Prokaryotic Diversity

Review Questions

The first forms of life on Earth were thought to be_________.

  1. single-celled plants
  2. prokaryotes
  3. insects
  4. large animals such as dinosaurs

Hint:

A

Microbial mats __________.

  1. are the earliest forms of life on Earth
  2. obtained their energy and food from hydrothermal vents
  3. are multi-layered sheets of prokaryotes including mostly bacteria but also archaea
  4. all of the above

Hint:

D

The first organisms that oxygenated the atmosphere were

  1. cyanobacteria
  2. phototrophic organisms
  3. anaerobic organisms
  4. all of the above

Hint:

A

Halophiles are organisms that require________.

  1. a salt concentration of at least 0.2 M
  2. high sugar concentration
  3. the addition of halogens
  4. all of the above

Hint:

A

Many of the first prokaryotes to be cultured in a scientific lab were human or animal pathogens. Why would these species be more readily cultured than non-pathogenic prokaryotes?

  1. Pathogenic prokaryotes are hardier than non-pathogenic prokaryotes.
  2. Non-pathogenic prokaryotes require more supplements in their growth media.
  3. Most of the necessary culture conditions could be inferred for pathogenic prokaryotes.
  4. Pathogenic bacteria can grow as free bacteria, but non-pathogenic bacteria only grow as parts of large colonies.

Hint:

C