8.8 Gas ecxchange in insects COPY Flashcards
What type of organism are insects
- Most are terrestial
- Many live in arid habitats
Do insects have a large or small surface area to volume ratio
small surface area to volume ratio
What is required for efficient gas exchange in terrestial organisms e.g. insects
- Efficient gas exchange required
- Thin permeable surface
- With a large surface area
- Which conflicts with the need to conserve water
What is one of the challenges which terrestial organisms e.g. insects face
- Water evaporates from their body surface
- There is a risk of dehydration
How does the way insects have adapted for efficient gas exchange conflict with their need conserve water
Efficient gas exchange required
Thin permeable surface
With a large surface area
What can also result in a loss of fluid causing dehydration
How do terrestial organisms overcome water loss?
- Some terrestial organisms
- have a waterproof layer around their body surface
- to prevent water loss
If an insect did not have an impermeable exoskeleton would it be able to exchange enough gasses by diffusion
- No
- Instead gas exchange occurs through paired holed along the side of the body, called spiracles
where does gas exchange occur
In an insect gas exchange occurs via paired holes along the side of the body known as spiracles
What do the spiracles lead into
A system
Of branched
Chitin lined air tubes
Tracheae
What to the tracheae branch into
Tracheaeoles
What is the role of the spiracles
What two things does a spiracle do
What is the role of spiracles in Gas exchange
What is the role of spiracles in the prevention of water loss
Gas enters spiracles when open
It travels down the tracheae
Into the tracheoles
Diffusion of gasses occur at the interface between the end of the tracheaeoles (which are fluid filled) and the muscle
The spiracles close to prevent water loss
Some insects have hair covering the spiracles which also help to prevent water loss and solid particles entering the system
What do insects rely on for diffusion when they are resting
Insects rely on diffusion through the spiracles, tracheae and tracheaeoles to take in oxygen and remove carbon dioxide
What do insects rely on for ventilation during periods of activity?
- During periods of activity
- e.g. flight
- Movements of the abdomen ventilate the tracheae
Where does gas exchange actually occur insects?
End of the tracheaeoles are fluid filled and close to the muscle fibres
The interface between tracheoeles and muscle fibres is where gas exchange takes place
How does gas exchange occur at the interface of tracheaeoles and muscle fibres
- O2 disoves in the fluid in the tracheaeoles
- And diffuses directly into the muscle cells
- No respiratory pigment or blood circulation is needed (C02 diffuses out by the reverse process)
