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Lesson 19: Vertebrates I Marine Biology. Vertebrates: Animals with a backbone. Animals in the sub-phylum Vertebrata have spinal cords and brains Marine vertebrates include: sharks, fish, turtles, birds, seals and whales Can you think of others?. Classification Overview Common Vertebrates - PowerPoint PPT Presentation
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Lesson 19: Vertebrates I
Marine Biology
Vertebrates: Animals with a backbone
Classification OverviewCommon Vertebrates
Phylum SubphylumChordata Vertebrata
ClassesChondrichthyes
Actinopterygii
Reptilia
Mammalia
Animals in the sub-phylum Vertebrata have spinal cords and brains
Marine vertebrates include: sharks, fish, turtles, birds, seals and whales
Can you think of others?
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Chondrichthyes: Cartilaginous fishes
Class Chondrichthyes means ‘cartilaginous fish’ and consists of sharks, rays, skates and close relatives
They share common features:– Jaws– Cartilage skeletons, not true bone– Fatty liver used for buoyancy– Lack swim bladder– Most have placoid scales
They are great predators because they have pore-like structures near their snouts called ampullae of Lorenzini, which detect electrical currents of other organisms
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Some Chondrichthyes
Basking shark2nd largest fish in the seabehind the whale shark. It feeds on plankton
Order: Lamniformes
Photo: NOAA
StingrayThey ‘fly’ through the water using flat, modified fins
Order:Rajiformes
Photo: NOAA
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Agnatha: The jawless fishes
Superclass Agnatha: Simple, more primitive fish that lack jaws Characteristics include:
– No jaws– Cartilaginous skeletons– Lack scales, paired fins– Long, eel-like
Two class divisions: – Myxini (hagfish)– Petromyzontida (lampreys)
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Some Agnathans
Pacific hagfish off Oregon Coast
Sea Lamprey
Photo: NOAA
Photo: NOAA6
Fish with 2 sea lampreys attached
Osteichthyes: The bony fishes
Superclass Osteichthyes contains the majority of the ocean’s fish Characteristics include:
– Bone skeletons– Operculum: bony skin flap outside gills that helps fish breathe
when not swimming– Most use a swim bladder to keep them from sinking
Two class divisions: – Actinopterygii (ray-finned fish including grouper, tuna and halibut)– Sarcopterygii (lobe-finned fish including lungfish and coelacanths)
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Some Osteichtyhes
Yellowfin tuna Ray-finned fish
Indonesian coelacanthLobe-finned fish
Walleye pollockRay-finned fish
Photo: SI
Photo: NOAA8
Fish use their fins to help them swim
Anatomy of a bony, ray-finned fish
pectoral fin
dorsal fin
caudal fin
pelvic fin
Photo:
NO
AA
anal fin
adipose fin
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Class Reptilia: Cold blooded animals
Reptilians generally share these common features:– Cold-blooded: they take on
the temperature of their surroundings
– Breathe with lungs– Reproduce by laying eggs
Classification OverviewCommon Reptilian Orders
Sub-Phlyum ClassVertebrata Reptilia
OrdersCrocodilia – Alligators
Crocodiles
Chelonia – Turtles, Tortoises
Squamata – Snakes, Lizards
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Some marine reptiles
Marine iguana – Order Squamata
•These reptiles eat algae in cold water near the Galapagos Islands•They warm themselves on rocksafter their dives
Green sea turtle – Order Testudines
•Sea turtles crawl onto the beachto lay their eggs•When eggs hatch,babies must crawl to sea – on the way they are highly vulnerable to seabirds and other predators 11
Managing fish populations
Fishing contributes significantly to the U.S. economy and provides a vital food source
Think back to the exercise at the beginning of class: how did you estimate the number of fish in your container?
Scientists use a combination of math, biology, and computer skills to best determine what levels of fishing can exist to provide food and support the economy without overfishing the resource
NOAA’s National Marine Fisheries Service works to sustainably manage our marine resources, including commercial fish populations, and to promote healthy ecosystems
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Fisheries management terminology
A fish stock is group of individuals of the same species that inhabitat the same geographic region and interbreed when mature
– Single species may be made up of multiple stocks (each in a different geographic region), and fisheries are managed at the stock level
– An example of a stock is a group of salmon that always use and return to particular stream for reproduction.
Biomass (B) is the total weight of fish in a stock (e.g., metric tons)
Fishing mortality rate (F) is the rate at which fishing removes fish from a stock
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Fisheries management terminology
Sustainability represents the ability to persist in the long term– If a fish stock remains at a constant level (or even grows)
despite fishing pressure over a long time period, it is considered sustainable
Maximum sustainable yield (MSY) is the greatest number of fish that can be caught each year without impacting the long-term productivity of the stock
Overfishing occurs when fishing mortality exceeds a specific threshold, usually set at a level to achieve MSY
A stock is considered overfished when the stock size falls below a specific threshold, either in terms of numbers or biomass
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Student activity
In today’s activity, we will discuss in more detail what it means to fish “sustainably” and you will evaluate sustainable seafood restaurants
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