Midterm Flashcards
Divisions of the lateral plate meso?
Splanchnic and somatic
Divisions of the intermediate meso?
genital ridge and nephric ridge
Divisions of Somitic mesoderm?
schlerotome, myotome, dermatome –> forms tendons and endothelial cells
Sclerotome
Somitic mesoderm - forms skeletal derivitives like bone and cartilage
myotome
somatic mesoderm - forms muscle blocks, skeletal muscle
dermatome
somatic mesoderm - forms base of skin (dermis is mesoderm)
Splanchnic
lateral plate mesoderm - towards the viscera (closest to the gut). Forms the circulatory system
somatic mesoderm
lateral plate mesoderm - forms the lining of organs/inside the body wall, body cavity lining, pelvis, limb bones
enamel
hydroxyapatite - contains ameloblasts
enameloid
hydroxyapatite - contains odontoblasts
Are gills internal or external to the gill supports in cyclostomes?
The gills are internal to the gill supports in cyclostomes
Are gills internal or external to the gill supports in gnathostomes?
Gill supports are median to the gill filaments which are more lateral
anadromous
migrating from sea water to fresh water to reproduce
catadromous
migrating from fresh water to sea water to reproduce
Ampullae of Lorenzeni
electroreceptors - sharks (and some rays) have pores which lead to canals - at the bottom of the canals there are sensory cells which attach to nerves. The gel allows them to detect changes in electrical potential (prey close by). There is a gel near the surface pore that is electrically conductive. Concentrated near the head
Challenges and adaptations of fresh water fishes
Need to remain saltier than their environment. Fish needs to hold on to salts and get rid of water. So they don’t drink, but they regulate salts at the gills where they can bring in salts actively. Retain salts in kidneys. Produce a dilute urine
Challenges and adaptations of marine fishes
Problem is getting rid of salt and keeping water because of their salty environment. Drink salt water, dump sodium and chloride at the gills. In the kidneys, they excrete as little water as possible - concentrated urine
What is the upper and lower jaw derived from in the jawless condition?
First branchial arch
What is the spiracle derived from in the jawless condition?
First gill slit
What is the hyoid arch derived from in the jawless condition?
second branchial arch
How are paired fins formed?
somitic mesoderm branches off and the body wall pouches out –> somitic mesoderm infiltrates into the pouched out area to form muscles of the limb/ fin
somite + lateral plate
Placoid scales
characteristic of chondrichthyans. Scales composed of dentine, enameloid and even traces of bone. Also known as dermal denticles
What kind of jaw suspension do Holocephalians have?
Autostylic or holostylic –> palatoquadrate (upper jaw) is fused to the brain case
How many basal elements do holocephalians have in their pectoral fin?
TWO
what is vitrodentine?
Covers the dentine layer of placoid scales – enamel-like: very hard
What type of jaw suspension do Selachii have?
Hyostylic jaw suspension: the upper jaw is attached directly to the chondrocranium in one spot at the ethmoid connection. The upper jaw also interacts caudally with the hyomandibula which is attached the the cranium posteriorally
What does the hyoid arch consist of?
Hyomandibula, ceratohyal, and hypohyal
What range of depth is the photic zone?
0-1000m. Most fishes live in this range. Biomass is highest here.
What range of depth is the aphotic zone?
1000m - 4000m
What range of depth is he mesopelagic zone?
200m - 1000m
What range of depth is the bathypelagic zone?
1000m - deepest
What range of depth is the epipelagic zone?
0m - 200m
What percentage of fishes live in the tropical reefs?
30%
What percentage of fishes live at the surface?
1%
What percentage if fishes live on the continental shelf?
44%
North Sea Herring lifecycle
The adults migrate from the North sea to spawn off the UK coast, and they spawn and the larvae drift off toward Scandanavia – juveniles feed of zooplankton – mature and go back to North sea – migration depends on changes in the ocean current.
Where does the swim bladder come from?
The swim bladder is a pouch off the gut – some teleosts use this as a lung- secondarily gain respiratory function!
Gar and bowfin breathing?
They have ridges in their swim bladder which is dorsal to the gut –> so they can use their swim bladder for gas exchange, especially in their low oxygen environments
