Ecology

ECOLOGY

Chapter 8

Learning Objectives

i. ii. iii. Define population, community and ecosystem Distinguish between inter and intraspecific interaction Describe community interactions (interspecific) that includes predation, herbivory, disease, parasitism, mutualism and commensalism Summarize the concept of an energy flow through a food chain and a food web Explain typical pyramids of numbers and biomass

iv. v.

Population

• A population is a group of individuals of the same species that is colonizing an area or habitat • Population ecology is a major subfield of ecology that deals with the dynamics of species populations and how these populations interact with the environment

Population

Community

• A community consists of all the organisms from different species that colonize an area • Community ecology consists of the study on number and types of species present, relative abundance of each species, interaction among species and community resilience to disturbances

Community

Ecosystem

• An ecosystem consist of all the abiotic factors in addition to the entire community of species that exist in a certain area.

Intra-specific interactions

• Among intra specific interaction between individuals are competition (A - / - effect) • Competition occurs when two or more individuals attempt to use the same essential resource, such as food, water, shelter, living space, or sunlight • Competition can occur among individuals from the same species within a population (intraspecific competition) or between different species (interspecific competition).

Intra-specific competition

• According to Darwin’s theory, genetic variation can be seen in a giraffe population according to the length of the neck where it varied. • Some have longer, intermediate and short neck. • This increase their chances in surviving, by having longer necks.

Intra-specific competition

• Due to competition in order to get food sources that is limited especially those...