Patterns of the Diversity of Characteristic Species Across Vegetation Ecosystems of Ethiopia
Debissa Lemessa,
Yayehyirad Teka
Issue:
Volume 2, Issue 3, June 2017
Pages:
34-44
Received:
27 April 2017
Accepted:
4 May 2017
Published:
27 May 2017
Abstract: Understanding plant species distribution across ecosystems is fundamental for designing conservation mechanisms at different ecological scales. Here, the aim of this study is to examine the pattern of plant species richness, unique/restricted, endemic and threatened species across eleven vegetation ecosystems of Ethiopia. The species data were compiled from the atlas of the potential vegetation of Ethiopia that describes the plant species by ecosystems and elevational gradients. Moreover, the data on threatened species was collated from the Red List Endemic Trees and Shrubs of Ethiopia and Eritrea. The comparative patterns of these different characteristic species were analyzed using descriptive statistics. Moreover, the relationship between the ecosystem characteristic species richness vs. species unique to each ecosystems; ecosystem characteristic species richness vs. species common to ecosystems; ecosystem characteristic species richness vs. species unique to each ecosystems and species unique to each ecosystems vs. endemic species richness across ecosystems was tested with Pearson’s correlation using R statistical program. The results showed that the Acacia-Commiphora woodland bushland ecosystem is comprised of the higher number of species (i.e., 37% of the total ecosystem characteristic species), while in contrast, the Afroalpine belt and Wooded grassland of the western Gambela region ecosystems had lower species richness (i.e., 1.4–1.5%) when compared with the other ecosystems. Dry evergreen Afromontane forest and grassland complex ecosystem is composed of the higher number of species that are common to the majority of other ecosystems, but Desert and semi-desert scrubland does not have any species which are common to other ecosystems. The number of ecosystem characteristic species, endemic and threatened species are higher in Acacia-Commiphora woodland bushland ecosystems and the majority are found in Euphorbiaceae and Fabaceae families. Moreover, the ecosystem characteristic species richness in general and of endemic in particular took hump-shaped pattern where the number of species was higher at “mid altitude”. These different patterns may indicate that conserving the whole system only at mega scale may not necessarily mean that the rare/unique, endemic and threatened species are conserved. Therefore, the overall results emphasize the importance of understanding the ecological processes in each ecosystem and the corresponding species specific properties to plan and design conservation system following either ecosystem approach or multiple spatial scales.
Abstract: Understanding plant species distribution across ecosystems is fundamental for designing conservation mechanisms at different ecological scales. Here, the aim of this study is to examine the pattern of plant species richness, unique/restricted, endemic and threatened species across eleven vegetation ecosystems of Ethiopia. The species data were comp...
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Relictual tRNAs Recognized not Chemically Inert Amino Acids, but Chemically Active Aminoacyl-Adenylates
Issue:
Volume 2, Issue 3, June 2017
Pages:
45-48
Received:
17 March 2017
Accepted:
10 April 2017
Published:
27 May 2017
Abstract: Some authors believe that the genetic code originated due to the ability of amino acids to form complexes with the corresponding antikodons. We believe that it is wrong and hypothesize that the relic tRNAs did not form complexes with chemically inactive amino acids. The formation of such complexes was devoid of “biological meaning”. Instead, they recognized of chemically active forms of amino acids, namely aminoacyl-adenylates. Thus, relict recognition of amino acids, which led to the formation of the genetic code do not occur through the formation of complexes, but through a chemical reaction between the corresponding aminoacyl-adenylates and tRNAs relic. All the necessary elements of the relic of the mechanism of recognition of aminoacyl-adenylates evolutionary entrenched in the structure of modern tRNAs. The main element of such mechanism is the uridine base, which is always before the anticodons of modern sense tRNAs. Thus, thanks to our hypothesis, we can answer two fundamental questions: 1. Why only ATP activates amino acids? 2. Why only U-bases are placed before the anticodons of modern sense tRNAs?
Abstract: Some authors believe that the genetic code originated due to the ability of amino acids to form complexes with the corresponding antikodons. We believe that it is wrong and hypothesize that the relic tRNAs did not form complexes with chemically inactive amino acids. The formation of such complexes was devoid of “biological meaning”. Instead, they r...
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