مخطط الموضوع

  • Populations and organisms biology

    Teacher: Dr, KHERIEF NACEREDDINE Saliha

    E-mail: s.kherief@centre-univ-mila.dz

    Tel: 0772179861

    Semestre : 6 

    Unité d’enseignement Fondamentale 1 (UEF 3.2.1) : Ecologie des populations et des communautés 

    Matière : Populations and organisms  biology

     Crédits : 7 

    Coefficient: 4 

    Teaching Objectives:
    The main objective of these courses is to familiarize students with population ecology. It aims to help them understand that the population constitutes the fundamental unit of any biocenosis. Animal and plant communities specific to each ecosystem are the result of the aggregation of a large number of populations belonging to one or another of the major kingdoms of living organisms that interact with each other, and that each population possesses its own characteristics.

    Recommended Prerequisite Knowledge:
    Basic concepts in plant and animal biology, as well as mathematics.

    Course Content:

    1. Concepts in Ecology (Ecology, Environmentalism, History of Ecology, Methodology, Definitions of Basic Concepts)

    2. Population Dynamics:
      Main population parameters (density and abundance, natality and mortality, sex ratio, age pyramid); growth laws (intrinsic rate of increase, growth as a function of limiting factors, temporal fluctuations, spatial distribution); population regulation (concept of density dependence, density-independent and density-dependent factors, role of biotic factors)

    3. Structure and Organization of Biocenoses (Definition, Metabolism, Quantitative and Qualitative Expression of Biocenoses)

    4. Interactions within the Biotic Component of Biocenosis (Interspecific competition, ecological niche)

    5. Evolution of Biocenoses:
      Concept of succession; concept of climax; concept of ecotone and ecocline; ecological succession concepts: models and succession; characteristics of biocenosis evolution

    6. Main Continental Biocenoses of the Biosphere:
      Introduction: review and definitions, forest biomes, non-forest biomes

      • Characterization of major biomes

      • Zonation of biogeocenoses and climate

      • Zonation of biogeocenoses and altitude

      • Zonation of biogeocenoses and soil types

      • Zonation of biogeocenoses and productivity

      • Ecological characteristics, particularities, species diversity (flora and fauna), structure, biomes and production

      • Forest biomes

      • Non-forest biomes.

  • Chaptre 1/ Concepts in Ecology

    The chapter addresses some basic definitions and concepts of interest to ecologists.

  • Chaptre 2: Population dynamic

    This chapter focuses on variations in population abundance. At the most basic level, it involves describing a population at a given point in time using several variables: abundance, structure, and demographic processes. Based on this knowledge, it is possible to develop projections that describe the expected changes in population size and structural changes in the populations under study.

  • Chapter 3: Structure and organization of biocenoses

    The chapter explains all the relationships that occur between living organisms on the one hand and between these organisms and their environment on the other. It states that a community (= biocenosis) is a biological system composed of the populations inhabiting a given biotope at a specific time. Although it consists of bacteria, fungi, plants, animals, and other living organisms, it represents a relatively uniform grouping in terms of structure and composition (floristic and faunistic). The populations forming such a biotic community live together in an organized and coordinated manner. Thus, the biocenosis can be subdivided into functional units: producers, consumers, and decomposers.

  • Chapter 4: Interactions within the biotic component of the biocenosis

    The chapter explains that competition for resources and living space (food, territory, shelter, etc.) can be both intra- and interspecific. It becomes more severe when ecological requirements are similar, when resources are available in limited quantities (“scarcity”), or when population density is high. In dense plant communities, competition occurs mainly for light; in dry environments, for water. When the roots of different species are intertwined, they compete directly with one another.

    Often, competition takes the form of a struggle for existence: species that are better adapted to site conditions eliminate those that are less adapted; among the latter, fast-growing species tend to outcompete the others. Competition is all the more intense when individuals are morphologically similar and therefore possess the same capacity for spatial expansion.


  • Chapter 5: Evolution of biocenoses

    This chapter explains ecological succession, which is the natural process of ecosystem evolution and development through a series of stages, from initial recolonization to a theoretical climax stage. This process varies depending on the type of ecological disturbance that has caused environmental modification, such as land clearing, logging, fire, or grazing by domestic animals.

  • Chapter 6: The Main Continental Biocenoses of the Biosphere

    In this chapter, we address terrestrial biomes, which are ecosystems characteristic of large biogeographical regions subjected to a particular climate and defined by a characteristic biocenosis, or climax community.