Exam 4 Ch 17

Question 1

List the 9 stages of the life cycle of frogs

Answer 1

external fertilization (male clasps female)
eggs surrounded by jelly coats
cleavage
embryo nourished by yolk
tadpole begins feeding on algea
Skinfold grows over external gill, water exits through spiracle
Hindlimbs, then forelimbs emerge
tail shortens by reabsortion, metamorphosis nears completion
Sexually mature frog at 3 years

Question 2

Eutstenopteron had what characteristics as evident from fossil records?

Answer 2

it had both lungs and walking fins

Question 3

Titaalik had what characteristics as evident from fossil records?

Answer 3

it could push itself up, had bones, and had the beginnings of a neck

Question 4

Acanthostega had what characteristics as evident from fossil records?

Answer 4

it had an enlarged, muscular tail and clearly formed digits in forelimbs and hindlimbs. `

Question 5

Icthyostega had what characteristics as evident from fossil records?

Answer 5

it had bulky limbs, a rib cage for protection that extended all the way down and stronger vertebrae allowing it to walk on land.

Question 6

Aquatic characteristics that were exapted for land use include…

Answer 6

the swim bladder (air filled cavity) became lungs

paired internal nares (nostrils) connected to pharynx and allowed oxygen to reach the air-filled cavity

Question 7

what is exaptation?

Answer 7

forming a new purpose for an existing structure.

Question 8

What characteristics are common in tetrapods?

Answer 8

skull
teeth
pectoral girdle
backbone
muscle support
ribs
modified ear structures

Question 9

What is an ectotherm?

Answer 9

an animal who receives heat from the environment

Question 10

In what three ways are Amphibians water dependent?

Answer 10

reproduction often occurs in water
larvae depend on gills
Their thin skin is effected rapidly by environmental changes making it prone to disease, toxins, etc.

Question 11

Explain the diversity of amphibians.

Answer 11

there are 6000+ species in three amphibian orders

Question 12

What percentage of amphibian species are in decline, worldwide?

Answer 12

40%

Question 13

What three adjustments occurred as life transitioned from water to land?

Answer 13

Density of air was lighter than water
Temperature fluctuations were greater on land than in water
More oxygen was available on land than in water

Question 14

With glandular skin, why are poison glands in most species not a concern for humans?

Answer 14

they are predator specific and not lethal, but taste bad so the predator will spit them out.

Question 15

What is Chythrid fungus?

Answer 15

most lethal infection of frogs. it si dermal necrotic, aagressive, and extremely contagious.

Question 16

True or false. Some species of frogs only exist in labs thanks to Chythrid fungus.

Answer 16

True.

Question 17

What is aposematic coloration?

Answer 17

Warning coloration

Question 18

Order Gymnophiona has the following characteristics:

Answer 18

1. Elongate, limbless, burrowing
2. many vertebrae
3. no limbs
4. eat worms and small invertebrates
   also have reduced/absent eyes

Question 19

In Order Gymnophiona, explain reproductive characteristics discussed in lecture.

Answer 19

1. internal fertilization
2. eggs deposited in moist ground near water and guarded
3. larvae development occurs in eggs

Question 20

In Order Urodela, what are two general characteristics discussed in lecture?

Answer 20

most have aquatic larvae and are terrestrial in adult form

Carnivorous larvae and adults

Question 21

In Order Urodela, what are the respiration characteristics discussed in lecture?

Answer 21

vascular skin

external gills, lungs, both or neither (diffusion)

Question 22

True or false. In order Urodela, young typically hatch with lungs which are lost during metamorphosis.

Answer 22

False.

Question 23

Name 2 characteristics we learned about in lecture in regard to Order Urodela and breeding behavior.

Answer 23

1. eggs/larvae stage require water

2. internal fertilization in most (female picks up spermatophore w vent/cloaca.)

Question 24

What is paedomorphosis?

Answer 24

Failure to complete metamorphosis. These animals retain gills and fin-like tail. (Order Urodela)

Question 25

in regards to Order Anura, what five characteristics were discussed in lecture?

Answer 25

1. must live near water
2. reproduction requires water
3. water-permeable skin
4. All have tailed larval stage and tailless jumping adults
5. there are 54 families, including Ranidae, Hylidae, and Bufonidae.

Question 26

What two Anura tricks did we discuss in lecture?/

Answer 26

winter hibernation

different reproduction strategies

Question 27

amplexus is what in frogs?

Answer 27

hugging motion that uses the male toe pad to hang onto the female partner during fertilization.