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Presentation on theme: "Ecosystems."— Presentation transcript:

1 Ecosystems

2 Realm of Ecology Biosphere Ecosystem Communities Populations Organisms

3 Realm of Ecology Species Population
All organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspring Population All the members of a species living in an area at the same time

4 Realm of Ecology, cont. Community Ecosystem
All of the populations of organisms living and interacting in a particular area Ecosystem Composed of a biological community and its physical environment

5 Ecosystems Ecosystem A community of different species interacting with one another and with their nonliving environment Can be small or large, e.g. a stream or Great Plains Can be natural or artificial, e.g. cropfields All of the Earth’s ecosystems together make up the biosphere

6 Biodiversity The forms of life that can best survive the variety of conditions currently found on earth Types of Biodiversity Genetic Diversity Species Diversity Ecological Diversity

7 Components of Ecosystems
Biotic (living components) Producers = make their own food from compounds obtained from their environment Photosynthesis = capturing sunlight to make sugars 6CO2 + 6H2O + sun  C6H12O6 + 6O2 Consumers = get their energy and nutrients by feeding on other organisms Aerobic respiration = uses oxygen to convert organic nutrients into carbon dioxide and water C6H12O6 + 6O2  6CO2 + 6H20 + energy

8 Types of Consumers Herbivores Carnivores Plant eaters
Primary consumers Feed directly on producers Carnivores Meat eaters Feed on other consumers Secondary and tertiary consumers

9 Types of Consumers, cont.
Omnivores Eat both plants and animals Scavenger Feed on dead organisms Decomposers Bacteria and fungi Complete the final breakdown and recycling of organic materials

10 Components of Ecosystem
Biotic (living components) Abiotic (nonliving components) Sunlight Temperature Precipitation wind

11 Major components of an ecosystem in a field

12 Major components of a freshwater pond ecosystem

13 How does energy flow through ecosystems?
Food chain The sequence of organisms, each of which is a source of food for the next Energy enters most ecosystems as high quality sunlight, which is converted to nutrients by producers. The energy is then passes on to consumers. As each organism uses the high-quality energy in its food to move, this energy is converted into low-quality heat (2nd law of thermodynamics)

14 Model of a Food Chain

15 Food Chain Trophic Level
All organisms that are the same number of energy transfers away from the original source of energy that enters an ecosystem Producers = 1st trophic level Primary consumers = 2nd trophic level Secondary consumers = 3rd trophic level But real ecosystems are more complex than this …

16 Food Web Most consumers feed on more than one type of organism
Food web = complex network of many interconnected food chains

17 Food Web

18 Energy Transfer in a Food Web
In a food chain or web, energy is transferred from one trophic level to another, with some usable energy degraded and lost to the environment as heat. At each successive trophic level, some of the available biomass isn’t digested and expelled as waste Only a small portion of what is eaten is converted into an organism’s biomass, and the amount of usable energy available to each successive trophic level declines (80-90% is lost)

19 Biomass Transfer

20 Pyramid of Energy Flow A diagram representing the flow of energy through each trophic level in a food chain or web With each energy transfer, only a small part (typically 10%) of the usable energy entering one trophic level is transferred to the organisms at the next trophic level

21 Generalized pyramid of energy flow

22 Energy Pyramid

23 Energy Pyramid for Grassland

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