This is how evolution changed planet earth

DAR ES SALAAM: ACCORDING to the Big Bang theory, the universe began with a massive explosion approximately 12 to 10 billion years ago.

This event led to the formation of atoms, and as the universe expanded and cooled over time, it gradually evolved into the cosmos we know today.

About 4.6 billion years ago, a region within a giant interstellar molecular cloud underwent what scientists call a gravitational collapse, leading to the birth of the Sun.

Most of the matter in this collapsing region accumulated at the centre to form the Sun, while the remaining material flattened into a rotating disk.

This disk eventually gave rise to what we now call the Solar System.

The formation of the Solar System was a gradual process. Scientists believe that it was largely completed around 4.6 billion years ago, marked by the formation of Jupiter— the largest planet—through the accumulation of scattered matter in the outer disk.

The four smaller inner planets—Mercury, Venus, Earth and Mars—known as terrestrial planets, are believed to have formed between 4.6 and 4.5 billion years ago. Earth is the third planet from the Sun and the only known place in the universe where life has originated and sustained habitability.

As a water world, Earth is unique in the Solar System for supporting liquid surface water. Nearly all of Earth’s water is contained within its global ocean, which covers about 70.8 per cent of the planet’s surface, while the remaining 29.2 per cent consists of land. Since its formation, Earth has undergone continuous changes.

In biological terms, evolution refers to the change in heritable traits of biological populations over successive generations.

This process drives the vast diversity of life observed today, influencing every level of biological organisation—from molecules and individual organisms to entire species.

Scientists believe that chemical reactions on the early Earth led to the formation of self-replicating molecules, a key step toward the origin of life.

These molecules eventually enabled the development of photosynthesis, allowing ancient life forms to harness the Sun’s energy directly. Fossil evidence indicates that life first emerged in the oceans about 4 billion years ago, likely in the form of single-celled organisms.

These simple life forms laid the foundation for the complex web of life that would evolve over billions of years.

Scientists say before the rose of what is called the last common ancestor about 3.7 billion years ago and allowed some ancient plants to start using photosynthesis to produce their own food.

Different scientific researches indicate these ancient plants appeared about 3.5 billion years ago but there was some development about 2.1 billion years ago during the diversification of blue green algae.

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 creature used water as a reducing agent to produce oxygen as their byproduct.

With that marvelous ability the green algae thrived and conquered ancient water bodies and about 434 million years ago those which stationed themselves on the sea shores evolved into a primitive plant and migrated into the land side by side with fungus.

Before that about 485 million years ago a jawless fish evolved into the sea and became one of the first vertebrate animals in the world, then they were followed by an ancient generation of ray finned fishes which together with other big fishes they ruled this planet from 419 to 359 million years ago.

Earlier from 369 million years ago the world witnessed the formation of earliest mountains due to volcanic activities which affected topography of the prehistoric super continents, on the other side this influenced the average temperature and the planet experienced a long period without tropical climates.

Scientists 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.

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 some ancient flowering plants such as lichen.

Scientists say the first seed plant appeared about 340 million years ago and 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.

At the same time the external skeleton animals made a massive rebound about 360 million years ago when the first crab crawled into the water thanks to the initial steps of evolution of arthropods which happened about 550 million years ago.

Scientists estimate that the first generation of reptiles evolved between 320 and 310 million years ago, this group was later dominated by dinosaurs which paleontologists 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.

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 to 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 with very hard shells which enabled them to survive in different tough situations.

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 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 per cent 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 paleontologists 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 years before a long period of volcanic activities pushed them into extinction about 66 million years ago.

Scientists say the extinction process was slow going stage after stage but by wiping off most of these prehistoric giants the Earth opened its land to be inhabited by new creatures, these were the ancestors of modern birds which appeared about 150 million years ago after evolving from Theropod dinosaurs.

Scientists continue to say some species of aquatic birds and great ancestor of modern Cormorants dwelled on the Earth’s surface about 120 million years ago after they managed to escape extinction.

This was only possible when they started using eggs which were elongated and more symmetric than all other birds but today cormorant lay eggs which are chalky blue in colour as special strategies to hide them against predators as they are incubated on trees, rock islets and cliffs.

Scientists say unlike modern ones, most of eggs of those days had ordinary size but were more porous a primary condition which allowed the exchange of adequate gas in hash condition.

This factor played an important role to the evolution of birds and reptiles at the time when the Earth was going through a dramatic climate changes which forced some creatures into extinction.

That was a crucial stage of evolution process which enabled some clever birds to bury their eggs in ground to protect them from volcanic activities which were blowing up from inner core as asteroids from the sky pounded its surface repeatedly.

On other hand, the ancient reptiles thrived because they managed to overcome different challenges as they developed a habit of eating every plants and animal at their disposal.

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 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.

Paleontologists say the slow, long and delicate reproductive procedure contributed into their extinction 66 million years ago.

Email:rstanslaus@yahoo.com