Lecture 5

Question 1

How did early tetrapods tend to be?

Answer 1

. Scales (like their Sarcopterygian fish ancestors)
. Superficially crocodile-like
. Non-amniotes tetrapods

Question 2

What are temnospondyls?

Answer 2

Sister group to modern amphibia (number of digits reduced to 5)

Question 3

When were most non-amniote tetrapods wiped out? But when did some survive until? When did the Lissamphibia (modern day amphibia (Lisa=smooth) diverge?

Answer 3

In Permian/ Triassic mass extinction (250mya) but some Temnospondyls survived until the early Cretaceous (130mya)
Lissamphibia (modern day amphibia) diverged from them in early Triassic

Question 4

What is cutaneous respiration?

Answer 4

Means they can take up oxygen across the skin, so not just reliant on lungs

Question 5

What is the only modern day amphibian that is associated with the marine environment?

Answer 5

The crab-eating frog (however it can only survive short periods in the marine environment, cannot live there)

Question 6

Why can’t modern day amphibians eat and breath at the same time?

Answer 6

Their lungs employ force pumps- they have no diaphragm and so to fill the lungs they have to force air in (like in the lung fish), this means that these animals cannot breath and eat at the same time

Question 7

What amphibians have gills?

Answer 7

Aquatic larvae and neotenic forms (some retain gills even in the adult form)

Question 8

Describe Urodela (salamanders and newts) (body shape, how many species, courtship)

Answer 8

. Unspecialised body form (probably most like the ancient amphibians)
. Undulate swimming (so have an undulate motion when on land walking)
. They have retained the tail
. Paedomorphosis common
. 400 species
. Troglodyty common (means many species live in caves)
. Precise courtship ritual for spermatophore transfer. Specialised reproduction e.g. could mean going back into the aquatic environment and broadcasting
. Example is a salamander or newt- has a very undifferentiated vertebral, has transverse processes but no ribs

Question 9

What does Troglodyty common mean?

Answer 9

Means many species live in caves

Question 10

What does an= and what does Uro= mean?

Answer 10

An= without 
Uro = tail

Question 11

Describe Anura (simply means without tail): frogs and toads (how many species, body shape/ features, skeleton)

Answer 11

. 3750 species
. Enlarged hind legs
. Urostyle (fused posterior vertebrae). Reduced vertebral column- few vertebrae
. Fast, powerful, hindlimb muscles
. Has an adapted skeleton to deal with the powerful muscles

Question 12

What does short, squat bones tend to suggest?

Answer 12

The attachment of large muscles

Question 13

Describe gymnophiona: caecilians (a rarer group of amphibians) (body form, where they live, reproduction)

Answer 13

. Legless and either burrowing in soil or aquatic
. Trophical Southern Hemisphere distribution
. Dermal scales (tend to have scales)
. Internal fertilisation
. Nests or viviparity (produce live young, get around having to use the aquatic environment or reproduce)
. Lost all external limbs

Question 14

Describe what the teeth of Lissamphibia (urodela, Anura, gymnophiona)/ modern day amphibia are like

Answer 14

. Pedicellate teeth- crown and vase dentine with uncalcified area in between
. The tooth has a crown and a pedicel. As the crown wears (but pedicel stays in the same place), it breaks off and is replaced by a new one

Question 15

Describe the amphibian skin/ the skim of modern day amphibia (Lissamphibia)

Answer 15

Moist (mucus) permeable skin, poison glands

Question 16

What are the two types of skin glands in the skin of modern day amphibians? Example why they are good/ explain the answer- give an example

Answer 16

. Mucous glands maintain moist skin for respiration
. Granular glands produce toxic secretions- making them distasteful and absolutely toxic to predators (protection for the animal against predation). Can be found all across or just in particular glands such as the paranoid gland in frogs and toads

Question 17

What is the type of skin gland that is only found in some species of amphibians? What is it for/ found in?

Answer 17

Hedonic gland produce pheromones used during courtship (only in males)

Question 18

The epidermis/ skin of amphibians is very thin/ minimal. Why is this? What is an issue with this?

Answer 18

This is linked to its role as a respiratory organ (for oxygen to diffuse across the skin you need as thin a layer as possible
The problem is that it is in danger as it is easily broken