Eukaryotes

What is a eukaryote? The simple answer is anything living thing that can is not capable of asexual (mitosis) reproduction or simply a life form that needs to have sex to reproduce (plant pollination is a simple form of sex). Eukaryote life forms include algae, protozoa, slime molds, plants, and animals including us humans. Eukaryotes appeared about a billion years ago, not long after oxygen had been introduced in the atmosphere. Why? At first the early Earth's only oxygen was in water. The first life forms, maybe like the ones which live in the hot springs of Yellowstone National Park, ate hydrogen out of the atmosphere and the primordial soup (pools of organic chemicals, probably where life originally began). Eventually, all that hydrogen had been depleted, so they moved to deep sea hydrothermal vents. That worked well, as the tops of the Earth's oceans were frozen over, two and a half billion years ago. Eventually most of that hydrogen had been depleted too. So they started extracting it out of the water. Soon copious amounts of oxygen were being released into the air. This oxygen killed most of the early life forms, causing a massive famine. Bacteria were dying everywhere. But quite by accident, one day, a bacteria ate a complex organic structure known as a mitochondrion. The mitochronion helped that bacteria breath the oxygen and even process it into food. Over millions of years, these bacteria evolved to have different sexes. Thus the very first eukaryote was born.  The first eukaryotes probably were single-celled, such as algae, protozoa, and Euglena, which lived at the top of the ocean. There are several more differences between prokaryotes and eukaryotes. Notably that prokaryotes have no cytoplasm, cell membrane, or nucleus (although prokaryotes still have DNA).

What Makes Something Alive?

Welcome to the first post of the Ed McMann Death Science blog. Today we are discussing what makes something alive. Some scientist, who consider viruses living, give up even try to define the definition, but its actually very clear. Life reproduces on its own. What I mean by reproducing on its own is that life doesn't need any living hosts to reproduce. This does not apply to viruses (smallpox, AIDS, coldsores, influenza, cold). A virus is actually a non-living giant (tiny compared even to bacteria) organic molecular protein structure, with DNA pack inside. For most of their existence, viruses just float around in water, blood, digestive juices and don't do much. But when a virus comes in contact with bacteria or body cells, they burrow in with protein spines. From there they inject their DNA. As we will discuss further in this blog, DNA is the code for every living thing on Earth. The virus DNA intercepts the cell's own DNA, and mixes in with it. The new genes inside the cell tell it to produce new protein parts for the virus. Slowly the virus parts assemble and the cell explodes, sending the new viruses everywhere. Those new viruses will attack even more cells, which will produce more new viruses and so on. Eventually the viruses will cause an infection, making you sick or even killing you. Remember, no one is safe from viruses. From amoebas, to your dog, to your mother, to you.