Ecology and Ecosystems

Ecology and Ecosystems

• Ecology is the study of the relationship between organisms and their environment (living and non-living).
• An ecosystem is the basic functional unit of ecology. It involves interacting organisms and their environment, exchanging energy and matter (e.g., forests, deserts).
• A biome is a smaller ecosystem within a larger ecosystem, characterized by dominant species with similar lifestyles, climates, and physical structures.

Types of Ecosystems

• Ecosystems are classified as natural or artificial/man-engineered.
• Natural ecosystems include terrestrial (e.g., croplands, dams) and aquatic (e.g., marine, freshwater).
  • Freshwater ecosystems can be lotic (running water, e.g., springs, streams, rivers) or lentic (standing water, e.g., lakes, ponds, pools).

Structure of an Ecosystem

• Ecosystems have two major components: abiotic and biotic.
• Abiotic components are non-living parts, including energy, climate, raw materials, and living space (e.g., air, water, soil, sunlight, nutrients).
• Biotic components are living parts, categorized as autotrophs/producers (prepare their own food, e.g., plants) and heterotrophs/consumers (cannot prepare food, relying on producers, e.g., herbivores, carnivores) and decomposers (break down dead organisms, e.g., bacteria, fungi).

Classification of Biotic Components

• Autotrophs/producers prepare food through photosynthesis (using chlorophyll, CO2 and sunlight).
• Heterotrophs/consumers depend on producers for food.
  • Primary consumers (herbivores) feed on plants.
  • Secondary consumers (primary carnivores) feed on primary consumers.
  • Tertiary consumers (secondary carnivores) feed on secondary consumers.
• Decomposers feed on dead organisms and return nutrients to the environment.

Function of an Ecosystem

• The main function of an ecosystem is to allow the flow of energy and nutrients between organisms. This happens via:
  • Primary function – producing matter through photosynthesis
  • Secondary function – distributing the matter in the form of food for consumers
  • Tertiary function – processes the dead organic matter to reintroduce the substances back into the environment through cycling by decomposers (decomposition)

Energy Flow in an Ecosystem

• Solar energy is the primary energy source on earth.
• Plants convert solar energy into chemical energy through photosynthesis.
• Energy flows through the ecosystem in a unidirectional manner from producers to consumers.
• 10% of energy is transferred to the next trophic level while 90% of energy is lost as heat.
• Energy flow is governed by the laws of thermodynamics, the first law stating energy can neither be created nor destroyed but can be converted from one form to another and the second law stating when energy or matter converts from one form to another, some energy is always lost as heat.

Ecological Succession

• Ecological succession involves the progressive replacement of one community by another until a stable community develops.
• This occurs in two ways, primary succession (development of biotic community on lifeless ground, like a newly formed volcanic land or a rock), or secondary succession (development of biotic communities in an already existing biotic community, like a forest fire).

Food Webs

• A food web is the interconnected feeding pattern of various food chains in an ecosystem.
• Interactions amongst various trophic levels (producer, primary consumer, secondary consumer, etc.; from the lowest and to the highest on the food chain) are interconnected.
• Food webs are essential for maintaining the stability of ecosystems.

Ecological Pyramids

• Ecological pyramids are graphical representations of the structure and function of trophic levels of an ecosystem.
  • Pyramids of energy – represent the amount of energy present in each trophic level.
  • Pyramids of biomass – represent the total mass of organisms at each trophic level.
• Significant loss of energy occurs at each trophic level (10%) which is lost as heat.

Forest Ecosystems

• Forests consist of densely growing trees, covering a significant portion of the Earth's land.
• Various types of forests exist, categorized by climate and vegetation (e.g. tropical rain forest, tropical deciduous forest, temperate rain forest, temperate deciduous forest).
• Forest ecosystems have specific abiotic and biotic components. These include producers (trees, shrubs), consumers (herbivores, carnivores), and decomposers (bacteria, fungi).

Grassland Ecosystems

• Grasslands are large areas dominated by grasses, with scattered trees.
• Different types of grasslands exist, categorized by temperature and rainfall (e.g., tropical grasslands, temperate grasslands, polar grasslands).
• Grasslands support different types of producers, consumers, and decomposers.

Desert Ecosystems

• Deserts are characterized by low precipitation, high temperatures, and sparse vegetation.
• Deserts support specific types of producers (shrubs, bushes, and some grasses) and consumers (reptiles, mammals).
• Decomposers (fungi and bacteria) are also present though less compared to other types of ecosystems.

Aquatic Ecosystems

• Aquatic ecosystems consist of freshwater (e.g., ponds, lakes, rivers, streams) and marine (e.g., oceans, estuaries).
• In fresh water ecosystems, the biotic components are producers (phytoplankton, algae, water grasses), consumers (insects, snails, birds, mammals), and decomposers (fungi, bacteria).
• In marine ecosystems like oceans, the biotic components are also the same as in freshwater ecosystems but may have different species.
• Aquatic ecosystems play a crucial role in global processes such as nutrient cycling and water regulation.

Estuarine Ecosystems

• Estuaries are transitional zones where freshwater rivers meet the ocean.
• Characterized by fluctuating salinity, periodic tidal changes, and high biodiversity and nutrient levels.
• Estuarine ecosystems are crucial for providing habitat and food for many species transitioning between freshwater and saltwater environments.
• Abiotic components include temperature, pH, sodium salts, potassium salts, and other elements.

Biodiversity

• Biodiversity means the variety of life on Earth.
• Levels of biodiversity include genetic, species, and ecosystem diversity.
• Key biodiversity components include producers, consumers, and decomposers.
• Various factors influence biodiversity in ecosystems, including climate, vegetation, and resources.

Conservation of Biodiversity

• Conservation of biodiversity is essential to maintain healthy ecosystems.
• Various conservation strategies exist, including in-situ (preserving species in their natural habitats) and ex-situ (preserving species outside their natural habitats).
• Both in-situ and ex-situ conservation strategies aim to maintain and preserve biodiversity to avoid extinction and assure their continued role in ecosystems.

Explore the fascinating world of ecology and ecosystems in this quiz. Learn about the relationships between organisms and their environment, the various types of ecosystems, and their structural components. Dive into natural and artificial ecosystems, and discover the complexities of biotic and abiotic factors.