Biological Communities Flashcards

Species and Populations

• Species consist of organisms that can breed naturally and produce fertile offspring.
• A population refers to all members of a specific species residing in a particular area simultaneously.

Biological Communities and Ecosystems

• Biological communities encompass all interacting populations within a specific location.
• Ecosystems comprise both biological communities and their physical environments, which include abiotic (non-living) and biotic (living) factors.
• Most ecosystems are open, allowing for the exchange of materials and organisms with adjacent ecosystems.

Producers and Productivity

• Producers, such as green plants and algae, perform photosynthesis to generate energy.
• Productivity measures the amount of biomass produced in an area over a specified time.
• Primary productivity is driven by photosynthesis, while secondary productivity involves biomass creation by organisms consuming plants.

Food Chains and Food Webs

• Food chains represent a linked feeding sequence within an ecosystem.
• Food webs consist of interconnected food chains, illustrating the complex feeding relationships among various organisms.

Trophic Levels and Consumers

• Trophic levels indicate an organism’s position in the feeding hierarchy of an ecosystem.
• Consumers digest energy harnessed by producers and are classified into primary (plant eaters), secondary (eat primary consumers), and tertiary (top predators).
• Herbivores consume plants, carnivores eat meat, and omnivores feed on both plants and animals.

Ecological Concepts

• Biomass refers to biological material produced within an ecosystem.
• Scavengers clear decomposing remains of larger organisms, while detritivores consume dead organic material, litter, and dung.
• Energy decreases as it moves up the ecological pyramid, with only 10% of energy passed to the next level.

Biogeochemical Cycles

• Important cycles include the hydrologic, carbon, nitrogen, phosphorus, and sulfur cycles, essential for ecosystem function.

Environmental and Community Dynamics

• Tolerance limits determine the distribution of species, defined by minimum and maximum environmental factor levels.
• Environmental indicators, often bioindicators, provide insights into ecological changes.
• Resource partitioning occurs when two species compete for the same resource, resulting in one species prevailing.

Evolutionary Interactions

• Convergent evolution describes how unrelated species evolve similar traits.
• Predators target weaker members of prey populations, while coevolution highlights the reciprocal pressures species exert on each other.
• Parasites derive nutrients from hosts without causing death, while pathogens lead to disease.

Symbiotic Relationships

• Symbiosis encompasses intimate relationships between different species.
• Commensalism benefits one organism without affecting the other; mutualism provides benefits to both partners.
• Batesian mimicry occurs when harmless species evolve traits resembling unpalatable or harmful species for protection.