COLUMN: IN THE WILD. The Savannah is the latest ecosystem to emerge in Africa

SOME historians say after the creation the Earth’s surface was covered by water and there was no any living thing on it. About 3.5 billion years ago to make life possible on Earth, the almighty God accumulated the water mass in one place and named it ocean.

It’s believed that Biosphere came after the decrease of hot waves from the core centre which is also known as Asthenosphere.

That situation led into the emerging of Lithosphere or dry land with fertile soil which also supports lives of animals, plants and microorganisms.

Scientists say in the long and complex evolution process, a prehistoric plant which used a primitive process of photosynthesis evolved into the ancient world about 3.4 billion years ago.

Fossil records show that there was some existence of life on the ancient world when a single cell organism appeared in the sea about 4 billion years ago before the rose of what is called the last common ancestor about 3.7 billion years ago.

Historians say the changes allowed some ancient plants to start using photosynthesis to produce their own food but detailed history of the world tells us that a primitive process of photosynthesis came into existence after the evolution of oxygen into the Earth about 3.5 billion years ago.

On their side scientists say that step was very crucial because different reports show the important chemical element appeared earlier about 3.7 billion years ago when the atmosphere was composed mainly by volcanic and greenhouse gases.

The evolution of plants which used photosynthesis became a catalyst for existence of life on the ancient planet because the process began to enrich the atmosphere with good amount of oxygen about 2.4 billion years ago when the world was still dominated with microscopic organisms. Historians say different research indicate that about 1.5 billion years ago the Earth passed through a long ice age which wiped out most of ancient plants that existed in the prehistoric world but scientists say different kind of earliest organisms continued to thrive.

It is estimated that about 580 million years ago the availability of enough oxygen contributed again into the evolution of complex multicellular organisms a group which was mainly made by bacteria, this shows that right from the beginning of the time photosynthesis played a very important role into the existence of life in different ecosystem of the world.

Scientists say the history of evolution of plants on the Earth is very complicated but it is estimated that the earliest plant appeared about 1.2 billion years ago, this was an algal scum which dominated the planet until about 450 million years ago when the first land plant evolved and thrived following advancement of the ancient photosynthesis process.

Different report show from that time ancient plants got further development when they adapted ability to multiply through pollination a process which started about 358.9 million years ago when average global temperatures rose to 20 °C or 68 °F. Scientists say that kind of climate favoured the expansion of ancient forests, meanwhile scientists say the presence of forests in different ecosystems around the world was an important step because they produced dry materials such as roots, foliage, barks, buds and woods which contributed into evolution of the first generation of termites that enjoyed an abundant supply of food.

On their sides, historians say the situation happened because between 410 and 359 million years ago the planet had 21.8 hours due to fast rotation which made 400 days of a year that was characterised by stronger winds which blocked development of forest until about 350 million years ago when climate changed and allowed the thriving of earliest land plants.

To survive in an ancient world which was experiencing low oxygen with big amount of carbon dioxide from volcanic activities, about 360 million years ago plants developed a well mechanism which used stomata and adapted xylem and phloem vascular tissues which enabled them to spread into different ecosystems including arid and semi-arid lands where the savannah is available today.

It was during this period about 360 million years ago when ancestors of modern green plants got well defined leaves, that was an important stage of evolution for plants because the presence of vascular conducting system helped them to use their environment effectively by obtaining carbon dioxide from the atmosphere and roots which draw water from the ground.

Unlike other creatures such as lions, primates and wildebeests which leave by eating food materials from others, from about 360 million years ago, plants survive by capturing light energy from the sky and drawing carbon dioxide from the atmosphere which was used with water during photosynthesis to produce their own food which is sugar consisting of glucose and sucrose.

Scientists say major group of plants which evolved between 100 and 40 million years ago had super metabolism mechanism which enabled them to survive in harsh condition dominated with long dry seasons and low oxygen.

From that time, plant played a significant role to control erosion and moderate climate as they remove carbon dioxide from the atmosphere and contributed into the creation of good condition for existence of other creatures.

This shows photosynthesis is mainly responsible for producing and maintaining the oxygen content of the Earth’s atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth, although it is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centres that contain green pigments.

Some ancient plant clades such as gymnosperms and angiosperms a group which consists of different species including cucumbers evolved about 319 million years ago and played key role in the evolution of flowerlike plant about 150 million years. Fossils records show that ancestors of flies and beetles were the first agents of the ancient pollination process but about 145 million years ago.

Prehistoric generation of bees contributed massively in this process as they collected nectars from one plant to another while playing a key role in distribution of pollens and enabled expansion of flowering plants into different ecosystems.

These primitive plants included huge trees with strong roots which were capable of penetrating deep into the ground after tearing apart rocks to produce soil that supported the growth of ancient some flowering plants such as lichen, scientists say the first seed plant appeared about 340 million years ago.

Historians say the situation triggered the flourishing of the ancient forests in different parts of the world, the existence of both flowering and seed plants enabled a smooth evolution of arthropods about 319 million years ago. From about 360 million years ago seed plant spread into different ecosystem and become source of food for different olden animals, birds and insects.

Scientists estimate that the first generation of reptiles evolved between 320 and 310 million years ago, this group was later dominated by dinosaurs which palaeontologists say they evolved on Earth more than 243 million years ago and managed to conquer rainforest and savannah when a mass extinction killed other creatures about 201 million years ago.

From an egg laying mammal, evolution of animals passed different stages but from those days to date their offspring start life without teeth to cut or grind food stuffs. Unlike fishes, reptiles and other creatures, from those prehistoric days to date mammals start their life without a well-developed digestive system.

This weakness is clearly seen among, primates, antelopes and bigger mammals such as buffaloes and elephant which have digestive system which function using the same mechanism which is found among cows. Scientists say the Savannah is the latest ecosystem to emerge in Africa and other parts of the World as a result of a huge climate changes accompanied with a rise of temperature and decrease of rainfalls.

Historians believe that these climatic and ecological changes took place on the Earth’s surface about 100 million years ago, fossil records dated this time indicate that the Earth came under Asteroids attacks from the Solar system which influenced geological and metrological changes on the ground and sky.

Scientists say at that time the world was very cold and dry but due to these attacks the climate the planet became warm and humid, worldwide different changes took place with subtropical vegetation growing in the northern hemisphere, the Earth’s poles became cool and temperate.

Some scientific researches indicate that antelopes evolved between 2,588,000 to 11,700 years ago while fossils records indicate that gazelles started to roam in Africa more than 2,588,000 years ago. Historians say the ancestors of modern impala were smaller and evolved in Ethiopia between 5.333 million and 2.58 million years ago when the world continued to cool and caused the disappearance of forests and the spread of grasslands and savannahs.

Different geological factors indicate for the past three million years ago at different time the savannah grassland of East Africa has contracted and expanded between two to three time and enabled Tanzania, Kenya, Uganda and Ethiopia to have one of the largest population antelopes in the world.

Scientists believe that during those days different pockets of animal’s sanctuaries were created and protected by natural forces through isolation which enabled antelopes to thrive in the greater Serengeti ecosystem which covers more than 30,000 square kilometres.

Different researches indicate that regardless of their enormous size, all species of dinosaurs shared on one feature of laying an egg which was incubated in a nest, these were amniotic eggs had very hard shells which enabled them to survive in different tough situation. Unlike bird’s eggs, amniotic eggs had special mechanism which was designed to enable the development of an embryo without the assistance of parents and the sex of the offspring would be determined by the amount of temperature of the surroundings.

By using geometric properties of eggs from 250 million years ago scientist say compared to modern birds few dinosaurs incubated their eggs for a long time with hatchlings being smaller and need more time to reach adulthood size, this slow, long and delicate reproductive procedure contributed into their extinction 66 million years ago.

Before that, this ability breeding through an egg enabled dinosaurs to conquer the world for about 160 million until about 175 million years ago when Pangaea the super continental started to breakup and triggered the beginning of the end of these mega fauna of the earliest world.

At the same time the world’s history shows that mammals evolved on the Earth about 320 million years ago but they were less known to other creatures until 250 million years ago when a mass extinction event killed 70% of vertebrates. From an egg laying mammal, evolution of this group passed different stages but from those days to date their offspring start life without teeth to cut or grind food stuffs.

Scientists say different fossils records show that mammals evolved into their full stage about 170 million years ago when they acquired a placenta which helps them to carry, protect and feed the embryo inside their bodies. Meanwhile some palaeontologists say earliest mammals developed their jaws about 201.3 million years ago when conifers forest dominated the world and from about 200 million years ago from an egg which was laid in water a common ancestor of all mammals evolved with more features.

At the same time the ancient world’s huge forests became source of food and home to million creatures include the dinosaurs who dwelled on Earth for the first time more than 200 million years ago and conquered it for about 160 million before a long period of volcanic activities pushed them into extinction about 66 million years ago. The writer can be reached via: rstanslaus@yahoo.com