Question

 A. Neurospora crassa, like Peziza, is an ascomycetes. It was frequently used in genetic research to investigate crossing over and linkage. What characteristics of its lifecycle make it an ideal genetic model organism?

 B. Distinguish between the three types of lichen based on their morphology and location in the environment. Which lichens are most commonly found in San Diego? Why?

 C. Lichens are often referred to as "pioneer species" by ecologists. Why and what role do they play in primary succession?

 D. Distinguish between primary and secondary succession. Provide an example of each in your comparison

Answer 1

A) Neurospora crassa is used as an ideal genetic model organism because of the following reasons,

• It is easy to grow
• It has haploid life cycle
• Recessive traits will easily show up in the offsprings because of haploid life cycle
• In its ascophores, there is an ordered arrangement of products of meiosis

B) The three main types of lichens are given below,

1. Crustose - edges are flat and unlobed
2. Foliose - circular growth, edges are lobed
3. Fructiose - vertical growth pattern, looks like shrubs

Foliose lichen is commonly found in San Diego as they are found in forested areas.

C) Primary succession usually occurs in abiotic areas such as rocks. Lichens can colonise bare rocks, secrete acids and breakdown the rocks leading to the formation of soil.

D) Primary succession occurs in previously uninhabited area. For example molten valconic lava, retracted glaciers, etc. Secondary succession occurs in response to disturbance of already existing habitat like in forest fire.