MANY people believe that after creation about 3.5 billion years ago the Earth’s surface was covered by water and there was no any living thing on it. To make life possible on Earth, the almighty God accumulated the water mass in one place and named it ocean.
Meanwhile, fossils records indicate modern birds are the last remnants of dinosaurs whereby their ancestors evolved from a primitive birdlike big reptile about 100 million years ago.
Last week we saw that one of prehistoric plants which started to use a primitive process of photosynthesis evolved into the ancient world about 3.4 billion years ago. Historians say that was an important step of creation and evolution because about 2.1 billion years ago a blue green alga thrived.
Different studies 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 kinds of earliest organisms continued to thrive.
Scientists say different fossils indicate that most ancient plants evolved about 1.2 billion years ago from single celled algae, and during the primitive process of photosynthesis these prehistoric creatures used water as a reducing agent to produce oxygen as their byproduct. Different scientific researches show between 750 and 590 million years ago the Earth was covered by heavy ice sheets, as the average temperatures were about −50 °C, making life impossible.
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 existence of life in different ecosystems in the world.
Scientists and paleontologists say as process of evolution continued to be active on the planet Earth. Between 555 and 539 million years ago ancestors of all arthropods started to evolve on the Earth’s surface. Historians believe that different changes on the planet happens for different reasons.
It is scientifically claimed that more than 541 million years ago one of the first generations of reptilians inhabited the Earth and thrived. These were ancient creatures, who about 530 million years ago, started to undergo different changes which enabled them to thrive under the seabed until 525 million years ago when some of them such as the giant dragonfly, which used its 55 to 70 centimetres wingspan to migrate, dominated the ancient world.
On the other side, scientists say the history of evolution of plants on the Earth is very complicated but about 450 million years ago the first land plant evolved and thrived following advancement of the ancient photosynthesis process. To survive in an ancient world which was experiencing low oxygen with high amount of carbon dioxide from volcanic activities, about 360 million years ago plants developed stomata and adapted xylem and phloem vascular tissues which enabled them to spread into different ecosystems.
It was during that period about 360 million years ago when ancestors of modern green plants got leave, and that was an important stage of evolution of plants because the presence of vascular conducting system helped them to use their environment effectively by obtaining carbon dioxide from the atmosphere and leaf which draw water from the ground.
From about 360 million years ago, plants survive by capturing light energy from the sky and drawing carbon dioxide from the atmosphere which is used with water during photosynthesis to produce their own food which is sugar consisting of glucose and sucrose.
The plant which evolved in the ancient world was very resilient because between 360 and 260 million years ago temperature on the Earth’s surface was still low and most lake zone and other parts of Africa ware covered by a huge blanket of ice.
About 340 million years ago some changes happened and the second generation of seed plants appeared. The amazing event triggered the flourishing of the ancient forests in different parts of the world. The existence of both flowers and seed plants enabled a smooth evolution of arthropods about 319 million years ago.
Scientists say 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. This kind of climate favoured the expansion of ancient forests.
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 per cent of vertebrates.
Some paleontologists say earliest mammals developed their jaws about 201.3 million years ago when conifers forest dominated the world. It is also stated that about 200 million years ago, from an egg which was laid in water, a common ancestor of all mammals evolved with more features.
Different research show that 250 million years ago compared to modern birds, few dinosaurs incubated their eggs for a long time with hatchlings being smaller that needed more time to reach adulthood size. In a very complex way, evolution got into a more advanced stage when other ancestors of modern reptiles came into existence. That was about 231 million years ago when a separate species of dinosaurs evolved in a place known today as Rukwa in Tanzania.
After acquiring the ability of breeding through an egg, dinosaurs conquered the world from about 160 million until about 175 million years ago when Pangaea, the super continent started to breakup, triggering the beginning of the end of these megafaunas of the earliest world.
On the other side, the history of the world indicates that the earliest avian evolved about 160 million years ago and this were ancestors of modern birds. Scientists say the first flowerlike plant evolved about 150 million years ago.
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 to this process as they collected nectars from one plant to another.
Paleontologists say it was during that period when climate restricted ice sheets on high lands and mountain and opened the rest of the world to more flowering plants to thrive in the world which supported evolution of wasps and termites into the growing forests and savannah of the ancient world.
Scientists believe that about 100 million years ago, different fossils records show as a result of a huge climate changes which were accompanied by a rise of temperature and decrease of rainfalls the savannah started to expand into different ecosystems of the world.
The presence of flowering plants enabled different species to thrive in the ancient world which witnessed the evolution of wasps and termites into the fast-growing forests and savannah. 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 by the rise of temperature and decrease in rainfalls.
That was between 100 and 40 million years ago when the world experienced long dry seasons and low oxygen. So, the group of plants which evolved had super metabolism mechanism which enabled them to survive in harsh condition.
Scientists say the Savannah is the latest ecosystem to emerge in Africa and other parts of the world as a result of 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. Fossils records dated this time indicate that the Earth came under asteroids’ attacks from the solar system which influenced geological and meteorological changes on the ground and sky.
At that time the world was cooler and dry but due to these attacks the climate became warm and humid worldwide with subtropical vegetation growing in the northern hemisphere, the Earth’s poles became cool and temperate.
The Equatorial areas of the world adapted tropical climate while the southern and northern parts of Equator became hot and arid. These were rapid changes which wreaked havoc, forcing many living creatures into mass extinction after killing all members of that particular species of plant and animals. Scientists say it was during this time when many species of plants, birds and animals were forcefully pushed into extinction while some changed their morphology and adapted new behaviours so that they could survive in a new environment.
At the time of the havoc because of different morphological weaknesses, almost all members of an Afrotheria family called Orycteropodidae were killed just like many prehistoric species. The catastrophe left behind an Aardvark as their sole representative in the list of mammals which dwell in the savannah of Africa today.
Based on fossils records history shows the first Aardvark appeared in a supercontinent which was called Gondwanaland on an area which is known as Madagascar today. Scientists say the grandparents of this unique mammal appeared in a geological period called Paleocene which happened about 66 to 56 million years ago.
To survive through a fast-changing environment, the ancestors of the modern aardvark had to go through habitual and morphological changes. To cope with these changes, the body of an ancestor of modern aardvark had gone through convergent evolution process which enabled the mammal to adapt rabbit-like long ears capable to peak sound of an approaching enemy quickly.
Their heads became elongated and equipped with flexible nasal with thick nostrils protected by long hairs which block debris from entering into the lungs. Aardvark’s noses are made up by nine turbinate bones which provide good space for a moist epithelium, this condition function superbly with nine olfactory bulb of nose than in any mammal in the entire savannah.
These features enable the aardvark to have a powerful sense of smell which is capable to locate termites and ants crawling underground or an enemy from any direction. For security reasons, Aardvarks wore tough skin which is covered by clusters of pale yellowish-gray furs with yellow and white tinges which make them to look like pigs.
The climatic and ecological changes of the Paleocene pushed ancestors of an aardvark into a point of do or die, through convergent evolution they were able to adapt new physical and chemical ability in their digestive system. While the number of vegetation species was dwindling, this capability helped the ancestors of aardvark to shift from living by eating grasses and specialised in feeding on termites and ants.
Their tongue was modified to a snake like figure which is flexible and capable of being stretched 30 centimetres out of the mouth. Their forelegs became shorter, stronger and armed with sharp claws which are used to dig a two feet burrow after 15 seconds and push their long tongue which is armed with glue to trap termites from their mound. Recent investigative reports from game reserves located in southern circuit such as Selous, Liparamba and Lukwika Lumesule show that poachers are using aardvark’s burrows to hide from game rangers.
To avoid the hot Sun’s rays which may hurt its almost bare skin, the aardvark changed the habit of grazing on daytime to work in nighttime where it avoids predators and competitors. Aardvark lives in a home range covering two to five square kilometres where different records show the mammal is capable to eat more than 50,000 termites in a single night. The aardvark doesn’t relate with any other termites eating mammals such as the aardwolf or the kangaroo which carry the same type of strong tail.
The animal has a pig like body, but it’s not related to the domestic mammal, with elongated snouts elephant shrew, hyraxes and elephants are considered to be related slightly to this animal in whole of African Savannah. From the side, scientists say genetically this mammal has no a living relative and the above-mentioned factors make the Aardvark to be called a living fossil that dwells in the modern savannah.
Ecologists say Savannah grassland is open grassland with few scattered bushes and Acacia trees while the Savannah woodland is an area with grasses dominated by Miombo and Baobab trees.
This is an important feature which made the Savannah of Africa to be a home for many species of mammals than any ecosystem in the entire world. Some of these mammals live in the Savannah as enemies who fight and kill each other but many of these beautiful creatures lead peaceful life while helping each other.
Through their daily activities the aardvarks dig long burrows which they abandon regularly, these ten metres holes are occupied by other mammals such as African hunting dogs and Warthogs. Historically aardvarks were found in many parks such as Serengeti, Mount Kilimanjaro, Arusha, Tarangire, Lake Manyara, Mikumi, Udzungwa, Saadani and Mahale.
Others are Moyowosi, Ugala, Swagaswaga, Maswa and Ngorongoro conservation area.