Kingdom Plantae and Protista

During your beachcombing experience you may refer to both seagrasses and algae as ‘marine plants’ – a broad term applied to both organisms, as they have the ability to produce their own food.

However, seagrasses and algae are in fact quite different organisms in relation to their classification.

Seagrasses belong to the Kingdom Plantae. Organisms within this group:

  • produce their own energy from sunlight (through the process of photosynthesis), due to the presence of chloroplasts; and
  • get strength from cellulose within their cell walls.

Algae belong to the Kingdom Protista. This kingdom includes organisms with a variety of life cycles and appearances. They can be broadly divided into:

  • heterotrophic protists, such as protozoans that ingest food particles, and
  • autotrophic protists, such as algae that produce their own food.

Protists are not plants or animals, and have no embryonic stage in their development.