Which group is incorrectly paired with its description? a. diatoms—important producers in aquatic communities b. red algae—eukaryotes that acquired plastids by secondary endosymbiosis c. apicomplexans—unicellular parasites with intricate life cycles d. diplomonads—unicellular eukaryotes with modified mitochondria

Verified step by step guidance

1. Identify the key characteristics of each group mentioned in the options to understand their general biological roles and features.
2. Review the concept of endosymbiosis, particularly primary vs. secondary endosymbiosis, to understand how different groups acquire plastids.
3. Analyze the description of red algae: they are indeed eukaryotes and they acquired plastids by secondary endosymbiosis from a red algal ancestor, confirming that this pairing is correct.
4. Examine the description of diplomonads: they are unicellular eukaryotes known for having modified mitochondria called mitosomes, which are adapted to their anaerobic environments, confirming this pairing is correct.
5. Conclude that all the groups are correctly paired with their descriptions as provided in the options.

Key Concepts

Diatoms

Diatoms are a group of microalgae characterized by their unique silica cell walls, which form intricate patterns. They are crucial primary producers in aquatic ecosystems, contributing significantly to the global carbon cycle through photosynthesis. Their abundance in both freshwater and marine environments makes them essential for supporting food webs.

Secondary Endosymbiosis

Secondary endosymbiosis refers to the process where a eukaryotic cell engulfs another eukaryotic cell that has already undergone primary endosymbiosis. This process is responsible for the acquisition of plastids in certain groups, such as red algae, which have evolved to perform photosynthesis. Understanding this concept is vital for grasping the evolutionary relationships among different eukaryotic organisms.

Diplomonads

Diplomonads are a group of unicellular eukaryotes known for having modified mitochondria called mitosomes, which are non-functional in terms of energy production. They are often found in anaerobic environments and include notable parasites like Giardia. Their unique cellular structure and lifestyle adaptations highlight the diversity of eukaryotic life forms.