Zoology Notes Amphibians

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Zoology NotesAmphibians
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Quick Question 1
What are some major evolutionary changes between
fish and amphibians?
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Amphibian basics

• Definition moist, glandular skin that lacks
  scales of reptiles. Complex life cycles. Lay eggs
  that are non-amniotic.
• The smallest major group of vertebrates
• The transition in evolution from water to land
  (amphi means both, bio means life). First
  vertebrates to invade the land. 

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Tied to the water

• Larvae are aquatic - gills while adults are
  terrestrial - breath through lungs and skin
• Eggs have no shells (water prevents drying out).
• Sperm swim through water to fertilize eggs
• Skin must stay moist

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Not stuck in the water

• Have lungs instead of gills
• Have legs to support body weight
• Improved heart to help deliver needed oxygen to
  muscles.

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Quick Question 2
Explain in your own words how amphibians are the
adapted to land but still need water.
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Types of Amphibians

• Urodela Salamanders
• Anura Frogs and Toads
• Gymnophiona Caecilians

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Caecilians (Gymnophiona)

• Legless amphibians

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Salamanders (Urodela)

• Keep their tails even as adults to aid in
  swimming
• Some are fully aquatic, some live in moist
  environments, some switch back and forth
  throughout their life
• Can regenerate limbs

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Frogs and Toads (Anura)

• Frogs have moist, smooth skin and have large hind
  legs
• Toads have dry, bumpy skin and have short hind
  legs

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Quick Question 3
Quick write everything you know about the life
cycle of a frog
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Life Cycle
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How do they eat?

• Tadpoles are filter feeding herbivores
• Adult amphibians are almost entirely carnivorous
• Jaws or long, sticky tongues are used to catch
  prey
• http//www.youtube.com/watch?vwXqK5QulbJ8

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Digestion

• Mouth to esophagus to stomach.
• Stomach connects with the small intestine then
  large intestine.
• At the end of the large intestine is the cloaca,
  a muscular cavity that stores wastes until they
  are expelled.

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Respiration

• Through the mouth
• Through the skin
• Through gills or lungs
• Frogs can also pass air through expandable vocal
  cords

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Internal Transport

• Three chambered heart
• Improved heart to deliver more oxygen to walking
  muscles.
• Tadpoles have a two-chambered heart

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Quick Question 4
Compare and Contrast a fish heart and a amphibian
heart
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Excretion

• Use kidneys to eliminate wastes
• Urine travels through tubes called ureters into
  the cloaca

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Response How does it survive?

• Developed nervous system
• Really moveable eyes to detect moving insects
• Ears have no external sound collectors but can
  distinguish between calls
• Clawless, soft-skinnedso they may be toxic with
  warning colors

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Reproduction

• Oviparous with external fertilization
• Many have internal fertilization and are either
  oviparous, ovoviviparous, or viviparous

Amplexus
Male Midwife Toad
Surinam Toad
http//video.nationalgeographic.com/video/animals/
amphibians-animals/frogs-and-toads/frog_greentree_
lifecycle/
http//video.nationalgeographic.com/video/animals/
amphibians-animals/frogs-and-toads/frog_strawberry
poisondart_tadpole/