TLS Online TPP Program

#Question id: 8935


What may have occurred to prevent species that are of the same grade from also belonging to the same clade?

#Unit 9. Diversity of Life Forms
  1. similar structures arising independently in different lineages
  2. convergent evolution among different lineages
  3. adaptation by different lineages to the same selective pressures
  4. A, B, and C
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TLS Online TPP Program

#Question id: 786

#Unit 1. Molecules and their Interaction Relevant to Biology

A = 27%                    G = 30%   T = 21%              C = 22%

If the genome of a newly isolated virus displays the base composition above, the virus most likely consists of ______.

TLS Online TPP Program

#Question id: 5670

#Unit 5. Developmental Biology

Embryonic stem cells can be induced in the laboratory to differentiate into muscle, nerve, pancreatic, and other specialized cell types. It has recently become possible to trigger the dedifferentiation of somatic cells back into pluripotent cells (so-called induced pluripotent stem cells or iPS cells) by artificially enhancing the production of a relatively small number of key transcriptional factors known to be required for maintenance of pluripotency. Examples of such transcription factors are OCT4 and NANOG. The production of OCT4 and NANOG (and other key regulatory proteins) is stimulated by a transcription factor known as FOXP1, a member of the Forkhead family of DNA-binding proteins. There are two isoforms of FOXP1.

Which of the following statement regarding to FOXP1 is incorrect?

TLS Online TPP Program

#Question id: 4944

#Unit 11. Evolution and Behavior

What is true of the amino acids that might have been delivered to Earth within carbonaceous chondrites?

TLS Online TPP Program

#Question id: 23754

#Unit 1. Molecules and their Interaction Relevant to Biology

Which one of the following is always found in 'Bravery'?

TLS Online TPP Program

#Question id: 13142

#Unit 10. Ecological Principles

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
There is a substantial number of heterozygotes in the population. Which of the following is the best explanation of this observation?