Chapter 21
Lesson Objectives <ul><li>At the end of the lesson, you should be able to </li></ul><ul><li>(a) briefly describe the non-c...
Definition: <ul><li>Ecology : the study of interactions between organisms and the physical and chemical factors making up ...
Terms to be familiar with <ul><li>Habitat : the place where an organism lives in </li></ul><ul><li>Population : a group of...
 
The World’s Major Land Biomes Tropical rain forest Tropical dry forest Tropical savanna Temperate woodland and shrubland D...
Abiotic and Biotic Factors Biotic Factors ECOSYSTEM Abiotic Factors - non living components of an ecosystem e.g. sunlight ...
Habitat: Mangrove swamp <ul><li>Biotic environment  </li></ul><ul><li>Plants </li></ul><ul><li>Mangrove trees, etc </li></...
Abiotic environment <ul><li>Salinity of sea water </li></ul><ul><li>pH </li></ul><ul><li>Temperature </li></ul><ul><li>Amt...
The Physical Environment
The Physical Environment <ul><li>Occurrence and distribution of plants and animals are determined by  </li></ul><ul><li>i)...
<ul><li>Why do some plants climb?   </li></ul><ul><li>Light intensity greater </li></ul><ul><li>A factor that affects dist...
2) Temperature <ul><li>Varies with seasonal changes </li></ul><ul><li>Affects physiological activities of plants and anima...
3) Water <ul><li>Adaptations of  xerophytes  to dry climate: </li></ul><ul><li>shed leaves (reduce transpiration) </li></u...
Other xerophytes…
Marram  grass <ul><li>a  species  of  perennial   grass   </li></ul><ul><li>used to prevent or stop  erosion  of  dune s <...
T.S. of marram grass leaf <ul><li>Adaptations of marram grass </li></ul><ul><li>Sunken stomata that lie in grooves on the ...
Casuarina <ul><li>Water loss reduced through </li></ul><ul><li>Leaves reduced to tiny sheaths at nodes </li></ul><ul><li>P...
Hydrophytes 3 types 1) Completely submerged e.g. hydrilla 2) Partially submerged e.g. water lily 3) Free floating e.g wate...
Hydrophytes (completely submerged) hydrilla fanwort
Hydrophytes (partially submerged) Cattail ( Typha latifolia )  Water lilies
Hydrophytes (free floating) water hyacinth duckweed
Adaptations of hydrophytes <ul><li>The presence of  little or no mechanical strengthening tissue in stems and leaf petiole...
Mangroves
Pneumatophores
4) Oxygen <ul><li>Aerobic organisms possess special adaptations for obtaining sufficient O 2  for respiration </li></ul><u...
5) Salinity Freshwater Seawater Low  water potential high  water potential H 2 O Lose water by osmosis Gain water by osmos...
<ul><li>Problems faced by freshwater fish: </li></ul><ul><li>excess water entering body cells </li></ul><ul><li>salt loss ...
Adaptations of marine fish <ul><li>Saltwater fish have slimy scaly skin (reduces rate of water loss) </li></ul><ul><li>Sec...
6) pH (of soil/water) <ul><li>Refers to the acidity or alkalinity of a solution </li></ul><ul><li>Changes in pH do occur e...
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Chapter 21 Ecology Lesson 1 - Biotic and abiotic factors

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Chapter 21 Ecology Lesson 1 - Biotic and abiotic factors

  1. 1. Chapter 21
  2. 2. Lesson Objectives <ul><li>At the end of the lesson, you should be able to </li></ul><ul><li>(a) briefly describe the non-cyclical nature of energy flow </li></ul><ul><li>(b) explain the terms producer , consumer and trophic level in the context of food chains and food webs </li></ul><ul><li>(c) explain how energy losses occur along food chains, and discuss the efficiency of energy transfer between trophic levels </li></ul>
  3. 3. Definition: <ul><li>Ecology : the study of interactions between organisms and the physical and chemical factors making up their external environment </li></ul><ul><li>Ecologists study both the </li></ul><ul><li>i) biotic (living environment) </li></ul><ul><li>– consists of all the living things that an organism interacts with </li></ul><ul><li>ii) abiotic (non-living environment) </li></ul><ul><li>- consists of physical factors e.g. light, water, pH of soil or water </li></ul>
  4. 4. Terms to be familiar with <ul><li>Habitat : the place where an organism lives in </li></ul><ul><li>Population : a group of organisms of the same species living in a particular habitat </li></ul><ul><li>Community : All the population of organisms living in a particular habitat </li></ul><ul><li>Ecosystem : is made up of a community and its physical/ abiotic environment </li></ul><ul><li>Biomes : distinct ecological communities of plants and animals living together in a particular climate </li></ul>
  5. 6. The World’s Major Land Biomes Tropical rain forest Tropical dry forest Tropical savanna Temperate woodland and shrubland Desert Temperate grassland Boreal forest (Taiga) Northwestern coniferous forest Temperate forest Mountains and ice caps Tundra
  6. 7. Abiotic and Biotic Factors Biotic Factors ECOSYSTEM Abiotic Factors - non living components of an ecosystem e.g. sunlight - the living components of the environment, such as plants, animals and fungi, that affect ecological functions.
  7. 8. Habitat: Mangrove swamp <ul><li>Biotic environment </li></ul><ul><li>Plants </li></ul><ul><li>Mangrove trees, etc </li></ul><ul><li>Animals </li></ul><ul><li>mud skippers </li></ul><ul><li>sand flies </li></ul><ul><li>monitor lizards </li></ul><ul><li>crabs </li></ul>
  8. 9. Abiotic environment <ul><li>Salinity of sea water </li></ul><ul><li>pH </li></ul><ul><li>Temperature </li></ul><ul><li>Amt. of dissolved O 2 in mud </li></ul><ul><li>Amt. of light available </li></ul><ul><li>Amt. of nutrients </li></ul>
  9. 10. The Physical Environment
  10. 11. The Physical Environment <ul><li>Occurrence and distribution of plants and animals are determined by </li></ul><ul><li>i) climatic (e.g. amt. of light, water, temperature) & </li></ul><ul><li>ii) topographical factors (physiogeographic characteristics of land in terms of elevation, slope, and orientation) </li></ul>
  11. 12. <ul><li>Why do some plants climb? </li></ul><ul><li>Light intensity greater </li></ul><ul><li>A factor that affects distribution and growth of plants & animals </li></ul><ul><li>Plants have adaptations to enable them to climb </li></ul>1) Light
  12. 13. 2) Temperature <ul><li>Varies with seasonal changes </li></ul><ul><li>Affects physiological activities of plants and animals (because enzymatic reactions affected) </li></ul><ul><li>Adaptations of some flowering plants: </li></ul><ul><li>Underground storage organs </li></ul><ul><li>Shedding of leaves </li></ul><ul><li>Forming seeds that are resistant to heat, drought or cold just before the seasons arrive </li></ul>
  13. 14. 3) Water <ul><li>Adaptations of xerophytes to dry climate: </li></ul><ul><li>shed leaves (reduce transpiration) </li></ul><ul><li>fleshy stems (store water) </li></ul><ul><li>green stems (able to photosynthesize) </li></ul>Xerophytes : plants which can live in conditions of prolonged drought in their habitat
  14. 15. Other xerophytes…
  15. 16. Marram grass <ul><li>a species of perennial grass </li></ul><ul><li>used to prevent or stop erosion of dune s </li></ul><ul><li>sand-binder and dune-builder </li></ul><ul><li>has shallow roots and a coarse, stiff structure </li></ul>
  16. 17. T.S. of marram grass leaf <ul><li>Adaptations of marram grass </li></ul><ul><li>Sunken stomata that lie in grooves on the upper surface </li></ul><ul><li>Spines (tiny hairs) </li></ul><ul><li>- discourage browsing animals </li></ul><ul><li>- trap water vapour diffusing out of the stomata (increases humidity around the stomata and reduces rate of transpiration) </li></ul><ul><li>3) Leaves roll up (reduces s.a exposed to surroundings when the leaves lose too much water) </li></ul>
  17. 18. Casuarina <ul><li>Water loss reduced through </li></ul><ul><li>Leaves reduced to tiny sheaths at nodes </li></ul><ul><li>Photosynthesis by long green stems whose stomata lie in grooves protected by minute hair </li></ul>
  18. 19. Hydrophytes 3 types 1) Completely submerged e.g. hydrilla 2) Partially submerged e.g. water lily 3) Free floating e.g water hyacinth
  19. 20. Hydrophytes (completely submerged) hydrilla fanwort
  20. 21. Hydrophytes (partially submerged) Cattail ( Typha latifolia ) Water lilies
  21. 22. Hydrophytes (free floating) water hyacinth duckweed
  22. 23. Adaptations of hydrophytes <ul><li>The presence of little or no mechanical strengthening tissue in stems and leaf petioles . They are normally supported by water all around them and so have no need of mechanical strengthening. </li></ul><ul><li>Lack the external protective tissues e.g. cuticle required by land plants to limit water loss </li></ul><ul><li>Have very specialized leaf shapes (often highly dissected or divided); creates a very large surface area for absorption and photosynthesis </li></ul><ul><li>Roots are reduced and main function is anchorage </li></ul><ul><li>Air-filled cavities often extend throughout the leaves and stems of aquatic plants, providing an internal atmosphere </li></ul>http:// www.countrysideinfo.co.uk/wetland_survey/adaptns.htm
  23. 24. Mangroves
  24. 25. Pneumatophores
  25. 26. 4) Oxygen <ul><li>Aerobic organisms possess special adaptations for obtaining sufficient O 2 for respiration </li></ul><ul><li>e.g. pneumatophores of mangrove (enable mangrove plants to breathe in O 2 -poor mud) </li></ul><ul><li>Fish are usually air breathers i.e. they come to the water surface to gulp air </li></ul>
  26. 27. 5) Salinity Freshwater Seawater Low water potential high water potential H 2 O Lose water by osmosis Gain water by osmosis H 2 O H 2 O H 2 O H 2 O H 2 O
  27. 28. <ul><li>Problems faced by freshwater fish: </li></ul><ul><li>excess water entering body cells </li></ul><ul><li>salt loss from cells </li></ul>Problems faced by marine fish: Water loss from cells Salts moving into cells from seawater
  28. 29. Adaptations of marine fish <ul><li>Saltwater fish have slimy scaly skin (reduces rate of water loss) </li></ul><ul><li>Secretion of salts into surroundings by cells in the gills </li></ul><ul><li>Kidney excretes salts and small amts. of water, producing highly concentrated urine </li></ul>Adaptations of freshwater fish <ul><li>Uptake of salts by cells in the gills </li></ul><ul><li>Kidney reabsorbs salts and produces large amts. of dilute urine </li></ul>
  29. 30. 6) pH (of soil/water) <ul><li>Refers to the acidity or alkalinity of a solution </li></ul><ul><li>Changes in pH do occur especially if the pH of water depends on the amt. of hydrogen carbonates / bicarbonates present in the water </li></ul><ul><li>During the day </li></ul><ul><li>Photosynthetic activity of the plants uses up the CO 2 in the water, making the water alkaline </li></ul><ul><li>During the night </li></ul><ul><li>Photosynthesis ceases and the CO 2 produced as a result of respiration makes the water more acidic </li></ul>

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