Periodic Reporting for period 3 - TEMPO (Terrestrial vertebrates and the evolutionary origins of morphological diversity)
Reporting period: 2019-05-01 to 2020-10-31
The approach of the project is to address three central questions:
(1) How have rates and constraints of phenotypic evolution varied through geological time? This is a quantitative statistical question. By quantifying the structure of the skeleton in many species, including both living and fossil animals, we hope to characterise how patterns of evolution vary among groups and through time. Understanding *how* they vary is the first step in answering *why* they vary.
(2) Are these patterns consistent with the occurrence of global niche-filling? This relates to the hypothesis of adaptive radiations, that evolution of organisms is a response to the distribution of ecological opportunities on Earth through time.
(3) Can evolutionary versatility enabled by key innovations explain these patterns? This relates to the hypothesis that some groups of animals are simply more versatile than others, due to features of their body plan, structure, or development.
We also have started to address questions of ecomorphology and evolution within groups such as marsupials, birds and dinosaurs. Ecomorphology is the study of relationships between the structure of organisms and their ecology. It is central to core macroevolutionary hypotheses such as the idea of adaptive radiation (that evolution is driven by availabilities of novel ecological opportunities) and also to interpreting the ecologies of extinct species known only from fossils (including dinosaurs). Among other findings made so far, the quantitative approaches of the project have uncovered new indicators of stance in extinct animals, allowing us to determine which dinosaurs were quadrupeds, and which were bipeds. We have also investigated links between the vestibule (organ of balance) in birds and their locomotion.
Becuase our data collection has now reached its critical phase, the second phase of the project has begun. In this second phase we will investigate wider patterns of evolution of the skeleton, how and why they vary among groups such as mammals and birds, and through time.
By the end of the project we expect to have synthesised and compared patterns of skeletal evolution from across birds, mammals, and their extinct relatives (dinosaurs mammal-like reptiles, and others). By doing so we hope to understand how patterns of the rate of evolution, and constraints on its outcomes, vary among groups and through time. This will shed light on the factors (e.g. evolutionary versatility, ecological opportunity) underlying the large-scale patterns of evolutionary history.