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Topic 2.1 species and populations (fc)

Topic 2.1 for the IB Environmental Systems and Societies course
Species
Habitat
Niche
Joseph Connells Barnacle experiment
Abiotic and Biotic factors
Populations
What regulates populations
Predator Prey relationships
Biotic interactions
Population growth
Competition and population growth

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Topic 2.1 species and populations (fc)

  1. 1. Topic 2: Ecosystems and Ecology Topic 2.1: Species and Populations fourcornerseducation.net
  2. 2. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Further Resources Detailed revision and learning material for this topic is available at: Four Corners Education Course page http://fourcornerseducation.net/four-corners-online-courses/ Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  3. 3. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Main ideas A species interacts with its abiotic and biotic environments, and its niche is described by these interactions. Populations change and respond to interactions with the environment. Any system has a carrying capacity for a given species. TOK Q: H ow does this species concept apply to asexual organisms ? Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  4. 4. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. Same species Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  5. 5. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. Different genus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  6. 6. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. Russula sardonia (Primrose bittergill) Identifying fungi species correctly can save your live Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  7. 7. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. Reindeer and caribou are thought of as the same species (Rangifer tarandus) but recent research suggest they may be closely related separate species Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  8. 8. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. However this idea of “the species” can cause problems Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  9. 9. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Species A group of organisms that interbreed and produce fertile offspring. However this idea of “the species” can cause problems Reindeer and caribou are thought of as the same species (Rangifer tarandus) but recent research suggest they may be closely related separate species Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  10. 10. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Atlantic Maritime sea cliff habitat Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  11. 11. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Atlantic Maritime sea cliff habitat Wild thyme (Thymus polytrichus) a common species of sea cliffs in Europe Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  12. 12. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Alpine grassland habitat Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  13. 13. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Alpine grassland habitat Gentiana nivalis The Alpine gentian a species found in Alpine grasslands Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  14. 14. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Estuarine wetland habitat Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  15. 15. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Estuarine wetland habitat Greylag geese (Anser anser) overwintering in Sweden a typical estuarine species Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  16. 16. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Habitat The environment in which a species normally lives. Tropical forest habitat Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  17. 17. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche A species’ share of a habitat and the resources in it. An organism’s ecological niche depends not only on where it lives but on what it does. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  18. 18. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche Falco pe reginus the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  19. 19. Food needed Climate needed etc. the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche Space needed Falco pe reginus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  20. 20. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche Fundamental niche: the set of resources a population is theoretically capable of using under ideal conditions the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  21. 21. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche Fundamental niche: the set of resources a population is theoretically capable of using under ideal conditions Realised niche: the resources a population actually uses the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  22. 22. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche The realised niche may be smaller than the fundamental niche because of competition with other species or other individuals in the same population the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  23. 23. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche The realised niche may be smaller than the fundamental niche because of competition Species 1 Species 2 Species 1 Species 2 with other species or other individuals in the Resource Overlap Resource Overlap same population The more competition the smaller the realised niche the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  24. 24. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche If the competition is too great between species ONE species will out compete the other If the competition is too great within a species then the population could collapse the sum total of an organism's use of the biotic and abiotic resources in an environment Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  25. 25. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche: Joseph Connells Barnacle experiment From observations of their distribution, Connell noted: Balanus mainly found on the lower shore between high and low Balanus tides Chthamalus was mainly on the upper area The larvae of each species can swim anywhere on the the rocky shoreline so should be able to survive Chthamalus The Research Question (RQ) that Connell posed was: Why are they not found together? Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  26. 26. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche: Joseph Connells Barnacle experiment Fundamental Niche High Tide Chthamalus Balanus Balanus Mean Tide Chthamalus Low Tide Realised Niche Rockyshore Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  27. 27. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche: Joseph Connells Barnacle experiment Connell conducted various experiments: ONE Balanus Chthamalus He removed Chthamalus from the top of the shore but Balanus did not replace it: His conclusion was that Balanus need to be in the tidal area and could not survive the often dry periods between the highest tides Balanus realised niche was the same as its fundamental niche Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  28. 28. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche: Joseph Connells Barnacle experiment Connell conducted 3 experiments: TWO Balanus Chthamalus He removed Balanus for the bottom of the shore and Chthamalus replaced it: His conclusion was that Balanus outcompeted Chthamalus in the lower tidal area Chathamalus has a smaller realised niche than its fundamental niche because of competition from Balanus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  29. 29. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Niche: Joseph Connells Barnacle experiment Together Connell had shown that: Biotic interactions between individuals of different species can Balanus explain the actual conditions and resources (abiotic) in which a species exists as its realised niche Chthamalus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  30. 30. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Biotic Factors = A living, biological factor that may influence an organism or ecosystem, eg predation, parasitism, disease, competition. Abiotic Factor = A non-living, physical factor that may influence an organism or ecosystem, eg temperature, sunlight, pH, salinity, precipitation. Atmosphere Windspeed Humidity Light intensity Precipitation Temperature Water pH and salinity Dissolved Nutrients DissolvedOxygen Disolved nutrients Biotic Factors Producers Consumers Detrivores Decomposers Interactions Competitors Parasites Pathogens Symbionts Predators Herbivores Soil Available nutrients Moisture pH Structure Temperature Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  31. 31. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Abiotic Factors affect animal and plant species, but also interact and change with time themselves E.g. Temperature depends upon: solar radiation, wind speed, time of year, time of day, altitude and aspect Temperature affects: water loss, respiration, photosynthesis Changes in temperature affect: relative humidity and evaporation from soils and water surfaces Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  32. 32. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Biotic and Abiotic factors vary both between and within ecosystems Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  33. 33. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tropical Rain Forests The Biotic Part Dominant Species Trees and Vines Floral community Highest Biodiversity of all Biomes Faunal community Very High biodiversity, mammals, bird, amphibians and arthropods Soil Community Very rich in decomposer species Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  34. 34. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tropical Rain Forests 26.0 19.5 13.0 6.5 0.0 Temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rainfall 300 225 150 75 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  35. 35. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Abiotic conditions can vary within an ecosystem Within the Tropical rainforest different levels of humidity and light exist at different layers Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  36. 36. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Abiotic conditions can vary within an ecosystem Within the Tropical rainforest different levels of humidity and light exist at different layers Humidity:67% Light:70% Humidity:75% Light:50% Humidity:80% Light:12% Humidity:85% Light:6% Humidity:90% Light:1% Humidity:98% Light:0% Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  37. 37. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Biotic conditions regulate populations The interactions between the organisms, such as predation, herbivory, parasitism, mutualism, disease, and competition, are termed biotic factors Atmosphere Windspeed Humidity Lightintensity Precipitation Temperature Water phand salinity Dissolved Nutrients DissolvedOxygen Disolved nutrients Biotic Factors Producers Consumers Detrivores Decomposers Interactions Competitors Parasites Pathogens Symbionts Predators Herbivores Soil Availablenutrients Moisture pH Structure Temperature Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  38. 38. Population A group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding Blue mussel (Mytilus edulis): Wormshead UK Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  39. 39. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations What regulates populations Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs Limited by available nest sites (same places each year) Average brood size was about 2.5 fledged young each summer Come the next breeding season the population was back to about 820 pairs Competition for suitable nesting sites regulated the population of Peregrine falcons Falco pe reginus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  40. 40. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations What regulates populations Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs Limited by available nest sites (same places each year) Average brood size was about 2.5 fledged young each summer Come the next breeding season the population was back to about 820 pairs Competition for suitable nesting sites regulated the population of Peregrine falcons Falco pe reginus Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  41. 41. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations What regulates populations E q u i l i b r i u m Poi n t R e so u rc e l i mi t re ach e d R e so u rc e s Pl e n t i f u l Population SteadyStateEquilibrium Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  42. 42. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations What regulates populations Boom or bust conditions for some species may also be driven by density dependent factors Some species are very good at taking full advantage of any opportunity Locust populations can explode They swarm in thousands eat everything in their path and eventually totally outstrip their food supply - the out compete themselves Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  43. 43. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Predator Prey relationships The balance between the population size of a prey species and that of its predator. Populations of predators and prey are linked. Include both carnivore and herbivore relationships. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  44. 44. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Predator Prey relationships When the interaction involves animals preying on other animals, then this is termed - PREDATION Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  45. 45. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Predator Prey relationships When the interaction involves animals preying plants, then this is termed - HERBIVORY Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  46. 46. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Parasitism Mosquitos are not only parasites of human populations but also of many other animals. Parasitism can be thought of as a special form of predation Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  47. 47. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Biotic interactions Interactions with other organisms both within the same species (intraspecific) or between species (interspecific) have an influence of the population size of a species. These interactions can be either positive or negative. As the graph illustrates as gull population size changes over the year so the size of fish population responds too either increased or decreased predation Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  48. 48. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population A group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding European Bumblebees on Lavender in France part of a declining population Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  49. 49. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth As long as their is a plentiful supply of resources populations grow But population growth is not simple If we put some bacteria cells in a culture - the bacteria reproduce exponentially As the population grows so to does the rate of growth 120 100 80 60 40 20 Bacterial Growth 0 0 50 100 150 200 250 300 Time (min) Numberofcells/ml Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  50. 50. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth As long as their is a plentiful supply of resources populations grow But population growth is not simple If we put some bacteria cells in a culture - the bacteria reproduce exponentially As the population grows so to does the rate of growth 120 100 80 60 40 20 Population The curve produced is sometimes called a J-curve The J curve assumes that there is no limit on resources 0 0 50 100 Time 150 200 250 300 Growth Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  51. 51. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth Darwin calculated that if you started with two elephants and exponential growth, after 700 years the world population of elephants would be 19,000,000 This obviously hasn’t happened http://evolutionchantelle09.weebly.com/uploads/ 2/2/7/1/22716838/2634763_orig.png Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  52. 52. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth The size of a population is limited by available resources and competition for them This results in a maximum population size that an environment can sustain This is known as an environments Carrying Capacity Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  53. 53. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth The in the example of bacterial growth the carrying capacity is around 120 bacterial cells / ml This can be clearly seen in the graph of growth Negative feedback operates keeping the population around the Carrying capacity Ecologists use K to represent carrying capacity 120 100 80 60 40 20 Bacterial Growth 0 0 100 200 300 400 500 600 Time (min) Numberofcells/ml Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  54. 54. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth This produces an S or Sigmoid curve that is typical of populations in equilibrium. IMPORTANT - Both the J curve and S curve only appear when new populations are growing or when a population is recovering from a crash. If you measure population size most of the time the results produce a graph of variation around the carry capacity. (look at the fish and gull example above) K 120 100 80 60 40 20 Population 0 0 100 200 300 400 500 600 Time Growth Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  55. 55. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Population growth - phases of growth Lag phase: population grows slowly (environmental adaption). Population is small so can not full exploit the resources available in the environment Exponential or Log phase: Population grows rapidly exploiting a plentiful resource supply (maximal growth) Resources are being exploited rapidly 120 100 80 60 Stationary Transitional Exponential Transitional phase: population growths slows as resources 40 start to be come limiting 20 Stationary phase: Population growth reaches a plateau Lag ( growth slows )- the maximum population size under the environmental conditions - Population is using all of the available resources with no additional resources for continued population growth 0 0 100 200 300 400 500 600 Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  56. 56. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Competition and population growth Interspecific competition (between different species) may result in a balance, in which both species share the resource. Intraspecific Competition Greater than Interspecific Competition 1,000 Carrying Capacity -Theoretical Maximum Population Size 800 But with the population size of each species reduced compared to without competition Species 1 Species 2 600 400 200 0 1 2 3 4 5 6 7 8 9 18 10 11 12 13 14 15 16 17 Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  57. 57. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Competition and population growth The other outcome is that one species may totally out compete the other. This is the principal of competitive exclusion If the interaction is a predator prey relationship then a series of population increases and decreases may develop Interspecific Competition Greater than Intraspecific Competition 750 Carrying Capacity -Theoretical Maximum Population Size 600 450 300 150 0 1 2 3 4 5 6 7 8 9 18 10 11 12 13 14 15 16 17 Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  58. 58. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Competition and population growth The other outcome is that one species may totally out compete the other. This is the principal of competitive exclusion If the interaction is a predator prey relationship then a series of population increases and decreases may develop This can be illustrated in the classic 80 60 40 20 0 1900 1910 1920 Snowshoe hare Lynx population cycle in North America Year Snowshoe Hare Lynx Numberofpelts(1000s) Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  59. 59. Topic 2: Ecosystems and Ecology Case study: Energy Pathways in the Sub-arctic - How biotic and abiotic factors control populations Some concepts that follow are covered in more detail in other parts of the course Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  60. 60. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Limited Solar Energy: abiotic factor At higher latitudes light required for photosynthesis is spread over a greater area This means the rate of photosynthesis is much lower than at the equator Therefore Gross Primary Productivity (GPP) is also lower AtthePoles thesuns energy is spread overalarge area At theEquator thesuns energy is spreadovera smallarea Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  61. 61. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Limited Solar Energy: abiotic factor The Earth also tilts at an angle of 23.5˚ Creating summer and winter in each hemisphere During the Northern Winter almost no solar energy reaches the high arctic This again reduces productivity at the poles NorthernHemisphere Winter SouthernHemisphere Summer 23.5˚ Tilt Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  62. 62. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Extreme seasonality: abiotic factor Tundra experiences very little “rainfall” - making it the driest terrestrial biome Limited solar energy and excessive albedo effect lead to extreme winter temperatures Summers are short but long hours of daylight help to compensate and slightly extend the “actual” growing season 30 20 10 0 -10 -20 -30 -40 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (˚c) Precipitation (mm) Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  63. 63. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Survival of the fittest!: biotic factor / abiotic cause Few plants can survive the extreme conditions found in the tundra All need adaptations to survive conditions that would freeze the cells of most plants while managing with very little moisture Lichens - a symbiotic associating between a fungus and a photosynthesising algae are the only available “plant” biomass during the winter Hard tough species like cotton grass manage to grow during the summer Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  64. 64. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Productivity Plant biomass can be thought of as the energy store for the entire ecosystem With the extreme climate and limited light Tundra biomass is very low Comparison of Net productivity in different Biomes 2500 2000 1500 1000 500 0 Based on a table from:Whittaker,R.H.and Likens,G.E. 1975. The biosphere and man. In:Leith,H.andWhittaker,R.H. (Eds.),Primary Productivity and the Biosphere,Ecological Studies 14,Springer-Verlag,Berlin,Germany,pp.305-328. Tropicalrainforest Temperatedeciduousforest Savanna BorealForest Temperategrassland Tundra Biomass(gm -2 yr -1 ) Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  65. 65. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Foodchain: biotic factor In winter reindeer survive eating lichen, in particular Cadonia Summer Foodchain rangiferina (Reindeer moss) In the summer there is a greater choice of plants - though all with relatively low Net Primary Production (NPP) Solarenergy PrimaryProducer Cottongrass PrimaryConsumer Reindeer SecondaryConsumer Grey Wolf Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  66. 66. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Foodchain: biotic factor The tundra food chain can be thought of as individual units - Summer Foodchain interlinked to create an entire system Solarenergy PrimaryProducer Cottongrass PrimaryConsumer Reindeer SecondaryConsumer Grey Wolf Input Process Output Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  67. 67. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Foodchain: biotic factor The tundra food chain can be thought of as individual units - Summer Foodchain interlinked to create an entire system Solarenergy PrimaryProducer Cottongrass PrimaryConsumer Reindeer SecondaryConsumer Grey Wolf Input Process Output Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  68. 68. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Foodchain: biotic factor The tundra food chain can be thought of as individual units - Summer Foodchain interlinked to create an entire system Solarenergy Input Process Output Each trophic level in the foodchain is an individual system inside a bigger system PrimaryProducer Cottongrass PrimaryConsumer Reindeer SecondaryConsumer Grey Wolf Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  69. 69. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Populations Tundra populations are dependent on the amount of energy that is passed on from one trophic level to the next The wolf population can only gain energy that has been passed on from the Reindeer, who can only gain whatever energy is passed on from the plant community This means there will always be fewer organisms at the top of the foodchain than at the bottom Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  70. 70. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Populations A population is defined as: group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding So the tundra populations occupy unique niches Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  71. 71. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Tundra Populations Reindeer population - St Matthew Island, Alaska Studies of Reindeer populations on islands show: That the amount of winter food available sets the carry capacity for that ecosystem The carrying capacity of the herbivore population controls the size of any predator population - (part of the predators niche) The studies also show that without predation to control the population, reindeer numbers often outstrip their food supply (Biotic control) 6000 5000 4000 3000 2000 1000 1944 1950 1955 1960 1966 Year After Klein 1968 Populationsize Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  72. 72. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Negative Feedback - Wolf and Reindeer In parts of Finland Grey Wolf populations changes appear to follow behind Reindeer population changes Is this evidence of a Negative feedback - predator / prey relationship? While the actual answer is more complex - the population numbers of all predator and prey systems do have an effect on each other Figures from: Kojola,I.,Tuomivaara,J.,Heikkinen,S.,Heikura,K.,Kilpeläinen,K.,Keränen,J.,Paasivaara,A.& Ruusila,V. 2009:European wild forest reindeer and wolves:endangered prey and predators.—Ann.Zool.Fennici 46:416–422 Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  73. 73. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Negative Feedback - Wolf and Reindeer In parts of Finland Grey Wolf populations changes appear to follow behind Reindeer population changes Is this evidence of a Negative feedback - predator / prey relationship? While the actual answer is more complex - the population numbers of all predator and prey systems do have an effect on each other Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  74. 74. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Negative Feedback - Wolf and Reindeer In parts of Finland Grey Wolf populations changes appear to follow behind Reindeer population changes Prey population grows Prey population falls Is this evidence of a Negative feedback - predator / More food Less food prey relationship? While the actual answer is more complex - the population numbers of all predator and prey systems do have an effect on each other Less hunting Predator population falls More hunting Predator population grows Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  75. 75. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations What does this mean? Interactions between and within species influence population dynamics of others, and upon the carrying capacity of the others’ environment. S and J population curves describe a generalized response of populations to a particular set of conditions (abiotic and biotic factors). Limiting factors (both biotic and abiotic) will slow population growth as it approaches the carrying capacity of the system. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  76. 76. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Work cited: Connell JH. 1961. The influence of interspecific competition and other factors on the distribution of the barnacle chthamalus stellatus. Ecology 42: 710-723. Jha, Ajit. “Are Reindeer And Caribou The Same Thing? New Study Says They Are Lost Cousins, Driven In Different Directions By The Ice Age.” International Science Times, 17 Dec. 2013, www.isciencetimes.com/articles/6533/20131217/reindeer-caribou-same-thing-cousins- ice-age-climate-change.htm. Klein, D.R. 1968. The introduction, increase, and crash of reindeer on St. Matthew Island. J. Wildlife Management 32: 350-367. Kojola, I., Tuomivaara, J., Heikkinen, S., Heikura, K., Kilpeläinen, K., Keränen, J., Paasivaara, A. & Ruusila, V. 2009: European wild forest reindeer and wolves: endangered prey and predators. — Ann. Zool. Fennici 46: 416–422 Whittaker, R.H. and Likens, G.E. 1975. The biosphere and man. In: Leith, H. and Whittaker, R.H. (Eds.), Primary Productivity and the Biosphere, Ecological Studies 14, Springer-Verlag, Berlin, Germany, pp. 305-328. NB* Unless stated in the presentation all illustrations, figures and images are the property and copyright of N Gardner. sciencebitz.com Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations
  77. 77. Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations Extended resources and further reading Problem of species caribou or reindeer: http://www.isciencetimes.com/articles/6533/20131217/reindeer-caribou-same- thing-cousins-ice-age-climate-change.htm Joseph Connell’s classic paper on interspecific competition in barnacles: http://www.life.illinois.edu/ib/453/connell.pdf What limits the Serengeti zebra population? A study of population dunbamics and limiting factors for zebra and wildebeest https://cbs.umn.edu/sites/cbs.umn.edu/files/public/downloads/ What_limits_the_Serengeti_zebra_population_Grange_et_al_2004.pdf Topic 2: Ecosystems and Ecology Topic 2.1:Species and Populations

Topic 2.1 for the IB Environmental Systems and Societies course Species Habitat Niche Joseph Connells Barnacle experiment Abiotic and Biotic factors Populations What regulates populations Predator Prey relationships Biotic interactions Population growth Competition and population growth

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