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Vertebrates > Lecture 7 > Flashcards

Lecture 7 Flashcards

1
Q

What are the 5 things to think about when adapting to life in the water?

A

Density, viscosity, oxygen content, heat capacity & conductivity and electrical conductivity

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2
Q

What are the pros of water in regards to density?

A

It supports an animal’s body, therefore, no need for weight-bearing skeleton & enables organisms to grow larger than terrestrial forms

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3
Q

What are the problems associated with viscosity?

A

It’s 18x denser than air so organisms must generate thrust to overcome drag

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4
Q

What part of a water organism’s body generates thrust?

A

The distal or tail end of the animal

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5
Q

What are the two types of drag?

A

Viscous and inertial drag

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6
Q

What is viscous drag?

A

Friction of water on the body

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7
Q

What is inertial drag?

A

Pressure differences through water displacement

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8
Q

Explain some components within viscous drag?

A

Affected by body surface and shape and it’s fairly constant across swimming speeds

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9
Q

How can viscous drag be reduced?

A

Smooth scales and mucous

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10
Q

What kind of body has a high viscous drag?

A

A thin body with a high surface area for muscles. Eels

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11
Q

Describe intertial drag

A

Affected by body shape, increases with speed and a thick body displaces a lot of water and results in high inertial drag

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12
Q

What is the common shape amongst sea animals to help cope with the different kinds of drag and increase the effectiveness of travel?

A

A torpedo/fusiform like shape with width/length ratios around 0.25

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13
Q

What also effects thrust?

A

The shape of the tail. A high aspect (width/length) ratio gives higher thrust relative to drag

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14
Q

Explain the availability of O2

A

O2 availability is low therefore demands efficient extraction from the water. This is why tidal ventilation is hard, hence one way flow of water over gills

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15
Q

Explain how water travels over the gills of fish

A

Buccal pumping sends the water over the gills and secondary lamellae

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16
Q

What is the countercurrent exchange system?

A

The blood flow travels opposite to the water flow to prevent exchanges from reaching an equilibrium and maximizing exchange of gases

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17
Q

What does the blood flow through?

A

The secondary lamellae

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18
Q

How do fish adjust buoyancy in the water? How does this work?

A

They use their impermeable swim bladder. They hold air within the swim bladder.

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19
Q

Where is the swim bladder located?

A

Between the peritoneal cavity and the vertebral column and occupies 5% volume in marine and 7% in fresh water teleosts

20
Q

Is buoyancy depth dependent true or false?

A

True

21
Q

How does a fish control their buoynacy if they want to move down in the water?

A

A fixed volume of air within the swim bladder will become compressed as pressure increases

22
Q

How does a fush control their buoyancy if they want to ascend?

A

They must release gas. Some do this through a pneumatic duct to the stomach

23
Q

What kind of fish have this pneumatic duct to control buoyancy?

A

Physostomous fish

24
Q

Explain the actions of a goldfish controlling its buoyancy

A

They gulp it down and burp it up

25
Q

What are physoclistous fish and how do they control their buoyancy?

A

They’re closed-bladder fish who’ve lost the pneumatic duct connection and regulate gas by secreting it from the blood

26
Q

What is the rete mirabile?

A

It is a gas gland that has capillaries and a counter-current exchange system

27
Q

Name some other things that the rete mirabile does

A

Releases lactic acid and acidifies blood

28
Q

What does the acidification of blood do in physoclistous?

A

Causes haemoglobin to release oxygen

29
Q

Explain how the rete mirabile function?

A

Oxygen accumulates until its rpesure exceeds that of the swim bladder. It then diffuses into the gas bladder and increases its volume.

30
Q

How does a physoclistous release gas from the rete mirabile?

A

It releases a muscular valve (ovale) so oxygen can diffuse into the blood

31
Q

How do sharks control buoyancy?

A

They have an oily liver

32
Q

What are bottom dwelling sharks?

A

Negatively buoyant and have fewer and smaller oil vacuoles

33
Q

What do fish (like deep sea fish) that make long vertical movements tend to rely on?

A

They tend to rely on more lipids than gas for buoyancy

34
Q

Water conducts heat faster and is a more stable thermal environment than air, true or false?

A

True

35
Q

Light is scattered and visibility isn’t as strong in water so what do organisms tend to use to compensate for this?

A

Mechanical and electrical sensitivity

36
Q

Name some of the mechanical senses organisms use

A

Internal ear, gravity detectors and sound pressure wave detection

37
Q

Explain the lateral line system

A

It is a line of dots on the lateral sides of an organism. It has clusters of neuromast organs dispersed over the head and body.

38
Q

What are the two things that the neuromasts can lie in?

A

Tubular canals or epidermal depressions

39
Q

What is a kinocilium?

A

Hair cells that are asymmetrically placed in a cluster of microvilli and is associated with two nerves

40
Q

What does each nerve associated with the kinocilium do ?

A

One carries impulses from hairs with one orientation and the other from those reversed 180 degrees

41
Q

Explain the cupula in association with detecting water flow

A

Pairs of hairs are within the cupula. When the hairs bend, either excites or inhibits nerve signals and signals the direction of water currents

42
Q

How do electric eels generate an electrical current?

A

Electrocytes. Muscle cells that have lost the ability to contract but are specialised for generating an ion current flow

43
Q

What are stenohaline fish?

A

Can only tolerate moderate changes in the salinity of water

44
Q

What are euryhaline fish?

A

Can tolerate wide changes in the salinity of water and can often change between fresh and salt water

45
Q

Explain the kidneys of a fish

A

Millions of tubular nephrons produce urea & remove excess water/salts/waste from blood. Blood filters through glomerulus to form ultrafiltrate

Vertebrates (11 decks)

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