skip to main content

Branches on the Tree of Life: The Biology of Chordates

18 minutes 8 seconds

Videos are generally available for preview to non-members as short clips. Limited full-length titles are also available. Log In to view the full length title.

Browse Full-length Non-member Titles
Still image from Branches on the Tree of Life: The Biology of Chordates

Part of the "Branches on the Tree of Life" series. The phylum Chordata includes tunicates, sea lancelets, hagfish, and all familiar vertebrate animals. Explores how these seemingly diverse animals evolved and how the group is unified by four characteristic structures: a hollow dorsal nerve chord, a supportive notochord, gill slits, and a post-anal tail. Key milestones in vertebrate evolution include improvements in swimming and feeding, the evolution of paired fins and a primitive lung, movement onto the land, and the emergence of the amniotic egg. Accessibility options on the DVD are: (1) expanded description, (2) English subtitles in a black box, (3) subtitled description.

Media Details

Runtime: 18 minutes 8 seconds

Illustration of plant structure. Caption: the photon's energy transfers to an electron.
Branches On The Tree of Life
Episode 1
14 minutes 1 seconds
Grade Level: 8 - 12
Sea floor with irregularly shaped white objects on it. Caption: composed almost entirely of hexactinellid sponges.
Branches On The Tree of Life
Episode 2
14 minutes 52 seconds
Grade Level: 8 - 12
Microscopic view of a transparent tube-shaped organism. Caption: an energy reserve the cell can draw on
Branches On The Tree of Life
Episode 3
20 minutes 4 seconds
Grade Level: 8 - 12
Tangle of thread-like substance. Caption: consisted of a nucleic acid core composed of either DNA or RNA
Branches On The Tree of Life
Episode 4
17 minutes 45 seconds
Grade Level: 8 - 12
Blurry microscopic view of an oval shaped object surrounded by green particles. Caption: In nature, these small organisms become links in food chains
Branches On The Tree of Life
Episode 4
17 minutes 19 seconds
Grade Level: 8 - 12
Straight line of light against a light blue background. Caption: in the 50-to-80-micrometer range.
Branches On The Tree of Life
Episode 5
19 minutes 31 seconds
Grade Level: 8 - 12
Closeup view of thin, light green tube-like structures growing off stone. Caption: and absorb the products of digestion,
Branches On The Tree of Life
Episode 6
21 minutes 20 seconds
Grade Level: 8 - 12
A cell being viewed under a microscope. Caption: you can clearly see many of the larger structures
Branches On The Tree of Life
Episode 7
17 minutes 33 seconds
Grade Level: 9 - 12
A sea anemone with a captured crab, surrounded by other plant life. Caption: Even a large crab can be digested within a few hours.
Branches On The Tree of Life
Episode 8
12 minutes 25 seconds
Grade Level: 8 - 12
Underwater plants with small fish swimming through them. Caption: Flatworms were around for a long time.
Branches On The Tree of Life
Episode 9
14 minutes 43 seconds
Grade Level: 8 - 12