Food Chains & Food Webs Food chain: linear sequence of organisms through which nutrients & energy pass Each organism occupies a trophic level: depends on role as producers or consumers Bottom of food chain: Primary producers: photosynthetic organisms plants and/or plankton Primary consumers: Consume primary producers Herbivores Secondary Consumers: Consume primary consumers Carnivores Tertiary consumers: Carnivores that eat other carnivores Apex Consumers: Top of food chain Energy Major factor that limits length of food chains Lost as heat between each trophic level due to 2nd law of thermodynamics Little energy remaining for another level of consumers in ecosystem [Chart Title: Relative Energy Content in Trophic Levels] Tertiary (apex) consumers: (Very little energy) Secondary consumers: Not available for next level (Less energy) Primary consumers: Not available for next level (More energy) Primary producers: (Most energy) Fewer organisms supported (by higher trophic levels) NOT completely descriptive of ecosystem structure Gibberellin: plants grow diff. fruit/more fruit 🍎 Shortstop: inhibits gibberellin production to use energy for places elsewhere, such as roots Plants contend w/ water stress (minimize water loss) open/closed stomata Impacts of herbivory - reserve sugar Hormones in play are different moose affects herbivory - winter - less response to herbivory Minimize herbivory: Tall trees cactus w/ spines chemicals 4 categories of adaptations avoid herbivory: Structural Chemical Appearance Indirect - spine-growing - toxins - "camouflage" - plano uses energy - turritella shells - aposematic coloration - years - hi