Understanding Ecosystems: Biotic and Abiotic Components, Food Chains, and Diversity Measurement
Ecosystems comprise both biotic (living) and abiotic (non-living) components. This section explores the structure of ecosystems, including food chains and pyramids of numbers, biomass, and productivity. It covers local food chains and examples of species interactions such as parasitism and mutualism. Furthermore, it discusses methods for measuring abiotic factors across terrestrial, marine, and freshwater ecosystems and techniques for estimating biotic components, including the Lincoln Index, quadrats, and Simpson’s Diversity Index, which assesses ecosystem stability.
Understanding Ecosystems: Biotic and Abiotic Components, Food Chains, and Diversity Measurement
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Presentation Transcript
Topic 2 – The Ecosystem 2.1 - Structure IB Topics 2.1.1-2.1.7
Biotic and Abiotic Components Biotic Abiotic All non-living components of the ecosystem Ex: • All living components of the ecosystem • Ex:
Food Chains • The position an organism occupies in a food chain is called the trophiclevel.
Food Webs • Ecosystems contain many interconnected food chains
Pyramid of Numbers • A graphical model of the number of organisms in a food chain
Pyramid of Biomass • A graphical model of the amount of biomass present in a food chain at a certain point in time
Pyramid of Productivity • A graphical model of the rate of energy production over time
Key Words (define and provide a local example of each) • Species • Population • Habitat • Niche • Community • Ecosystem • Parasitism • Mutualism • Predation • Herbivory
Topic 2 – The Ecosystem 2.2 – Measuring Abiotic Components IB Topics 2.2.1-2.2.2
Significant Abiotic Factors • Terrestrial Ecosystem • Marine Ecosystem • Freshwater Ecosystem
Topic 2 – The Ecosystem 2.3 – Measuring Biotic Components IB Topics 2.3.1-2.3.5
Estimating abundance of organisms • Counting the number of organisms is almost always done using an estimate
Lincoln Index • A mathematical model to estimate population size • Capture-mark-release-recapture
Example 1 Example 2 75 Ladybugs were caught and marked 80 Ladybugs were caught the second time and 3 were marked • 13 deer were caught and marked • 14 deer were caught the second time and 5 were marked
Quadrats • A square of area used to measure the population of non-mobile organisms • Can help to calculate population density and percentage cover
Diversity • The number of different species • The number of individuals of each species
Simpson’s Diversity Index • Used to compare diversity between areas • High value of D implies stable ecosystem • Low value of D implies unstable ecosystem