Australopithecus afarensis and the single species hypothesis

Primates ◽  
1991 ◽  
Vol 32 (1) ◽  
pp. 125-130 ◽  
Author(s):  
William R. Leonard
Keyword(s):  
Single Species ◽  
Australopithecus Afarensis

scholarly journals New footprints from Laetoli (Tanzania) provide evidence for marked body size variation in early hominins

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Fidelis T Masao ◽  
Elgidius B Ichumbaki ◽  
Marco Cherin ◽  
Angelo Barili ◽  
Giovanni Boschian ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Size Variation ◽  
Single Species ◽  
Australopithecus Afarensis ◽  
Body Size Variation ◽  
Northern Tanzania ◽  
The World ◽  
Marked Body ◽  
Considerable Body

Laetoli is a well-known palaeontological locality in northern Tanzania whose outstanding record includes the earliest hominin footprints in the world (3.66 million years old), discovered in 1978 at Site G and attributed to Australopithecus afarensis. Here, we report hominin tracks unearthed in the new Site S at Laetoli and referred to two bipedal individuals (S1 and S2) moving on the same palaeosurface and in the same direction as the three hominins documented at Site G. The stature estimates for S1 greatly exceed those previously reconstructed for Au. afarensis from both skeletal material and footprint data. In combination with a comparative reappraisal of the Site G footprints, the evidence collected here embodies very important additions to the Pliocene record of hominin behaviour and morphology. Our results are consistent with considerable body size variation and, probably, degree of sexual dimorphism within a single species of bipedal hominins as early as 3.66 million years ago.

Plio-pleistocene Hominids: Epistemological and Taxonomic Problems

1970 ◽  
Vol 9 (1) ◽  
pp. 169-202
Author(s):  
Jolanta Koszteyn
Keyword(s):  
Homo Sapiens ◽  
Single Species ◽  
Homo Erectus ◽  
Australopithecus Afarensis ◽  
Homo Heidelbergensis ◽  
Genealogical Tree ◽  
Homo Neanderthalensis ◽  
Homo Habilis ◽  
Homo Antecessor ◽  
Historical Times

Within the historical times, which roughly corresponds with the Holocene epoch, the whole of mankind is believed to be a single species. Homo sapiens. But the human genealogical tree (phylogeny) is populated by a really astounding number of paleontological species and paleontological genera: Ardipithecus ramidus, Australopithecus anamensis, Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, Paranthropus boisei, Homo habilis, Homo georgicus. Homo erectus, Homo ergaster, Homo antecessor, Homo heidelbergensis, Homo neanderthalensis, Homo sapiens. (cf. Gyula 2002). In fact there are many more (Sahelanthropus tchadensis, Orrorin tugenensis, Kenyanthropus platyops, Australopithecus garhi, Australopithecus aethiopicus) but Foley (2002), quite reasonably, states that the evidence for their existence is, at present, insufficient. The existence of these multiple forms is beyond any doubt. The doubt, however arises concerning the human or „prehuman" status of them. Were they really true specific forms, half-way between the apes and Holocene man? Is it possible that they constitute a number of different ecotypes (or paleoraces) within the same natural species of Homo sapiens?

In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

1994 ◽  
Vol 52 ◽  
pp. 276-277
Author(s):  
Mary Beth Downs ◽  
Wilson Ribot ◽  
Joseph W. Farchaus
Keyword(s):  
Cell Wall ◽  
Molecular Sieves ◽  
Cell Envelope ◽  
Single Species ◽  
Supporting Cell ◽  
Surface Layers ◽  
Rabbit Igg ◽  
In Vitro Assembly ◽  
Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

A STUDY ON ICHTHYO-DIVERSITY OF MUNTJIBPUR POND OF ALLAHABAD (U.P.) INDIA

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
ASHOK KUMAR VERMA
Keyword(s):  
Single Species ◽  
Single Genus ◽  
One Year

An attempt was made to find the ichthyo-diversity of Muntjibpur pond of Allahabad. Systematic surveys were conducted during a period of one year. A total of 13 species of fishes belonging to 12 genera, 8 families and 5 orders were identified. Siluriformes order is represented by 5 genera and 5 species while Cypriniformes order by 4 genera and 5 species. Each of the orders Clupeiformes, Osteoglossiformes and Ophiocephaliformes is represented by single genus and single species.

Fine-scale taxonomic and temporal variability in the energy density of invertebrate prey of juvenile Chinook salmon Oncorhynchus tshawytscha

2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes
Keyword(s):  
Energy Density ◽  
Chinook Salmon ◽  
Temporal Variability ◽  
Energy Content ◽  
Single Point ◽  
Single Species ◽  
Fine Scale ◽  
Temporal Differences ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.

POTENTIAL PRODUCTIVITY ADAPTIVE AGROPHUTOCENOZIS ON SLOPING LANDS OF THE STEPPE TRANS-URALS

2020 ◽  
Author(s):  
R.А. Idrisov ◽  
Keyword(s):  
Protein C ◽  
Nutritional Value ◽  
Energy Content ◽  
Single Species ◽  
Exchange Energy ◽  
Metabolic Energy ◽  
Potential Productivity ◽  
Maximum Productivity ◽  
Sloping Lands ◽  
Natural Herb

The correct construction of agrophytocenoses on the slopes of the steppe trans-Urals helped to create maximum productivity. In the arid climate, the most productive were the double mixtures of alfalfa with brittle sitnik, wheatgrass is syd, providing an average of 41.6 and 40.2 quintals per hectare (c/ha) of hay, 32.1 and 31.0 GJ/ha OE (exchange energy per hectare), 4.5 and 4.3 quintals per hectare of boiled protein (c/ha) over 5 years. Single-species steppe ecotypes, brittle sieve and wheatgrass sieve in productivity slightly gave way to double components, providing respectively hay- 32.2 and 37.2 cents per hectare, exchange energy 22.2 and 25.7 GJ/ha, digested protein 1.93 and 2.53 c/ha. The enrichment of agrophytocense by the legume component allowed to increase the metabolic energy content to the level of 32.1 and 31.0-GJ/ha, digested protein to 4.5 and 4.3 quintals per hectare, which is 14 times the nutritional value of the metabolic energy, the digested protein is 10 times higher than the natural herb.

BOTANICAL COMPOSITION AND PRODUCTIVITY OF PERENNIAL GRASSES AGROPHYTOCENOSES WITH TETRAPLOID MEADOW CLOVER

1970 ◽  
pp. 59-62
Author(s):  
N. I. Kasatkina ◽  
Zh. S. Nelyubina
Keyword(s):  
Dry Weight ◽  
Single Species ◽  
Lotus Corniculatus ◽  
Specific Weight ◽  
Biological Properties ◽  
Phleum Pratense ◽  
Perennial Grasses ◽  
High Yield ◽  
Botanical Composition ◽  
The Third

The biological properties of plants, their mutual relations under different growth conditions and at different periods of their life, must be known for obtaining highly productive agrophytocenoses with participation of a meadow clover (Trifolium pratense L.). Botanical composition and fodder productivity of perennial grasses in agrocenoses with participation of meadow tetraploid clover Kudesnik were studied in 2014-2017. It was revealed that in the first and second years of use the agrophytocenosis, the yield of green mass was formed due to meadow tetraploid clover, the share of its participation in the first mowing was at level of 71-87% and 64-97% respectively. Specific weight of clover in multispecies agrocenoses considerably decreased by the third year of use: in the first mowing up to 32-68%, in the second - up to 8-52%. At the same time, the percentage of long-term herbaceous grasses increased: meadow timothy (Phleum pratense L.) - up to 34-54%, eastern galega (Galéga orientális Lam.) - up to 33%, changeable alfalfa (Medicago x varia Martyn) - up to 22-54%, lotus corniculatus (Lotus corniculatus L.) - up to 14-19%. The proportion of weed admixture in single-species clover planting was 12%, in agrocenoses - 2-14%. The grass mixtures clover + timothy and clover + alfalfa + timothy were less infested by weeds. High yield of dry weight of single-species sowing of meadow tetraploid clover was obtained in the first two years of use - 7.8 and 6.5 tons / ha, respectively. By the third year of use, the productivity of clover has decreased to 2.9 t / ha. On average, for three years of use, the highest yield (6.2-6.3 t / ha) was formed by agrocenoses meadow tetraploid clover + meadow timothy and meadow tetraploid clover + changeable alfalfa + meadow timothy.

Syntaxonomic changes in the plant cover of meadow steppe in the «Mikhailovskaya Tselina» reserve (Sumy Region, Ukraine)

2006 ◽  
pp. 43-57 ◽  
Author(s):  
H. N. Lysenko ◽  
I. A. Korotchenko
Keyword(s):  
Nature Reserve ◽  
Plant Cover ◽  
Ecological Factors ◽  
Single Species ◽  
Meadow Steppe ◽  
Total Species

Changes in the set of syntaxa have been traced for the plant cover of the «Mikhaylovskaya Tselina» meadow-steppe (an isolated part of the Ukrainian Steppe Nature Reserve, Sumy Region, Ukraine) with the help of the Braun-Blanquet approach. The area vegetation syntaxa prodromus includes 2 classes, 2 rders, 3 alliances, 9 associations, and 6 subasso­ciations, 2 of the latter described anew. The plant cover is highly dynamic and undergoes expressed meso­phytization, especially within the area where strict protection has been maintained since 1961. Amplitudes of the principal ecological factors and also peculiarities of their shift under exogenic regulation are determined with the help of the method of synecological phyto­indication (i. e. not single species but total species sets of communities serve as indicators). The essential transformations of the reserve meadow steppes are probably caused by the «insular» character of the reserve, its small size, also by the poorness of the set of natural grazers and hence the inadequacy of regulation by means of mowing.

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