Test: Organic Evolution - SSC CGL MCQ

Scientists hypothesize that the universe came into existence around 15 billion years ago with a colossal explosion known as the Big Bang. This event marked the beginning of the universe as we know it today, leading to the formation of galaxies, stars, and planets over billions of years.

Around 3.8 billion years ago, Earth's atmosphere consisted of elements such as nitrogen, hydrogen, sodium, sulfur, and carbon. These elements played a crucial role in the early environment of the planet, contributing to the conditions necessary for the emergence of life.

Some of the elements present in Earth's early atmosphere combined to form substances like hydrogen sulfide, methane, water, and ammonia. These compounds were essential building blocks for the complex chemical processes that eventually led to the development of life on Earth.

Evolution primarily involves the study of changes in populations of organisms over time, driven by genetic variations and environmental factors. This process leads to the adaptation and diversification of species, shaping the biodiversity we observe in the natural world.

Gene-environment interactions play a crucial role in driving changes in populations of organisms over time. These interactions influence how genetic traits are expressed in response to environmental pressures, leading to adaptations that can enhance the survival and reproductive success of individuals within a population.

Lamarck famously used the example of giraffes stretching their necks to reach food as a way to explain his theory of acquired characteristics. According to Lamarck, this stretching behavior would lead to longer necks in giraffes over successive generations. Despite later evidence showing this theory to be inaccurate, it was one of the early attempts to explain how species change over time.

Charles Darwin's theory of evolution is primarily based on the concept of natural selection. Darwin proposed that living organisms with advantageous traits that better suit them to their environment are more likely to survive and reproduce, passing on those traits to their offspring. This process of natural selection is a driving force behind evolutionary change.

Hugo de Vries' Mutation Theory suggests that genetic mutations, sudden inheritable changes in an organism's genome, are responsible for leading to speciation, the formation of new species. These mutations introduce genetic variation that can drive evolutionary change over time.

The basis of Neo-Darwinism in evolution is the concept of natural selection. This theory, supported by Hugo de Vries' Mutation Theory, emphasizes that natural selection acts on the genetic variation present in populations, favoring traits that increase an organism's fitness for survival and reproduction.

Three types of speciation: sympatric, allopatric, and parapatric. These different modes of speciation describe how new species can arise through various mechanisms, such as geographic isolation or adaptation to different habitats within the same geographical area.

Dryopithecus is considered the ancestor of both apes and humans. This genus lived in various regions such as Africa, China, India, and Europe. The name Dryopithecus means oak wood apes.

The first remains of Ramapithecus were discovered in the Shivalik hills of Punjab. Subsequently, remains were also found in Africa and Saudi Arabia. Ramapithecines lived in regions that were not just forests but also open grasslands, with evidence suggesting adaptations for an upright posture and the use of hands for various activities.

The first Australopithecine find was made by Raymond Dart in 1924 at the Taung limestone quarry site in South Africa. Australopithecines were known for walking erect, living on the ground, and potentially using stones as tools for hunting small animals.

The first evidence of the Homo species was discovered in Java by Eugene Dubois in 1891. This discovery led to the naming of Pithecanthropus erectus, signifying the erect ape man. Homo erectus had a larger cranial capacity compared to Australopithecus and exhibited communal living and the use of fire.

Homo sapiens sapiens, also known as Cro-Magnon, is associated with the final reduction of jaws, the appearance of the modern man's chin, and a rounded skull. Their mean cranial capacity was about 1350 cc, and they are closely related to modern humans, with a culture dating back to 35,000 years known as the Upper Paleolithic culture.