Unit 1: The dynamics of biological populations

Topic & Major Objective

Subject Content

Knowledge expected

Factors governing population size

Natality

Mortality

Immigration

Emigration

Recruitment

Awareness that, in nature, population sizes are generally in a state of stable equilibrium mediated by interaction between various factors.

Crude birth and death rates

The use of crude birth rate, crude death rate and doubling time in simple calculations is expected.

Approximate doubling time of an exponentially increasing population

t=70/G (where G is growth rate as a percentage and t is doubling time). The derivation of the relationship between doubling time and growth rate of an exponentially increasing population is not required. Candidates should appreciate why birth and death rates calculated in this way are ‘crude’.

Limitations to population growth

Environmental resistance

Carrying capacity

Density-dependence and density-independence in control of population growth

An appreciation of these concepts is required for interpretation of the population models which are to be presented at a later stage. No mathematical treatment of these concepts is required.

Selected models of population growth

Linear growth

Exponential growth

Sigmoid growth

Irruptive growth

Treatment should be mostly qualitative, Nevertheless, candidates would be expected to handle simple calculations concerning linear growth and exponential growth. The ability to interpret population cycles from all four models is also expected.

Unit 2: The dynamics of the human population

Topic & Major Objective

Subject Content

Knowledge expected

Patterns of growth of the human population

Growth patterns during the Palaeolithic period

Growth patterns during the Neolithic period

Growth patterns throughout recorded history up to the Industrial Revolution

Growth patterns following the Industrial revolution

Basic overview of changes throughout human history and prehistory. No elaborate details of human history are required, although candidates should be acquainted with growth patterns throughout the Palaeolithic period (500000 BP - 10000 BP), Neolithic period (from 10000 BP) and following the Industrial revolution. In all cases, candidates should be aware of the main limitations on the growth of the human population operating in each period of time. Candidates should be familiar with recent patterns of population growth but are not expected to memorise any dates or landmark sizes of the population.

Present patterns of human population growth

Population growth in less developed countries (LDCs)

Population growth in more developed countries (MDCs)

Candidates are expected to be aware of the different rates of growth in MDCs and LDCs and should also be capable of suggesting reasons as to why this is so. The implications of a high population growth rate on food supply and on the exploitation of land should also be stressed.

The demographic transition

Stage 1 (high birth rate and high death rate)

Stage 2 (high birth rate and falling death rate)

Stage 3 (Falling birth rate and low death rate)

Stage 4 (low birth rate and death rate)

A brief overview of the probable changes in population growth patterns with increasing economic development. Candidates should be capable of drawing and/or interpreting data, either graphical or in tabulated form pertaining to a demographic transition.

Age-gender structure of populations

Construction and interpretation of age-gender diagrams

Awareness of the age structure of a growing population, a stable population and a diminishing population. Comparison between age structures of LDCs and MDCs.

Use of age-gender diagrams for predictions of future population sizes and future needs of a population.

Candidates should be capable of projecting the future growth of a hypothetical population using age-gender diagrams. Incidental reference to the main implications of various patterns of population growth is also expected.

Recent history of population growth in the Maltese Islands as given by age-gender diagrams.

Candidates should be acquainted with recent patterns of population growth in the Maltese Islands and should be capable of interpreting age-gender diagrams for the population of the Maltese Islands. (Age-gender diagrams for the Maltese Islands may be obtained from the Demographic Review).

Unit 3: Properties of biological communities

Topic & Major Objective

Subject Content

Knowledge expected

Interactions between species

Competition.

Interspecific and Intraspecific competition

Outcome of competition: coexistence or competitive exclusion

Treatment of competition should be neither mathematical nor elaborate. Nevertheless, candidates should be capable of interpreting hypothetical and real-life situations in order to distinguish between different modes of competition.

Predation

Predation is defined as removal of prey organisms from their population. Candidates are expected to illustrate their accounts with examples.

Parasitism

Treatment of parasitism should be basic and qualitative. Candidates should be familiar with the general process of parasitism and with the general characteristics of endoparasites and ectoparasites. Candidates are expected to illustrate their accounts with examples.

Mutualism

Treatment of mutualism should not be elaborate. The general dynamics and evolutionary advantages of mutualism. Candidates are expected to illustrate their accounts with examples.

Ecological Niche

Concept of ecological niche. Fundamental niche and realised niche. Effect of competition on niche breadth. Relative niche breadths of generalist and specialist species

Definition and scope. The niche as the role and relationships of an organism within its community. Relative advantages and disadvantages of specialist species and generalist species.

Biological Diversity

Species richness. Associated evenness. Genetic diversity. Habitat diversity. Landscape diversity. Patterns in species richness

Treatment of biological diversity need not be mathematical, but should stress the relative importance of species richness and associated evenness of species in a community. Other aspects of diversity should also be presented in order to familiarise candidates with different forms of variety in biological communities. Candidates would also be expected to have a very basic understanding of the increasing trend of species diversity from the poles towards the equator,

Ecological succession

Mechanism of ecological succession.

The treatment is qualitative and should be illustrated by examples of a terrestrial example (succession from grassland to woodland) or a transition from an aquatic ecosystem to a terrestrial ecosystem. Familiarity with the following terms in required: pioneer community, pioneer species, climax community, sere, seral stage.

Forms of succession.

Primary and secondary succession. Autogenic and allogenic succession.

Effects of disturbance of succession

Brief treatment of the role of disturbance in reverting a succession to an earlier seral stage.

Unit 4: Ecosystems

Topic & Major Objective

Subject Content

Knowledge expected

Definition of ecosystem

Scope of definition

Different implications of the term “ecosystem”. Candidates should be familiar with the scope of the term, from large-scale ecosystems to very small-scale ecosystems.

Transitional ecosystems (ecotones)

Candidates should be aware that the borders of ecosystems are seldom well-defined and are therefore characterised by ecotone development, where biological diversity is often higher than in adjacent (“parent”) ecosystems.

Food chains and food webs

Food chains and food webs. Relative stability of food chains and food webs. Keystone species

Elementary introduction to food chains and food webs. Distinction between grazer food chains and decomposer food chains. Candidates should be capable of interpreting simple food webs and should also be capable of predicting the possible implication of removing or adding species from or to the system in order to demonstrate the level of stability. Awareness of the unequal role of the organisms within a food web; keystone species as organisms exerting significant effect on the other components of the food web without necessarily being present in high abundance.

Energy flow in ecosystems

Trophic levels

Candidates should be aware of the basic trophic structure of food webs and are expected to be familiar with the following terms: producer, primary consumer, secondary consumer and higher, top carnivore, decomposer.

Transfer of energy across trophic levels

Treatment of energy transfer across trophic levels should familiarise candidates with the concept of ecological efficiency. This would be supplemented by realisations as to why food webs do not have a large number of trophic levels and why organisms at the top of the food chain are rare.

Pyramids of number and pyramids of biomass

Treatment of pyramids of number and pyramids of biomass is expected to be elementary.

Stability of ecosystems

Resistance and resilience of ecosystems

Candidates should be aware of the meaning and significance of resistance and resilience in determining the dynamics of ecosystems. The implications of resistance and resilience should be illustrated by examples. No elaborate treatment is necessary.

Unit 5: Biomes

Topic & Major Objective

Subject Content

Knowledge expected

Physical, climatic and biological characteristics of the main terrestrial biomes

Tundra

Desert

Temperate forests

Grassland

Mediterranean scrubland

Tropical rainforest

The influence of precipitation and temperature on biome development should be stressed as should the role of dominant vegetation in defining major terrestrial biomes. Discussion of each of the major biomes is not expected to be exhaustive, rather, candidates would be expected to acquire an appreciation of a broad spectrum of ecosystems which may be compared with one another in terms of vegetation and climate. Candidates would be expected to be familiar with the climatic patterns, dominant vegetation (in terms of lifeform, not species) and adaptations of organisms in each of the biomes that shall be treated.