Which group is correctly paired with its description?


A. diatoms—important consumers in aquatic communities
B. diplomonads—protists with modified mitochondria
C. apicomplexans—producers with intricate life cycles
D. red algae—acquired plastids by secondary endosymbiosis

Key Concepts

Diatoms

Diatoms are a group of microalgae characterized by their unique silica cell walls, which form intricate patterns. They are primarily photosynthetic organisms and play a crucial role as primary producers in aquatic ecosystems, forming the base of the food web. While they are not consumers, they are essential for oxygen production and carbon fixation in marine and freshwater environments.

Diplomonads

Diplomonads are a group of protists known for having modified mitochondria called mitosomes, which lack the ability to perform aerobic respiration. They are often found in anaerobic environments and include species like Giardia, which can cause intestinal infections in humans. Their unique cellular structure and lifestyle distinguish them from other eukaryotic organisms.

Red Algae and Secondary Endosymbiosis

Red algae are a group of photosynthetic eukaryotes that possess chlorophyll a and are known for their red pigments, which allow them to thrive in deeper waters. They acquired their plastids through a process called secondary endosymbiosis, where a eukaryotic cell engulfed a red alga. This evolutionary event has significant implications for the diversity of photosynthetic organisms in aquatic environments.