Heterokont

Heterokont is a major line of eukaryotes currently containing more than 25,000 known species. This group also includes many economically important species. The term "heterokont" refers to the type of flagella (whip-like appendages) in the mobile stage, where typically one flagellum is smooth and the other is covered in fine, hair-like projections.

Characteristics

Heterokonts are characterized by the presence of two unequal flagella in the motile stage. The anterior flagellum is covered with small, hair-like projections, while the posterior flagellum is smooth and whip-like. This is the feature that gives the group its name, which means "different flagella".

Classification

Heterokonts are a diverse group of organisms. They are typically classified into several subgroups, including the diatoms, golden algae, and brown algae. However, this classification is not universally accepted, and some scientists prefer to use a broader definition of heterokonts that includes other groups such as the oomycetes and hyphochytriomycetes.

Evolution

The heterokonts are believed to have originated from a common ancestor that engulfed a red alga, in a process known as secondary endosymbiosis. This event is thought to have occurred around 1.3 billion years ago, during the Proterozoic eon.

Economic importance

Many heterokonts are economically important. For example, diatoms are used in various industries for their silica shells, which have unique optical properties. Brown algae are used in the production of alginate, a thickening agent used in foods and other products. Some heterokonts, such as the oomycetes, are also significant plant pathogens.

See also

• Algae
• Protist

Heterokont Resources
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