Question

6. The RNA World hypothesis includes the idea that: a. RNA is the most important molecule in living organisms today b. Ear;ly cells could not produce because they did not yet have DNA c. Viruses evolved from RNA d. Early cells was made entirely of RNA e. Proteins may not have been necessary for the earliest biological reactions to occur 7. In early human embryos, the gene HoxB7 is involved in patterning the central nervous system. In later embryos, the same HoxB7 gene plays a critical role in growth and development of the kidneys. These different roles of the same gene at different times and locations within the body of the organism are an example of: a. Taphonomy b. Pleiophoty c. Homology d. Unconformity e. Uncertainty 8. Homoplasy refers to: a. Another term for plasticity b. Similarity of traits between organisms due to common ancestry C. Ability of an organism to use different structures to perform the same task d. Ability of an organism to use the same structures to perform the same task e. Similarity of traits between organisms due to similar selection pressures

Answer 1

1. According to the RNA World hypothesis the world filled with life based on ribonucleic acid (RNA) can predate the current world of life based on deoxyribonucleic acid (DNA) and protien.

It suggests that RNA can store information like DNA and also act as an enzyme like protein may have supported pre- cellular life and the origin of life based on RNA might have been the first step in the evolution of cellular life.

Therefore, it can be concluded that the hypothesis suggests that the early cells was entirely made of RNA.

2. Hox genes also known as homeotix genes are involved in controlling the polarity of the embryo and the development of various segments or structures of the body. These act like a genetic switch that turn on and off genes and so control the timing and route of development.

They exihibit colinearity and control more than one trait/development of more than one structure. Therefore, it can be said that they are pleiotropic in nature

3. Homoplasy refers to a character or trait shared that is shared by a set of species but not present in their common ancestor. It is a result of convergent evolution in which different species create analogous structures due to the same habitat and conditions they are living in.

Therefore, the correct option is similarity in trait between organism due to same selection pressure.