Caspian

Christopher Packham writes: Though humans, along with other vertebrate and invertebrate organisms, don’t photosynthesize, we’re definitely the downstream beneficiaries of the life forms that do. Phototrophic organisms at the bottom of the food chain convert abundant sunlight into the energy that ultimately powers all other life. The two metabolic systems for harvesting light energy are fundamentally different. The most familiar is the chlorophyll-based photosynthesis by which plant life uses light to power the conversion of carbon dioxide and water into sugars and starches; the other system consists of proton-pumping rhodopsins. Microbial rhodopsins, retinal-binding proteins, provide ion transport driven by light (and incidentally, sensory functions). It’s a family that includes light-driven proton pumps, ion pumps, ion channels and light sensors. Microbial rhodopsins are Read More ›

What very old trees can teach us about life, death, and time. Jared Farmer writes: What’s the oldest known living thing, and how do we know? Why should we even want to know? The explanation is a history of curiosity and care. It’s about our long-term relationships—spiritual and scientific—with long-lived plants, as long as long can be. It’s all about trees. A tree is a plant that people call a tree—a term of dignity, not botany. Although people construct the meaning of “trees” and assign age value to the vascular plants they call “ancient trees,” people cannot themselves create life that grows in place for centuries. Exclusively, solar-powered organisms enact that miracle. Among plants, there are ephemerals, annuals, biennials, perennials—and, Read More ›

Nicoletta Lanese writes: Ancient microbes whose existence predates the rise of nucleus-carrying cells on Earth may hold the secrets to how such complex cells first came to be. Now, for the first time, scientists have grown a large enough quantity of these microbes in the lab to study their internal structure in detail, Science reported. Researchers grew an organism called Lokiarchaeum ossiferum, which belongs to a group of microbes known as Asgard archaea, according to a new report, published Wednesday (Dec. 21) in the journal Nature. Named after the abode of the gods in Norse mythology, Asgard archaea are thought by some scientists to be the closest evolutionary relatives of eukaryotes, cells that package their DNA in a protective bubble called a nucleus.  On the evolutionary Read More ›

Stephen J. Iacoboni‘s article contains a profound question… One cannot understand organisms — that is, life itself — without incorporating the concept of purpose within biology, the science of organisms. Such purpose is observable and measurable, and therefore well within the bounds of scientific inquiry. In order to understand life, it is not sufficient to simply observe what is happening. The real question is why things are the way they are. However, did we not just decide that animals eat because they are hungry and avoid danger to eschew harm? Yes, these are clearly purpose-driven activities, and they all have a biochemical or physiologic basis. True enough. But the deeper question is, why are these physiologic stimuli there in the first place? Answer: to allow for Read More ›