Evolution Test - 28

The term proterozoic comes from the Greek words proteros (meaning first) and zoon (meaning life). Although early fossils are now thought to occur in older, archean rocks, for many years the oldest evidence of life was known from proterozoic strata. The proterozoic represents the last stage of what was once called, precambrian, 3.7-billion-year-long period before the paleozoic era. Many of these life forms developed the ability to photosynthesize. As a byproduct of photosynthesis, they created oxygen and over billions of years this oxygen transformed the Earths atmosphere. Because oxygen was toxic to some early life forms, many went extinct. Others thrived and evolved into the first multicellular organisms, which are preserved as the ediacaran fauna. Both the beginning and end of the proterozoic were marked by widespread glaciation. About one billion years ago the dominant organisms of earth were cyanobacteria and protozoans, therefore, it was named 'proterozoic'. Proterozoic era is called as age of prokaryotic microbes. During archaezoic era, precambrian era and phaenerozoic era microbes are not dominant. So, they are not called as age of prokaryotic microbes. Thus, option D is correct.

A primate is a mammal of the order Primates, which includes lemurs, lorises, tarsiers, monkeys, apes and humans. They exhibit menstrual cycle.

The primitive reducing atmosphere of earth was rich in water vapour, carbon monoxide, carbon dioxide and hydrogen. Absorption of infrared radiation by green house gases ($$CO_2$$ and $$CH_4$$) imparted high temperature to primitive earth.  The high temperature, UV light and lightening facilitated reaction between above-mentioned elements. Oxygen did not occur in the free state as the prevailing reduced substances immediately combined with it to form oxides (iron oxides, silicon oxides). Abundant hydrogen combined with free oxygen, nitrogen and carbon to form water, ammonia, methane and cyanides. This makes option D correct. 

Eobionts are hypothetical primordial life-form or chemical precursor to a living organism. The coacervates got transformed into the primitive living systems, which have been called as, protobionts or eobionts. These are the first formed cells. So, called as, pre cells or protocells or protobionts. Thus, option D is correct.

The Azoic era is the era without life which includes the origin of the earth, its cooling down and other changes to make it suitable for life forms.  The Proterozoic era (2000 million yrs ago and spanned for 1500 million years), the era of early life, is marked by a build-up of oxygenic atmosphere and appearance of the first eukaryotic cell.  Mesozoic era (from 230 million years ago to 63 million yrs ago) is the era of medieval life and includes three periods namely, Cretaceous (135 million years), Jurassic (180 million years) and Triassic (225 million years). It is also known as the age of gymnosperms or age of reptiles. The Cenozoic era is the era of modern life and is also known as the age of mammals and angiosperms. It began 63 million yrs ago and is still continuing which makes it the most recent/latest. Thus the correct answer is option C.

Flowering plants (angiosperms) arose close to the beginning of the Cretaceous and became more abundant as the period progressed. The Late Cretaceous was a time of great productivity in the worlds oceans, as borne out by the deposition of thick beds of chalk in western Europe, eastern Russia, southern Scandinavia, the Gulf Coast of North America, and western Australia. The Cretaceous ended with one of the greatest mass extinctions in the history of Earth, exterminating the dinosaurs, marine and flying reptiles, and many marine invertebrates. Thus, option B is correct. Angiosperm were not arose in carboniferous period, triassic period and tertiary period.

Arm and leg of man and horse are examples of homologous organs. A homologous structure is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor. In other words, its when very different animals have bones that appear very similar in form or function and seem to be related. So, we can say there is a phylogenetic relationship between man and horse. Thus, option A is correct.

Darwin's finches (also known as the Galapagos finches) are a group of about fifteen species of passerine birds. They often are classified as the subfamily Geospizinae or tribe Geospizini. It is still not clear to which bird family they belong, but they are not related to the true finches. They were first collected by Charles Darwin on the Galapagos Islands during the second voyage of the Beagle. All are found only on the Galapagos Islands, except the Cocos finch from Cocos Island. Thus, the correct answer is option B.

Convergent evolution is the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function, but that were not present in the last common ancestor of those groups. Dogfish is a cartilaginous fish and a whale is a mammal both have streamlined body and show vivipary but belong to totally different groups. The former is a fish and later being a tetrapod mammal. Dogfish and whale are the examples of convergent evolution in animals as both of them have more or less similar body organization. 
Therefore, the correct answer is option D.

Convergent evolution describes the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function, but that were not present in the last common ancestor of those groups. Convergent evolution is not related to descent with modification. Thus, option A is wrong.
Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades. Parallel evolution is not related to descent with modification. Thus, option C is wrong.
In biology, co-evolution is "the change of a biological object triggered by the change of a related object.". In other words, when changes in at least two species' genetic compositions reciprocally affect each others evolution, co-evolution has occurred. Co-evolution is not related to descent with modification. Thus, option D is wrong.
The evolutionary term descent with modification is most often associated with human evolution, but it is actually a more general term than that would suggest. Simply put, descent with modification means that traits are passed down from generation to generation and sometimes undergo changes or modifications over time. These changes may be caused by Natural Selection or even a mutation of DNA. The term became popular when Charles Darwin used it in his book The Descent of Man. Adaptive radiation is an evolutionary pattern whereby a single ancestral form diversifies into several or many related forms. Adaptive radiation is a subset of the theory of descent with modification, expressing evolution within closely related forms rather than new designs. Thus, option B is correct.