Protochordates
A notochord at least once in life.
A rod appears
In some animals a flexible rod appears during at least one stage of life.
What would that rod do for the animal's body?
What this lesson covers
The idea
Protochordates possess a notochord at least once in their life; it gives internal support without restricting movement, showing how animals with a notochord may have arisen from simpler forms.
A rod appears
In some animals a flexible rod appears during at least one stage of life.
What would that rod do for the animal's body?
- Give internal support without restricting movement
- Make it stay fixed in one place
- Take in food through pores
The notochord appears
Press Next step.
An early chordate
Protochordates are placed in the chordates because they have a notochord at some stage of life. The notochord supports the body from inside and still lets it move, which was an important change.
Protochordates possess a notochord at least once in their life; it gives internal support without restricting movement, showing how animals with a notochord may have arisen from simpler forms.
Notes
Protochordates have a notochord at least once in life, giving internal support without restricting movement.
Check yourself
Which structure do protochordates have at least once in their life?
What does the notochord provide?
Which animal is given as an example of a protochordate?
What do protochordates help us understand?
- A vertebral column. The vertebral column belongs to vertebrates.
- A hard external skeleton. A hard external skeleton is a feature of arthropods.
- A notochord — correct. Yes!
- Internal support without restricting movement — correct. Yes!
- Water flow through pores. Pores that let water flow belong to sponges.
- A shell for protection. Shells protect the soft bodies of many molluscs.
- Earthworm. The earthworm is an annelid.
- Amphioxus — correct. Yes!
- Starfish. The starfish is an echinoderm, which lacks a notochord.
- How plants make food. Protochordates are animals. Plants make food by photosynthesis.
- How fungi absorb nutrients. Protochordates are animals with a notochord, so they help us understand animal history.
- How animals with a notochord may have arisen from simpler forms — correct. Yes!