gas exchange in small animals Flashcards
amoeba:
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
what is the gas exchange surface of amoeba ?
cell membrane
what is the diffusion path in ameoba like?
it is short as it is a short distance ot the centre of cell
what is the SA:V ratio in flat worms?
high SA:V ratio as they are lonf and flat but smaller ratio than ameoba
what type of organism is flatworm?
multicellular
what is the diffusion path of flatworms like?
they have a flattened body which shortens the diffusion pathway to the centre of the body
so they have a short diffusion pathway
what is the gas exchange surface of flatworm?
external body surface
why do flatworms not need a specialised exchange surface?
their shape allows them to gain sufficient oxygen fast enough to meet their needs over the surface
what type of organisms are earthworms?
terrestrial
multicellular
what is the SA:V in earthworms?
due to their long cylindrical shape they have a high SA:V
what is the diffusion gradient like in earthworms?
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
what is the gas exchange surface of earthworms?
external body surface
what is the diffusion path like in earthworms?
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
in earthworms what pushes blood around dorsal and ventral blood vessels?
5 pseudo hearts
what do the 5 pseudo hearts do?
pushes blood around dorsal and ventral blood vessels
what type of organism is an adult amphibia?
aquatic and terrestrial
what type of organism is a tadpole amphibia
aqautic
what is the life cycle of amphibia?
spawn
tadpole
adult amphibia
what is the gas exchange surface of adult amphibia?
thin moist skin
how does amphibia get its oxygen supply when resting state?
a closed circulatory system containing blood with haemoglobin transports oxygen to tissues
how does amphibia get its oxygen supply during activity?
uses primitive lungs
this increases SA for gas exchange
lungs are internal which reduces water loss and heat loss
how do tadpole of amphibia get its oxygen supply?
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
why do tadpoles of amphibia have a large SA?
gills give a large SA
what is the diffusion pathway in tadpole amphibia?
short diffusion pathway between water and gills
