planarian
planarian — noun
1. a small flatworm that belongs to the order Tricladida, having a body with three
a small flatworm that belongs to the order Tricladida, having a body with three branches in its digestive system and living mainly in freshwater places such as lakes and streams.
Under the microscope, the planarian's three-branched gut showed it belonged to the Tricladida group.
classification: belongs to Tricladida order
Dr. Okafor classified the freshwater flatworm as a planarian after studying its body structure.
Planarians of the Tricladida order are found in lakes, rivers, and slow-moving streams worldwide.
In zoology class, the students learned to identify a planarian by its flat body and simple eyespots.
The planarian's soft body and ciliated surface help it glide smoothly through the water.
- triclad
a more technical term that refers specifically to members of the order Tricladida
- turbellarian
a broader category of free-living flatworms that includes planarians
文法句型
a planarian
the family of planarians
用法筆記
Frequently appears in biology textbooks and zoology lessons when discussing flatworm classification. The term triclad is sometimes used as a shorter name for planarians belonging to this order.
常見錯誤
2. a small freshwater flatworm that scientists often use in laboratory experiments
a small freshwater flatworm that scientists often use in laboratory experiments because it can regrow parts of its body that have been cut off or damaged.
The lab researchers cut a planarian into three pieces and watched each piece grow into a new worm.
demonstrates regeneration ability
Mei-Lin placed a planarian under the microscope to observe how its tail section began to regenerate.
Scientists study planarians because these tiny flatworms can regrow a complete head in about one week.
Each planarian in the experiment was kept in a shallow dish of cool, clean pond water.
The biology class observed planarian regeneration by cutting one worm and recording the new growth every day.
- flatworm
a broader term for any worm with a flat body, not just the regenerating type
- turbellarian
a scientific term for free-living flatworms that includes planarians
文法句型
a planarian
planarians (plural)
用法筆記
Most often found in school and university lab reports about regeneration and stem cell research. Unlike sense 1, which focuses on taxonomic classification, this sense describes the organism's practical use as a research model.