Ecology Lecture 2

Fundamental Features of a Community

• Community structure includes species diversity, species interactions, and the physical environment.
• A community has both biotic (living) and abiotic (non-living) components that interact.

Components of Species Diversity

• Species richness refers to the number of different species in a community.
• Species evenness indicates how evenly individuals are distributed among those species.

Role of Producers in Trophic Structure

• Producers, primarily plants and phytoplankton, convert solar energy into chemical energy through photosynthesis.
• They form the base of the food chain, supporting all other trophic levels.

Food Web in Trophic Structure

• A food web consists of interconnected food chains, illustrating the complex feeding relationships among organisms in a community.
• It represents multiple pathways of energy flow and nutrient cycling.

Role of Decomposers

• Decomposers break down dead organic matter, returning vital nutrients to the soil.
• They play a crucial role in recycling materials within the ecosystem.

Proportion of Species in a Community

• The term for the proportion each species represents of all individuals in the community is relative abundance.

Levels of Heterotrophic Organisms

• Heterotrophic organisms are categorized into primary consumers, secondary consumers, and tertiary consumers based on their feeding levels in the trophic structure.
• Primary consumers eat producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers.

Variety of Organisms in a Community

• The variety of organisms within a community is referred to as biodiversity.

Specific Set of Resources for an Organism

• The specific set of biotic and abiotic resources an organism uses is known as its ecological niche.

Competition Between Species

• Competition occurs when two species vie for limited resources such as food, space, or mates.

Beneficial Interactions

• Mutualism describes interactions where both species involved benefit from the relationship.

Organisms That Eat Parts of Plants or Algae

• Herbivores are organisms that consume parts of plants or algae.

Neutral Interactions

• Commensalism is the interaction where one species benefits while the other is neither helped nor harmed.

Parasitism

• Parasitism involves an organism deriving nourishment from a host, which is harmed in the process.

Consequences of Overlapping Niches

• If two species’ niches overlap significantly, it may lead to competition, potential exclusion, or evolutionary adaptations.

Consumer-Target Species Interaction

• Predation is the interaction where a consumer feeds on another species, potentially leading to its death.

Population Interactions in a Community

• Interactions between populations in a community are known as community ecology.

Effects of Interactions Between Populations

• The term for interactions between populations categorized by their effects on survival and reproduction is species interactions or ecological interactions.

Test your knowledge of community ecology with this quiz! Explore the interactions between different populations in the same area, including species diversity, feeding relationships, and interspecific interactions. Learn about species richness, relative abundance, and other fundamental features of a community.