Evolution of Life (Biology)

• Paleocene:

The first epoch of the Cenozoic (66-56 million years ago), following the extinction of the dinosaurs. Modern placental mammals began to diversify during this time.

• Eocene:

The second epoch (56-33.9 million years ago), marked by the further evolution of mammals, including the appearance of horses and primates. Whales also evolved during this period.

• Oligocene:

The third epoch (33.9-23 million years ago), characterized by the expansion of grasslands and the evolution of new mammal species, such as the first elephants, cats, and dogs.

• Miocene:

The fourth epoch (23-5.3 million years ago), saw the rise of grazing animals and further evolution of mammals adapted to the expanding grasslands.

• Pliocene:

The fifth epoch (5.3-2.6 million years ago), which saw a transition from warm, humid climates to cooler, drier conditions and the beginning of the ice ages in the Northern Hemisphere.

It is likely that hundreds of millions of years separated the first biological production of oxygen by unicellular organisms and its eventual accumulation in the atmosphere.

Over the history of the Earth, the magnetic field has reversed every several hundred thousand years. Over the last 5 million years, the Earth's magnetic field reversed itself at least 20 times. Over the last 20 million years, the reversal happens about every 200 thousand to 300 thousand years. However, it has been about 780 thousand years since the last reversal. Hence, statement 1 is correct.

When Earth was created, there was no oxygen in the atmosphere. Oxygen, although always present in compounds in Earth's interior, atmosphere, and oceans, did not begin to accumulate in the atmosphere as oxygen gas (O₂). The earliest atmosphere contained carbon dioxide, methane, water vapour, carbon monoxide, ammonia, nitrogen, hydrogen, etc. Hence, statement 2 is incorrect.

When living organisms originated, they modified the early atmosphere of the Earth. However, it is likely that hundreds of millions of years separated the first biological production of oxygen by unicellular organisms and its eventual accumulation in the atmosphere. Thus, statement 3 is correct.

It states that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. It is called Darwinian theory.

It states that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. It is called Darwinian theory.

French biologist Lamarck is best known for his "Theory of Inheritance of Acquired Characters", first presented in 1801. He was the first person to explain the theory of evolution to the public. In 1809, this theory was published in his book 'Philosophie Zoologique'.

Lamarck's theory, also known as Lamarckism, proposed that evolutionary change could be driven by the inheritance of acquired traits. key component of Lamarckism was the idea that organisms could develop or lose traits based on their use or disuse during their lifetime.

For example, if an organism frequently used a particular limb, it would become stronger and that strength would be passed on to its offspring. In his book, Lamarck outlined his theory of evolution, including the concept of the inheritance of acquired characteristics.

While Lamarck's specific mechanism for inheritance is not supported by modern genetics, his ideas were influential in sparking early scientific inquiry into evolution. His work laid some groundwork for later evolutionary theories, such as Darwin's theory of natural selection.