A few links to interesting listening and reading.
1) Tracking the first animals on earth: Unequivocal evidence of animals is preserved in soft sediments from about 570 million years ago. The fossil record of the Ediacaran to early Cambrian times (570 to 500 million years ago) has yielded rich information about the patterns of animal evolution. Apart from fossils, comparative genetic studies have given insights into how different animal groups are related to each other and the order of branching of these groups. Amazingly, organic molecules recovered from enigmatic fossilized taxa have been used to differentiate between animal and non-animal remains. Zoologist Matthew Cobb explains all this and much more about early animal evolution in about 30 minutes. Give it a listen!
2) Plant-eating and meat-eating in Australopithecus: What did our ancient relatives eat? By ancient, I mean going back a million years or more. We can use isotopes of nitrogen to tease out information about diets. Carnivores have more nitrogen-15 enriched tissue than plant eaters. Carbon isotopes (C13 and C12) also yield information about the diet of herbivores. Grazers munching on grass take in more of the heavier isotope of carbon than browsers eating leaves and stems. Paleoanthropologist John Hawks discusses some recent work on nitrogen and carbon isotopes of Australopithecines and how the patterns of isotopic variation extracted from tooth enamel can be interpreted in terms of diets and life history. Fascinating stuff.
3) Addressing Depletion in Alluvial Aquifers: Why Context Matters in Participatory Groundwater Management: India relies a lot on groundwater for agriculture. There are signs from many parts of the country of acute groundwater distress. Participatory Groundwater Management initiatives have had some success in addressing this distress. Pratik Kumar and Veena Srinivasan point out that these cooperative movements have been more successful in hard rock aquifers from different parts of the country than alluvial aquifers of northwest India. Geology matters. Aquifer properties matter. Hard rock aquifers are more sensitive to abstraction and are rapidly de-watered and recharged seasonally. Alluvial aquifers are spread over vast areas and water levels are less sensitive to abstraction. The amount you can extract doesn't vary with lowering of water level.
People depending on hard rock aquifers experience the limitation of the resource yearly and are more willing to join cooperative initiatives to manage the resource.
I have just given a gist of the more elaborate arguments in the paper. The graphic below very neatly compares hard rock and alluvial aquifers.
Source: Pratik Kumar and Veena Srinivasan 2025
