Feeding Relationships & Food Webs

Feeding Relationships & Food Webs

• Producers: Organisms that make their own food (plants, algae).
• Primary Consumers: Herbivores that feed on producers (rabbits, deer).
• Secondary Consumers: Carnivores that eat herbivores (snakes, lions).
• Tertiary Consumers: Carnivores that eat other carnivores (hawks, orcas).
• Decomposers: Break down dead organic matter (fungi, bacteria).
• Food Webs: Show complex feeding interactions; interconnected food chains; arrows show energy flow (prey to predator).

Food Webs, Nutrition, Producers & Consumers

• Food Webs: Show how energy and nutrients move through an ecosystem (broader than food chains).
• Autotrophs (Producers): Create their own food via sunlight (photosynthesis) or chemical processes (chemosynthesis).
• Heterotrophs (Consumers): Obtain energy by consuming other organisms (herbivores, carnivores, omnivores, detritivores).
• Herbivores: Eat only plants.
• Carnivores: Eat only animals.
• Omnivores: Eat both plants and animals.
• Producers: Organisms (plants, algae, some bacteria) that convert sunlight into energy via photosynthesis.

Biotic vs Abiotic & Kingdoms and Taxonomy

• Biotic Factors: Living components (plants, animals, bacteria).
• Abiotic Factors: Non-living physical & chemical aspects (temperature, water, light, soil).
• Kingdoms: Classification of organisms based on characteristics (e.g., Animals - multicellular, heterotrophic organisms; Plants - multicellular, autotrophic organisms; Fungi – multicellular/unicellular, decomposers; Protists – mostly unicellular, varied nutrition; Bacteria – unicellular prokaryotes).
• Taxonomy: Scientific practice of classifying organisms into categories (Kingdom, Phylum, Class, Order, Family, Genus, Species).

Modern Classification, Species & Genus, and Scientific Names

• Relevance of Classification: Helps scientists communicate clearly about organisms; supports biodiversity studies; advances in genetics (e.g., DNA sequencing).
• Species: Group of organisms capable of interbreeding and producing fertile offspring.
• Genus: Group of closely related species; scientific names (e.g., Homo sapiens).
• Taxonomy: Organizes organisms based on shared characteristics & evolutionary history.
• Binomial Nomenclature: Two-part Latin name (Genus species) for each species.

Photosynthesis and Respiration

• Photosynthesis: Process where plants, algae, and some bacteria convert sunlight into chemical energy (glucose).
• Photosynthesis Equation: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2
• Photosynthesis Stages: Light-dependent reactions, Calvin Cycle (Light-independent reactions).
• Respiration: Process of turning glucose into carbon dioxide.
• Respiration Equation: C6H12O6 + 6O2 → 6CO2 + 6H2O
• Light Intensity Effects: Photosynthesis rate increases with light, but plateaus at a certain point (light saturation). Limiting factors include light intensity, CO2, and temperature.

Graphs Analysis, Interspecific Competition, and Symbiotic Relationships

• Graphs Analysis: Relationships between light intensity and photosynthesis rate. Diagrams showing competition between species for resources (food, space).
• Interspecific Competition: When two species compete for limited resources.
• Modes of Nutrition: Autotrophs produce their own food (plants, algae). Heterotrophs rely on other organisms for food (animals).
• Symbiotic Relationships: Mutualism (both benefit), parasitism (one benefits, other harmed), commensalism (one benefits, other neither helped nor harmed).

Experiment (Photosynthesis)

• Research Question: Example: How does light intensity affect photosynthesis rate in Elodea?
• Variables: Independent (light intensity), Dependent (rate of photosynthesis), Controlled (CO2, water temp, plant type).
• Method: Set up aquatic plant; use varying light intensities; measure oxygen production over time.
• Validity: Internal validity (controlling variables), External validity (generalizing to other species).

Taxonomy & Classification

• Taxonomy & Classification: Scientific naming conventions and the importance of modern classification.