Maintenance

Question 1

what does it mean to be a heterotroph

Answer 1

obtain energy from food—chemical energy stored in molecular bonds.

Question 2

how does digestion release energy?

Answer 2

by breaking the bonds of the molecular bonds in food

Question 3

1st law of thermodynamics

Answer 3

energy is neither created nor destroyed, only transformed.

Question 4

2nd law of thermodynamics and how it relates to vertebrates

Answer 4

entropy increases in closed systems—but vertebrates, as open systems, maintain low entropy through energy input and biological ‘work’.

Question 5

how is energy used, stored and lost in vertebrates?

Answer 5

Used: for growth, repair, activity, and thermoregulation.

Stored: as fat or glycogen.

Lost: mostly as heat—a side effect of inefficient conversion (Seebacher & Franklin, 2005).

Question 6

how do usage patterns of energy vary?

Answer 6

Usage patterns vary with environmental conditions, especially temperature (Mitchell et al., 2018).

Question 7

what is the difference between ectothermy and endothermy

Answer 7

Ectothermy: temperature regulation via external sources; metabolic rate rises with ambient temperature (Seebacher & Franklin, 2005).

Endothermy: relies on internal metabolic heat for thermoregulation.

Question 8

what groups of vertebrates are ectotherms

Answer 8

fish, reptiles and amphibians

Question 9

what does it mean for ectotherms to mostly be poikilothermic?

Answer 9

A poikilotherm is an animal whose internal temperature varies considerably depending on the environment.

Question 10

what behavioural changes do ectotherms do to manage heat?

Answer 10

basking or burrowing to manage heat (Seebacher & Franklin, 2005).

Question 11

what are two physiological adaptation examples of ectotherms

Answer 11

Antifreeze proteins in Antarctic fish (e.g., glycoproteins that prevent ice crystal growth).

Freeze tolerance in wood frogs via urea and glucose for cryoprotection.

Question 12

what are the strategies when ectotherms are too hot?

Answer 12

Seeking shade, burrowing, or cutaneous evaporation in amphibians.

Aestivation: dormancy during heat with reduced metabolism (Geiser 2010).

Question 13

what groups of vertebrates are endotherms

Answer 13

All birds, mammals, and a few fish and reptiles

Question 14

what is a homeotherm?

Answer 14

maintaining stable body temperatures even in extreme conditions

Question 15

what adaptations do endotherms have when they’re too cold

Answer 15

Shivering, vasoconstriction, piloerection, and torpor help conserve energy.

Hibernation is a deeper, seasonal torpor used to survive prolonged cold and food scarcity (Ruf & Geiser, 2015).

Question 16

what is topor?

Answer 16

• Torpor is a state of reduced metabolic rate and body temperature, used to save energy during food shortages or cold conditions.
• Daily torpor lasts less than 24 hours, with animals continuing to forage.

Question 17

what is the difference between topor and hibernation?

Answer 17

Hibernators tend to be larger and live in higher latitudes than species using daily torpor.

Daily torpor is regulated by the circadian clock, meaning it follows a daily rhythm.
- Hibernation is not controlled by the circadian clock and depends more on external conditions and energy reserves.

Question 18

what adaptations do endotherms have when it’s too hot?

Answer 18

Panting, sweating, vasodilation, and aestivation reduce overheating (Mitchell et al., 2018).

Some mammals, like Commerson’s leaf-nosed bat, use hot torpor to reduce water loss in heat (Reher & Dausmann, 2021).

Question 19

what are the forms of thermal insulation?

Answer 19

Feathers, Fur and Blubber

Question 20

what are the two types of feather and their functions

Answer 20

outer contour feathers for waterproofing, inner down for air trapping.

Question 21

what are the two layers of fur and an example animal relying on fur?

Answer 21

guard hairs (long, oily) and underfur (dense and insulating).

Sea otters rely on fur, with the highest hair density of any mammal (150,000 hairs/cm²).

Question 22

what is blubber and provide an example marine mammal’s thickness

Answer 22

a vascularized fat layer for insulation and energy storage—essential for aquatic life due to water’s heat sink properties (Mitchell et al., 2018).

Bowhead whales have blubber up to 50 cm thick.

Question 23

what is heterothermy and the two types?

Answer 23

A strategy between homeothermy and poikilothermy.

Temporal heterothermy includes daily torpor and hibernation.

Regional heterothermy includes mechanisms like counter-current heat exchange in limbs.

Question 24

what is Bergmann’s rule in terms of SA:V and thermoregulation

Answer 24

Larger body sizes are found in colder climates due to lower SA:V ratios.

Question 25

what is Allen's rule?

Answer 25

Appendage size varies with climate for heat conservation or dissipation. Body shape and size are crucial to thermal tolerance and adaptability to climate change (Mitchell et al., 2018).

Question 26

what are the two strategies of water regulation and salt balance in vertebrates?

Answer 26

Osmoconformers: body fluids match the environment's osmotic pressure (e.g. hagfish, some sharks). Osmoregulators: maintain internal osmotic pressure independent of the environment (Evans, 2001).

Question 27

how do freshwater fish and amphibians osmoregulate?

Answer 27

Constant osmotic water influx, so they excrete dilute urine and actively uptake salts via gills and skin.

Question 28

how do marine teleosts osmoregulate?

Answer 28

Face water loss; they drink seawater, absorb salts in the gut, and excrete salts via gills.

Question 29

what are sharks and rays methods of osmoregulation

Answer 29

Use high urea concentrations to retain water and secrete excess salt via rectal glands.

Question 30

how do amphibians, reptiles and birds differ in osmoregulation

Answer 30

Amphibians absorb water via skin; adults use active transport to regulate ions. Reptiles and birds have impermeable skin and salt glands for excreting excess salt (Evans, 2001).

Question 31

How do marine mammals osmoregulate?

Answer 31

Use renal adaptations, especially long Loops of Henle, to produce concentrated urine. Rely on metabolic water and dietary management (Evans, 2001).

Question 32

how do terrestrial vertebrates conserve water? What do desert animals do differently?

Answer 32

Impermeable skin, efficient kidneys, and behavioral adaptations (e.g., seeking shade, burrowing). Desert animals use long Loops of Henle, dry breath, faecal water reabsorption, and lipid metabolism to retain water.

Question 33

what % of land vertebrates are predicted to be impacted by future extreme heat events? which groups are particularly at risk?

Answer 33

Murali et al. (2023) highlight the growing risk of extreme heat events, projected to impact 41% of land vertebrates under high-emission scenarios (4.4 degree increase). Reptiles and amphibians are particularly at risk due to limited thermal flexibility.