of processing information
about the world around them. Although based on a long and essential evolutionary history, the modern human cognitive style
is not predicted by that history: it is emergent rather than the product of an incremental process of refinement. Homo sapiens is physically very distinctive and is clearly the result of a significant developmental reorganization with ramifications
throughout the skeleton and presumably beyond. It is reasonable to suppose that the neural underpinnings of symbolic thought
were acquired in this reorganization. However, the fossil and archeological records indicate that the first anatomically recognizable
members of the species substantially predated its first members who behaved in a demonstrably symbolic manner. Thus, while
the biological potential for symbolic thinking most likely arose in the morphogenetic event that gave rise to H. sapiens as a distinctive anatomical entity, this new capacity was evidently exaptive, in the sense that it had to await its “discovery”
and release through a cultural stimulus. Plausibly, this stimulus was the invention of language. One expression of symbolic
reasoning is the adoption of technological change in response to environmental challenges, contrasting with earlier responses
that typically involved using existing technologies in new ways. As climates changed at the end of the last Ice Age, the new
technophile proclivity was expressed in a shift toward agriculture and sedentary lifestyles: a shift that precipitated a fundamentally
new (and potentially self-destructive) relationship with nature. Thus, both of what are arguably the two most radical (and
certainly the most fateful) evolutionary innovations in the history of life (symbolic thinking and sedentary lifestyles) were
both very recent occurrences, well within the (so far rather short) tenure of H. sapiens. 相似文献
2.
Regarding the arts as something peopledo — as behaviors, rather than the residue or artifacts of behavior — makes possible a theoretical grounding about their nature
and importance, an endeavor that current anthropology of art has largely abandoned. A reconsideration of the suspect and largely
discarded terms “functionalism” and “evolutionism” is presented in light of current evolutionary thinking. It is suggested
that a contemporary reformulation of these concepts, illustrated by the author's Darwinian or “adaptationist” perspective
on art, supports aims and claims of current anthropology of art, and contributes new focus and direction to its endeavors. 相似文献
3.
As the origin(s) of life on Earth remains an open question, detailed characteristics about the “last universal ancestor” (LUA)
continue to be obscured. Here we provide arguments that strengthen the bacterial-like nature of the LUA. Our view attempts
to recreate the evolution of archaeal lipids, the major components of the distinctive membrane that encapsulates these ancient
prokaryotes. We show that (S)- 3-O-geranylgeranylglyceryl phosphate synthase (GGGPS), a TIM-barrel protein that performs the committed step in archaeal lipid
synthesis, likely evolved from the duplication and fusion of a (βα)4 half-barrel ancestor. By comparison to the well-characterized HisA and HisF TIM-barrel proteins, we propose a time line for
the invention of this diagnostic archaeal biosynthetic pathway. After excluding the possibility of horizontal gene transfer,
we conclude that the evolutionary history of GGGPS mirrors the emergence of Archaea from the LUA. We illustrate aspects of
this “lipid capture” model that support its likelihood in recreating key evolutionary events and, as our hypothesis is built
on a single initiating event, we suggest that the appearance of GGGPS represents an example of enzyme-driven speciation.
Reviewing Editor: Dr. Niles Lehman 相似文献
4.
To explore how chemical structures of both nucleobases and amino acids may have played a role in shaping the genetic code,
numbers of sp2 hybrid nitrogen atoms in nucleobases were taken as a determinative measure for empirical stereo-electronic property to analyze
the genetic code. Results revealed that amino acid hydropathy correlates strongly with the sp2 nitrogen atom numbers in nucleobases rather than with the overall electronic property such as redox potentials of the bases,
reflecting that stereo-electronic property of bases may play a role. In the rearranged code, five simple but stereo-structurally
distinctive amino acids (Gly, Pro, Val, Thr and Ala) and their codon quartets form a crossed intersection “core”. Secondly,
a re-categorization of the amino acids according to their β-carbon stereochemistry, verified by charge density (at β-carbon)
calculation, results in five groups of stereo-structurally distinctive amino acids, the group leaders of which are Gly, Pro,
Val, Thr and Ala, remarkably overlapping the above “core”. These two lines of independent observations provide empirical arguments
for a contention that a seemingly “frozen” “core” could have formed at a certain evolutionary stage. The possible existence
of this codon “core” is in conformity with a previous evolutionary model whereby stereochemical interactions may have shaped
the code. Moreover, the genetic code listed in UCGA succession together with this codon “core” has recently facilitated an
identification of the unprecedented icosikaioctagon symmetry and bi-pyramidal nature of the genetic code. 相似文献
5.
Nathalie Gontier 《Evolution》2011,4(3):515-538
It is a popularly held view that Darwin was the first author to draw a phylogenetic tree diagram. However, as is the case
with most popular beliefs, this one also does not hold true. Firstly, Darwin never called his diagram of common descent a
tree. Secondly, even before Darwin, tree diagrams were used by a variety of philosophical, religious, and secular scholars
to depict phenomena such as “logical relationships,” “affiliations,” “genealogical descent,” “affinity,” and “historical relatedness”
between the elements portrayed on the tree. Moreover, historically, tree diagrams themselves can be grouped into a larger
class of diagrams that were drawn to depict natural and/or divine order in the world. In this paper, we trace the historical
roots and cultural meanings of these tree diagrams. It will be demonstrated that tree diagrams as we know them are the outgrowth
of ancient philosophical attempts to find the “true order” of the world, and to map the world “as it is” (ontologically),
according to its true essence. This philosophical idea would begin a fascinating journey throughout Western European history.
It lies at the foundation of the famous “scala naturae,” as well as religious and secular genealogical thinking, especially
in regard to divine, familial (kinship), and linguistic pedigrees that were often depicted by tree images. These scala naturae
would fuse with genealogical, pedigree thinking, and the trees that were the result of this blend would, from the nineteenth
century onward, also include the element of time. The recognition of time would eventually lead to the recognition of evolution
as a fact of nature, and subsequently, tree iconographies would come to represent exclusively the evolutionary descent of
species. 相似文献
6.
Louise S. Mead 《Evolution》2009,2(2):310-314
A common misconception of evolutionary biology is that it involves a search for “missing links” in the history of life. Relying
on this misconception, antievolutionists present the supposed absence of transitional forms from the fossil record as evidence
against evolution. Students of biology need to understand that evolution is a branching process, paleontologists do not expect
to find “missing links,” and evolutionary research uses independent lines of evidence to test hypotheses and make conclusions
about the history of life. Teachers can facilitate such learning by incorporating cladistics and tree-thinking into the curriculum
and using evograms to focus on important evolutionary transitions. 相似文献
7.
Molecular sequencing has helped resolve the phylogenetic relationships amongst the diverse groups of algal, fungal-like and
protist organisms that constitute the Chromalveolate “superkingdom” clade. It is thought that the whole clade evolved from
a photosynthetic ancestor and that there have been at least three independent plastid losses during their evolutionary history.
The fungal-like oomycetes and hyphochytrids, together with the marine flagellates Pirsonia and Developayella, form part of the clade defined by Cavalier-Smith and Chao (2006) as the phylum “Pseudofungi”, which is a sister to the photosynthetic chromistan algae (phylum Ochrophyta). Within the oomycetes,
a number of predominantly marine holocarpic genera appear to diverge before the main “saprolegnian” and “peronosporalean”
lines, into which all oomycetes had been traditionally placed. It is now clear that oomycetes have their evolutionary roots
in the sea. The earliest diverging oomycete genera so far documented, Eurychasma and Haptoglossa, are both obligate parasites that show a high degree of complexity and sophistication in their host parasite interactions
and infection structures. Key morphological and cytological features of the oomycetes will be reviewed in the context of our
revised understanding of their likely phylogeny. Recent genomic studies have revealed a number of intriguing similarities
in host–pathogen interactions between the oomycetes with their distant apicocomplexan cousins. Therefore, the earlier view
that oomycetes evolved from the largely saprotrophic “saprolegnian line” is not supported and current evidence shows these
organisms evolved from simple holocarpic marine parasites. Both the hyphal-like pattern of growth and the acquisition of oogamous
sexual reproduction probably developed largely after the migration of these organisms from the sea to land. 相似文献
8.
P. Slurink 《Human Evolution》1993,8(4):265-273
In contrast to many other models of human evolution the “balance of power” theory of Alexander has a clear answer to the question
why a runaway selection process for unique social and moral capacities occurred in our ancestry only and not in other species:
“ecological dominance” is hypothesized to have diminished the effects of “extrinsic” forces of natural selection such that
withinspecies, intergroup competition increased (Alexander, 1989). Alexander seems to be wrong, however, in his claim that
already the common HUCHIBO (Humans, Chimps, Bonobo's)-ancestor has crossed the ecological dominance barrier. In this paper
an adapted version of Alexander's model is presented and several different ways are proposed to make this adapted version
testable. A preliminary survey of the available paleontological and paleoecological data suggests that there is some evidence
of a less vulnerable position towards predators in earlyHomo and that there are clear signs related to a crossing of the ecological dominance barrier inHomo sapiens sapiens. 相似文献
9.
Brace C. Loring 《Human Evolution》2005,20(1):19-38
There is a widespread assumption, even among those who reject the Synthetic Theory of Evolution, that the form of “modern”Homo sapiens is somehow superior to that of archaicHomo sapiens (Tattersall 2000). Those who accept the general outlook of evolutionary biology also tend to assume that “modern” form emerged
because it was selected for, which also implies that it was better than that which preceded it. However, after years of using
craniofacial measurements to compare human populations, I finally came to realize that, with only a few exceptions, the dimensions
measured have no relation to differences in adaptation (Brace 1989, 1996, 2000; Brace et al., 1993). Elsewhere the conclusion
has been supported that what is shown by craniometrics is selectively neutral on the average (Relethford 2002). With the documentation
that approximately 95% of the genome is not functional, molecular genetics has proved to be useful in documenting the length
of time of separation of related human populations by investigating the differences that have accumulated in the neutral parts
of the genome. Not surprisingly, the picture revealed by the study of genetic differences is very similar to the one revealed
by the study of craniometric differences (Brace et al., 2001).
For this reason, the logic behind the “neutral theory” in molecular genetics is very similar to that applied to what happens
to morphological characteristics when selection ceases (Brace 1963; Kimura 1968). The difference is that random changes in
the neutral part of the genome have no other consequences. However, random changes in the genes that produce specific aspects
of morphology will be visible even when selection is no longer controlling the particular trait in question. From an assessment
of what random changes in genes controlling morphological traits are likely to do, it follows that the most likely change
will probably be a reduction in the trait in question, i.e. the Probable Mutation Effect will produce structural reduction.
When survival in the temperate zone during the last glaciation dependend on “obligatory cooking”, one of the unintended consequences
was a reduction in the selective pressures maintaining a Middle Pleistocene-sized dentition. The result was a gradual reduction
in tooth size and a conversion, of a Neanderthal-sized face into one of “modern” dimensions. The manufacture and use of string
for snares and nets similarly reduced the selective pressures maintaining post-cranial levels of robustness and muscularity.
The reduction in the latter resulted in the emergence of moderm post-cranial robustness out of what had been a Neanderthal
level,in situ wherever the technology can be documented and without any need for invasions and replacements. 相似文献
10.
Salenko VB Kotnova AP Karpova NN Lyubomirskaya NV Ilyin YV 《Molecular genetics and genomics : MGG》2008,279(5):463-472
Mobile genetic elements constitute a substantial part of eukaryotic genome and play an important role in its organization
and functioning. Co-evolution of retrotransposons and their hosts resulted in the establishment of control systems employing
mechanisms of RNA interference that seem to be impossible to evade. However, “active” copies of endogenous retrovirus gypsy escape cellular control in some cases, while its evolutionary elder “inactive” variants do not. To clarify the evolutionary
relationship between “active” and “inactive” gypsy we combined two approaches: the analysis of gypsy sequences, isolated from G32 Drosophila melanogaster strain and from different Drosophila species of the melanogaster subgroup, as well as the study of databases, available on the Internet. No signs of “intermediate” (between “active” and
“inactive”) gypsy form were found in GenBank, and four full-size G32 gypsy copies demonstrated a convergence that presumably involves gene conversion. No “active” gypsy were revealed among PCR generated gypsy ORF3 sequences from the various Drosophila species indicating that “active” gypsy appeared in some population of D. melanogaster and then started to spread out. Analysis of sequences flanking gypsy variants in G32 revealed their predominantly heterochromatic location. Discrepancy between the structure of actual gypsy sites in G32 and corresponding sequences in database might indicate significant inter-strain heterochromatin diversity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Jeffrey H. Schwartz 《Primates; journal of primatology》1983,24(2):231-240
Although most mammals develop relatively large double anterior palatine fenestrae that patently communicate with the nasal
cavity, four extant primates—Homo sapiens, Pongo, Pan andGorilla—do not. While these four have closed-down these foramenal structures,Homo sapiens andPongo are unique in forming a single foramen palatally. Among fossil taxa,Homo, Australopithecus, Sivapithecus (=Ramapithecus) andRudapithecus also develop a single foramen palatally. Dryopithecines, the presumed fossil apes, preserve the two patent fenestrae. In
light of dental features that are considered diagnostically “hominid,” which are also found in the orangutan, it is suggested
that this “ape,” rather thanPan, is phylogenetically closer toHomo. 相似文献
12.
The notion of “pressure” as an evolutionary “force” that “causes” evolution is a pervasive linguistic feature of biology textbooks,
journal articles, and student explanatory discourse. We investigated the consequences of using a textbook and curriculum that
incorporate so-called force-talk. We examined the frequency with which biology majors spontaneously used notions of evolutionary
“pressures” in their explanations, students’ definitions and explanations of what they meant when they used pressures, and
the structure of explanatory models that incorporated evolutionary pressures and forces. We found that 12–20 percent of undergraduates
spontaneously used “pressures” and/or “forces” as explanatory factors but significantly more often in trait gain scenarios
than in trait loss scenarios. The majority of explanations using “force-talk” were characterized by faulty evolutionary reasoning.
We discuss the conceptual similarity between faulty notions of evolutionary pressures and linguists’ force-dynamic models
of everyday reasoning and ultimately question the appropriateness of force-talk in evolution education. 相似文献
13.
Géant E Mouchel-Vielh E Coutanceau JP Ozouf-Costaz C Deutsch JS 《Development genes and evolution》2006,216(7-8):443-449
The “hopeful monster” has haunted evolutionary thinking since Richard Goldschmidt coined the phrase in 1933. The phrase is directly related to genetic mechanisms in development and evolution. Cirripedes are peculiar crustaceans in that they all lack abdomens as adults. In a previous study aimed at describing the repertoire of Hox genes of the Cirripedia, we failed to isolate the abdominal-A gene in three species representative of all three cirripede orders. To address the question of whether the cirripede ancestor could have been a “hopeful monster” arising from a rearrangement of the Hox complex, we have performed a cytogenetic analysis of the Hox complex of the cirripede Sacculina carcini. We present here molecular and cytogenetic evidence for the grouping of the Hox genes on a single chromosome. This is the first direct evidence reported for the grouping of Hox genes on the same chromosome in a non-insect arthropod species. 相似文献
14.
Shuichi Matsumura 《Primates; journal of primatology》1999,40(1):23-31
Recent studies of captive macaques have revealed considerable inter-species differences in dominance styles among females.
In “egalitarian” species such as stumptail (Macaca arctoides) or tonkean macaques (M. tonkeana), social interactions are more symmetrical and less kin-biased than in “despotic” species such as Japanese (M. fuscata) or rhesus macaques (M. mulatta). Field observations of moor macaques (M. maurus), close relatives of tonkean macaques, suggest that tolerance during feeding characterizes their egalitarian dominance style
in the natural habitat. Although it has been proposed that communal defense against other groups may be the main selective
force in the evolution of egalitarian dominance style among females, few field data support this prediction. A game theory
analysis showed that both an “egalitarian” strategy and a “despotic” strategy are possible evolutionarily stable strategies
(ESS) under certain conditions. The difference in dominance styles might reflect the difference in ESS. This means that an
egalitarian dominance style can emerge without strong between-group contest competition. A phylogenetic comparison among macaques
suggests that despotic dominance styles very likely evolved from egalitarian dominance styles. In the future, primate socioecological
studies should pay more attention to the evolutionary history of each species. 相似文献
15.
Unsurprisingly, survey results indicate that Texas biology and biological anthropology faculty with expertise in an evolutionary
area strongly support teaching “just evolution” (100%; N = 54) and not creationism/intelligent design. Importantly, they do not think that religious faith is incompatible with acceptance
of evolutionary biology (91%; N = 55), even though 50% (N = 52) describe themselves as “not at all religious.” As school boards nationwide debate science standards, it is important
that faculty with relevant expertise have a voice. Biological anthropologists should not be overlooked as a public resource
in these debates. 相似文献
16.
17.
In North America, public understanding and acceptance of evolution is alarmingly low. Moreover, acceptance rates are declining,
and studies suggest that even students who have taken courses in evolution have the same misunderstandings as the general
public. These data signal deficiencies in our educational system and provide a “call to arms” to improve how evolution is
taught. Many studies show that student education can be improved by replacing lecture-based pedagogy with active learning
approaches—where the role of students changes from passive note taking to active problem solving. Here, we describe changes
made to a second-year undergraduate evolution course to facilitate a shift to active learning and improve student understanding
of evolution. First, lectures were used only sparingly and were largely replaced by problem-solving activities. Second, standard
textbooks were replaced by “popular” books applying evolutionary thinking to topics students encounter on a daily basis. Lastly,
predefined laboratory exercises were replaced by student-designed and implemented research projects. These changes led to
increased student engagement and enjoyment, improved understanding of evolution and ability to apply evolutionary thinking
to biological problems, and increased student recognition that evolutionary thinking is important not only in the classroom
but also in their daily lives. 相似文献
18.
Molecular genetic assays can contribute to conservation of aquatic taxa by assessing evolutionary and taxonomic distinctiveness,
levels of genetic variation within and between populations, and the degree of introgression with introduced taxa. The Athabasca
River drainage of␣western Alberta, Canada is one of only three (and the largest) drainages flowing east of the continental
divide that contain native populations of rainbow trout (Salmonidae: Oncorhynchus mykiss). The “Athabasca” rainbow trout has been considered a preglacial relict worthy of special conservation measures. In addition,
the native range of Athabasca rainbow trout has seen many instances of introductions of non-native populations since the beginning
of the 20th century. We assayed rainbow trout from the Athabasca River drainage, from hatchery populations, and from representative
populations in adjacent regions (N = 49 localities) for variation at 10 microsatelite loci to assess the level of evolutionary distinctiveness of Athabasca rainbow
trout, and to assess the levels of introgression with non-native hatchery fish. We found that native Athabasca rainbow trout
did not form a distinctive genetic assemblage and that the greatest amount of allele frequency variation was attributable
to contemporary drainage systems (29.3%) rather than by a Athabasca/non-Athabasca distinction (12.6%). We found that 78% of
all fish were confidently assigned to a “wild” rather than a “hatchery” genetic grouping and that most of the inferred introgression
with hatchery fish was restricted to a few localities (N = 6). Our results suggest that: (i)␣Athabasca River rainbow trout are likely postglacial immigrants from adjacent populations
of the Fraser River, and (ii) that there is no evidence of widespread introgression of hatchery alleles into native Athabasca
River drainage rainbow trout. 相似文献
19.
Exceptional chromosomal variability makesCtenomys an excellent model for evolutionary cytogenetic analysis. Six species belonging to three evolutionary lineages were studied
by means of restriction endonuclease and C-chromosome banding. The resulting banding patterns were used for comparative analysis
of heterochromatin distribution on chromosomes. This combined analysis allowed intra- and inter-specific heterochromatin variability
to be detected, groups of species belonging to different lineages to be characterized, and phylogenetic relationships hypothesized
from other data to be supported. The “ancestral group”,Ctenomys pundti andC. talarum, share three types of heterochromatin, the most abundant of which was also found in C. aff.C. opimus, suggesting that the latter species also belongs to the “ancestral group”. Additionally, within the subspeciesC. t. talarum, putative chromosomal rearrangements distinguishing two of the three chromosomal races were identified. Two species belong
to an “eastern lineage”,C. osvaldoreigi andC. rosendopascuali, and share only one type of heterochromatin homogeneously distributed across their karyotypes.C. latro, the only analyzed species from the “chacoan” lineage, showed three types of heterochromatin, one of them being that which
characterizes the “eastern lineage”.C. aff.C. opimus, because of its low heterochromatin content, is the most primitive karyotype of the genus yet described. The heterochromatin
variability showed by these species, reflecting the evolutionary divergence toward different heterochromatin types, may have
diverged since the origin of the genus. Heterochromatin amplification is proposed as a trend withinCtenomys, occurring independently of chromosomal change in diploid numbers. 相似文献
20.
Neurological complexity has increased over evolutionary time for invertebrates and vertebrates alike, with the hominid brain
tripling in size over the last 3 million years. Since magnetic resonance imaging (MRI) studies among humans indicate a significant
correlation (meanr>0.40) between individual differences in brain size and general cognitive ability, it is reasonable to hypothesize that increasing
brain size confers greater intelligence. However, larger brains have associated costs, taking longer to build and requiring
more energy to run. Sufficient advantages must have accrued for them to override these trade-offs. The present paper documents
that in hominoids, as brain size increased from 380 to 1364 cm3 over seven hominoid groups (chimpanzees to australopithecines toHomo habilis toHomo erectus to differences amongHomo sapiens), it was accompanied by changes in 74 musculo-skeletal traits (rs=0.90). These occurred on both cranial traits (temporalis fossae, post-orbital constrictions, mandibles, dentition, nuchal
muscle attachments) and on post-cranial traits (pelvic widths, femoral heads, tibial plateaus). It is concluded that in the
evolutionary competition to find and fill new niches, there was “room at the top” for greater behavioral complexity and larger
brain size, leading to cascading effects on other traits. 相似文献