Understanding Ecosystems: Biotope, Biocenosis, and Environmental Factors
Ecosystem: The biosphere formed from a fragment of a live set, the physical environment.
Biotope: The physical space of the ecosystem, the non-living component that supports the ecosystem and its environmental factors.
Environment: The living environment where organisms move within an ecosystem, maintaining constant exchanges of energy.
Aquatic Environment
Formed by water, characteristic of aquatic ecosystems. Water contains dissolved gases and nutrients used by various aquatic organisms for nutrition.
Terrestrial Environment
The surface of the Earth’s crust is in contact with atmospheric gases needed by organisms.
Environmental Factors
A set of chemical and physical conditions of the biotope. These factors define and determine the biocenosis, limiting the species of organisms that can colonize the ecosystem. Each species exhibits different tolerances and adaptations.
Light
Light, pressure, CO2, and O2 condition the distribution of photosynthetic organisms, so zooplankton are near the water surface.
Water
All living things need water to live. For example, cacti store water in their stems, and their leaves are thorns to avoid transpiration and for protection.
Temperature
Temperature conditions vary within a body. Some species prefer cold weather; for example, the arctic fox has less prominent legs, ears, and nose than warm-weather species.
Salinity
Salinity is a significant factor in the aquatic environment, as species are adapted to small oscillations in the concentration of dissolved salts in the water. For example, sea corals live in the Caribbean Sea, not the Dead Sea.
pH
The presence of certain substances in soil or water determines pH. If the pH is too low or too high, organisms may not survive. This is seen in mine water and some volcanic lake regions.
Biocenosis
All living beings within an ecosystem.
Habitat
The physical place where an organism lives.
Ecological Niche
The function of a species within an ecosystem. In the same habitat, different ecological niches often exist. For example, many species feed in different ways, like the bat.
Population Density
The number of individuals per unit area.
Birth Rate
The number of individuals born in a given period of time.
Mortality Rate
The number of individuals who die at a certain time.
Environmental Changes
Changes can be accidental, such as a forest fire, or cyclic, such as temperature or moisture changes throughout the seasons.
Migrations
Displacements of individuals within a population caused by changes in the natural habitat. For example, the migration of butterflies from Canada to Mexico.
Relations
Intraspecific Relations
Relations established between individuals of the same species, forming groups or populations. Individuals join together to obtain food, defend themselves from predators, and reproduce.
Territoriality and Dominance
Some species, like leopards, are solitary. Populations of individuals defend their own territory and form groups to manage and defend the group.
Sexual Behavior
Pairing often requires fighting with other suitors and performing ritual dances to gain acceptance from the female.
Interspecific Relations
Relations that occur between individuals of different species, usually involving trophic and feeding interactions.
Predator-Prey Relationship
One species captures another for food. Prey species have developed strategies to escape or hide from predators.
Parasite-Host Relationship
An organism lives at the expense of another, obtaining the food it needs.
Symbiotic Relationship
A mutually beneficial relationship between two organisms. In many cases, total dependence between the two species has been reached. For example, a fungus (heterotroph) and algae (autotroph, producing organic matter).