6 - Amphibians 2

Question 1

Amphibian skin functions

Answer 1

• defense
• gas exchange
• temperature regulation
• absorption and storage of water
• keratin deposits may produce warts, claws, or other hard structures
• glands
• chromatophores

Question 2

Skin glands

Answer 2

• granular glands - noxious or toxic secretions

- mucous glands - prevents drying

Question 3

Chromatophores

Answer 3

colour and colour changes

Question 4

Skeleton in fish

Answer 4

• for protection of internal organs
• points of attachment for muscles
• keep body from collapsing during movement

Question 5

Terrestrial vertebrate skeleton uses

Answer 5

provide support against gravity and support more powerful muscles
- depend on appendages, not body wall for locomotion

Question 6

Skull modifications

Answer 6

• flattened, fewer bony elements than fish

- jaw structure and musculature modified for capturing and holding prey

Question 7

Vertebral column modifications

Answer 7

• provides support and flexibility on land
• zygapophyses on vertebrae prevent twisting
• single cervical and sacral vertebra

Question 8

Sternum modifications

Answer 8

supports forelimbs and protects internal organs

Question 9

Pelvic girdle modifications

Answer 9

supports hindlimbs

Question 10

Tongue in fish

Answer 10

just a fleshy structure on floor of mouth. no food manipulation

Question 11

Tongue in amphibians - anurans

Answer 11

tongue is used to capture prey

Question 12

Circulation and gas exchange adaptations for life divided between aquatic and terrestrial habitats

Answer 12

• similar separation of pulmonary and systemic circuits to lungfishes
• cutaneous gas exchange results in highly oxygenated blood returning to the heart from the systemic circuit

Question 13

Lymphatic system

Answer 13

• well-developed
• returns fluids, proteins an ions from tissues to circulatory system
• transports water absorbed across skin
• multiple lymphatic hearts help move fluid made mostly of water
• belly patch takes up water in skin

Question 14

Gas exchange

Answer 14

• moist thin surface with blood vessels = exchanges gas
• cutaneous respiration
• buccopharyngeal respiration (mouth has lots of blood vessels for gas exchange)
• gills (larva)
• lungs
• uses depend on species and circumstances (ex when completely submerged = just cutaneous, blood flow to lungs constricts)

Question 15

Salamander lungs

Answer 15

simple sacs

Question 16

Frog lungs

Answer 16

more surface area than salamander lungs

Question 17

Lungs used when

Answer 17

when increased activity and higher temperatures

Question 18

Temperature regulation

Answer 18

• ectothermic like fish
• behavioural temperature regulation
• cooling: nocturnal, burrowing
• warming: basking

Question 19

Nitrogenous wastes

Answer 19

aquatic forms: ammonia

terrestrial forms: urea (more energy to make but less toxicity since not in water)

Question 20

Osmoregulation in water

Answer 20

excrete excess water and conserve ions with kidneys and urinary bladder

Question 21

Osmoregulation on land

Answer 21

conserve water with behaviours:

• nocturnal
• body posture that maximizes surface area when sitting in puddle
• can reabsorb water from bladder
• cocoons (aestivation, basically hiding in body secretions while it’s dry)
• cutaneous absorption
• storage in lymph sacs and urinary bladder

Question 22

Reproduction extrinsic factors

Answer 22

temperate regions - temperature

tropical regions - rainy season

Question 23

Courtship

Answer 23

salamanders: olfactory and visual cues
anurans: tactile and auditory cues

Question 24

Vocalizations

Answer 24

• male anurans
• attract females and territorial for males
• calls are species specific
• useful for organisms in dispersed habitat that must get together for breeding

Question 25

Maternal care

Answer 25

Salamanders and caecilians with internal fertilization

Question 26

Paternal care

Answer 26

anurans (external fertilization): - aeration of aquatic eggs - cleaning or moistenng of errestrial eggs - protection of eggs from predators - removal of dead or infected eggs In some species parent caries eggs externally

Question 27

Rheobatrachus

Answer 27

- presumed extinct - females brooded young in stomachs - young emerged through mouth

Question 28

Metamorphosis

Answer 28

- most dramatic in anurans but happens in salamanders and caecilians - controlled by neurosecretions of the hypothalamus, hormones of anterior pituitary and thyroid gland - mechanisms explain paedomorphosis

Question 29

Hypothalamus

Answer 29

Hypothalamus links nervous and endocrine systems by pituitary gland. Secretes hormones that stimulate or inhibit productions of hormones in anterior pituitary

Question 30

Explain metamorphosis

Answer 30

- timed changes [ ] of prolactin, theyroxine (T4) and triiodothyronine (T3) control it - hypothalamus and pituitary develop in tadpole, hypothalamus releases thyrotropin-releasing hormane and prolactin-inhibiting hormone - causes pituitary gland to release thyroid stimulating hormone to stop production of prolactin - concentrations of t4 and t3 rise, starting metamorphosis