Glossary

Endemic = unique to a particular geographical region. In Malta, there are 78 endemic organisms (23 plants and 55 animals), including the Malta fungus (which is a plant in reality), the Maltese rock-centaury (Widnet il-Bahar – the national tree) and the white-toothed shrew, which is found only in Gozo. These are all terrestrial (found on land) endemic species. It is more difficult to find endemic marine species – the only one found locally is a small snail called the Maltese topshell (which is speckled with white spots, as is covered with snow).

Ecosystem = an ecological community with its physical environment, regarded as a unit. The living components of an ecosystem (e.g. the organisms) form the biotic part, whilst the non-living (abiotic) part is composed of physical factors, such as the soil, water, rocks, air, etc. Within ecosystems, a complex network/web of interactions between organisms and their surroundings takes place – all the combined ecosystems on Earth form the biosphere, which is the part of our planet which sustains life. The scale of an ecosystem ranges tremendously – as long as it a close system, even an aquarium can be considered as an ecosystem.

Keystone species = A species that has a major influence on community structure. In fact, if the keystone species is lost from a community, a large number of other species will be negatively affected, since they directly or indirectly depend upon it. The keystone is the middle stone in an arch – if this stone is removed, the whole arch collapses.

Sessile = Attached or fastened, incapable of moving from place to place; attached directly without a stem; opposite of motile or vagrant.

Tropics = The tropics are the geographic region of the Earth centered around the equator. The equator is taken to be 0 degrees latitude, whilst the North Pole is 90 degrees North and the South Pole is 90 degrees South. These areas are characterized by a single season all year round (i.e. by a very constant weather), with high temperatures and abundant rainfall. This favours the growth of lush forests. Countries through which the equator runs include Brasil, Congo and Indonesia.

Photosynthesis = The process by which plants convert water and carbon dioxide into carbohydrates, using sunlight as the source of energy and the aid of the green pigment chlorophyll. All green plans and some bacteria can photosynthesize. This process makes life on Earth possible, through the harvesting of the sun’s energy. In order to perform the process, organisms must possess small organelles in their cells, called chloroplasts.