Unit 7: Ecosystems Components

Ecosystems

• An ecosystem consists of the organisms in a given area and their interactions with the biotic and abiotic components of that area.
• Biotic components include living organisms, while abiotic components include physical and climatic characteristics of the environment.

Components of an Ecosystem

• Habitat: the natural environment in which an organism or species normally lives or occurs.
• Population: a group of individuals of the same species living in a specific geographic area.
• Community: a group of different species living in a specific geographic area.
• Niche: the role and position of a species within its environment.
• Intraspecific competition: competition between individuals of the same species for limited resources.
• Interspecific competition: competition between individuals of different species for limited resources.

Maltese Ecosystems

• Woodland ecosystem: characterized by high water availability and deep soil, with vegetation consisting of trees, shrubs, and climbing plants.
• Maquis ecosystem: characterized by shallow soil and low water availability, with vegetation consisting of shrubby, evergreen plants.
• Garigue ecosystem: characterized by shallow pockets of soil in cracks and depressions between rocks, with vegetation consisting of aromatic plants that are adapted to survive dry conditions.
• Freshwater ecosystem: characterized by temporary rainwater pools and streams, with vegetation consisting of deciduous trees and aquatic plants.

Interactions between Biotic Components

• Predator: an organism that hunts and feeds on other organisms.
• Prey: an organism that is hunted and fed upon by a predator.
• Intraspecific competition: competition between individuals of the same species for limited resources.
• Interspecific competition: competition between individuals of different species for limited resources.
• Parasitism: a relationship in which one organism (the parasite) benefits from another organism (the host) without harming it.
• Mutualism: a relationship in which both organisms benefit from each other.

Plant Tropism

• Tropism: the growth response of a plant to a stimulus, such as light or gravity.
• Phototropism: the growth response of a plant to light.
• Geotropism: the growth response of a plant to gravity.
• Auxins: plant hormones that promote cell elongation and differentiation.

Representing Ecosystems

• Producer: an organism that produces its own food through photosynthesis.
• Consumer: an organism that obtains energy by consuming other organisms.
• Food chain: a series of organisms that eat other organisms, with energy flowing from one level to the next.
• Food web: a network of food chains that are interconnected.
• Pyramid of numbers: a graphical representation of the number of organisms at each trophic level.
• Pyramid of biomass: a graphical representation of the total biomass at each trophic level.
• Pyramid of energy: a graphical representation of the energy available at each trophic level.

Closed Systems and Carrying Capacity

• Closed system: a system that does not exchange matter with its surroundings.
• Carrying capacity: the maximum number of organisms that an ecosystem can support indefinitely.
• The planet cannot support unlimited growth of a population because resources are limited.