Lesson 7

Question 1

locomotion

Answer 1

• ## thrust can be broken down into the forward thrust and lateral thrust which add to the reaction of water

Question 2

lateral thrust

Answer 2

has to be offset by the dorsal fin to make sure the fish doesn’t go in circles
– eels can bend in ore than half of a sine wave

Question 3

trout

Answer 3

• carangiform
• undulations are limited
• bends into half the sine wave length

Question 4

boxfish

Answer 4

ostraciiform
—- even less of a sine wave
—- restricted by the caudal din

Question 5

shapes of fishes

Answer 5

• cross section to length ration is very close to 0.25 –>AKA sweet spot forhydrodynamics
  –> drag is reduced to its minimum
  –> SHAPE again and again

Question 6

shape of fishes (why does breadth and length matter)

Answer 6

• a wider fish pushes away a lot of water – cross sectional area
• have to be longer to be narrower
  -but length also has some drag to it

Question 7

viscous frictional drag

Answer 7

• resistance of water following across the surface area of the fish
• super long and narrow fish (greatly increased friction drag, but greatly decreased pressure drag)

Question 8

reproduction

Answer 8

lof of variation between freshwater and marine telosts

Question 9

freshwater reproducition

Answer 9

small numbers of large eggs (maximize quality over quantity)
- eggs attach to a surface like rock
- look like mini adults

Question 10

marine reproduction

Answer 10

tend to lay large number of very small bouyant eggs
- will float
- look like true larvae

Question 11

teleosts have many interesting sex changing behaviors

Answer 11

most are ghonochronystic –> sex does not chage
BUT … are a number of exceptions
Clown fish – immature –> male –> female
- female needs to grow and have enough energy to make the strong and robust eggs

Question 12

protogynous hermaphroditism

Answer 12

born female, them eventually become male

Question 13

pelagic fishes

Answer 13

• open ocean
• away from shore

Question 14

benthic

Answer 14

• along the bottom
• bottom of the open ocean

Question 15

where is most of the biomass

Answer 15

• along the top of the ocean
  – meaning you have usually go to the surface if you wanna eat

Question 16

mesopelagic migration

Answer 16

• fishes that migrate from the deep ocean to the top
• undergo daily movements

Question 17

surface irradance

Answer 17

measure of light on the surface of water throughout the course of the day

Question 18

isolume

Answer 18

the depth that maintants that amount of bright light changes throughout the day
ex: to still have 1 lumen of light during sunset, you have to be higher up in the water column

Question 19

scattering lines

Answer 19

proportional to the time of a sound wave emitted from the surface of the water (from a speaker_ returning to the durface
– why does the time get shorter and shorter?
– has to do with what its bouncing off of (FISH)
– as the sun is setting – the time for the sound wave to come back got shorter and shorter MEANING that almost all the mesopelagic fish are going from the deep to the surface everynight to feed
– can’t go during the day becuase their primary predators can only really see in the day

Question 20

benthipelagic

Answer 20

• deep deep dwelling fishes
• have reduction in bone
• some have really enlarged stomachs
  WHY
• when you live in the sea, you don’t come across food that often
• if you come across food, even bud food – engulf it while you can
• most go their whole life without reproducing
• lot of them have these light emitting bacteria to find eachother, or even to use to lure prey in

Question 21

coral reef fish

Answer 21

• many have this incredible mouth protruding ability
• vast majority are acanthopterygian fish
• different modes of feeding
• coral reef itself gives them places to hide like nowhere else
  — great place to escape predation
  —maybe why they’re so brightly colored
  — bright colors are great for attracting a mate – but also for predators