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Ecosystems: What They Are Chapter 2. 2.1 Ecosystems: A Description.

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Presentation on theme: "Ecosystems: What They Are Chapter 2. 2.1 Ecosystems: A Description."— Presentation transcript:

1 Ecosystems: What They Are Chapter 2

2 2.1 Ecosystems: A Description



5 The Structure of Ecosystems

6 2.2 The Structure of Ecosystems

7 The Structure of Ecosystems Producers photo or chemo Herbivores Secondary Consumer eat plants carnivore eats meat secondary consumer omnivore eats meat & plants primary consumer secondary consumer parasite feeds on organism, usually without killing it secondary or primary

8 The Structure of Ecosystems


10 Africa

11 Egypt

12 Ghana ountry/ghana/home.htm

13 2.1 Ecosystems: A Description  Most basic plant community is the association  Plant community supports or limits the animal population  Populations of species are constantly interacting with the abiotic factors of an ecosystem

14 2.1 Ecosystems: A Description  A distinctive biotic community living in a certain environment  EX: forest, grassland, wetland, marsh, river, reef, log, sand dune  Transition between ecosystems is call ecotone  Landscape is the study of interactions between ecosystems

15 2.1 Ecosystems: A Description  Biomes are groupings of similar or related ecosystems or landscapes

16 The Structure of Ecosystems  Producers:  Create energy (food) from sunlight mostly through photosynthesis  Some bacteria can create energy through chemosynthesis

17 The Structure of Ecosystems  Key feature of organic material is the presence of carbon-hydrogen bonds

18 The Structure of Ecosystems  Parasites  Medical profession calls bacteria and virus parasites, pathogens  Found in nearly every major organism group  May live inside or out  Usually does not kill host but may weaken it so much it is more easily killed by other predators  Athletes foot, intestinal worms, mistletoe, bedbugs, ticks

19 The Structure of Ecosystems

20  Food Chain: life is not this simple!  Food Web: now we’re talkin!  Levels of these webs are called trophic levels

21 The Structure of Ecosystems

22  Usually no more 3-4 trophic levels (maybe 5 in marine systems)  Fundamental movement of chemical nutrients and stored energy through each level  Biomass is highest at first level (producers)  Biomass decreases with each subsequent level

23 The Structure of Ecosystems Why does biomass decrease? 3 reason:  Not all consumed material is converted to body mass, some used as energy  Some biomass is never eaten but goes to decomposers  Carnivores must be bigger than their prey. There is limit to animal size and space to live in

24 The Structure of Ecosystems  Not all ecosystem relationships are predator-prey  Some are mutualistic

25 The Structure of Ecosystems

26  Competition is kept to a minimum in habitats because each organism has it’s own niche  This niche gives each organism a distinct time, place, and food type for living and eating  If 2 species share the same niche, one will be eliminated, competitive exclusion principle

27 The Structure of Ecosystems

28  The degree to which each of these factors is present profoundly affects the type and number of organisms present in each habitat

29 The Structure of Ecosystems  Each species thrives under specific environmental regimes  Changing even one factor can create stress for the organism  For each environmental factor there is an optimum level  Anything above or below stresses or kills the organism (Law of Limiting Factors)

30 The Structure of Ecosystems Fundamental Principle Every species of plant and animal has an optimum range, zones of stress, and limits of tolerance with respect to every biological factor.

31 2.3 Ecosystems to Global Biomes  Climate is average temperature and precipitation  These occur in great variation creating wide variety of climates  Population densities will be greatest where conditions are optimal  Population decreases as any condition departs from optimal

32 2.3 Ecosystems to Global Biomes  6 major biomes (p. 45)  Precipitation is the primary deciding factor in a biome  Temperature is secondary

33 2.3 Ecosystems to Global Biomes Microclimates Affecting Biomes  Temp & precipitation may vary greatly within a climate region due to location  Altitude, soil type, topography, direction of slope, acidity, alkalinity, salinity, proximity to large body of water

34 2.3 Ecosystems to Global Biomes Biotic Factors Affecting Biomes  One species may change biome for another, EX tall plant creates too much shade for a sun lover  Absence of one species will eliminate other species due to lack of food

35 2.3 Ecosystems to Global Biomes Physical Barriers Affecting Biomes  Ocean, desert, mountain range, dams, croplands, human constructed sites

36 2.4 The Human Factor

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