My Ancestors

So, here I am. A living organism. A product of some four billion years of biological evolution on Planet Earth; a descendant of many million generations of ancestors – of mothers and fathers, every one of which lived long enough to successfully produce living offspring. Millions of them started life as tadpoles.

My ancestors of around 12,000 generations, or 300,000 years, ago, were among the earliest specimens of Homo sapiens (a human generation is taken to be 25 years}.. They lived in Africa.

Ancestors of 50 generations ago lived at the same time as the first farmers. The number of people on Earth at that time was probably about 5 million.

My ancestors of eight to ten generations ago would have lived at the beginning of the techno-industrial phase of human history, now commonly referred to as the Anthropocene. The total human population had risen to around one billion at that time. My grandparents witnessed the first motor vehicles and the introduction of electric light.

Some changes during my own lifetime:

  • The global human population has increased from 2 billion to 8 billion. It is still increasing at the rate of 1.4 million per week.
  • Nuclear weapons were invented, two of which were dropped on Hiroshima and Nagasaki, killing between 129,000 and 226,000 people. Thousands of thermonuclear weapons now exist. Some of them are a thousand times more powerful than those exploded in 1945.
  • Television, computers and smart phones have been introduced.
  • Humans have walked on the moon.
  • Life expectancy in Australia has increased from 68 years to 84 years.
  • Global carbon dioxide emissions from the use of fossil fuels have increased from about 3.7 million tonnes to 37.15 million tonnes.
  • The average global surface temperature has increase by about 1.5 degrees Celsius due to human activities. especially the use of fossil fuels, deforestation and breeding ruminants.
  • Humans have launched large numbers of satellites into space. There are now, at the time of writing, 4,800 active satellites in orbit, and several thousand dead satellites, as well as many thousands of pieces of space junk.