TLS Online TPP Program

#Question id: 7113


In flies, frogs, and chicks, gradients of morphogens determine the future antero-posterior and dorso-ventral axes of the developing embryo. How is the antero-posterior axis determined in C. elegans?

#Unit 5. Developmental Biology
  1. bicoid protein is translated in the anterior of the fertilized egg, leading to a gradient that determines the antero-posterior axis
  2. nodal triggers formation of an organizer that will determine the dorsal, and hence the anterior, side of the embryo
  3. beta-catenin becomes localized to the nucleus in the future anterior cells after fertilization
  4. sperm entry leads to a reorganization of the cytoskeleton and redistribution of maternally packaged PAR proteins, which in turn determine the antero-posterior axis
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TLS Online TPP Program

#Question id: 9224

#Unit 9. Diversity of Life Forms

Which of the following strategies would most rapidly increase the genetic diversity of a population in an extinction vortex?

TLS Online TPP Program

#Question id: 9225

#Unit 9. Diversity of Life Forms

Use the following figure to answer the question


In looking at the species-area plot in the figure, what can be concluded?


TLS Online TPP Program

#Question id: 9226

#Unit 9. Diversity of Life Forms

The main purpose of movement corridors is to ________.

TLS Online TPP Program

#Question id: 9227

#Unit 9. Diversity of Life Forms

A land developer and several ecologists are discussing how a parcel of private land should be developed with housing while saving 20 hectares as natural habitat. The land developer suggests that the 20 hectares be divided into 20 separate 1-hectare areas, spread out across the area. The ecologists suggest that it would be better to have one intact parcel of 20 hectares on one side of the larger area. What is the significance of these different arrangements of the 20 hectares?

TLS Online TPP Program

#Question id: 9228

#Unit 9. Diversity of Life Forms

Use the following figure to answer the question


Looking at the figure showing the results of forest fragmentation, what can be said about edge effects?

TLS Online TPP Program

#Question id: 9229

#Unit 9. Diversity of Life Forms

Which of the following is a generally accurate statement about the current research regarding forest fragmentation?