Evolution Test - 35

Pithecanthropus also known as Java man is an extinct hominin known from fossil remains discovered in Java in 1891. Java Man was about 5 feet 8 inches (170 cm) tall and his thigh bones show that he walked erect like modern humans. The skull was characterized by thick bones and a retreating forehead and no chin, as well as protruding brow ridges and a massive jaw. With 900 ccm, his cranial capacity was smaller than that of later H. erectus specimens. He had human teeth with large canines. 

The cenozoic era began about 65 million years ago and continues to the present. It is the third documented era in the history of Earth. The cenozoic era is also known as the 'age of mammals', because of the extinction of many groups of giant mammals, allowing smaller species to thrive and diversify, because their predators no longer existed. 

Homo erectus  present around 1.8 - 1.3 million years ago, they migrated to Asia, Europe and other continents from Africa. Those that stayed back in Africa were identified as H. ergaster who then evolved into Homo sapiens

The mesozoic era is an interval of geological time from about 252 to 66 million years ago. The climate was warmer, the seasons were very mild, the sea level was higher, and there was no polar ice. It is known as age of reptiles because this era becomes dominated by dinosaurs and reptiles. Therefore, the correct answer is option B.

Cro Magnon man is the direct ancestor of a modern human. These are the first early Modern Humans of the European Upper Paleolithic. It appeared during Holocene period that lived about 40,000 years ago. The brain capacity was about 1,600 cc, larger than the average for modern humans. They were robustly built and powerful. The body was generally heavy and solid with a strong musculature. The face was short and wide and chin is prominent. 

A- The timeline of human evolution is divided into different periods or epochs. An epoch points at the years before the present. Pleistocene time period existed from 2.58 million years ago - 0.012 million years ago. Neanderthals existed in this period whereas the last glaicial period, the Pleistocene, and the glacial Paleolithic age ended.

Carbon is present in living organism in from of organic compounds. The carbon dioxide and carbon monoxide gases served as source of carbon for synthesis of organic compounds during origin of life. The primitive atmosphere of earth was reducing atmosphere with little or no oxygen but was rich in water vapour, carbon monoxide, carbon dioxide, nitrogen and hydrogen. The high temperature, UV light and lightening provided energy for chemical reactions between hydrogen and free oxygen, nitrogen and carbon to form, ammonia, methane and cyanides. Primitive atmosphere had water in form of superheated steam which condensed with lowering of earth temperature and wash down the simple compounds (ammonia, methane and cyanides) formed in atmosphere. Water served site for origin of life as it supports both polymerizing and hydrolysing reactions as well as buffers the high temperature owing to its high latent heat of evaporation. Formation of simple compounds from primitive gases in atmosphere and their polymerization in ocean was possible due to absence of oxygen. Presence of free oxygen would have immediately oxidized the monomers and polymers and thereby would not have allowed build up organic compounds in primitive ocean followed by their complex reactions to form first life form. This makes oxygen the most important element for origin of life because its presence in present day oxidizing atmosphere does not allow the origin of life as it occurred in primitive reducing atmosphere. Correct answer is B. 

Proconsul africanus, a common ancestor of both humans and apes that lived 23 to 14 millions years ago during the Miocene epoch. It was a fruit eater and had a brain larger than a monkey. Its fossils was discovered by Leakey's team in 1948 at Rusinga Island in lake victoria, Kenya. Hence option A is correct.

Homo habilis is the earliest known species in the human lineage. Cranial capacity of them is between 550-650cc. Anthropologists date that H. habilis originated between 2 and 1.9 million MYA, followed by Homo erectus, which dates to approximately 1.7 MYA. As a result, H. habilis was the first species that possessed the characteristic enlarged brain. This enlarged brain is also closely associated with the ability of using stones for tool-making.