The NtrC protein from E. coli

a. is a σ54 RNA polymerase.  b. stimulates transcription of the glnA gene.

c. is activated by a protein kinase called NtrB.

d. binds both to an enhancer site upstream of the glnA gene and to RNA polymerase.

e. has ATPase activity.

#Question id: 13183

#Unit 10. Ecological Principles

The MacArthur-Wilson equilibrium model of island biogeography predicts the number of species found on islands. The figure below depicts two volcanic islands located off a section of mainland coast.

According to the MacArthur-Wilson model, how would the number of bird species change from the time of an island's formation (assuming it remains constant in size and isolation)?

#Question id: 13184

#Unit 10. Ecological Principles

The MacArthur-Wilson equilibrium model of island biogeography predicts the number of species found on islands. The figure below depicts two volcanic islands located off a section of mainland coast.

According to  the  MacArthur-Wilson model, the  number of  bird  species present on  Island 2  at  any  one  time is  a function of the relative rates of

#Question id: 13185

#Unit 10. Ecological Principles

#Question id: 13186

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance

This model predicts that recruitment of new individuals into the population should be

#Question id: 13187

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance

Which of the following factors is most likely to generate the seed density curve shown? 

#Question id: 13188

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance

Which of the following factors is most likely to generate the seed survivorship curve shown?