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Research Interests

My research focuses on the origin and early evolution of land plants.

Life is believed to have evolved in the sea some 3,500 million years ago (Ma), and following the Cambrian explosion (550 Ma) the oceans teemed with a bewildering diversity of multicellular life. However, the surface of the planet is considered to have been essentially barren, until the mid-Ordovician (475 Ma), when plants first invaded the land. There followed an adaptive radiation as land plants evolved rapidly and spread across the surface of the planet. The land plants also paved the way for other organisms to migrate onto the land, including invertebrates and vertebrates, by providing shelter and food.

I am interested in when the plants invaded the land, the nature of their ancestors and their evolutionary relationships, how they overcame the huge physiological barriers necessary for successful exploitation of the terrestrial habitat, and what effects the greening of the landscape had on the environment of planet earth.

My research is conducted primarily through study of the fossil record of the earliest land plants (dispersed microfossils, including spores and phytodebris, and megafossils). Particular emphasis is placed on:- (1) establishing a dispersed spore biostratigraphy in order to create a temporal/spatial framework for analysis of the origin and adaptive radiation of land plants (including patterns of palaeophytogeography and palaeobiodiversity); (2) analysis of in situ spores in order to facilitate integration of the dispersed spore/plant megafossil fossil records; (3) utilizing spore morphology and wall ultrastructure characters to analyse phylogenetic relationships among early land plants and their ancestors.

Clearly the fossil record can only be interpreted in light of our knowledge of extant "primitive" land plants (bryophytes and pteridophytes). To this end I am interested in phylogenetic relationships among "primitive" extant land plants (particularly when such phylogenies incorporate fossil evidence). Analysis of land plant phylogeny has recently been invigorated because of the opportunity to use molecular sequence data in phylogenetic analysis. Combined use of fossil plants (morphology) and extant plants (morphology and molecules) is leading to reassessment of the evolutionary relationships of land plants, and creation of robust phylogenies critical for correct interpretation of the evolution of land plants.

New developments in the rapidly progressing field of developmental genetics are also proving interesting regarding the origin of land plants. Progress in this fledgling discipline promises to shed light on the processes and patterns of evolutionary change, and perhaps provide an explanation for the macroevolutionary changes that led to the evolution of land plants from aquatic algal ancestors.

Finally, the invasion of the land by plants had dramatic effects on the physio-chemical environment of planet earth, particularly regarding atmospheric composition, climate patterns, rates of weathering and sedimentation patterns. Multidisciplinary research based on sedimentology and climate modelling are identifying these changes. Studies of plant physiology in "primitive" extant plants are helping us relate the evolving vegetation to environmental change.