by Verity Bennett1
The size and shape of an organism is the product of genetics and environment. It is the raw material on which the process of natural selection (survival of particular animals over others) acts, and so is of central interest in studies of the evolution of ancient forms of life for which DNA information is not available. Fossil morphology, or shape, is the basis of most palaeontological studies, be they describing new species or making deductions about the animal’s lifestyle. Phylogenetic studies, those that place species in groups depending on how closely they are related to each other, are based on the presence and absence of particular features. This works on the theory that the more closely related two animals are, the more features they are likely to h
by Russell Garwood *1
Breathe in. Breathe out. It’s a good bet that you’re currently sitting in front of a computer, reading; I’m going to go ahead and assume that you’re breathing, too. In, and out. You probably weren’t even thinking about breathing until I mentioned it, but all the same, it’s keeping you alive. Oxygen from the air is being transported into the cells of your body, which are using it to create energy. So far, so good. But what you may not realize is that the cellular machinery performing this process so integral to our existence (Fig. 1) has roots buried deep in the geological past. It’s a story that begins before the origin of organized cells, in an ancient, alien world. But if we’re going back that far, we might as well go all the way back, to the very be
by Jonathan B. Antcliffe1
The transition between the Precambrian and the Cambrian period (about 550 million to 500 million years ago) records one of the most important patterns of fossils in all the geological record. Complex animals with a suite of shells, intricate body plans and associated movement traces appeared for the first time, suddenly and unambiguously, in sequences all over the world during this interval. This ‘Cambrian explosion’ remains one of the most controversial areas of research in all of the history of life, and one of the most exciting. Palaeontological data like this is definitive in its support for evolutionary theory, the relative sequence of first appearances in the fossil record over the past several billion years ties very closely with what we wou
by Javier Ortega-Hernández *1
The principle of parsimony, also known as Occam’s razor, has been widely attributed to the English Franciscan friar William of Occam (c. 1288–1348). It states Pluralitas non est ponenda sine necessitate, which translates to ‘Plurality is not to be assumed without necessity’. In other words, when one is faced with a problem or question that can have several different answers, the solution that requires the fewest assumptions is most likely to be correct, unless there is evidence that proves that it is false. Parsimony has an enduring influence in most scientific activities, as it allows researchers to make comparisons and choose between different hypotheses that aim to explain a phenomenon using the same body of evidence. The incomplete nature
by Phil Jardine*1
The Paleocene–Eocene Thermal Maximum (PETM) is one of the most intense and abrupt intervals of global warming in the geological record. It occurred around 56 million years ago, at the boundary between the Paleocene and Eocene epochs. This warming has been linked to a similarly rapid increase in the concentration of greenhouse gases in Earth’s atmosphere, which acted to trap heat and drive up global temperatures by more than 5 °C in just a few thousand years. The fossil record gives us the means of understanding how life was affected by the PETM, and so provides an excellent opportunity to study the relationships between evolution, extinction, migration and climate change.
The early Palaeogene world:
At the time of the PETM, the world was already much w
by Alistair J. McGowan*1
Biological diversity, or biodiversity, shot to prominence among non-specialists in 1992, after the Rio Earth Summit (Fig. 1). Media coverage of the summit did a tremendous amount to raise awareness of the need to gather baseline data on species, and of the spectre of extinction hanging over some of them. The international Convention on Biodiversity declared 2010 the International Year of Biodiversity, and 2011–20 the Decade of Biodiversity. The use of the term biodiversity in the media has increased greatly, and the word is now in general use. Many countries now have biodiversity action plans that start locally and move through various levels and habitat types to the national level (for example, see the United Kingdom’s Biodiversity Action Plan).