Exam 3: Chapter 8-11

Question 1

Major characteristics of chordates vs. vertebrates

Answer 1

Chordates: Dorsal hollow nerve cord, notochord, post-anal tail, pharyngeal pouches.

Vertebrates: Vertebrae (segmented notochord), skull, internal skeleton.

Question 2

Evolutionary history of fishes

Answer 2

Evolved from jawless fish (Agnatha: hagfish, lampreys) → cartilaginous fish (Chondrichthyes: sharks, rays) → bony fish (Osteichthyes). Ancestors include ostracoderms.

Question 3

Three major classes of marine fishes

Answer 3

1) Agnatha
2) Chondrichthyes
3) Osteichthyes

Question 4

1) Agnatha

Answer 4

Jawless, cartilaginous (hagfish, lampreys).

Question 5

2) Chondrichthyes

Answer 5

Cartilaginous skeleton, placoid scales, urea retention (sharks, rays)

Question 6

3) Osteichthyes:

Answer 6

Bony skeleton, swim bladder, cycloid/ctenoid scales (tuna, cod).

Question 7

Difference of major classes of marine fishes

Answer 7

Agnatha lack paired fins; Chondrichthyes rely on oil livers for buoyancy; Osteichthyes use swim bladders.

Question 8

Agnatha members and anadromous species

Answer 8

Hagfish: Marine scavengers, produce slime for defense.

Lampreys: Parasitic, freshwater spawners; anadromous (migrate from sea to freshwater to breed).

Question 9

Cartilaginous vs. bony fish differences

Answer 9

Cartilaginous: No swim bladder, heterocercal tail, urea/osmolyte retention.

Bony: Swim bladder, homocercal tail, osmoregulate via gills/kidneys.

Question 10

Cartilage and body mass

Answer 10

Cartilage is less rigid; larger skeletal mass compensates for structural support. This reduces space for muscles, impacting locomotion efficiency.

Question 11

Sharks and water balance

Answer 11

Retain urea and TMAO to match seawater osmolarity, preventing water loss. TMAO neutralizes urea toxicity.

Question 12

Sharks vs. skates/rays

Answer 12

Sharks: Ventral mouth, 5–7 lateral gill slits, active predators.

Skates/Rays: Dorsoventrally flattened, ventral gill slits, demersal, crush prey with dental plates.

Question 13

Coloration patterns

Answer 13

1) Pelagic
2) Demersal
3) Tropical

Question 14

1) Pelagic:

Answer 14

Countershading (dark dorsal, light ventral).

Question 15

2) Demersal:

Answer 15

Mottled/cryptic patterns (e.g., flounder).

Question 16

3) Tropical:

Answer 16

Bright colors for camouflage (e.g., clownfish) or warning (e.g., lionfish).

Question 17

Fin shapes and propulsion

Answer 17

Lunate fins (tuna) for sustained speed; heterocercal tails (sharks) generate lift.

Question 18

Swimming types and body forms

Answer 18

1) Cruisers
2) Burst swimmers
3) Maneuverers
4) Bottom dwellers

Question 19

1) Cruisers

Answer 19

Torpedo-shaped (tuna)

Question 20

2) Burst swimmers

Answer 20

Elongated (barracuda)

Question 21

3) Maneuverers

Answer 21

Flexible bodies (eels)

Question 22

4) Bottom dwellers

Answer 22

Flat bodies (flounder)

Question 23

Drag reduction

Answer 23

1) Streamlined bodies
2) Flattened shapes

Question 24

1) Streamlined bodies

Answer 24

reduce form drag (e.g., mackerel).

Question 25

2) Flattened shapes

Answer 25

minimize induced drag (e.g., rays)

Question 26

Tuna adaptations

Answer 26

Red muscle (aerobic endurance), retractable fins, endothermy, lunate tail.

Question 27

Buoyancy mechanisms

Answer 27

Sharks: Oil-filled liver, dynamic lift from pectoral fins. Bony fish: Gas-filled swim bladder.

Question 28

Swim bladder evolution

Answer 28

Freed fins from buoyancy control, enhancing maneuverability.

Question 29

Rete mirabile

Answer 29

Countercurrent exchange system in swim bladders/gills; maximizes gas exchange efficiency

Question 30

Fish vs. mammalian circulation

Answer 30

1) Fish: Single circulatory loop (heart → gills → body). 2) Mammals: Double loop (heart → lungs → heart → body).

Question 31

Oxygen extraction challenges

Answer 31

Low O₂ solubility in water; countercurrent exchange in gills extracts 80–90% of O₂.

Question 32

Electroreception in sharks

Answer 32

Ampullae of Lorenzini detect bioelectric fields of prey; critical for hunting in murky waters.

Question 33

Pressure wave detection

Answer 33

Lateral line system with neuromasts senses water movements.

Question 34

Sensing direction

Answer 34

Otoliths in inner ear detect gravity and acceleration.

Question 35

Fish migration

Answer 35

1) Anadromous: Salmon (sea → freshwater). 2) Catadromous: Eels (freshwater → sea). Navigate via magnetic fields, olfaction, celestial cues.

Question 36

Internal fertilization vs. spawning

Answer 36

Internal: Claspers in sharks; direct sperm transfer. Spawning: External gamete release (e.g., coral reef fish).

Question 37

Reproductive strategies

Answer 37

1) Oviparous: Eggs laid externally (most bony fish). 2) Ovoviviparous: Eggs hatch internally (e.g., some sharks). 3) Viviparous: Live birth with placental nourishment (e.g., surfperches).

Question 38

Gender plasticity

Answer 38

Ensures reproductive success in fluctuating populations (e.g., sequential hermaphroditism in wrasses

Question 39

Hermaphroditism types

Answer 39

Simultaneous: Both sexes at once (e.g., hamlet fish). Sequential: Sex change (protogynous: female→male; protandrous: male→female).

Question 40

Advantage of sequential hermaphroditism

Answer 40

Maximizes reproductive output; larger males defend territories (e.g., California sheephead).

Question 41

Tetrapod evolution

Answer 41

Evolved from lobe-finned fish (~365 mya). Tiktaalik: Transitional fossil with limb-like fins and neck.

Question 42

Reptile/bird dispersal

Answer 42

Reptiles: Amniotic eggs, scales, and ectothermy allow colonization of arid regions. Birds: Endothermy, flight, and feathers enable global distribution

Question 43

Sea turtles vs. terrestrial turtles

Answer 43

Sea turtles: Flippers, non-retractable heads, salt glands, marine habitats.

Question 44

Sea turtle reproduction

Answer 44

Nest on natal beaches; temperature-dependent sex determination (warmer = females). Migrate thousands of miles.

Question 45

Threats to sea turtles

Answer 45

Bycatch, plastic ingestion, coastal development, climate change (rising temperatures skew sex ratios).

Question 46

Sea snakes vs. terrestrial snakes

Answer 46

Laterally flattened tails, ovoviviparous, venomous (e.g., yellow-bellied sea snake).

Question 47

Marine iguanas

Answer 47

Endemic to Galápagos; graze algae; salt glands excrete excess salt; dark skin absorbs heat.

Question 48

Saltwater crocodiles

Answer 48

Found in Indo-Pacific; apex predators; aggressive. Use "death roll" to dismember prey.

Question 49

Bird adaptations

Answer 49

1) Flight 2) Thermoregulation 3) Waterproofing

Question 50

1) Flight

Answer 50

Hollow bones, fused skeleton, powerful pectorals

Question 51

2) Thermoregulation

Answer 51

Feather insulation, countercurrent heat exchange in legs.

Question 52

3) Waterproofing

Answer 52

Preen gland oils.

Question 53

Seabird groups

Answer 53

1) Penguins: Flightless, counter-shaded, Antarctic. 2) Tubenoses (albatross): Salt glands, long-distance gliders. 3) Pelicans: Pouch for plunge-diving.

Question 54

Marine mammal classification

Answer 54

1) Cetaceans (whales) 2) Pinnipeds (seals) 3) Sirenians (manatees) 4) Fissipeds (otters, polar bears)

Question 55

Whale mammalian traits

Answer 55

Hair (vestigial), mammary glands, viviparity, endothermy

Question 56

Baleen vs. toothed whales

Answer 56

1) Baleen (Mysticeti): Filter feeders (e.g., blue whale) 2) Toothed (Odontoceti): Echolocation hunters (e.g., sperm whale)

Question 57

Whale migration

Answer 57

Breed in warm waters (e.g., Hawaii), feed in polar regions (krill-rich)

Question 58

Baleen function

Answer 58

Keratin plates trap krill/small fish; allows bulk feeding

Question 59

Breaching

Answer 59

Leaping out of water; possible functions: communication, parasite removal, play.

Question 60

Echolocation

Answer 60

Clicks produced in nasal sacs; melon focuses sound; echoes received via lower jaw. Used by Odontoceti.

Question 61

Whale stranding

Answer 61

Causes: Sonar-induced trauma, illness, navigational errors

Question 62

Marine mammal adaptations

Answer 62

1) Buoyancy: Blubber. 2) Diving: Bradycardia, collapsible lungs. 3) Feeding: Baleen/teeth specialization

Question 63

Seals vs. sea lions

Answer 63

Seals: No external ears, crawl on land. Sea lions: External ears, walk on flippers.

Question 64

Ecological factors

Answer 64

Abiotic (temperature, salinity), biotic (competition, predation), disturbance.

Question 65

Competition effects

Answer 65

Reduces diversity unless resource partitioning occurs (e.g., barnacles on rocky shores)

Question 66

Disturbance and succession

Answer 66

Disturbance: Storms, predation. Succession: Recolonization post-disturbance (e.g., mussels after sea star removal).

Question 67

Species interactions

Answer 67

Predation, competition, mutualism (e.g., clownfish-anemone), parasitism

Question 68

Predation effects

Answer 68

Decrease diversity: Overgrazing. Increase diversity: Keystone predators (e.g., sea otters control urchins, preserving kelp forests).

Question 69

Energy flow

Answer 69

Trophic pyramid: 10% energy transfer between levels (e.g., 1000 kg algae → 100 kg zooplankton → 10 kg fish).

Question 70

Trophic levels

Answer 70

1) Primary producers: Phytoplankton. 2) Primary consumers: Zooplankton. 3) Secondary consumers: Small fish

Question 71

DOM

Answer 71

Dissolved organic matter; recycled by bacteria via microbial loop.

Question 72

Primary vs. secondary consumers

Answer 72

1) Primary: Herbivores (e.g., copepods). 2) Secondary: Carnivores (e.g., sardines)

Question 73

Physical factors

Answer 73

Tidal exposure, wave shock, temperature extremes.

Question 74

Sediment size effects

Answer 74

Coarse sand: Drains quickly, oxygen-rich. Fine silt: Waterlogged, anoxic

Question 75

Sandy beach instability

Answer 75

Wave action shifts sediments; no attachment points for sessile organisms.

Question 76

Sandy intertidal adaptations

Answer 76

Burrowing (clams), tube-building (polychaetes), rapid reburial (mole crabs).

Question 77

Food web base

Answer 77

1) Sandy: Detritus/plankton. 2) Rocky: Algae.

Question 78

Zonation

Answer 78

1) Upper intertidal: Lichens, periwinkles. 2) Middle: Mussels, barnacles. 3) Lower: Seaweeds, anemones

Question 79

Zonation causes

Answer 79

1) Upper limit: Desiccation tolerance. 2) Lower limit: Predation (e.g., sea stars control mussels).

Question 80

Maintaining diversity

Answer 80

Keystone predators (e.g., Pisaster sea stars) prevent competitive exclusion.

Question 81

Foraging types

Answer 81

1) Deposit feeders: Sand dollars. 2) Suspension feeders: Clams. 3) Predators: Moon snails.

Question 82

Rocky vs. sandy shores

Answer 82

1) Rocky: High diversity (niches). 2) Sandy: Low diversity (homogeneous substrate).

Question 83

Desiccation adaptations

Answer 83

Shell closure (barnacles), mucus (snails), clustering (anemones)

Question 84

Limited resource

Answer 84

Space on rocky shores (e.g., barnacle competition).

Question 85

Examples in North America

Answer 85

Rocky: Pacific Coast (e.g., Monterey Bay). Sandy: Gulf Coast (e.g., Padre Island).