primary disruptions could be signaling the plant that a change in environmental conditions has occurred and that it’s time to respond by altering existing pathways or by activating stress-response pathways. At least five different types of stress-sensing mechanisms can be distinguished:

COLUMN I	COLUMN II
A) Physical sensing	i) usually results from the detection of by-products that accumulate in cells due to the uncoupling of enzymatic or electron transfer reactions, such as the accumulation of ROS during stress caused by too much light.
B) Biophysical sensing	ii) often involves the presence of specialized proteins that have evolved to sense a particular stress; for example, calcium channels that can sense changes in temperature and alter Ca2+ homeostasis.
C) Metabolic sensing	iii) refers to modifications of DNA or RNA structure that do not alter genetic sequences, such as the changes in chromatin that occur during temperature stress.
D) Biochemical sensing	iv) refers to the mechanical effects of stress on the plant or cell structure, for example, the contraction of the plasma membrane from the cell wall during drought stress.
E) Epigenetic sensing	v) might involve changes in protein structure or enzymatic activity, such as the inhibition of different enzymes during heat stress.

 

  

Match the correct sequence sensing mechanism during in stress;

#Question id: 4989

#Unit 11. Evolution and Behavior

If the malesʹ halteres have species-specific size, shape, color, and use in courtship displays, and if the speciesʹ ranges overlap, then the speciation events may have been driven, at least in part, by which of the following?

#Question id: 4988

#Unit 11. Evolution and Behavior

If the foods preferred by each species are found on different parts of the island, and if the flies mate and lay eggs on their food sources, regardless of the location of the food sources, then the speciation events involving these fly species may have been driven, at least in part, by which of the following?

#Question id: 4987

#Unit 11. Evolution and Behavior

A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (i.e., halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.In each fly species, the entire body segment that gave rise to the original flight wings is missing. The mutation(s) that led to the flightless condition could have

#Question id: 4986

#Unit 11. Evolution and Behavior

A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (i.e., halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap. If these fly species lost the ability to fly independently of each other as a result of separate mutation events in each lineage, then the flightless condition in these species could be an example of

#Question id: 4985

#Unit 11. Evolution and Behavior

The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic affects of Pitx1 gene

#Question id: 4984

#Unit 11. Evolution and Behavior

A hypothetical mutation in a squirrel population produces organisms with eight legs rather than four. Further, these mutant squirrels survive, successfully invade new habitats, and eventually give rise to a new species. The initial event, giving rise to extra legs, would be a good example of