The evolution of organisms leads to biodiversity. Many of the researchers at SNG are therefore focused on evolution-related topics
Evolution is the result of small, stepwise changes in the hereditary traits of living organisms from one generation to the next. These traits are encoded in the form of genes that are being copied during reproduction and passed on to the offspring. Spontaneous, random mutations create variants (alleles) of these genes, which lead to genetically determined differences between individuals. In species that procreate by means of sexual reproduction, the mixing (recombination) of the parents’ genes additionally increases the genetic diversity. Evolution occurs when the frequency of these alleles changes within a population; i.e., these characteristics increase or decrease in the population. This either occurs through natural selection (different reproduction rate) or randomly through so-called genetic drift. The description of the theory of evolution by Charles Darwin 150 years ago in the course of the Enlightenment led to a revolutionary new world view.
[ALPHABETICAL – Section head/researcher with a special focus on evolution]
Evolution research at the DZMB (German Center for Marine Biodiversity Research) For many years, the study of deep sea organisms has been at the center of the research activity at the DZMB. Questions concerning the origin and evolution of the species diversity in this hitherto only inadequately studied biotope are of particular interest here: Which evolutionary processes lead to the diversity of deep sea denizens? What are the morphological and genetic adaptations of deep sea organisms, as compared to shallow water species? The answers to these questions help us to better understand the immense diversity in this alien habitat.
Photo: Deep sea isopod | Size: 5 mm | CLSM image, colored
Dr. Jörg Habersetzer – Senckenberg (Frankfurt) Bats, as actively flying mammals, are only rarely found in the fossil record. However, approx. 700 individuals from four different families have been documented from the World Heritage Site “Messel Pit. “ The exceptional state of preservation of stomach contents, inner ears and flight apparatus made it possible to draw conclusions regarding the habits of these Eocene mammals. Among others, micro-radiography and micro-CT were used to demonstrate the inner ear’s ability for echo-location, and, in comparison with individual specimen from America and Africa, the “flight first” hypothesis could be supported.
Dr. Jörg Habersetzer – Senckenberg (Frankfurt) Darwinius masillae was described as a new genus and species by an international team of researchers, which included the scientists Dr. Franzen and Dr. Habersetzer from Frankfurt. The world’s most completely preserved fossil primate to date came from the World Heritage Site “Messel Pit” and was examined using various methods, among others micro-CT. The fossil (“Ida”) triggered a discussion of the evolution of early primates on an international level (48 mio., wet-nosed vs. dry-nosed primates). The original publication and all of the high-resolution images are available for free (J. L. Franzen et al. PLoS ONE 4, e5723; 2009).
All images: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0005723
Human-ethological Film Archive - Frankfurt This is the world’s largest archive of humanity’s bio-cultural diversity. Founded 50 years ago by Eibl-Eibesfeldt, the archive candidly documents the everyday life of people all over the world, in particular in five cultures that were studies continuously over many years. Handed over to Senckenberg in 2014, this unique and comprehensive documentation is now being made available to researchers from a wide array of disciplines. In our work regarding biocultural evolution, it is an ideal starting point for the study of the interrelationship between universality and diversity in the culture and behavior of humans.
Fig.: weltkarte-HF-kulturen2015ak1400x743.png © I. Eibl-Eibesfeldt, R. Krell, A. Kuper
Prof. Axel Janke – BiK-F Long-scale evolutionary processes such as the origin of mammals and species formation are described by genome data with an amazing level of precision. Using sequence analyses and the distribution patterns of mobile genetic elements, we examine the relationships, speciation and gene flow in mammals. The genome data show that evolution is not necessarily a bifurcate process, as described by Darwin 150 years ago. We are particularly interested in these processes in bears, giraffes and kangaroos.
© Hans-Rüdi Weyrich
Prof. Sven Klimpel, Dr. Thomas Kuhn – BiK-F, SGN Parasites and pathogens are integral components of all ecosystems. They infect and harm other organisms for a brief period or for a longer duration, and their survival is not only determined by the physiological capacity, but in particular by the genetic adaptability to changing abiotic and biotic factors. Based on phylogenetic and phylogeographic, population-genetic and genomic analyses, we examine the co-evolutionary connections in host-parasite/pathogen systems within various invertebrate and vertebrate classes.
Abb.: Ice fish liver with nematodes
The development of different types of teeth in the dentition is among the selective key developments in the evolution of mammals. The Cenozoic saw the development of an incredible diversity of tooth shapes with specialized adaptations. We apply innovative computer methods to compare the bite contact of various teeth, and we compare the structural adaptations in the masticatory apparatus with function-morphological and biomechanical movement and stress analyses, in order to gain a better understanding of the impact of the habitat and the food in the developmental history of humans.
Prof. Markus Pfenninger – BiK-F All evolutionary changes originate in frequency changes of genetic traits in populations. We use population-genomic and experimental methods to study neutral and selective processes that lead to an adaptation to environmental factors, the emergence of reproductive isolation and thus speciation. Our main focus is on the impact of spatial and temporal climate differences on the genetic composition of populations. We use chironomids, Limnaeid snails and fishes as model organisms for our studies.
Dr. Christian Printzen – Botany and Molecular Evolution Research, Cryptogam Section Lichens constitute ancient, perfected symbioses between fungi and photosynthetic algae or cyanobacteria. In most cases, one partner is unable to survive without the other. Their evolution is therefore subject to rather specialized restrictions. The Cryptogam section applies methods from the fields of population genetics, ecology and phylogenetic tree calculation to study various aspects of the evolution of lichen fungi and algae, from their ecological adaptation to their phylogeny. [4 sentences 60 words]
[Caption: Letharia columbiana on a dead pine branch Yosemite National Park USA]
Hybridization and ployploidy (multiplication of complete sets of chromosomes) play an important role in the evolution of terrestrial plants. Both processes are frequently coupled and can also be understood as “evolutionary leaps.” In polyploid hybrids, both the genome and the transcriptome are reorganized, which often leads to reproductive isolatition and consequently speciation. We work with plants from the rose family as model systems (genera Potentilla and Rosa) in order to study these phenomena by means of population-genetic, genomic and transcriptomic methods.
Caption: Potentilla thuringiaca, Southern Tyrol, Italy; Rosa inodora, Weißenberg, Germany
PD Dr. Irina Ruf – SGN Frankfurt The mammalian skull shows remarkable evolutionary transformations, in particular in the nasal and ear regions. By means of histology, micro-computer tomography and virtual 3D reconstruction, we record internal skull structures, which we analyze under comparative anatomical, function-morphological, ontogenetic, systematic and evolutionary aspects. Our special emphasis in this area is on the evolution and the functional adaptation of the mammalian ear. Our research is currently focused on rodents, lagomorphs, carnivores, even-toed ungulates and various extinct groups of mammals.
Prof. Imke Schmitt - BiK-F Mutualistic symbioses are interrelationships between organisms of two species that are beneficial for both parties. In addition to Darwinian evolution (gradual changes in hereditary traits), mutualistic organisms have the possibility to adapt to their environment by selecting locally adapted symbionts. We analyze how evolutionary processes, e.g., selection, coevolution or exchange of symbionts, and ecological factors (climate) influence the genomes and the association patterns of mutualists. Our model organisms are lichen-forming fungi and their symbiotic green algae.
Dr. Krister T. Smith – Senckenberg-Frankfurt By hosting transitional forms, the fossil record contains the only direct proof of the evolutionary process. We study the evolutionary history of reptiles, using fossils from widely scattered deposits in Europe and North America. We focus on the historical impact on the distribution patterns of lower vertebrates, which can be traced back to prehistoric climate change, and the origin of adaptations that are documented by the outstanding level of preservation of the fossils from the Eocene pit in Messel (preserved scales on the lizard foot, left).
Prof. Marco Thines – BiK-F Biotic interactions shape the evolution of organisms, both in long- and short-scale processes. Paired with molecular-biological studies and experiments, genomic, phylogenetic and population-biological studies can shed light on the question how organisms evolve in interaction with their biotic environment. We examine the processes of adaptation, niche occupation and speciation as well as superordinate evolutionary patterns, primarily in the fungus-like Oomycetes and plant pathogens.
Dr. Sonja Wedmann – Senckenberg Research Station Messel Pit Insects are an extremely diverse group of organisms, both in respect to their high number of species as well as their wealth of diverse life forms. Currently, science is still far from describing and understanding the full diversity of recent insects; the diversity and evolutionary history of fossil insects has been studied in even less detail. Fossils can give us essential insights into the evolution of insects, and we place special emphasis on an intensive study of the 47 million year old insects from the Messel pit.
Prof. Dr. Georg Zizka – Senckenberg Research Institute and Nature Museum Frankfurt and Goethe University Based on systematic-taxonomic processes, we study the phylogeny, evolution of traits, historical biogeography as well as population genetics of various groups of flowering plants, in particular Bromeliaceae, Poaceae, and Ochnaceae. Besides the question about the role of key characteristics and environmental factors in species formation and distribution, we are interested in genetic analyses as a means of reconstructing the speciation process and supporting species boundaries.