Amphibians, Tetrapods Flashcards
What are tetrapods?
Gnathostomes with limbs and four limbs.
What is the function of the pelvic girdle in tetrapods?
Fused to backbone, transfers weight to legs and feet, aids movement on land.
What is a key feature of the neck in tetrapods?
Single cervical vertebrae allows up and down movement of head.
What do tetrapods lack that is found in their aquatic ancestors?
No gill slits; pharyngeal clefts develop into ears in adults.
When did the earliest tetrapods appear?
During the Devonian period.
What is Eusthenopteron?
An early tetrapod that lived 385 million years ago, lobe-finned and pelagic.
What transitional features does Panderichthys have?
Tetrapod-like head; lived around 380 million years ago.
Where was Tiktaalik discovered and what are its characteristics?
Found in the Canadian Arctic; has fish characteristics (scales, fins, gills, lungs) and tetrapod characteristics (neck, ribs, flat head, wrists, shoulders, ear notches).
What significant transition do tetrapods undergo?
Progression from aquatic to terrestrial lifestyles.
What is Acanthostega known for?
Found in Greenland; has groove on gill arches suggesting it might be an aquatic animal; has 8 toes per foot.
What are the characteristics of Ichthyostega?
Has robust limbs, primarily lungs for breathing, and 7 toes per foot.
What physical change occurs in terrestrial life compared to aquatic life?
Less support for body weight due to lower water density.
How does chemical regulation change for terrestrial organisms?
Loss of salt and water necessitates more regulation; higher O2 levels mean faster aerobic metabolic rates.
What temperature-related changes do terrestrial organisms face?
Temperatures change rapidly and are more extreme.
How many modern groups (orders) are in Class Amphibia?
Three groups: Apoda, Urodela, Anura.
Name the three modern groups of amphibians.
- Apoda – caecilians
- Urodela – newts and salamanders
- Anura – frogs and toads
What are the stages of the amphibian life cycle?
- Larvae – aquatic, herbivorous, gills, lateral line, long tail
- Adult – terrestrial, carnivorous, gills & lateral line replaced by lungs/skin and ears
What is a unique feature of Apoda (Gymnophiona)?
Legless, burrowing or aquatic, eyes covered by skin or bone.
What reproductive strategies do Urodela exhibit?
Mostly internal fertilization; can be viviparous, oviparous, or ovoviviparous.
What adaptations do Anura have for jumping?
Fused tibia and fibula, elongated metatarsals, elongated and fused pelvic bones.
What methods do amphibians use for respiration?
- Gills – tadpoles and salamanders
- Skin – most
- Lungs – most (anurans and newts)
What is the buccal pump process in amphibians?
A method of respiration involving expansion and contraction of the buccal cavity.
Describe the skin of amphibians.
Delicate, no scales, permeable, well vascularized for respiration.
What types of glands are found in amphibian skin?
- Mucous
- Lipid waterproofing
- Pigment
- Poisons/toxins
- Antibiotics
