Flashcards
Temperature, Dessication and Exposure
Cards in this deck (26)
- 1Name some factors that determine the distribtuion of settlementFood availability, algal cover, presence of adults
- 2Give examples of species that hide to avoid stressLittorina saxatillis - forages at night. Helicon pectunculus, hides in crevice of rock which is 10 degrees lower than exposed rock. Large molluscs adopt a permanent home
- 3Williams, et al., 2005Reduction of contact with conductive surface allows evaporation across the foot. Lifting shell of rock during heat stress
- 4Do high shore gasrtopods use evaporative cooling?No - They close the oeprculum to reduce water loss, but this elevates the body temperature
- 5Why don't high shore organisms use evaporative cooling as much?Organism can lose too much water
- 6What are shells like at the high shore?the li of the shell is attached to the rock with mucus to reduce contact. The spire is pointed towards the sun. They are light in colour to reflect light. they have ridges to increase surface area. Tissues can be +- 5 degrees to rock surface
- 7Garrity, 1984Littorina aspera in Panama - spire of shell is pointed towards the sun
- 8McMahon, 1990Lower body temperature relative to rock surface at high shore - there is a trade off between water loss and ehat loss.
- 9What is Aestivation?A vastly reduced metabolism that conserves energy. The heart may even stop. Shown in cenchritis muricatus
- 10How does Mytulis edulis cope with oxygen demand?The valvue closes and the heart rate drops, ocassionally taking in a bubble.
- 11How are respiratory organs changed to cope with stress?Gills are often reduced in size or replaced by vascularised epithelia that function as lungs. High-shore littorinids have reduced gills, much of oxygen transport occurs at mantle surface.
They can be tucked away in the body to avoid water loss. - 12What interactions do mid-shore and low-shore organisms have with the air?There is more oxygen in the air than in seawater, organisms like barnacles replace water with bubbles of air and absorb oxygen. Siphonariid limpets will fill mantle cavity with air and use it as a lung.
- 13How do excretory systems change to deal with stress?Some gastropods carry water with them, however this is quickly used up. Well adapted kidneys that reabsorb water from urine and can store excretory products for a long time
- 14What are podocytes?Cells in the heart wall which produce copious amounts of urine
- 15Waller, et al., 2006Invertebrates may produce some antifreeze-like compounds that delay the onset of freezing, found in one antarctic species
- 16What is the problem with low temperatures?The formation of ice causes osmotic stress and cell bursting.
- 17Stillman & Somero, 1996The pacific porcelain crab, even in the same genus orgaisms have very different repsonses to temperature stress
- 18How do Cenchritis muricatus and Lattia scabra sustain weight loss?they both increase osmotic pressure by increasing free amino acid content by producing osmolytes.
- 19Halpin, et al., 2002Mytulis californicus, mussels on high shore exposed to longer periods of stress produce more proteins
- 20What are heat-stress proteinsGeneral stress response proteins - expressed due to temperature change, anoxia, pH change and osmotic pressure change. They may potect or restore heat damaged proteins
- 21Give examples of species that grow fasteron exposed shores, and one that doesnt.Perna perna grows 2x as fast on exposed shores. Littorina obtusata grows 2x faster on sheltered shores (it is a forager)
- 22What is the boundary layer?The layer where velocity is <99% of mainstream velocity - important to hiding organisms. It has laminar flow.
- 23What is beneath the boundary layer?The viscous sub-layer, it is thin with turbulent flow
- 24How do sedentary organisms cope with the waves and currents physically?Barnacles - memraneous and calcareous base glues to rock. Mussels produce byssus threads which attach them. The threads are made from collagen proteins and are very elastic, they move to account for water movement.
- 25How do mobile organisms physically cope with waves and currents?They have mucus systems (Patella argenvillei - 100kg to move it) and can increase clinging power using things like chelipeds (e.g. pachygrapsus crastipes)
- 26—
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- Second Semester Flashcards on Temperature, Dessication and Exposure, created by Molly Stockill on 18/02/2019.
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- Molly Stockill
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