Ecology Fundamentals: Exploring Ecosystems and Their Interactions
Ecology Fundamentals
Food
Establishing relationships with their living environment for the matter and energy needed for nourishment.
Producers, Consumers, and Decomposers
- Producers (Autotrophs): Manufacture their own organic matter from inorganic substances.
- Consumers (Heterotrophs): Feed on living organic matter. Types include herbivores, carnivores, and omnivores.
- Decomposers (Heterotrophs): Feed on detritus and turn it into inorganic matter.
Food Chain
A series of linearly ordered organisms.
Food Web
A set of interconnected food chains in an ecosystem.
Biomass
The amount of organic matter that forms an individual, a trophic level, or an entire ecosystem.
Production
- Net Primary Production (NPP): Increased biomass of producers, calculated by subtracting respiration from gross primary production (GPP).
- Net Secondary Production (NSP): Increased biomass at different consumer levels, calculated by subtracting respiration and waste from ingested organic matter.
- Net Ecosystem Production (NEP): Increased biomass accumulated in an ecosystem over a period, calculated by subtracting respiration from photosynthesis.
Biogeochemical Cycles
Cycles that move chemicals from the inert medium and back again.
The Carbon Cycle
- Plants, algae, and some bacteria capture atmospheric CO2 and convert it into organic compounds.
- Organic carbon flows through trophic levels via feeding.
- Much of the carbon in organic molecules returns to the environment through respiration.
- Organism remains can be buried and become coal or oil.
- Atmospheric CO2 is enriched by burning plant materials and volcanic eruptions.
- Marine organisms use dissolved carbon to build shells.
The Nitrogen Cycle
- Plants use nitrogen in the form of dissolved salts.
- Certain organisms convert atmospheric nitrogen into usable compounds for plants.
- Organic nitrogen compounds pass to consumers through food.
- Decomposers transform organic nitrogen into nitrates.
- Artificial inorganic fertilizers can also fix atmospheric nitrogen.
Habitat
The kind of place where an organism or species lives, possessing the necessary environmental factors.
Biotic Factors
Factors arising from the presence of other living beings.
Abiotic Factors
Factors independent of living things, though they can modify their activity.
Abiotic Factors on Land
Texture
- Sandy: Predominantly large particle size.
- Clay: Predominantly fine particle size.
- Mixed: A combination of particle sizes.
Water and Air
- Soil pores are filled with water or air.
- Water needs vary among organisms.
- Air fills soil pores not occupied by water.
Chemical Composition and pH
- Affects the types of plants and animals that can live in the soil.
- Salty soils support halophilic organisms.
- Neutral soils are generally preferred by plants.
Biotic Factors
Competition
- Intraspecific: Occurs between individuals of the same species.
- Interspecific: Occurs between individuals of different species.
Cooperation
An intraspecific relationship benefiting involved individuals.
Predation
One organism feeds on another living organism.
- True Predators: Kill and consume prey.
- Grazers: Attack but don’t kill prey.
- Parasites: Maintain a close relationship with prey, often living on or inside it.
Mutualism, Commensalism, and Inquilinism
- Mutualism: Benefits both species.
- Commensalism: One species benefits, the other is unaffected.
- Inquilinism: One species benefits by using another for housing.
Life in Air or on Land
Temperature
- Ectotherms: Body temperature depends on external heat sources.
- Endotherms: Regulate their internal body temperature.
Humidity
- Terrestrial animals lose water through evaporation and waste.
- Plants lose water through their aerial parts.
Life in the Aquatic Environment
Salinity
Most aquatic species live in fresh or saltwater.
Light
- Euphotic: Up to 50m deep.
- Oligophotic: Twilight zone.
- Aphotic: Total darkness from 500m.