Evolution Test - 10

Tasmanian tiger cat belongs to Australian marsupials. The remaining options belong to placental mammals. The Tasmanian tiger cat resembles bobcat of placental mammals. They show convergent evolution.

amount of uranium present

Natural selection is the survival of members of species having some new traits that may help the organism in given surrounding. Sexual selection is a kind of natural selection as mating between similar organisms only leads to reproduction.

Palaeritological evidences for evolution refer to the fossils. Fossils provide direct and solid evidence in favour of organic evolution through ages. Fossils are studied for knowing about extinct organisms. Birbal Sahni Institute of Palaeobotany is situated at Lucknow. Birbal Sahni is called ‘Father of Indian Palaeobotany ’. Age of fossils is determined by Uranium-Lead method (U²³⁸ ) or Potassium-Argon method or Radioactive Carbon dating (C¹⁴ ). ESR (electron-spin-resonance method) is the most accurate method of dating of fossils.

The Hardy-Weinberg principle states that allelic and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. There are five factors which are known to affect the equilibrium. These are gene flow, genetic drift, mutation, genetic recombination and natural selection. In population genetics, gene flow (also known as gene migration) is the transfer of alleles or genes from one population to another. Migration into or out of a population may be responsible for a marked change in allele frequencies (the proportion of members carrying a particular variant of a gene). Genetic drift (also known as allelic drift) is the change in the frequency of a gene variant (allele) in a population due to chance events. Genetic recombination is the production of offspring with combinations of traits that differ from those found in either parent. Mutation causes variations in the species, which influences the gene pool. Natural selection favours certain variations over others, resulting in an increase in allelic frequency of the favourable variations in the gene pool. Reproduction is a natural process in all organisms, which as such, does not affect Hardy-Weinberg equilibrium; it would be the genetic recombinations that arise from sexual reproduction, that affect it.

Darwin finches and Australian marsupials are example of adaptive radiations as all the birds evolve from same birds having different beaks and Australian marsupials arise from common ancestors.

Wolf and Tasmania Wolf are examples of convergent evolution of placental mammals and Australian marsupials. They are evolved differently due to different in climatic and geographic regions.

When more than one adaptive radiation appeared in isolated geographical area it called a convergent evolution. Tiger cat, kangaroo, wombat and sugar gliders are example of Australian marsupials.

Homo sapiens arose in Africa and moved across continents and developed into distinct races during ice age between 75000-10000 years ago modern Homo sapiens arose.

Human settlement started around 10, 000 years ago due to starting of agriculture. After starting of agriculture, the human civilization started the grows and decline many times.

Common origin of man and chimpanzee is best shown by chromosomes. Both human beings and chimpanzee shows similar kinds of chromosome in terms of number and size.

Pre-historic man who gave proper burial to the dead for the first time was Neanderthal man of brain size 1400 cc lived in near east and central Asia about 100000 –40000 years back.

Among primates Chimpanzee is closet relative to the present day humans.The banding pattern of autosomes 3 and 6 of humans and Chimpanzee is remarkably similar.

Homo habilis  is a species of the tribe Hominini, during the Gelasian and early Calabrian stages of the Pleistocene period, between roughly 2.8 and 1.5 million years ago.

Homo erectus  is an extinct species of hominid that lived throughout most of the Pleistocene geological epoch. Its earliest fossil evidence dates to 1.9 million years ago and the most recent to 70,000 years ago.

Homo sapiens  is a common name that has been used to describe the first early modern humans.

Evolution of modern man is most interesting and appears parallel evolution of human brain and language. Homo habilis have brain size 650cc-800cc that evolved to 1400cc in Homo sapiens.