Question

1. a gradual process of change and replacement of the types of species in a community. primary succession a tertiary cycle b ecological succession c pioneer species d 8. which of the following is part of the nitrogen cycle? conversion of atmospheric nitrogen into usable organic a compounds by bacteria b nitrogen fixation c all answers are correct. d conversion of nitrogen from decaying organisms into ammonia 9. the type of organisms that convert the nitrogen in the atmosphere into chemical compounds that other organisms can use are ____. 10. nitrogen is needed by organisms to make ____.

Explanation:

• Question 7:
• Primary succession is a type of ecological succession where a community develops in an area that was previously uninhabited (like bare rock). It is a subset of ecological succession.
• Tertiary cycle is not a recognized term in this ecological context.
• Ecological succession is the gradual process of change and replacement of species in a community.
• Pioneer species are the first species to colonize a barren area (e.g., lichens on bare rock) during primary succession.
• Question 8:
• Conversion of atmospheric nitrogen into usable organic compounds by bacteria: Bacteria play a crucial role in the nitrogen cycle. For example, nitrogen - fixing bacteria convert \(N_2\) (atmospheric nitrogen) into ammonia (\(NH_3\)) which can be used by plants.
• Nitrogen fixation: This is the process of converting \(N_2\) into more reactive nitrogen compounds (such as ammonia). It is a key part of the nitrogen cycle.
• Conversion of nitrogen from decaying organisms into ammonia: Decomposers break down dead organisms. In the process, they convert organic nitrogen (in proteins, nucleic acids etc. of dead organisms) into ammonia (ammonification), which is also part of the nitrogen cycle.

Answer:

• Question 7: C. ecological succession
• Question 8: C. All answers are correct.