The first form of life

Microorganisms smaller than the human eye can see

The first form of life to develop on the Earth were microbes, and they remained the only form of life until about a billion years ago when multi-cellular organisms began to appear. Microorganisms are single-celled organisms that are generally microscopic, and smaller than the human eye can see.

Aerial photography
The tiger’s mouth is the great Eyjafjorour, a deep fjord at the northern coast of Iceland – photo: USGS

The planetary ecosystem

These life forms are found in almost every location on the Earth where there is liquid water, including in the Earth’s interior.

Their reproduction is both rapid and profuse. The combination of a high mutation rate and a horizontal gene transfer They form an essential part of the planetary ecosystem. However, some microorganisms are pathogenic and can post health risk to other organisms.

Remnants of plant life

Among the many ways of classifying plants are by regional floras, which, depending on the purpose of study, can also include remnants of plant life from a previous era. People in many regions and countries take great pride in their individual arrays of characteristic flora, which can vary widely across the globe due to differences in climate and terrain.

Regional floras commonly are divided into categories such as native flora and agricultural and garden flora, the lastly mentioned of which are intentionally grown and cultivated. Some types of ‘native flora’. actually have been introduced centuries ago by people migrating from one region or continent to another, and become an integral part of the native, or natural flora of the place to which they were introduced. This is an example of how human interaction with nature can blur the boundary of what is considered nature.

Climate changes

Climate is a measure of the long-term trends in the weather. Various factors are known to influence the climate Based on historical records, the Earth is known to have undergone drastic climate changes in the past, including:

  • Ocean currents
  • Surface
  • Greenhouse gases
  • Variations in the solar luminosity
  • Changes to the Earth’s orbit

Based on historical records, the Earth is known to have undergone drastic climate changes in the past, including ice ages. Weather is a chaotic system that is readily modified by small changes to the environment, so accurate weather forecasting is limited to only a few days.

Major oceanic divisions

The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Smaller regions of the oceans are called seas, gulfs, bays and other names. There are also salt lakes, which are smaller bodies of landlocked saltwater that are not interconnected with the World Ocean. Two notable examples of salt lakes are the Aral Sea and the Great Salt Lake.


Jane Roe

Jane Roe

Jane is a 24-year-old researcher who enjoys charity work, cycling and cookery. She is allergic to artificial food colourings. She has a severe phobia of sharks, and is obsessed with milkshakes.


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1) Fossil flora

Paleobotany is the branch of botany dealing with the recovery and identification of plant remains from geological contexts.

2) Albedo temperature effects

High albedo areas in the arctic and antarctic regions are cold due to low insolation, whereas areas such as the Sahara Desert, which also have a relatively high albedo, will be hotter due to high insolation.