gas exchange other

Question 1

what can effect exchange surfaces?

Answer 1

volume - increase layers of cells, shorter diffusion pathway
level of activity - very active animals require more oxygen and nutrients as they need more energy

Question 2

what is the gas exchange like in an amoeba (unicellular organism)?

Answer 2

simple diffusion across phospholipid bilayer
large SA:V
thin cells so short diffusion pathway
pseudopodia

Question 3

what is the gas exchange like in a flatworm (small multicellular organism)?

Answer 3

large SA:V
permeable surface
thin and flat
simple diffusion across skin
no haemoglobin

Question 4

what is the gas exchange like in an earthworm (small multicellular organism)?

Answer 4

simple diffusion across skin
outer layer secretes mucus (moist and thin)
slow moving so low metabolic rate
has closed circulatory system with haemoglobin as simple diffusion is not enough

Question 5

what is the gas exchange like in a vertebrate?

Answer 5

need to conserve water so moist for diffusion
thin and permeable
large surface area

Question 6

what is the gas exchange like in an amphibian?

Answer 6

larvae - gills
adults - moist and permeable skin, well developed capillary network, lungs

Question 7

what is the gas exchange like in birds?

Answer 7

need large volume of oxygen due to flight
lungs (no diaphragm)
counter current exchange in blood system

Question 8

how do birds breathe?

Answer 8

breathes in
air moves into rear air sacs
expels air into lungs, through lungs, into front air sacs
air expelled by sacs as bird breathes out