Trophic levels describe how energy flows through ecosystems, starting with primary producers that harness sunlight. Each level, from herbivores to top predators, plays a vital role in maintaining balance and supporting diverse life forms within the environment.
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Primary producers (autotrophs)
- Convert sunlight or inorganic compounds into organic matter through photosynthesis or chemosynthesis.
- Form the base of the food web, providing energy for all other trophic levels.
- Examples include plants, algae, and some bacteria.
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Primary consumers (herbivores)
- Feed directly on primary producers, obtaining energy and nutrients.
- Play a crucial role in transferring energy from producers to higher trophic levels.
- Examples include rabbits, deer, and insects.
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Secondary consumers (carnivores)
- Consume primary consumers, gaining energy and nutrients from herbivores.
- Help regulate herbivore populations, maintaining ecosystem balance.
- Examples include foxes, birds of prey, and small mammals.
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Tertiary consumers (top predators)
- At the top of the food chain, they feed on secondary consumers.
- Often have few natural predators, playing a critical role in controlling population dynamics.
- Examples include wolves, eagles, and large cats.
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Decomposers
- Break down dead organic matter, recycling nutrients back into the ecosystem.
- Essential for soil health and fertility, supporting primary producers.
- Examples include fungi, bacteria, and detritivores like earthworms.
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Energy flow through trophic levels
- Energy decreases as it moves up trophic levels due to metabolic processes and heat loss.
- Typically, only about 10% of energy is transferred from one level to the next.
- This inefficiency shapes the structure and dynamics of ecosystems.
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Ecological pyramids (biomass, energy, numbers)
- Visual representations of the distribution of energy, biomass, or number of organisms at each trophic level.
- Pyramid of energy shows energy flow, while biomass and numbers illustrate the amount of living material and organisms.
- Helps in understanding ecosystem productivity and health.
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Trophic efficiency
- Refers to the percentage of energy transferred from one trophic level to the next.
- Generally low, averaging around 10%, which limits the number of trophic levels in an ecosystem.
- Influences the structure and stability of food webs.
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Food chains and food webs
- Food chains depict a linear sequence of energy transfer between trophic levels.
- Food webs illustrate the complex interconnections and multiple feeding relationships in an ecosystem.
- Both are essential for understanding ecosystem dynamics and energy flow.
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Keystone species and trophic cascades
- Keystone species have a disproportionately large impact on their ecosystem relative to their abundance.
- Their removal can lead to significant changes in community structure and function (trophic cascades).
- Examples include sea otters, wolves, and certain plants that support diverse communities.