Midterm

Question 1

Divisions of the lateral plate meso?

Answer 1

Splanchnic and somatic

Question 2

Divisions of the intermediate meso?

Answer 2

genital ridge and nephric ridge

Question 3

Divisions of Somitic mesoderm?

Answer 3

schlerotome, myotome, dermatome –> forms tendons and endothelial cells

Question 4

Sclerotome

Answer 4

Somitic mesoderm - forms skeletal derivitives like bone and cartilage

Question 5

myotome

Answer 5

somatic mesoderm - forms muscle blocks, skeletal muscle

Question 6

dermatome

Answer 6

somatic mesoderm - forms base of skin (dermis is mesoderm)

Question 7

Splanchnic

Answer 7

lateral plate mesoderm - towards the viscera (closest to the gut). Forms the circulatory system

Question 8

somatic mesoderm

Answer 8

lateral plate mesoderm - forms the lining of organs/inside the body wall, body cavity lining, pelvis, limb bones

Question 9

enamel

Answer 9

hydroxyapatite - contains ameloblasts

Question 10

enameloid

Answer 10

hydroxyapatite - contains odontoblasts

Question 11

Are gills internal or external to the gill supports in cyclostomes?

Answer 11

The gills are internal to the gill supports in cyclostomes

Question 12

Are gills internal or external to the gill supports in gnathostomes?

Answer 12

Gill supports are median to the gill filaments which are more lateral

Question 13

anadromous

Answer 13

migrating from sea water to fresh water to reproduce

Question 14

catadromous

Answer 14

migrating from fresh water to sea water to reproduce

Question 15

Ampullae of Lorenzeni

Answer 15

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

Question 16

Challenges and adaptations of fresh water fishes

Answer 16

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

Question 17

Challenges and adaptations of marine fishes

Answer 17

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

Question 18

What is the upper and lower jaw derived from in the jawless condition?

Answer 18

First branchial arch

Question 19

What is the spiracle derived from in the jawless condition?

Answer 19

First gill slit

Question 20

What is the hyoid arch derived from in the jawless condition?

Answer 20

second branchial arch

Question 21

How are paired fins formed?

Answer 21

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

Question 22

Placoid scales

Answer 22

characteristic of chondrichthyans. Scales composed of dentine, enameloid and even traces of bone. Also known as dermal denticles

Question 23

What kind of jaw suspension do Holocephalians have?

Answer 23

Autostylic or holostylic –> palatoquadrate (upper jaw) is fused to the brain case

Question 24

How many basal elements do holocephalians have in their pectoral fin?

Answer 24

TWO

Question 25

what is vitrodentine?

Answer 25

Covers the dentine layer of placoid scales -- enamel-like: very hard

Question 26

What type of jaw suspension do Selachii have?

Answer 26

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

Question 27

What does the hyoid arch consist of?

Answer 27

Hyomandibula, ceratohyal, and hypohyal

Question 28

What range of depth is the photic zone?

Answer 28

0-1000m. Most fishes live in this range. Biomass is highest here.

Question 29

What range of depth is the aphotic zone?

Answer 29

1000m - 4000m

Question 30

What range of depth is he mesopelagic zone?

Answer 30

200m - 1000m

Question 31

What range of depth is the bathypelagic zone?

Answer 31

1000m - deepest

Question 32

What range of depth is the epipelagic zone?

Answer 32

0m - 200m

Question 33

What percentage of fishes live in the tropical reefs?

Answer 33

30%

Question 34

What percentage of fishes live at the surface?

Answer 34

1%

Question 35

What percentage if fishes live on the continental shelf?

Answer 35

44%

Question 36

North Sea Herring lifecycle

Answer 36

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.

Question 37

Where does the swim bladder come from?

Answer 37

The swim bladder is a pouch off the gut -- some teleosts use this as a lung- secondarily gain respiratory function!

Question 38

Gar and bowfin breathing?

Answer 38

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