gas exchange in small animals

Question 1

amoeba:

Answer 1

have a high SA:V
it is a small distance to the centre of the cell so diffusion path is short

by diffusion they can gain sufficient oxygen and glucose fast enough to sustain their metabolism and dont need specialised gas exchange surfaces becuase diffusion paths are short and have large SA:V

Question 2

what is the gas exchange surface of amoeba ?

Answer 2

cell membrane

Question 3

what is the diffusion path in ameoba like?

Answer 3

it is short as it is a short distance ot the centre of cell

Question 4

what is the SA:V ratio in flat worms?

Answer 4

high SA:V ratio as they are lonf and flat but smaller ratio than ameoba

Question 5

what type of organism is flatworm?

Answer 5

multicellular

Question 6

what is the diffusion path of flatworms like?

Answer 6

they have a flattened body which shortens the diffusion pathway to the centre of the body

so they have a short diffusion pathway

Question 7

what is the gas exchange surface of flatworm?

Answer 7

external body surface

Question 8

why do flatworms not need a specialised exchange surface?

Answer 8

their shape allows them to gain sufficient oxygen fast enough to meet their needs over the surface

Question 9

what type of organisms are earthworms?

Answer 9

terrestrial
multicellular

Question 10

what is the SA:V in earthworms?

Answer 10

due to their long cylindrical shape they have a high SA:V

Question 11

what is the diffusion gradient like in earthworms?

Answer 11

circulatory system maintains the gradient

as blood flows in blood vessels, earthworms have a closed circulatory system

blood has haemoglobin which has a high affinity for oxygen and transports the oxygen to tissue

Question 12

what is the gas exchange surface of earthworms?

Answer 12

external body surface

Question 13

what is the diffusion path like in earthworms?

Answer 13

the diffusion pathway from the surface to centre is too large for diffusion alone

blood vessels are close to the external surface of the earthworm so pathway from surface to blood is short

Question 14

in earthworms what pushes blood around dorsal and ventral blood vessels?

Answer 14

5 pseudo hearts

Question 15

what do the 5 pseudo hearts do?

Answer 15

pushes blood around dorsal and ventral blood vessels

Question 16

what type of organism is an adult amphibia?

Answer 16

aquatic and terrestrial

Question 17

what type of organism is a tadpole amphibia

Answer 17

aqautic

Question 18

what is the life cycle of amphibia?

Answer 18

spawn
tadpole
adult amphibia

Question 19

what is the gas exchange surface of adult amphibia?

Answer 19

thin moist skin

Question 20

how does amphibia get its oxygen supply when resting state?

Answer 20

a closed circulatory system containing blood with haemoglobin transports oxygen to tissues

Question 21

how does amphibia get its oxygen supply during activity?

Answer 21

uses primitive lungs
this increases SA for gas exchange
lungs are internal which reduces water loss and heat loss

Question 22

how do tadpole of amphibia get its oxygen supply?

Answer 22

gills which have a good capillary supply in close contact with water. haemoglobin has high oxygen affinity
gills gives a large SA
short diffusion pathway between gills and water

Question 23

why do tadpoles of amphibia have a large SA?

Answer 23

gills give a large SA

Question 24

what is the diffusion pathway in tadpole amphibia?

Answer 24

short diffusion pathway between water and gills