6.6 Transitional Fossils and Tetrapods

What is the primary focus of paleontologist Jenny Clack's research?

• Marine invertebrates

• Early tetrapods and their transition to land

• Dinosaur migration patterns

• Ancient plant life

What defines a tetrapod?

• Animals with fins and gills

• Creatures with four legs and digits

• Organisms that live exclusively in water

• Vertebrates with wings

What kind of fossil is considered a "transitional form" by paleontologists like Jenny Clack?

• A fossil that shows a complete evolutionary lineage

• A fossil that links two familiar groups

• A fossil that represents a fully evolved species

• A fossil that is difficult to classify

The fossil named "Boris" represents a transitional form between which two groups of animals?

• Birds and reptiles

• Fish and tetrapods

• Mammals and amphibians

• Insects and arachnids

What anatomical feature in the fossil "Boris" suggests it still used gills to breathe?

• A large lung cavity

• Grooved rods in the back of the skull

• Fin-like structures on its back

• A streamlined body shape

How did the animal represented by the "Boris" fossil breathe?

• Exclusively through lungs

• Exclusively through gills

• Using both gills and lungs

• Through its skin

Where were some of the earliest footprints of limbed ancestors discovered?

• Greenland

• Valentia Island, Ireland

• Cambridge, England

• The Amazon rainforest

What evidence found on Valentia Island provides insight into how early limbed ancestors moved?

• Fossilized bones

• Ancient cave paintings

• Preserved footprints

• DNA analysis of modern species

What can be inferred about the environment and movement of the animal that left the footprints on Valentia Island?

• It was a fully terrestrial animal walking on dry land

• It was a fully aquatic animal swimming in deep water

• It was semi-aquatic, using water for support in wet, waterlogged sediment

• It was an arboreal animal climbing trees

Approximately how old are the footprints found on Valentia Island?

• 100 million years old

• 250 million years old

• 370 million years old

• 500 million years old