Vertebrates 2

Question 1

Can amphibians live on land?

Answer 1

Yes amphibians can lay on land however they have to go back into the water to lay their eggs

Question 2

Why did fish move to land from the water?

Answer 2

1. Devonian droughts (shallow waters, low dissolved O2)
2. Increased competition in water(no predators on land)
3. New food resources on land(plants, arthropods)

Question 3

Differences between land and water?

Answer 3

Water:
- float(water is dense)
-less UV radiation
-Stable temperature
Land:
-Gravity (skeleton needs to be strong to hold you up)
-Less moistures
-More oxygen
-Temperature is a lot less stable on land

Question 4

Advantages of terrestrial respiration

Answer 4

-Gasses diffuse faster through air
-Air has a higher concentration of oxygen than water

Question 5

Lung evolution

Answer 5

-Precursors to lungs came from lobed-fish
-Swim bladder evolved as a connection to the gut
-Lungs evolved off a projection of our gut

Question 6

Why do humans choke?

Answer 6

The pathway for air and food go together for a while making it easier to choke. The pathway for air and go together for awhile because the lungs developed off a projection of our gut

Question 7

Problems that amphibians had on land

Answer 7

1. Amphibians needed to stay moist and needed water for fertilization and larval development
   2.Air is less dense than water, amphibians needed to evolve stronger skeletons in order to support themselves and needed more energy/muscles to move around

Question 8

Early Tetrapod

Answer 8

Tiktalik

Question 9

How did the first tetrapods fight gravity?

Answer 9

1. Stronger limbs, girdles, ribs and vertebral columns
2. Tail was used for balance
3. Lungs were the primary respiratory organ
4. Had external and internal nostrils(allows for more O2 to be brought in which is needed when expending more energy)

Question 10

How many chambers does the amphibians heart have?

Answer 10

-Amphibians heart has 3 chambers which causes mixing between oxygenated and deoxygenated blood

Question 11

How is blood pumped throughout amphibians bodies?

Answer 11

-Heart contracts pushes deoxygenated blood to the lungs, the blood moves back to the heart where it is repressurized

Question 12

Negative pressure breathing(how humans breathe)

Answer 12

Diaphragm starts up and then goes down increasing the volume of our lungs, when the volume increases the pressure goes down within the lungs which creates a pressure differential from inside the lungs and the air out outside. Oxygen moves to low pressure areas and goes into lungs. To get the oxygen out the diaphragm goes back up making the lungs have higher pressure than the air.

Question 13

Positive pressure breathing in amphibians(2 step process)

Answer 13

1. Amphibians close the glottis and mouth, increase the volume of the mouth by lowering the mouth, this creates lower pressure than the air and then sucks air in through the nostrils .
2. Nostrils close, glottis opens and air is forced into the lung

Question 14

Amphibian Larvae vs adults

Answer 14

Larvae(similar to fish):
- Many live in water
-2 chambered heart
-Gills

Adults:
-3 chambered heart
-Can live on land
-Lungs

Question 15

Types of amphibians

Answer 15

Salamander, newts, frogs, toads, caecilians

Question 16

Parental investment strategies(2)

Answer 16

1. Produce billions of offspring and provide no care and hope some will survive
2. Produce 1 offspring care for it until it matures (humans)