Die Wälder der Antarktis

Forests of Antarctica Antarctica is a continent of extremes, demanding a lot from the organisms living there. Antarctic macroalgae, as an important component of the coastal ecosystem of the Southern Ocean, have adapted their metabolism to permanent cold and to long periods of darkness. Due to the long cold‐water history and the isolation of the continent, a high number of endemic species developed in Antarctica. Antarctic macroalgae are important primary producers and serve as food for many organisms. Their more detailed investigation began relatively late and is far from complete. Climate change is visible in Antarctica as well, threatening the fragile ecosystem. Increased UV radiation e. g. can lead to changes in the depth zonation and increased temperature to changes in the geographical distribution of the individual macroalgal species.     

36. D. Phitos: Die Gattung Symphyandra in der Ägäis

• 1 . Die Chromosomenzahlen der Arten Symphyandra cretica, S. samothra-cica und S. sporadum werden zum erstenmal mitgeteilt.
• 2 . Die phylogenetischen Beziehungen der erwähnten Arten sowie ihr En-demismus werden besprochen.

     

Die Evolution der Religiosität. Hat Gott Naturgeschichte?

In this essay the author combines research findings and hypotheses to reach the conclusion that human religiousness may well arise from a variety of evolutionary adaptations. Though religions cannot be put to the test of hard science, religious customs and behaviour appear to be linked to adaptive advantages. These include improved ability to deal with crises and to overcome the temptation to benefit from the fruits of others' labours without paying, hence strengthening cooperation and moral solidarity, whilst improving competitiveness of the group with others. These behavioural traits fit well with the observation that human cognitive strategies are highly pre‐programmed to generate religious convictions.     

Die Torsion der Gastropoda - ein biomechanischer Prozeß

The recently proposed biomechanical model of gastropod torsion (edlinger 1988 a, b) is rejected on various reasons. First, the assumed original conditions in Polyplacophora and Tryblidiida as well as the constructed original condition in the Gastropoda do not emst in reality. Secondly, the mollus-can musculature is a very dynamic structure (continuous assembly and disassembl) so that biomechanic rocesses are of much minor importance than assumed by Edlinger . Thirdly, the biomechanical model resented does not explain the change of the relative position of the lateral (= visceral) nerve cords which are surrounding the dorsoventral muscles in Polyplacophora and Tryblidiida (also Scaphopoda and Bivalvia), but are situated between the muscles in Cephalooda and Gastropoda. The consequences of these considerations to the early evolution of Gastropoda are briefly outlined.