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AMPHIBIAN LIFE HISTORIES. I. AMPHIBIAN LIFE HISTORIES I.WHAT IS AN AMPHIBIAN? II. AMPHIBIAN EVOLUTION III. ECOLOGICAL IMPORTANCE IV. FEEDING BEHAVIOR.

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Presentation on theme: "AMPHIBIAN LIFE HISTORIES. I. AMPHIBIAN LIFE HISTORIES I.WHAT IS AN AMPHIBIAN? II. AMPHIBIAN EVOLUTION III. ECOLOGICAL IMPORTANCE IV. FEEDING BEHAVIOR."— Presentation transcript:

1 AMPHIBIAN LIFE HISTORIES

2 I. AMPHIBIAN LIFE HISTORIES I.WHAT IS AN AMPHIBIAN? II. AMPHIBIAN EVOLUTION III. ECOLOGICAL IMPORTANCE IV. FEEDING BEHAVIOR V. VOCALIZATIONS I.WHAT IS AN AMPHIBIAN? II. AMPHIBIAN EVOLUTION III. ECOLOGICAL IMPORTANCE IV. FEEDING BEHAVIOR V. VOCALIZATIONS

3 I. WHAT AN AMPHIBIAN IS From the Greek - Amphibios - leads two lives Ectothermic vertebrates with aquatic, gilled larval stage and terrestrial adult stage. All possess glandular skin and lack nails or claws. Kingdom - Animalia Phylum - Chordata Subphylum - Vertebrata Class - Amphibia Order Caudata - Salamanders 390 spp Order Anura - Frogs and Toads 4000 spp Order Apoda - Caecilians 163 spp From the Greek - Amphibios - leads two lives Ectothermic vertebrates with aquatic, gilled larval stage and terrestrial adult stage. All possess glandular skin and lack nails or claws. Kingdom - Animalia Phylum - Chordata Subphylum - Vertebrata Class - Amphibia Order Caudata - Salamanders 390 spp Order Anura - Frogs and Toads 4000 spp Order Apoda - Caecilians 163 spp

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7 II. EVOLUTION Evolved from Lobe-finned fishes common in Devonian Period mya During Devonian, sea levels rise and fall repeatedly; coastal area swamps flood and dry many times. Characteristics –Lungs –Some possessed true internal nares –Fins supported by bony elements Evolved from Lobe-finned fishes common in Devonian Period mya During Devonian, sea levels rise and fall repeatedly; coastal area swamps flood and dry many times. Characteristics –Lungs –Some possessed true internal nares –Fins supported by bony elements

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10 II. EVOLUTION Amphibians diverse by close of Devonian mya Key evolutionary traits/adaptations Most return to water to breed - aquatic larvae have gills Moist skin aids in respiration Improved circulatory system Toxic skin glands offer protection Sensory regions of brain processing vision,hearing,balance expanded compared to fishes Locomotion - salamanders less efficient; anurans capable of hopping, jumping, become most successful group Amphibians diverse by close of Devonian mya Key evolutionary traits/adaptations Most return to water to breed - aquatic larvae have gills Moist skin aids in respiration Improved circulatory system Toxic skin glands offer protection Sensory regions of brain processing vision,hearing,balance expanded compared to fishes Locomotion - salamanders less efficient; anurans capable of hopping, jumping, become most successful group

11 III. ECOLOGICAL IMPORTANCE In many moist, terrestrial habitats, amphibians may be the most important links in the food chain amphibians may exceed in numbers and biomass each of other vertebrates annual production of new tissue exceeds birds, mammals Salamanders in NE had densities of 7-10/sq m; 2X biomass of breeding birds, same as small mammals In Michigan marsh, amphibians most important 2nd and 3rd level consumers in food chain In Texas, standing crop of Lesser Siren greater than that of total of 7 species of fish in same habitat In many moist, terrestrial habitats, amphibians may be the most important links in the food chain amphibians may exceed in numbers and biomass each of other vertebrates annual production of new tissue exceeds birds, mammals Salamanders in NE had densities of 7-10/sq m; 2X biomass of breeding birds, same as small mammals In Michigan marsh, amphibians most important 2nd and 3rd level consumers in food chain In Texas, standing crop of Lesser Siren greater than that of total of 7 species of fish in same habitat

12 III. ECOLOGICAL IMPORTANCE Amphibians are the primary vertebrate predators on small invertebrates in many freshwater and moist terrestrial environments A small pond population of cricket frogs (Acris crepitans) estimated to consume ~ 4.8 million arthropods/yr Amphibians are major conveyor belt of energy transfer from arthropods to other vertebrates Amphibians have low metabolic rates, slow maturation and are relatively long-lived, thus serving as energy reservoir for ecosystems Amphibians are the primary vertebrate predators on small invertebrates in many freshwater and moist terrestrial environments A small pond population of cricket frogs (Acris crepitans) estimated to consume ~ 4.8 million arthropods/yr Amphibians are major conveyor belt of energy transfer from arthropods to other vertebrates Amphibians have low metabolic rates, slow maturation and are relatively long-lived, thus serving as energy reservoir for ecosystems

13 IV. FOOD HABITS Most adults are carnivorous - feeding on a variety of live animals - anything they can swallow! Larvae mostly herbivorous - algae, plant material, debris Tongues of many species can be extended well beyond opening of mouth Sticky pad impacts on, adheres to and pulls in prey Action is so fast - 10 msec - as to be nearly undetectable by human eye Most adults are carnivorous - feeding on a variety of live animals - anything they can swallow! Larvae mostly herbivorous - algae, plant material, debris Tongues of many species can be extended well beyond opening of mouth Sticky pad impacts on, adheres to and pulls in prey Action is so fast - 10 msec - as to be nearly undetectable by human eye

14 V. VOCALIZATIONS Male anurans use ADVERTISEMENT CALLS to attract females Vocal sac(s) modify, amplify sound as air forced from lungs over larynx Call intensity varies with species - audible from several yards to over a mile. SPL: dB Energetically expensive - O 2 consumption up 4-7X Intensity may be related to spacing of local males Male anurans use ADVERTISEMENT CALLS to attract females Vocal sac(s) modify, amplify sound as air forced from lungs over larynx Call intensity varies with species - audible from several yards to over a mile. SPL: dB Energetically expensive - O 2 consumption up 4-7X Intensity may be related to spacing of local males

15 PseudacrisBufo Rana Anuran Distended Vocal Sacs

16 V. VOCALIZATIONS Chorus Formation Advertisement calls first attract other males, then females Calls often alternated when males close to each other Tendency to call in groups of 2-4 with “choir master” always initiating, each with noticeably different quality Dominant males call louder, longer, lower pitched - may reflect age, size, vigor - all factors in female selection Chorus Formation Advertisement calls first attract other males, then females Calls often alternated when males close to each other Tendency to call in groups of 2-4 with “choir master” always initiating, each with noticeably different quality Dominant males call louder, longer, lower pitched - may reflect age, size, vigor - all factors in female selection

17 V. VOCALIZATIONS Warning Calls/Release Calls Vocalizations cease or are modified under threat of predation Fright calls often given before jumping into water Release, distress calls given if anuran grabbed by wrong sex or if captured by predator Warning Calls/Release Calls Vocalizations cease or are modified under threat of predation Fright calls often given before jumping into water Release, distress calls given if anuran grabbed by wrong sex or if captured by predator

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