Wednesday, July 16, 2025

Joshimath Landslide, Human Evolution, Early Animals

Sharing some of my readings over the past couple of weeks- 

1) Movement of Joshimath Landslide in India: The town of Joshimath in Gharwal Himalaya is built on an ancient landslide. Geological reports going as far back as the 1970’s had warned that excessive modification of the slope due to urbanization may result in slope movement and eventual failure. These warnings proved correct as slope movement since 2018 has caused major damage to houses and livelihoods. Landslide expert Dave Petley reports on a new study of the region that uses radar technology to track earth movements. 

It concludes that removal of vegetation, mismanaged groundwater seepage and blocked drainage paths contributed to accelerated movements of the Joshimath landslide system. There is unplanned and unregulated construction happening in other Himalayan towns. Authorities must take geological advice seriously and plan their growth accordingly.

2) The Olduvai Effect- New questions about meat eating in human origins: How about some food for thought?… I mean literally. Was meat eating connected to the evolution of larger brains in our human ancestors beginning around 2 million years ago? Paleoanthropologist John Hawks writes about recent work on East African sites across the period from 2.6 to 1.2 million years ago that throws doubt on the “meat made us human” hypothesis. 

The study he discusses finds no evidence for a systematic increase in meat eating across the studied period. The evidence also points to different hominin groups having flexible strategies for obtaining meat. But can we tie increased meat eating to one particular branch of the hominin tree? This is a very interesting article on how anthropologists retrieve and analyze evidence from sites and how the geography and time depth of sampling influence the conclusions that are drawn. 

3) Complex animals living millions of years before the Cambrian Explosion revealed by seabed tracks: What do we know about early animal life before the evolution of shells made their preservation more likely starting around 530 million years ago? That animals were present much before they acquired shells is inferred from molecular data that places their origin and diversification a good 50-100 million years before the Cambrian. But there is another way to understand animal evolution before body fossils appeared. It is through studying their movement on the sea bed. Tracks and burrows made by mobile animals start appearing in the rock record by 550 million years ago. 

James Ashworth describes some recent fascinating work that has decoded the morphology of these fossil trails and compared their shape with those made by some common modern sea floor animals. The researchers then propose that the changing shapes of trails across a 10 million year period is indicative of increasing complexity in animal locomotion. Early trails were made by simpler animals with short round bodies and limited sensory capabilities. Later in time, sinuous tracks made by worm like animals characterized by a slender anterior-posterior body profiles appear. A very clever way of understanding morphological changes during early animal evolution.