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Vertebrate > Lecture 3 > Flashcards

Lecture 3 Flashcards

1
Q

The blood and other tissue of sharks and Chondrichthyes in general is isotonic. What does this mean?

A

The blood and other tissue is the same or similar salt concentration (so same osmotic pressure pretty much) to their marine environments

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2
Q

What allows sharks and Chondrichthyes to be in osmotic balance with the seawater? What does this adaptation prevent?

A

Due to the high concentration of urea and trimethylamine N-oxide (TMAO) stabilises the proteins present in the urea, allowing them to be in osmotic balance with the seawater.
This adaptation prevents most sharks from surviving in fresh water

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3
Q

Which shark is the exception in being able to survive in fresh water and why?

A

The bull shark. It has developed a way to change its kidney function to excrete large amounts of urea and allow it to move far up in rivers

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4
Q

Most sharks are ectotherms, which family are not and are endotherms?

A

The family Lamnidae

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5
Q

What is unique about sharks which are members of the family Lamnidae, such as the shortfin mako shark and the great white shark? Give a feature of these sharks

A

They are endothermic and maintain a higher body temperature than the surrounding water (only certain areas of the body are maintained at a higher temperature compared to that of he environment). These kind of sharks tend to be the long distance movers/ travelling vast distances, the ones that are constantly swimming

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6
Q

Describe what happens during shark copulation

A

. During copulation sharks meet face to face
. The male inserts one of his claspers into the cloaca of the female
. Sperm contained within spermatophore are delivered to the female via a groove in the clasper
. The spermatophore are forcefully ejected by contracting organs known as siphon sacs which use seawater to carry the spermatophores

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7
Q

When is photo-id a useful technique for studying sharks? Give an example

A

For species such as the mantaray with individuals that have distinctive patterns

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8
Q

Give an example of a shark that has very limited distribution (vertically stay in the same place)

A

Northern river shark (a species of requiem shark found in tidal rivers in northern Australia)

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9
Q

Give the Latin name for a northern river shark

A

Glyphis garricki

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10
Q

Give examples of sharks that travel vast distances

A

Whale, basking, blue, salmon, great white sharks

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11
Q

What is morphometrics?

A

Some skeleton structure that is selected for and show measurable differences between non-interbreeding populations

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12
Q

When are morphometrics useful?

A

Useful in size of the animals as the size of these animals is almost directly linked to its age
Can also identify sub-populations from these morphometric features

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13
Q

How are genetics and DNA forensics used to investigate population structure?

A

. Using polymerase chain reaction (PCR) amplification of mitochondrial (mtDNA) and nuclear DNA followed by restriction enzyme analysis to generate a form of DNA fingerprint (for species, populations or individuals)
. Using a combination of direct sequence comparison and clustering approach to determine similarities between DNA sequences from sample of unknown origin to reference species (phylogenetic approach)

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14
Q

What determines or limits a species abundance?

A

Prey availability, mortality (predators and anthropogenic- linked to their age range- how long they take to become sexually mature) and life history characteristics

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15
Q

How long do most sharks live?

A

20-30 years

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16
Q

Which shark lives the longest?

A

Greenland shark (392y)

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17
Q

How long to spiny dogfish and whale sharks live?

A

70-100y

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18
Q

Unlike most bony fishes sharks are k-selected reproducers. What does this mean?

A

That they produce a small number of well-developed young, so they have a lot of resources put into them- so the chances of that offspring surviving is quite high, as opposed to a large number of poorly developed young

19
Q

What is fecundity?

A

The number of eggs or young produced by an individual

20
Q

What is the fecundity range of sharks per reproductive cycle?

A

Ranges from 2-over 100 per reproductive cycle (every 1-3y)

21
Q

When do lemon sharks become sexually mature? What is the problem with this?

A

They become sexually mature at 13-15 years. This is a problem if things like fishing increase mortality, especially before they get to sexual maturity, can have huge impacts on the population of the species

22
Q

What is an issue with being a K-selected species and increased mortality?

A

Population increase is very slow and therefore impacts will have a more long term effect

23
Q

What is the annual rate of increase in shark populations? Give examples of ones at either end of the spectrum

A

Between <1-30%

thresher sharks at the lower end and blue shark in the North Atlantic at the higher end

24
Q

What percentage of sharks are classed as threatened to some extent according to the the global scale evolution (finished jan 2014)?

A

77%

25
Q

How many sharks are estimated to be killed each year due to commercial and recreational fishing (sharks are eaten around the world and considered a delicacy in many places e.g Japan, China, Iceland)?

A

40-100 million

26
Q

In 2013 which species of sharks And rays were added to the appendix II by CITIES (convention on international trade in endangered species)?

A

Oceanic whitetip shark, scalloped hammerhead shark, great hammerhead shark, smooth hammerhead shark, porbeagle shark and manta rays

27
Q

What does CITIES stand for?

A

Convention on international trade in endangered species

28
Q

What are the 7 most threatened families of Chondrichthyes?

A
  1. Sawfishes (pristidae 7/7)
  2. Angel sharks (squatinidae 12/15)
  3. Wedgefishes (rhynchobatidae 6/6)
  4. Sleeper rays (narkidae 4/4)
  5. Stingrays (dasyatidae 21/42)
  6. Guitarfishes (rhinobatidae 15/28)
  7. Thresher sharks (Alopiidae 3/3)
29
Q

What are the 5 least threatened families of Chondrichthyes?

A
  1. Lanternsharks (Etmopteridae 0/21)
  2. Cat sharks (scyliorhinidae 8/50)
  3. Softnose skates (arhynchobatidae 7/45)
  4. Softnose chimaeras (chimaeridae 0/9)
  5. Kitefin sharks (Dalatiidae 0/7)
30
Q

What happens to the ecosystem when and if you remove large-scale apex predators?

A

. Lack of prey regulation (so their populations increase which has an impact on their prey)- instability in the ecosystem
. Ecosystem shift
. Possible cascading effects (we know too little to know these ecosystems work so it not possible to predict effects it could have but the likelihood is that it will have a cascade effect) (an example in the terrestrial environment is reintroducing wolves into Yellowstone national park)
. Loss of important indicator species on the health of the marine system

31
Q

When did bony fish and the cartilaginous fish split? What did they split from? What don’t we know about these animals?

A

423mya
The ones without jaws
Whether it was these animals that made up the early jawed fish (Gnathostomata)

32
Q

What are early jawed fish called?

A

Gnathostomata

33
Q

When did the class Osteichthyes (bony fish) originate?

A

Around 500 million years ago

34
Q

Bony fish is an extremely diverse and abundant group with how many species alive today?

A

Around 30,000 (100 new describes every year)

35
Q

What group are the most diverse of all the vertebrates?

A

Bony fish

36
Q

What percent of bony fish (Osteichthyes) are marine?

A

60% (these animals can survive in fresh water unlike the Elasmobranchs)

37
Q

What are Osteichthyes divided into?

A

The ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii)

38
Q

Give the features of Osteichthyes

A

. Skeleton made of bone
. Hinged jaws
. Paired fins
. Body covered by scales
. Gills for respiration/ gas exchange with operculum (simple a protection of the gills)
. Ectotherms however, some members of the family scombridae e.g. swordfish and tuna have some level of endothermy
. Lateral line sensory cells

39
Q

What is the biggest group among ray-finned fish?

A

Teleost’s

40
Q

What can the size range between in Ray-finned (Actinopterygii) fishes? Give examples

A

Extant species can range in size from Paedicypris at 8mm, to the massive ocean sunfish, at 2,300kg and the long- bodies oarfish, at 11m. (Huge range in size, shape and distribution)

41
Q

Where are ray-finned (Actinopterygii) fishes found?

A

They are distributed throughout freshwater and marine environments from the deep sea to the highest mountain streams

42
Q

What are the dominant class of vertebrates?

A

Actinopterygiams (comprising of nearly 99% of the over 30,000 species of fish)

43
Q

Describe ray-finned (actinopterygii) fishes and how do they different from sarcopterygii?

A

Have ‘fin rays’, their fins being webs of skin supported by bony or horny spines (‘rays’), as opposed to the fleshy, loved fins that characterise the class lobe-finned fishes Sarcopterygii

44
Q

What percentage of all living fishes do teleosts account for?

A

96%

Vertebrate (20 decks)

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