Aquatic and Terrestrial Ecosystems: Factors and Interactions
Life in Aquatic and Terrestrial Environments
Environmental Factors
Salinity
Plants often prefer neutral soil, though some, like pine, thrive in slightly acidic conditions, while others, like beech, prefer alkaline environments. Aquatic life is significantly affected by salinity. Freshwater contains less than 5g/L of salts, while saltwater in seas ranges from 33 to 37g/L. Brackish water, found in some inland areas, has an intermediate salt concentration. Most aquatic species can only survive in either fresh or saltwater, with few exceptions like salmon.
Light
Marine environments are categorized into three zones based on light penetration: the euphotic zone receives ample light for photosynthesis (up to approximately 50m), the oligophotic zone (twilight zone) receives limited light, and the aphotic zone (from 500m and below) experiences total darkness.
Temperature and Oxygen
Water temperature significantly influences oxygen levels. Even a slight temperature increase in a river can deplete oxygen, leading to the death of many organisms. Temperature differences between the surface and depths of oceans create currents that redistribute nutrients and oxygen.
Biotic Factors and Species Interactions
Intraspecific and Interspecific Competition
Intraspecific competition occurs between individuals of the same species vying for similar resources. The individual that secures the resource expends more energy in doing so. Interspecific competition happens between individuals of different species using the same resource. If one species is more effective at exploiting the resource, it can displace the other.
Cooperation
Cooperation benefits all involved individuals of the same species. This is evident in raising young, defending against predators, or obtaining food. Social insects like bees and ants exemplify this behavior.
Predation
Predation involves a predator feeding on prey. There are three types of predators: true predators (e.g., lions) kill and consume many prey; grazers (e.g., herbivores) attack numerous prey throughout their lives but don’t kill them, consuming only parts that regenerate; and parasites often live on or inside their host, and while their attacks may not be immediately fatal, they can eventually lead to the host’s death.
Mutualism, Commensalism, and Tenancy
Mutualism benefits both species involved, such as the relationship between flowers and insects. In some cases, the organisms are so interdependent that they cannot live separately (symbiosis). In commensalism and tenancy, one species benefits while the other is unaffected. The benefiting species may gain extra food (commensalism) or shelter (tenancy).
Ecological Niche and Survival Strategies
An ecological niche is a species’ role in an ecosystem, encompassing how it uses resources and affects other components of the biocenosis. It’s rare for two species to occupy identical niches due to subtle differences that minimize competition. Two extreme survival strategies exist: specialists exploit niches inaccessible to others (e.g., pandas), avoiding competition but facing high risk from environmental changes; and generalists (e.g., rats) exploit various niches, enabling survival in diverse environments.
Threats to Species
Habitat Destruction and Fragmentation
The primary cause of species extinction is habitat destruction. Even partial destruction or fragmentation has significant consequences: it reduces available habitat, limits population sizes, hinders inter-population exchange, and increases exposure to external threats.
Introduction of Exotic Species
Introducing exotic species can disrupt existing relationships within an ecosystem, potentially leading to the decline or extinction of native species.
Exploitation of Species
ON eto may have several reasons: to obtain certain products … collecting for a long time on was the main cause esplotaacio of extinction today is the third leading cause. Climate change affects the intense pollution on biodiversity. currently the biggest threat is global climate change caused by the emission of gases to reach pueen effect atmosferasus alarming dimensions.