1 / 30

Exchange and Transport in Living Organisms

This text provides an overview of the exchange of materials between organisms and their environment, including the need for specialized exchange surfaces. It also explores the thermal classification of animals and the adaptations they have evolved for regulating body temperature. Additionally, the text discusses the surface area to volume ratio and how it affects efficient exchange in small and large organisms. The topics covered include gas exchange in fish and insects, mammalian circulation, and the structure of blood vessels.

mollyc
Download Presentation

Exchange and Transport in Living Organisms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Y12 AS Unit 2

  2. GCE BIOLOGY specification • UNIT 1 BIOL1 BIOLOGY AND DISEASE 33.3% AS exam in Jan • UNIT 2 BIOL2 THE VARIETY OF LIVING ORGANISMS 46.7 % AS exam in June • UNIT3 INVESTIGATIVE AND PRACTICAL SKILLS IN AS BIOLOGY 20% AS exam in June

  3. 13 Exchange and Transport

  4. questions • What materials need to be exchanged between an organism and the environment • How are the materials exchanged ? • Do they have specialised exchange surfaces? • Why do they need them ?

  5. thermal classification of animals • Homoiotherms e.g. mammals and birds, regulate their body temperature close to a value 37-38 oC in mammals and 40oC in birds by controlling heat gain and loss

  6. Poikilotherms e.g. fish and reptiles allow their body temperatures to fluctuate with the temperature of the air or water around them

  7. But this is a bit simplistic

  8. Classification on the basis of their source of body heat • ENDOTHERMS animals which generate their own body heat e.g. mammals ,birds, a few large fish, flying insects. • ECTOTHERMS animal which depend almost entirely on the environment for their body heat . They regulate their body temperature by behavioural means

  9. Task sheet • Look at data and describe the patterns shown

  10. Surface area to volume ratio • Small organisms have a large surface area to volume ratio to allow efficient exchange across their body surface

  11. Surface area to volume ratio • Large organisms have a small surface area to volume ratio and simple diffusion would only meet the needs of inactive organisms

  12. Surface area to volume ratio To overcome this organisms have evolved 1 or more of these features: • A flattened shape • Specialised exchange surfaces with a large surface are to volume ratio E.g. gills, lungs.

  13. Exchange and Transport UNIT 2 • SA/Vol Ratio • Gas Exchange in fish • Gas Exchange in Insects • Mammalian circulation • Blood vessel structure • Exchange in the tissues

  14. SA/Vol ratio Objectives: • Understand how the size and structure (shape & design) of an organism affect it’s SA/Vol ratio • Know which features of exchange surfaces facilitate exchange (fick’s law) • Explain how larger organisms have evolved to overcome the problems caused by a small SA/Vol ratio

  15. Fick’s law Diffusion is proportional to surface area X difference in concentration length of diffusion pathway

  16. Gas Exchange in Fish

  17. http://www.biotopics.co.uk/pot/animals/fishcy.html

  18. Counter current flow

  19. Gas Exchange in Insects

  20. Main features of insect gas exchange • A large surface area due to extensive internal network of tracheoles which penetrate deep into tissues. Atmospheric air is brought directly to tissues • Small bodies allows diffusion pathway to be short. • Air diffuses 10 000 times more rapidly in air than in blood • Some species use muscle contraction to create mass movement of air in and out of tracheae (ventilation) • Note blood system has no respiratory pigments

  21. Insect has to balance • Needs of gas exchange • Need to conserve water and reduce water loss Therefore for much of the time spiracles are closed to prevent water loss

More Related