Section 31.3 (Exam 3) Flashcards
More Than Half of Chordates Are Also Aquatic
What are the 3 main chordate synapomorphies?
Dorsal hollow nerve cord
Post-anal tail
Notochord
What is a notochord?
A dorsal supporting rod that is rigid and flexible
What is a post-anal tail?
a tail that extends beyond the anus
What are lancelets also called?
cephalochordates
What are some characteristics of lancelets, or cephalochordates?
Very small, less than 5 cm
Notochord is retained throughout life
Enlarged pharynx
What does the enlarged pharynx form in lancelets?
forms a pharyngeal basket for filtering prey from the water
What are tunicates also called?
urochordates or sea squirts
What are some characteristics of tunicates/urochordates/sea squirts?
Adult body is enclosed in a tough “tunic” of proteins and polysaccharides secreted by the epidermis
Adults are sessile
Pharyngeal basket filters prey from the water (like lancelets)
Why are they called tunicates?
Adult body is enclosed in a tough “tunic” of proteins and polysaccharides secreted by the epidermis
In vertebrates, a __________________ replaces the notochord.
vertebral column
Aside from a vertebral column, what are 4 additional features of vertebrates?
Anterior skull encloses a large brain
Rigid internal skeleton
Internal organs suspended in a coelom
Well-developed circulatory system driven by a ventral heart
What functions do the features of vertebrates allow?
These features can support large, active animals, allowing vertebrates to diversify widely.
What are the two groups of vertebrates?
Jawless fishes and jaw-mouthed fishes/gnathostomes
What are the two groups of jawless fishes?
hagfishes and lampreys
What are the two groups of jaw-mouthed fishes/ gnathostomes?
Bony vertebrates and chondrichthyans
What are the two groups of bony vertebrates?
Ray-finned fishes and lobe-limbed vertebrates
What are the 4 groups of lobe-limbed vertebrates?
Coelacanths
Lungfishes
Amphibians
Amniotes
What are some characteristics of hagfishes?
Marine, partial cranium, jawless
Cartilaginous skeleton, lacking vertebrae
Blind, large amounts of slime as defense
What are some characteristics of lampreys?
Complete skull and vertebrae (cartilaginous)
Many species are parasitic
Round mouth used to attach to fish and rasp at flesh, some adults are non-feeding
Live in freshwater or anadromous
What does it mean to be anadromous?
live in saltwater, but breed in freshwater
What are gnathostomes also known as?
jaw-mouths
What are some advantages that gnathostomes have?
Jaws and teeth improved feeding efficiency and prey capture
Most jawed fishes have paired fins for stabilization and swimming
What happened as a result of jaws and teeth improving feeding efficiency and prey capture?
Jawed fishes diversified rapidly and became dominant
What are 4 types of chondrichthyans?
Sharks
Rays
Skates
Chimaeras
What are some characteristics of chondrichthyans?
Skeletons of cartilage
Flexible, leathery skin
What are some characteristics of sharks?
Swim by using lateral undulations of the body
Most are predators
What are some characteristics of skates and rays?
Swim by vertically flapping enlarged pectoral fins
Live on sea floor and feed on buried animals
What is a characteristic of chimaeras?
Live in deep sea cold waters
What material makes up the vertebrae of hagfishes, lampreys, and sharks?
cartilage
What did one lineage of gnathostomes give rise to?
Bony vertebrates with internal skeletons of calcified, rigid bone
What are some characteristics of ray-finned fishes?
Covered by scales
Swim bladder for buoyancy
Gills covered by operculum
Exploit all types of food
What is the function of the operculum?
Structure that covers and protects the gills
Moves to enhance water flow over the gills
Why are coastal waters and estuaries extremely important to marine fish?
This is where they go to lay eggs
Some ray-finned fish are anadromous. Name one example of this and what it means.
Salmon are anadromous. They move from the ocean to the fresh water to breed.
