Study Guide: Evolution and Diversity of Prokaryotes, Eukaryotes, Plants, and Fungi

Q1. Draw a phylogeny representing the three domains of life. Which two are prokaryotes?

Background

Topic: Phylogeny and Domains of Life

This question tests your understanding of the evolutionary relationships among the three domains of life (Bacteria, Archaea, Eukarya) and your ability to distinguish prokaryotic from eukaryotic domains.

Key Terms and Concepts:

• Phylogeny: Evolutionary tree showing relationships among organisms.

• Prokaryote: Organisms without a nucleus (Bacteria and Archaea).

• Eukaryote: Organisms with a nucleus (Eukarya).

Step-by-Step Guidance

1. Start by drawing a root that splits into three main branches, each representing one domain: Bacteria, Archaea, and Eukarya.

2. Label each branch clearly with the domain name.

3. Recall which domains lack a nucleus (prokaryotes) and which have a nucleus (eukaryotes).

4. Indicate on your diagram which two domains are prokaryotic.

Try drawing and labeling the phylogeny before checking the answer!

Q2. What do members of all three domains have in common? What traits are different? (e.g., How are Archaea different from Bacteria? From Eukarya?)

Background

Topic: Comparative Biology of Domains

This question asks you to compare and contrast the three domains of life, focusing on shared and unique characteristics.

Key Terms and Concepts:

• Universal traits: Features found in all life forms (e.g., genetic code, cell membrane).

• Domain-specific traits: Unique features of Bacteria, Archaea, or Eukarya.

Step-by-Step Guidance

1. List features that are common to all three domains (e.g., DNA as genetic material, ribosomes).

2. Identify traits that distinguish Archaea from Bacteria (e.g., cell wall composition, membrane lipids).

3. Compare Archaea and Eukarya (e.g., similarities in some genetic processes).

4. Note unique features of Eukarya (e.g., presence of nucleus, membrane-bound organelles).

Try listing similarities and differences before revealing the answer!

Q3. How old are the earliest prokaryotic fossils?

Background

Topic: Fossil Record and Early Life

This question tests your knowledge of the geological timeline and the origin of prokaryotes.

Key Terms:

• Fossil: Preserved remains or traces of ancient organisms.

• Prokaryote: Single-celled organism without a nucleus.

Step-by-Step Guidance

1. Recall the approximate age of Earth (about 4.6 billion years).

2. Think about when life is believed to have first appeared (hint: prokaryotes are among the earliest life forms).

3. Consider the age of the oldest known prokaryotic fossils (stromatolites).

Try recalling the timeline before checking the answer!

Q4. What themes occur in the evolution of prokaryotes?

Background

Topic: Evolutionary Biology

This question asks you to identify major patterns and processes in prokaryote evolution.

Key Terms:

• Adaptation

• Metabolic diversity

• Lateral gene transfer

Step-by-Step Guidance

1. List major evolutionary themes such as metabolic innovation, gene transfer, and adaptation to diverse environments.

2. Think about how prokaryotes have diversified and colonized many habitats.

3. Consider the role of horizontal (lateral) gene transfer in their evolution.

Try identifying themes before revealing the answer!

Q5. What is a biofilm and why are biofilms adaptive for the prokaryotes that make them? Can you describe an example?

Background

Topic: Microbial Ecology

This question tests your understanding of biofilms and their ecological significance.

Key Terms:

• Biofilm: A community of microorganisms attached to a surface and embedded in a self-produced matrix.

• Adaptation: Trait that increases fitness in a particular environment.

Step-by-Step Guidance

1. Define what a biofilm is and describe its structure.

2. Explain why forming a biofilm can be advantageous for prokaryotes (e.g., protection, resource sharing).

3. Think of a real-world example (e.g., dental plaque, biofilms in water pipes).

Try describing a biofilm and its advantages before checking the answer!

Q6. What is the Gram stain and how does it separate bacteria into two distinct groups?

Background

Topic: Microbiology Techniques

This question tests your knowledge of bacterial classification using the Gram stain.

Key Terms:

• Gram stain: A differential staining technique.

• Gram-positive: Bacteria with thick peptidoglycan cell walls.

• Gram-negative: Bacteria with thin peptidoglycan and outer membrane.

Step-by-Step Guidance

1. Describe the steps of the Gram staining procedure.

2. Explain how the structure of bacterial cell walls affects the outcome of the stain.

3. State the main differences between Gram-positive and Gram-negative bacteria.

Try outlining the Gram stain process before revealing the answer!