FIRST LIVING THINGS ~ Suman Blogz

| More

What were the first living things?

The first living things on earth were simple cells, probably consisting of nucleic acids and proteins surrounded by a thin cell membrane. These cells must have been far simpler than most modern bacteria. None could use sunlight to make food the way modern plants and some bacteria do. Their environment was also very different from the environment today: the air had lmost no oxygen, and the ocean water was very warm.

Although these simple cells lived billions of years ago, scientists today have found similar organisms living at the bottom of the ocean. At spots more than 2 Km deep, where molten rock is just below the seafloor, hot water blasts up ward from earth’s interior. These jets of water – called black Smokers carry a heavy load of gases and minerals that turns the water black. Most of the deep ocean floor is without life, but black smokers form the centres of busy communities. Anaerobic bacteria which live without atmospheric oxygen, thrive here with no oxygen on light, getting energy from hydrogen sulphide and other compounds forced upward by the hot water. Similarities between modern bacteria found around these black smokers and earth’s first simple cells suggest that life may have began around such hot water vents.

The simplest modern day cell:

Of all life on earth, bacteria are among the simplest – small cells with no specialized compartments inside. And the anaerobic bacteria living around black smokers may be the most primitive. Some scientists believe these organisms – called archaebacteria or ancient bacteria – are descentants of the ancestors of all living things. Others say the bacteria evolved long after other life forms and adapted to such harsh environments as sewage, hot springs, and the intestines of some animals. Archaebacteria thrive today, for instance, in the boiling springs found in Yellowstone national Park in the Western US.

1. 1. Bacteria living near: black smokers process gases and minerals to grow. The energy they release as a by-product helps provide food for clams as large as footballs gaint tube worms and other organisms in the deep sea community.

2. 2. Black smoker form when water seeps in to cracks in the seafloor and meets molten rock just below the surface. The water is superheated and surges upward, carrying with it dissolved minerals. When the scalding water meets the cold seawater above the ocean floor, some of the minerals solidify and form tall chimneys. Other collect into particles – the black “smoke” that gives the vents their name – and spray out of the chimneys. Pressure keeps the water from boiling, allowing it to reach 315C to 345C. scientists think black smokers have existed since continents first began to drift apart.