Chapter 19: Amphibians rth-new-amphibians-emerge-in- colombia.html.
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Transcript of Chapter 19: Amphibians rth-new-amphibians-emerge-in- colombia.html.
Chapter 19: Amphibians
http://news.discovery.com/videos/earth-new-amphibians-emerge-in-colombia.html
Amphibians
• Include frogs, toads, salamanders, and caecilians
• Tetrapods: 4 muscular limb and feet with toes and fingers
Order Caudata
• Possess a tail throughout life• Both pairs of legs are
unspecialized• Live in moist forest-floor
litter • Have aquatic larvae• Many live in caves• Lay eggs on land• Spend most of their lives in
water and retain caudal fins• Internal fetilization
Salamanders
• Males produce a pyramidal gelatinous spermatophore that is capped with sperm and deposit it on a substrate
• Females pick up the sperm cap and store the sperm in a pouch called the spermatophore
• Eggs are fertilized as they pass through the cloaca and deposited singly, in clumps or in strings
Giant Salamanders
• The largest amphibians• Can be up to 5.9 ft long• Lay eggs in strings of
200• Eat insects, frogs,
invertebrates• http://news.discovery.c
om/videos/animals-japanese-giant-salamander.html
Axolotl: endangered salamander
• Found in Mexico• Lives entire life in water
so it retains its gills into adult hood
California Tiger Salamander
• Live in Northern California
• Eats earthworms and other invertebrates
• Spends most of its life on land but returns to aquatic environments to breed
• Endangered due to loss of habitat and non-native predation
Order Gymnophiona (Apoda)
• Caecilians• Wormlike burrowers that
feed on worms and other invertebrates in soil
• Appear segmented• Retractile tentacles between
their eyes and nostrils may transport chemicals from their environment to olfactory cells in the roof of the mouth
• Skin covers their eyes
Caecilians
• Internal fertilization• Larval stages are in the
oviduct where they scrape the inner lining of the oviducts with fetal teeth to feed
• Young emerge as miniature adults
Order Anura
• 4,000 species of frogs and toads
• Live in moist environments
• Adults lack tails and caudal vertebrae fuse into a rodlike structure called the urostyle
• Hindlimbs are long and muscular and end in webbed feet
Anurans continued
• Fertilization is external• Eggs and larvae are
usually aquatic• Larval stages-tadpoles• Larvae are herbivores
Frogs vs. Toads
Frogs• Smooth slimy skin• 2 bulging eyes• Strong, long webbed feet
used for leaping and swimming
• Lay eggs in clusters• Found on every continent
except Antartica
Toads• Stubby bodies with short
hind legs used for walking• Warty and dry skin• Lay eggs in long chains• Found worldwide except in
Australia, polar regions, Madagascar and Polynesia
Poison Dart Frogs
• Live in warm humid habitats
• Eat small insects• Poison cannot
permeate through a humans skin but if it gets into the body then it is deadly
Strawberry Poison Dart Frog
• Eats arthropods• Use external
fertilization• Care for one clutch at a
time (4-6 tadpoles)• Female lays eggs on a
leaf and the male makes sure they stay hydrated
Cane Toad
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/toad_cane.html
• Possess poisonous glands and its tadpoles are poisonous if ingested
Northern Leopard Frog
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_northern_leopard.html
Misc. videos
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_strawberrypoisondart_tadpole.html
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_waterholding.html
• http://video.nationalgeographic.com/video/player/animals/bugs-animals/spiders-and-scorpions/spider_fishing_eats_frog.html
Red-eyed tree frog
• http://video.nationalgeographic.com/video/player/news/animals-news/red-eyed-tree-frogs-shaking-vin.html
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_greentree_lifecycle.html
Support and movement• Water buoys and supports
aquatic animals• Skeletons protect internal organs
and provide attachments for muscles and keep the body from collapsing during movement
• Have powerful muscles to propel themselves across land
• Skull is flattened and light so it can support itself out of water
• Vertebral column provides support and flexibility
• Zygapophyses prevent twisting
Support and movement cont
• Salamanders uses undulating movements
• Ceacilians uses accordion like movements
• Long hindlimbs of frogs and toads are modified for jumping
Locomotion
• http://video.nationalgeographic.com/video/player/news/animals-news/frog-muscle-study.html
External structure
• Skin lacks a covering of scales, feathers or hair
• Highly glandular• Secretions aid in protection• Glands keep skin moist• Produce sticky secretions
that help a male cling to a female during mating and produce toxic chemicals that discourage potential predators
External structure
• Possess glandular secretions that are toxic to varying degrees
• Chemicals are secreted when the amphibian experiences stress
• Chromatophores are specializes cells that are responsible for skin color and color changes
Nutrition and digestion
• Carnivores• Bullfrog: preys on small
mammals, birds and other anurans
• Main factors that determine diets are availability and prey size
• Salamanders: use jaws to capture prey
Nutrition and Digestion
• Use tongues to capture prey
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_bull.html
Circulation
• Separation of pulmonary and systemic circuits
• When submerged blood is highly oxygenated. BV to the lungs constrict, reduce blood flow to the lungs and conserve energy
Gas Exchange
• When submerged it takes place across the skin
• Skin is moist and has a lot of capillary beds
• Cutaneous respiration: exchange across the skin
• Buccopharyngeal respiration: exchange across moist surfaces
Gas Exchange
• Most amphibians possess lungs
• Lungs of anurans are subdivided increasing surface area
• Buccal pump: muscles of the mouth and pharynx create a positive pressure to force air into the lungs
• Increase in temp, increase in activity, increase in lung activity
• Larvae use gills
Temperature Regulation
• Ectothermic• When submerged, they
are the same temp as the water but on land they can be different temps than their environment
• Many are nocturnal
• Critical temperatures– Salamanders: -2 to 27
degrees Celsius– Anurans: 3-41 degrees
Celsius
Nervous and Sensory Functions
• Forebrain: regions that regulate color change
• Midbrain: visual sensory information and motor responses
• Hindbrain: motor coordination, regulates heart rate and respiration
Nervous and Sensory Functions
• Sensory receptors on skin
• Lateral line: responds to low frequency vibrations in the water
• Most important sense is vision
• Nicitating membranes: movable eyelids
• Tympanic membranes• Middle ear• Inner ear• Semicircular canals
Excretion and Osmoregulation
• Kidneys– Water: produce large
amounts of urea
• Freshwater: ammonia• Land: urea• Must conserve water on
land• Skin absorbs water
Reproduction, Development and Metamorphosis
• External fertilization• Amplexus: male
releases sperm as female release eggs– Can last 1-24 hours
Reproduction
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_mudpuddlemate.html
• http://video.nationalgeographic.com/video/player/animals/amphibians-animals/frogs-and-toads/frog_tadpole_development.html
Vocalization
• Used to attract mates• https://
www.youtube.com/watch?v=PY61G2hXhXI
Parental Care
• http://video.nationalgeographic.com/video/frog_strawberrypoisondart_tadpole
• https://www.youtube.com/watch?v=LFTMgaZyVSA
Metamorphosis
• https://www.youtube.com/watch?v=jR0EPHyo128