Animal Adaptations PDF

Animal Adaptations Temperature fluctuations Latitudinal, daily, seasonal…. NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  Posted Only Range extends to arctic Tundra NOT FOR...

Animal Adaptations Temperature fluctuations Latitudinal, daily, seasonal…. NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  Posted Only Range extends to arctic Tundra NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY Frozen Frogs Ice-nucleating proteins outside cells serve as sites of slow, controlled ice formation. Additional solutes, such as glucose and glycerol are made inside the cells to lower the freezing point. → Freezing water is limited to spaces outside cells NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY Variation in temperature: dormancy states Hibernating mammals Body temperature drops to less than 10oC During hibernation, body temp usually not constant Body temperatures of hibernating European ground squirrel 6 Bears are not true hibernators Their body temperature drops only a few degrees They are relatively easily awakened Don’t eat, drink, urinate or defecate during “hibernation” Urea is recycled --> new amino acids Give birth, nurse young while sleeping 7 Torpor Drop in body temperature for part of each day E.g. hummingbirds - at night → Reduces energy needs during inactive periods 8 Variation in temperature Tolerate, e.g. Dormancy periods Special enzymes E.g. Antarctic fish and crustaceans: enzymes function at –2C OR Modify, through: Behaviour Physiology Morphology NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY Behavioural solutions to variations in temperature Seasonal migration By Steve Corey from San Luis Obispo, CA, USA - String of Monarchs, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=61410493 ©Samantha Franks NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  Behavioural thermoregulation Seeking out sun or shade, shelter etc. Lizards and snakes: body temperature varies only 4-5oC/day NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  Behavioural thermoregulation Using water to cool down By Charles J Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68277454 NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  But there is a fundamental difference… By Charles J Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68277454 endotherm ectotherm NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  Posted Only Endothermy: internal heat production, “warm-blooded” →~ Constant internal temperature: homeothermy e.g. birds, mammals Ectothermy: acquiring heat from the environment, “cold- blooded” →Variable body temperature: poikilothermy e.g. most fish, amphibians, reptiles, invertebrates Heterothermy: Sometimes endotherms, other times ectotherms e.g. bats, bees, hummingbirds, hibernating animals NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  endotherm ectotherm By Charles J Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68277454 Maintain body temp. using energy Increase in temperature → from respiration increase in metabolic rate Advantage: enzymes can function Active only when sufficiently most of the time at/near their warm optimum temp. Maintain relatively constant body temp. by behavioural means NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY  endotherm ectotherm By Charles J Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68277454 Tradeoffs Active over wider environmental Need fewer calories → Can live in low productivity temperature range environments, e.g. deserts Cost: need more calories from food Cost: body temperature not always → fewer available for growth, optimal & behavioural reproduction thermoregulation needed NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY Adaptations of endotherms morphological Insulation: fat, fur, feathers Changes thickness with changing seasons Sometimes used to keep heat out E.g. camels - fur dissipates absorbed heat; light-coloured Brown fat: in hibernators Metabolized → heat physiological 17 Temperature and body size 18 Temperature and body size Large, rounded body →Low surface: volume ratio →Slow heat exchange Small, flattened body →High s:v ratio Salt water crocodile: the world’s largest living reptile. Found in S.E. Asia →Rapid heat exchange and N. Australia. Ectotherms: large size possible only in warm, non- seasonal environments The largest snake of all time, Titanoboa cerrejonensis, lived in the late Paleocene Epoch during a time of exceptionally warm global climate 19 Temperature and body size Endotherms Cold environment: need to retain heat round bodies, fewer small species, dense fur, short ears Warm environment: need to lose heat often small-bodied, long limbs/ ears 20  White-tailed deer Posted Only Odocoileus virginianus Avg. body weight In Canada: > 136 kg In Kansas: 93 kg In Louisiana: 60 kg In Florida Keys: 23 kg An example of clinal variation within a species 21  Posted Only Juveniles Because of their small size (high surface: volume ratio) and their need to invest energy in growth, juvenile birds and mammals are often ectothermic, obtaining heat from their parents. NOT FOR SALE OR DISTRIBUTION PROPERTY OF YORK UNIVERSITY