Lecture 9 RH - Amphibians Flashcards Preview

Animal Diversity > Lecture 9 RH - Amphibians > Flashcards

Flashcards in Lecture 9 RH - Amphibians Deck (45)
1

What are the defining features of phylum chordata?

Dorsal, hollow nerve cord

Notochord

Pharyngeal slits

Postanal tail

2

What is the distinguishing feature of all vertebrates?

The brain case

3

What is the reasoning behind the brain case being the distinguishing feature between hagfishes and lampreys?

Hagfishes don't have vertebrae but lampreys do. They are both vertebrates nevertheless

4

Where did the amphibians and primitive amniotes arise from?

From the early tetrapods of the devonian period

5

Is the tetrapod clade mono, para, or polyphyletic?

Monophyletic

6

Where do all 5 chordate traits appear?

During embryonic life

7

Why are some reptiles, birds, and mammals living in water?

Due to secondary adaptations to aquatic life

8

What appeared in sarcopterygii?

Lungs

Tetrapod limbs

9

What are sarcopterygii?

Lobe-finned fishes

10

How do air breathing fishes use air to breathe?

Air breathing fishes gulp air and store it in a pocket of the oesophagus.

11

Where did the lungs arise from in lunged fishes?

The lung formed from an outpocketing of the oesophagus

12

How did tetrapod limbs arise?

Tetrapod limbs arised in a lineage of lobe-finned fishes in the devonian period 400mya

13

What do the transitional species between fish and tetrapods show?

The transitional limbs, skull, neck, ribs, etc.

14

What is the skeleton of amphibians made of?

Strong bony skeleton

15

How many limbs and digits do amphibians have?

4 limbs and 4 digits per limb

16

What does amphibian skin feel like?

Smooth and moist

17

How do amphibians respire?

Lungs, skin, and/or gills

18

Are amphibians homeothermic or poikilothermic?

They are ectothermic and poikilothermic

19

How does fertilization happen in amphibians?

External fertilization in toads and frogs.

Internal fertilization in caecilians and salamanders

20

Do amphibians have a cloaca?

Yes

21

How are amphibians adapted to both terrestrial and aquatic life?

Most live close to water for some part of the life cycle (for example reproduction in toads and frogs)

Aquatic larvae with gills rely on living in water to survive

Respiration across skin that must be kept moist

22

What is the double circulation system of tetrapods?

2 circuits of blood delivery:

Pulmonary circulation

Systemic circulation

23

What variation of the double circulation system exists with amphibians?

Amphibians have a 3 chambered heart.

Septum between atria is absent in lungless salamanders

Septum is complete in anurans

24

How do amphibians breathe?

Amphibians use positive pressure to force air into the lungs.

1) Lowering of mouth floor draws air through nostrils.

2) Nostrils are closed

3) Floor of mouth is raised forcing air into the lungs

25

What are the kind of amphibians in order gymnophiona?

Caecilians - 173 species

26

How many limbs do gymnophiona have?

no limbs

27

What do gymnophiona look like?

No limbs

Small or no eyes

Mesodermic scales in skin

28

Where do gymnophionas live?

Burrow in tropical forest soil and ponds.

29

What do gymnophionas eat?

Worms and small invertebrates

30

How do gymnophionas reproduce?

Some lay eggs and guard those eggs

Some are viviparous

31

What kind of amphibians are urodela?

Mostly salamanders and newts - about 550 species

32

What are the anatomical features of urodela?

Made up of a body which consists of a head, trunk, and tail.

Limbs are at a right angle with the body

Most are less than 15cm long but can be up to 1.5m long

33

What do urodela eat?

Carnivorous as larvae and as adults.

They eatworms, small arthropods, and molluscs

34

Is fertilization internal or external in urodelas?

Internal

35

How does fertlization take place in urodelas?

Spermatophore is deposited inside of the female.

Aquatic species lay eggs

Terrestrial species have direct development

36

What is paedomorphosis?

An evolutionary change in which larval features of an ancestor are retained to adulthood in the descendent.

*The Axolotl is a salamander that retains larval gills and aquatic habit as an adult

37

What kind of animals are contained within order anura?

Frogs

Toads

*Over 5200 species in 44 families

38

What are the clear differences between toads and frogs?

Toads have thicker skin

Toads are more terrestrial

39

What mode of reproduction do anurans have?

External fertilization fertilizaed eggs develop into tadpoles. Tadpoles are herbivorous and adults are carnivorous

40

What is the breeding and life cycle of frogs?

1) Sexually mature at 3 years of age.

2) Male clasps female and eggs are released as well as sperm

3) Eggs are surrounded by jelly coats

4) Fertilized eggs are cleaved

5) Embryo is nourished by yolk

6) Tadpole feeds on algae

7) Skinfold grows over external gil. Water exits through spiracle

8) Hindlimbs and then forelimbs emerge

9) Adult forms when tail shortens

41

What are some adaptations for frogs' breeding and life cycle?

Some frogs have dorsal brooding pouches. Eg. male pouched frog in NSW and QLD.

Female gastric breeding frogs (QLD) brood tadpoles in their stomach.

Water-holding frog burrows during drought and creates water tight cocoon from shed skin, holds water of 1/3 body weight in bladder

42

What is happening to anurans today?

Worldwide, frog populations are declining, becoming patchy, and going extinct

43

What are some possible causes of declining frog populations?

Habitat loss

Climate warming

Acid rain

Increased UV (lowering wter levels expose eggs to more UV)

Disease

Pollution

Displacement by introduced species (eg cane toads)

Harvest by humans for their skin or meant

44

What kind of grouping are amphibians?

Monophyletic. Common ancestor is believed to be bony fish (osteolipis)

45

Which amphibian orders are sister taxa?

Gymnophiona and urodela