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- Orr, Russell J.S., et al.
(author)
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Paleozoic origins of cheilostome bryozoans and their parental care inferred by a new genome-skimmed phylogeny
- 2022
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In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 8:13
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Journal article (peer-reviewed)abstract
- Phylogenetic relationships and the timing of evolutionary events are essential for understanding evolution on longer time scales. Cheilostome bryozoans are a group of ubiquitous, species-rich, marine colonial organisms with an excellent fossil record but lack phylogenetic relationships inferred from molecular data. We present genome-skimmed data for 395 cheilostomes and combine these with 315 published sequences to infer relationships and the timing of key events among c. 500 cheilostome species. We find that named cheilostome genera and species are phylogenetically coherent, rendering fossil or contemporary specimens readily delimited using only skeletal morphology. Our phylogeny shows that parental care in the form of brooding evolved several times independently but was never lost in cheilostomes. Our fossil calibration, robust to varied assumptions, indicates that the cheilostome lineage and parental care therein could have Paleozoic origins, much older than the first known fossil record of cheilostomes in the Late Jurassic.
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| 2. |
- Hannisdal, Bjarte, et al.
(author)
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Long-term evolutionary and ecological responses of calcifying phytoplankton to changes in atmospheric CO2
- 2012
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 18:12, s. 3504-3516
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Journal article (peer-reviewed)abstract
- Calcifying phytoplankton play an important role in marine ecosystems and global biogeochemical cycles, affecting the transfer of both organic and inorganic carbon from the surface to the deep ocean. Coccolithophores are the most prominent members of this group, being well adapted to low-nutrients environments (e.g., subtropical gyres). Despite urgent concerns, their response to rising atmospheric carbon dioxide levels (pCO 2) and ocean acidification is still poorly understood, and short-term experiments may not extrapolate into longer-term climatic adaptation. Current atmospheric pCO 2 (~390 ppmv) is unprecedented since at least 3 million years ago (Ma), and levels projected for the next century were last seen more than 34 Ma. Hence, a deep-time perspective is needed to understand the long-term effects of high pCO 2 on the biosphere. Here we combine a comprehensive fossil data set on coccolithophore cell size with a novel measure of ecological prominence: Summed Common Species Occurrence Rate (SCOR). The SCOR is decoupled from species richness, and captures changes in the extent to which coccolithophores were common and widespread, based on global occurrences in deep-sea sediments. The size and SCOR records are compared to state-of-the-art data on climatic and environmental changes from 50 to 5 Ma. We advance beyond simple correlations and trends to quantify the relative strength and directionality of information transfer among these records. Coccolithophores were globally more common and widespread, larger, and more heavily calcified in the pre-34 Ma greenhouse world, and declined along with pCO 2 during the Oligocene (34-23 Ma). Our results suggest that atmospheric pCO 2 has exerted an important long-term control on coccolithophores, directly through its availability for photosynthesis or indirectly via weathering supply of resources for growth and calcification.
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| 4. |
- Henderiks, Jorijntje, et al.
(author)
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Phytoplankton size : Climatic adaptation and long-term evolution
- 2010
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Conference paper (other academic/artistic)abstract
- Marine phytoplankton, such as diatoms and coccolithophores, constitute the base of the marine food chain and are a fundamental component in biogeochemical cycles. The overall ecological success of marine phytoplankton, but also its taxonomic diversity and size distribution, determines the efficiency by which fixed carbon is transferred to higher trophic levels and into the deep ocean- and sedimentary carbon reservoirs. Therefore, we need a better understanding of the mechanisms and rates of adaptation within phytoplankton to evaluate marine ecosystems under present-day and future climate scenarios of rapidly rising ocean temperatures and lowering of ocean pH (‘ocean acidification’). The likely response of coccolithophores, the most prominent group of calcifying algae, in particular has provoked controversy.We have hypothesized that species-specific responses to climatic perturbations within extant members of this group are due to differences in the mechanism and rate of climatic adaptation inherent to their respective evolutionary lineages (Henderiks, J. and Rickaby, R.E.M., A coccolithophore concept for constraining the Cenozoic carbon cycle, Biogeosciences 4: 323-329, 2007). The Cenozoic ancestors of all extant coccolithophores have experienced much higher levels of CO2 and lower ocean pH than today, according to proxy reconstructions over the past 60 million years. However, we show that different lineages display different levels of variation in coccolith shape and cell size, and that this could indicate that some species are more adaptable to climatic change than others. The observed geological trends in algal cell size also have implications for long-term feedbacks in the Cenozoic carbon cycle.
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| 7. |
- Love, Alan C., et al.
(author)
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Evolvability in the fossil record
- 2022
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In: Paleobiology. - : Cambridge University Press (CUP). - 0094-8373 .- 1938-5331. ; 48:2, s. 186-209
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Research review (peer-reviewed)abstract
- The concept of evolvability - the capacity of a population to produce and maintain evolutionarily relevant variation - has become increasingly prominent in evolutionary biology. Paleontology has a long history of investigating questions of evolvability, but paleontological thinking has tended to neglect recent discussions, because many tools used in the current evolvability literature are challenging to apply to the fossil record. The fundamental difficulty is how to disentangle whether the causes of evolutionary patterns arise from variational properties of traits or lineages rather than being due to selection and ecological success. Despite these obstacles, the fossil record offers unique and growing sources of data that capture evolutionary patterns of sustained duration and significance otherwise inaccessible to evolutionary biologists. Additionally, there exist a variety of strategic possibilities for combining prominent neontological approaches to evolvability with those from paleontology. We illustrate three of these possibilities with quantitative genetics, evolutionary developmental biology, and phylogenetic models of macroevolution. In conclusion, we provide a methodological schema that focuses on the conceptualization, measurement, and testing of hypotheses to motivate and provide guidance for future empirical and theoretical studies of evolvability in the fossil record.
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| 8. |
- Orr, Russell J.S., et al.
(author)
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A molecular phylogeny of historical and contemporary specimens of an under-studied micro-invertebrate group
- 2021
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:1, s. 309-320
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Journal article (peer-reviewed)abstract
- © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Resolution of relationships at lower taxonomic levels is crucial for answering many evolutionary questions, and as such, sufficiently varied species representation is vital. This latter goal is not always achievable with relatively fresh samples. To alleviate the difficulties in procuring rarer taxa, we have seen increasing utilization of historical specimens in building molecular phylogenies using high throughput sequencing. This effort, however, has mainly focused on large-bodied or well-studied groups, with small-bodied and under-studied taxa under-prioritized. Here, we utilize both historical and contemporary specimens, to increase the resolution of phylogenetic relationships among a group of under-studied and small-bodied metazoans, namely, cheilostome bryozoans. In this study, we pioneer the sequencing of air-dried cheilostomes, utilizing a recently developed library preparation method for low DNA input. We evaluate a de novo mitogenome assembly and two iterative methods, using the sequenced target specimen as a reference for mapping, for our sequences. In doing so, we present mitochondrial and ribosomal RNA sequences of 43 cheilostomes representing 37 species, including 14 from historical samples ranging from 50 to 149years old. The inferred phylogenetic relationships of these samples, analyzed together with publicly available sequence data, are shown in a statistically well-supported 65 taxa and 17 genes cheilostome tree, which is also the most broadly sampled and largest to date. The robust phylogenetic placement of historical samples whose contemporary conspecifics and/or congenerics have been sequenced verifies the appropriateness of our workflow and gives confidence in the phylogenetic placement of those historical samples for which there are no close relatives sequenced. The success of our workflow is highlighted by the circularization of a total of 27 mitogenomes, seven from historical cheilostome samples. Our study highlights the potential of utilizing DNA from micro-invertebrate specimens stored in natural history collections for resolving phylogenetic relationships among species.
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