Ecology Food Chains and Food Webs

Energy Flow and Trophic Levels

• Food chains illustrate a linear pathway of energy transfer between organisms in an ecosystem.
• Food webs showcase a complex network of interactions, representing multiple food chains.
• Producers (first trophic level) generate their own food; primary consumers (herbivores) eat producers.
• Secondary, tertiary, and quaternary consumers include carnivores and omnivores feeding on other consumers.
• Energy flow through trophic levels is typically upward and is generally inefficient; only about 10% of energy is transferred to the next level.

Predator-Prey Dynamics

• Predators capture and consume prey; predation significantly influences prey populations.
• Coevolution occurs as predators and prey adapt in response to each other over time.
• Camouflage, chemical defenses, and mimicry (Batesian and Müllerian) are common adaptations for avoiding predation.

Symbiosis and Interactions

• Symbiosis involves relationships between different organisms, which can be mutualistic, commensal, or parasitic.
• Mutualism benefits both species, commensalism benefits one without harming the other, and parasitism benefits one while harming the other.
• Ectosymbiosis (living on another organism) and endosymbiosis (living inside another organism) are variants of symbiotic relationships.

Carrying Capacity and Population Dynamics

• Carrying capacity refers to the maximum population size that an ecosystem can sustain based on resource availability.
• Population growth is exponential until it reaches carrying capacity, after which it stabilizes.
• Dispersion patterns describe how individuals spread within an area: uniform, clumped, or random based on resource distribution.

Ecological Succession

• Primary succession occurs after catastrophic events that destroy soil; it takes a long time to establish a community.
• Secondary succession happens after disturbances like fires or floods that leave soil intact and allows quicker regrowth.
• Pioneer species first colonize disturbed areas, gradually leading to increased biodiversity and eventual climax communities.

Biomes Classification

• Biomes are large ecological areas defined by climate, soil, plants, and animals.
• Major biomes include grasslands (savannas and temperate), deserts (hot and dry, semi-arid), forests (deciduous, tropical, taiga), aquatic biomes (freshwater and marine), and tundras (polar deserts with permafrost).
• Each biome exhibits unique adaptations and biodiversity that reflect environmental conditions.

Nitrogen Cycle and Eutrophication

• Nitrogen fixation transforms atmospheric nitrogen into ammonia for plant use, facilitated primarily by nitrogen-fixing bacteria.
• Nitrification processes turn ammonia into nitrite and then nitrate, both accessible to plants.
• Eutrophication, caused by excess nutrient input (from fertilizers or sewage), leads to harmful algae blooms that deplete oxygen and disrupt aquatic ecosystems.

Carbon Cycle Dynamics

• Carbon is essential for energy storage, with plants converting CO2 into carbohydrates via photosynthesis.
• Cellular respiration returns CO2 to the atmosphere, maintaining a continuous cycle, although some carbon sequesters for long periods in organic material or coral structures.

Energy Conservation and Types

• Energy is the capacity to do work and can be kinetic (in motion) or potential (stored).
• Important energy forms include thermal, electric, and nuclear.
• Energy is conserved in transformations, rarely lost entirely but dissipated as heat.

Energy Sources

• Energy sources include non-renewable (coal, oil, natural gas) and renewable (wind, solar, hydroelectric).
• Non-renewable resources are finite and formed over millions of years, while renewable resources can be quickly replenished and utilized sustainably.

Fossil Fuels and Environmental Impact

• Fossil fuels are derived from ancient organic materials, with coal, oil, and natural gas being the primary forms.
• All fossil fuels generate greenhouse gases that contribute to global warming and environmental degradation when burned.
• New technologies aim to make fossil fuel use less harmful through methods like coal washing, flue gas desulfurization, and carbon capture and storage.

Clean Coal Technologies

• Technologies such as coal washing and low-NOx burners help reduce coal's environmental impact by removing impurities and minimizing harmful emissions.
• Carbon capture and storage (CCS) mitigates atmospheric CO2 by capturing it before it is released.