Lecture 2: Fish Biodiversity, Phylogeny, and Biogeography Flashcards
What is the main challenge in defining fish?
Fish are extremely diverse, making it difficult to define them precisely as a single group.
What is a general definition of a fish?
A fish is an aquatic vertebrate with gills and limbs shaped like fins.
Are fish a monophyletic group? Why or why not?
No, fish are not monophyletic because tetrapods (land vertebrates) evolved from lobe-finned fish, making “fish” a paraphyletic group.
What are Cyclostomata, and what fish belong to this group?
Cyclostomata are jawless fish, including hagfish and lampreys.
What is the significance of Actinopterygii?
Actinopterygii (ray-finned fish) are the most diverse group of fish, accounting for 99% of all fish species.
What evolutionary adaptation distinguishes Sarcopterygii?
Sarcopterygii have fleshy, lobed fins supported by a single bone, which are precursors to tetrapod limbs.
What extreme ranges of diversity do fish exhibit?
Fish show diversity in size (e.g., pygmy goby to whale shark), habitats, lifespan, and physiology.
What are extreme sensory adaptations seen in fish?
Examples include bioluminescence, electroreception, and advanced vision systems.
Which regions have the fastest fish speciation rates?
High-latitude, cold-water regions like the Arctic and Antarctic.
What is parental care in fish, and why is it important?
Parental care protects eggs or fry, increasing survival rates but costing the parent energy.
How do polar regions exhibit high speciation despite low diversity?
Extreme environmental pressures and endemism drive speciation in polar fish.
Why are reef-associated fish significant for tropical biodiversity?
They contribute to species richness through long-term accumulation, despite relatively low recent speciation rates.
