Amphibians 1 Flashcards Preview

Diversity of Life 2 > Amphibians 1 > Flashcards

Flashcards in Amphibians 1 Deck (13)
Loading flashcards...
1
Q

What are the 3 main lineages of amphibians?

A
  • Frogs & toads - anura
  • Salamanders - urodeles
  • Caecilians (snakes) - gymnophionans.
2
Q

Describe the stages of amphibian metamorphosis.

A
  1. Pre-metamorphosis: tadpole size increases.
  2. Pro-metamorphosis: hind legs appear, growth slows.
  3. Meta-morphic climax: forelegs emerge and tail regresses.
3
Q

What triggers and controls metamorphosis?

A

Controlled by hormones and associated receptors in response to environmental cues. Thyroid hormones are involved.
(Gundersnatch fed tadpoles thyroid hormones and they began to metamorphose)

4
Q

What are the shared derived characteristics of modern amphibians?

A
  • Smooth moist skin
  • Multiple respiration methods
  • Pedicellate teeth
  • Green rods
  • Operculum - Columella complex (hearing)
  • Levator bulbi muscle.
5
Q

Describe amphibian skin features.

A
  • Absence of bony/ keratinised scales
  • Absence of keratinised true claws
  • Mucus glands
  • Poison glands.
6
Q

Describe the multiple respiration methods in amphibians.

A
  • Cutaneous - gas exchange occurs across moist skin
  • Buccopharyngeal - gas exchange occurs in buccal cavity/ pharynx
  • Pulmonary - gas exchange occurs in paired lungs
  • Gills - larval forms and neotenics (neoteny - adults that retain juvenile characteristics).
7
Q

Describe blood circulation in amphibians.

A
  • 3 chambers
  • Right atrium - deoxygenated blood
  • Left atrium - oxygenated blood from the lungs and skin
  • Both atria empty into single ventricle
  • Left atrium blood sent to head via carotid arteries
  • Right atrium blood sent to skin and lungs to pick up more oxygen via pulmocutaneous arteries
  • Blood in aortic arches has been mixed and supplies rest of body.
8
Q

In what period did amphibians arise?

A

Devonian.

9
Q

What is the main environmental cue for metamorphosis?

A

Day length. 🌤

10
Q

Describe amphibian skeleton structure.

A
  • Skulls are flattened, relatively small and have fewer bones than water-dwelling animals
  • Vertebral column lost much flexibility to transmit force from limbs to body
  • Have pelvic girdle which attach pelvic appendages to vertebral column to provide support on land.
11
Q

What are Pedicellate teeth?

A

Crown and base separated by uncalcified dentine/fibrous tissue. May allow for flex of tooth for handling prey.

12
Q

What are green rods?

A
  • Present in frogs and salamanders

* Distinct type of retinal cell (photoreceptors).

13
Q

What is a levator bulbi muscle?

A
  • Muscle found beneath eye
  • Bulges eye forward and increases buccal activity
  • Used in breathing and swallowing.