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TLS Online TPP Program

#Question id: 5002

All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.

The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?

#Unit 11. Evolution and Behavior

  1. Pax-6 in all of these animals is not homologous; it arose independently in many different animal phyla due to intense selective pressure favoring vision.

  2. The Pax-6 gene is really not ʺoneʺ gene. It is many different genes that, over evolutionary time and due to convergence, have come to have a similar nucleotide sequence and function.

  3. The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian. Animals with eyes or eyespots are descendants of this ancestor.

  4. The perfectly designed Pax-6 gene appeared instantaneously in all animals created to have eyes or eyespots.

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TLS Online TPP Program

#Question id: 13141

#Unit 10. Ecological Principles

Five similar populations of a herbaceous annual plant are monitored for three years; then, the numbers of individuals in populations I-IV are increased by an experimenter. Subsequent changes in the sizes of all the populations are shown in the graph below.

If size distributions of individuals do not vary among these populations, which of the following relationships best illustrates the occurrence of population regulation?
TLS Online TPP Program

#Question id: 13140

#Unit 10. Ecological Principles

One summer the moose population on Island was unusually high, and park naturalists noticed signs of malnutrition among the  adults.  The wolf population  was  fairly  low,  near  20.  That  winter,  for  the  first  time  in  many  years,  a substantial  number of seemingly healthy adult moose as well as calves and crippled animals were killed and eaten by wolves. This description is part of a general situation in which the wolf and moose populations
TLS Online TPP Program

#Question id: 13139

#Unit 10. Ecological Principles

The logistic equation above is used to describe the rate of change of a population, N, with time, t, where r is the intrinsic rate of increase and K is the carrying capacity. Which of the following statements is true for this equation?
TLS Online TPP Program

#Question id: 13138

#Unit 10. Ecological Principles

Life-history characteristics associated with K-selected ordgtanisms include K
TLS Online TPP Program

#Question id: 13137

#Unit 10. Ecological Principles

Reproductive value (Vx ) calculated from population life-table data provides a measure of the 
TLS Online TPP Program

#Question id: 13136

#Unit 10. Ecological Principles

The figure below illustrates the relationship between population density in the present generation (Nt) and population equilibrium density of this population in the next generation (Nt+1). The dashed reference line has a slope of 1. Which of the following represents equilibrium density of this population?