Ecosystem functioning: food webs and trophicl evels.ppt
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The document discusses trophic levels, food chains, and energy transfer through ecosystems. It defines key terms like trophic levels, producers, consumers, and explains how energy flows from producers to different consumer levels in a food chain. Energy is lost at each transfer, which is why there are generally fewer organisms at higher trophic levels. This relationship is depicted by ecological pyramids that show the decrease in energy and biomass from the base to the top of the pyramid.
Ecosystem functioning: food webs and trophicl evels.ppt
- 1. Trophic Levels, Energy transfer and Pyramids 30-03-2024 1400-1500 h
- 2. Vocabulary Trophic Levels – is the position an organism occupies in a food chain. It refers to food or feeding. Apex predator – top level predators with few or no predators of their own. Detritavore – feeds on dead organisms, helps with decomposition Review Vocab – carnivore, omnivore, herbivore, scavenger, decomposer
- 3. Food Chain
- 4. A food chain is a model that shows how energy flows through an ecosystem. It represents a sequence of feeding relationships between organisms. Think of it as a one-way street for energy transfer.
- 5. Food Chains The energy flow from one trophic level to the other is know as a food chain Producers are at the first TROPHIC LEVEL Primary Consumers are the SECOND TROPHIC LEVEL Secondary consumers are at the THIRD TROPHIC LEVEL Tertiary consumers are at the FOURTH TROPHIC LEVEL In some ecosystems you can go out to Quaternary consumers
- 6. Trophic Levels (feeding levels) 3 2 1
- 7. Food Chain Players • Producers: • Also called autotrophs. • Make their own food using sunlight (photosynthesis) or chemicals (chemosynthesis). • Examples: Plants, algae, some bacteria. • Consumers: • Also called heterotrophs. • Get their energy by eating other organisms. • Herbivores: Eat plants only. (e.g., rabbits) • Carnivores: Eat other animals only. (e.g., lions) • Omnivores: Eat both plants and animals. (e.g., bears)
- 8. Food Web Most organisms eat more than JUST one organism When more organisms are involved it is know as a FOOD WEB Food webs are more complex and involve lots of organisms
- 9. Energy flows through a food chain in one direction. Producers capture energy from the sun and store it in chemical bonds. Consumers obtain energy by eating producers or other consumers. With each transfer, some energy is lost as heat and cannot be used again. This is why there are fewer organisms at higher trophic levels (feeding positions) in a food chain.
- 11. • Food chains are a simplified model. • In reality, most organisms have more complex feeding relationships. • A food web is a network of interconnected food chains. • It shows the many feeding relationships between different organisms in an ecosystem
- 12. Food webs
- 13. Trophic Level Producer, primary consumer, secondary consumer, tertiary consumer Grass 1st Producer Mouse 2nd Primary consumer Grasshopper 2nd Primary consumer Frog 3rd Secondary consumer Owl 3rd and 4th Secondary and tertiary consumer Hawk 3rd Secondary consumer
- 15. Aquatic Food web
- 16. Transfer Between Ecosystems If an organism that lives in a terrestrial ecosystem consumes an organism in an aquatic (or aquatic to terrestrial) energy is transferred between the two. Ex. Bear eats a fish (energy from aquatic to terrestrial) or fish eats a caterpillar (energy from terrestrial to aquatic)
- 17. Energy Transfer • Energy flows through a food chain or web in one direction, usually starting with the sun. • Producers capture energy from the sun and store it in organic molecules. • Consumers obtain energy by eating producers or other consumers. • With each transfer of energy from one trophic level to the next, a significant amount of energy (up to 90%) is lost as heat and is unavailable for use by the next level. • This is why food chains typically have fewer organisms at higher trophic levels. The limited energy available restricts the number of organisms a food chain can support.
- 18. Transfer of Energy When a lion eats a zebra, it does not get all of the energy from the zebra. Energy lost is usually in form of heat Energy lost from chain “link” to “link” is significant!
- 19. from grass to sheep, loss is about 90%! 10% Original Energy! 1% Original Energy! 100% Energy Available HEAT 90% HEAT 90%
- 20. Energy lost from one trophic level (energy level) to the next level can be represented by a pyramid PRODUCERS 1 CONSUMERS 2 CONSUMERS 3 CONSUMERS 4⁰ CONSUMERS
- 21. Trohic levels and energy transfer. There are three main types: • Pyramid of Energy: • The widest base represents producers, who capture the most energy. • Each higher level is a smaller layer, showing the decrease in energy available at each trophic level.
- 22. Trohic levels and energy transfer. There are three main types: • Pyramid of Biomass: • Represents the total amount of living organic matter (biomass) at each trophic level. • Similar to the pyramid of energy, it shows a decrease in biomass as you move up the trophic levels.
- 23. Trohic levels and energy transfer. There are three main types: • Pyramid of Numbers: • Depicts the number of individual organisms at each trophic level. • It can vary depending on the ecosystem. For example, a grassland might have many producers (plants) supporting fewer herbivores, which in turn support even fewer carnivores.
- 24. Each level above only gets 10% of the energy from below Ex: 10,000 J of producers (plants) only give 10% of energy to primary consumers 1,000 J to primary consumers (snails, minnows, dragonflies) 100 J to secondary consumers (small fish) 10 J to tertiary consumers (big fish) 1 J to quaternary consumers (fish hawk)
- 25. ENERGY PYRAMID 10,000 J 1,000 J 100 J 10 J 1 J
- 26. Energy Pyramid
- 27. Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)
- 28. Usually no more than 5 trophic levels since 6th level would have very little energy to keep it alive
- 29. REASONS Energy Loss: Energy flows through a food chain as organisms consume each other. However, this transfer is inefficient. According to the 10% law, only about 10% of the energy captured by producers (like plants) is transferred to the next trophic level (herbivores). The remaining 90% is lost through things like respiration, waste, and heat. So, with each step in the food chain, there's less and less usable energy available. By the 4th or 5th trophic level, the amount of energy remaining is simply too small to support a large population of organisms.
- 30. REASONS Limited Biomass: Biomass refers to the total amount of living matter in an ecosystem. As you move up the trophic levels, the number of organisms inevitably decreases. This is because it takes a lot of smaller organisms to support a single larger organism. There's simply not enough biomass at higher trophic levels to sustain a long chain of predators.
- 31. Ecological Pyramid • Which level has the most energy? • Which level has the most organisms? • Which level has the least organisms? • Which level has the least energy?
- 32. Pyramid of Numbers • Shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary consumers primary consumers producers 5 5000 500,000 5,000,000 5,000,000 producers • A vast number of producers are required to support even a few top level consumers.
- 33. Biomass pyramid • Biomass is a measure of the total dry mass of organisms in a given area. tertiary consumers secondary consumers primary consumers producers 75 g/m2 150g/m2 675g/m2 2000g/m2 producers 2000g/m2
- 34. Pyramid of Energy: • This is the most common and fundamental type of ecological pyramid. • It depicts the flow of energy through the trophic levels. • Because of the energy loss at each level, this pyramid is always upright with the widest base representing the producers (capturing the most energy from the sun) and tapering to a point at the top representing the apex predators (who have the least available energy).
- 36. Pyramid of Biomass • This pyramid shows the total amount of living matter (biomass) at each trophic level. Similar to the pyramid of energy, the pyramid of biomass is typically upright. • However, there can be exceptions in certain ecosystems where the producer biomass is much lower than the consumer biomass. • For example, in a deep-sea ecosystem, the primary producers (phytoplankton) may have a much smaller total biomass than the secondary consumers (zooplankton) who feed on them.
- 38. Pyramid of Numbers: • This pyramid depicts the number of individual organisms at each trophic level. • Unlike the other two pyramids, the pyramid of numbers can be upright or inverted depending on the ecosystem. • For example, a forest ecosystem will typically have an upright pyramid of numbers with many more plants (producers) than herbivores (primary consumers). • However, a parasite pyramid would be inverted because there are many more individual parasites than the host organisms they feed on.
- 39. SPINDLE SHAPED • Large Producers, Fewer Individuals: At the base of the pyramid are the producers, such as trees. These trees are massive and can live for hundreds or even thousands of years. However, there are relatively few individual trees compared to the next trophic level. • Many Herbivores: The next level consists of herbivores that feed on the trees. This level includes animals like deer, insects, and birds. There are many more individual herbivores than there are producer trees. • Fewer Top Predators: As you move up the pyramid, the number of individuals decreases again. There are far fewer top predators, like wolves or hawks, than there are herbivores.