Exam Flashcards
Ectotherm
Relies on external environment for heat
Endotherm
Make their own heat
What is the most important physiological variable for ectotherms?
Temperature
Temperature Tolerance Range
Range of temperatures between the boundaries of too hot and too cold
What do zebra-tailed lizards when the substrate is hot?
Curl up their toes and tails
Zone of Intolerance
Animal cannot survive and does not exist in this zone
Law of Tolerance Curve
Zone of intolerance at ends beyond the curve, survival zone at the ends of the curve, then growth, then greatest fitness in the centre (survival, growth, and reproduction)
Water and Salt Balance
Constant gradient/diffusion of salt and water in the body. Makes it more difficult to maintain internal balance
Why is a stable internal environment required for cells?
For metabolic processes
Water Flux
Water moves in an out of cells and bodies in a variety of ways
Why does water exchange differ between reptiles an amphibians?
Because their skin types differ
Routes of Water Transfer
Drinking (reptiles only), from food, across skin (amphibians mostly), metabolism, through highly vascularized tissues in the lining of the cloaca or esophagus
Uptake of Water by Amphibians
Across skin by osmosis and diffusion
Morphological Modifications of Amphibian Skin for Water Uptake
Smooth ventral skin in aquatic species and granular ventral skin of terrestrial species
Granular Ventral Skin
Dark spot on belly of terrestrial amphibians, made up of highly vascularized tissue for water uptake
Smooth Ventral Skin
Smooth, slippery skin of aquatic amphibians to help take up water
Granular Skin
Highly vascularized to enhance water absorption
Purpose of Costal Grooves on Salamanders
Channel water from underside to back
Uptake of Water by Reptiles
Drinking, methods vary by species. May drink from puddles, condensation drops in caves, or use body to channel water to mouth.
How do reptiles drink from condensation?
The water that evaporates in the desert is collected on the ceilings of caves, and the reptile drinks those drops.
How do reptiles use their body posture to drink?
Arch back and stretch out front arms to channel water down to their mouth
Rain Harvesting in Agamid Lizard
Honeycomb-shaped microstructures cover the surface of dorsal scales. There is a complex capillary system involved with the scale hinges. Water flow in these hinges is directed towards the mouth.
How do herps prevent water loss?
Must adjust behaviours and most would not last more than a day without them. Adjust daily/seasonal activity patterns. Seek humid retreats when inactive.
Anuran Burrowing and Water Retention
Burrow into the soil when it is moist and hunker down into a ball so there is less surface area for water loss. The soil is wet, they are protected by the wind, and the ground insulates them.