Specification of different mesodermal cell types in the frog Xenopus laevis by activin, a paracrine factor of the TGF-beta family. Which of the following observation is correct at the high concentration of activin?

TLS Online TPP Program

#Question id: 12230

#Unit 10. Ecological Principles

Historically, most ecological research on the community has focused on which of the following? 

TLS Online TPP Program

#Question id: 12231

#Unit 10. Ecological Principles

Which of the following studies would a community ecologist undertake to learn about competitive interactions? 

TLS Online TPP Program

#Question id: 12232

#Unit 10. Ecological Principles

White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree trunk to the top, while the White-breasted nuthatch searches from the top of the trunk down. These hunting behaviours best illustrate which of the following ecological concepts?

TLS Online TPP Program

#Question id: 12233

#Unit 10. Ecological Principles

Monarch butterflies are protected from birds and other predators but the cardiac glycosides they incorporate into their tissues are from eating milkweed when they were in their caterpillar stage of development. The wings of a different species of butterfly, the Viceroy, look nearly identical to the Monarch so predators that have learned not to eat the bad-tasting Monarch avoid Viceroys as well. This example best describes

TLS Online TPP Program

#Question id: 12234

#Unit 10. Ecological Principles

All of the following have been used by plants to avoid being eaten except

TLS Online TPP Program

#Question id: 12235

#Unit 10. Ecological Principles

Which  of  the  following  are  important  biotic  factors  that  can  affect  the  structure  and  organization of  biological communities?