Ecological Niches

• An ecological niche - The role and position a species has in its environment
• Obligate anaerobes cannot survive in oxygen-present environments
• Photosynthetic prokaryotes are capable of photosynthesis while Animals, fungi and Archaea are not
• Holozoic is a type of nutrition involving the ingestion of solid food, followed by internal digestion
• The fundamental niche represents the full range of environmental conditions and resources an organism can possibly use, while the realized niche is the actual conditions and resources it uses
• According to the competitive exclusion principle, no two species can occupy the same ecological niche indefinitely when resources are limiting.
• Obligate aerobes require oxygen to survive, whereas facultative anaerobes can survive with or without it
• Mixotrophic nutrition in some protists combines autotrophic and heterotrophic methods, allowing them to switch between photosynthesis and consuming other organisms.
• Autotrophs = producers, photosynthetic organisms (plants, bacteria, algae)
• Heterotrophs = consumers that internally digest the consumption of other organisms. Type of detritivores
• Mixotrophs = mix of both eating styles- can produce its own food but also consume extra. Obligate=must consume both ways, Facultative=can use one or the other depending on what is present in environment
• Saprotrophs are like heterotrophs/detritivores but they consume other organisms EXTERNALLY
• An ecological niche has zones of tolerance that consider the ranges of conditions in which a species can live
• A fundamental niche only considers all the physical zones of tolerance a species can habitat (optimistic view)
• A realized niche considers the zones of tolerance a species can habitat without being outcompeted (realistic view)
• Ecological niches are the roles a species fulfills in an ecosystem including the zone of tolerance for different biotic and abiotic variables.
• Resource partitioning includes species showing adaptations specific to their niche to avoid competition/outcompete other species
• Obligate aerobes need consistent O2 supply and include animals and plants
• Obligate anaerobe would be killed by O2 and include some bacteria like clostridium tetani (tetanus bacterium)
• Facultative anaerobes can use O2 if available/favorable and they include saccharomyces (yeast) or eschericia coli (gut bacterium)
• Algae, plants, bacteria, prokaryotes and eukaryotic algae are capable of photosynthesis
• Holozonic nutrition are for heterotrophs and allow nutrient absorption through consumption of foods that is then internally digested properly to be able to use the nutrients consumed.
• Holozonic digestion also includes single-celled organisms such as amoeba without multi-organ digestive systems and are simply taken in by engulfment of the substance (endocytosis) before digestion in specialized vesicles.
• Another heterotroph are saprotrophic digesters that secrete digestive enzymes into DOM for their important elements and nutrients to be broken down externally before they are consumed.
• A mixotroph uses different and multiple nutritional sources (can be autotrophs AND heterotrophs). This population includes unicellular eukaryotic cells (protists) that are part of marine plankton
• Facultative mixotroph can use both modes interchangeably
• Obligate mixotroph must use both modes because one cannot be done to the extend of fulfilling ALL demands
• Predators have eyes in front for depth perception, incredible speeds and specialized sense organs (ex. shark's smell) and some have chemicals to lure prey (pheromones) and toxins to kill them
• Vines can climb tree trunks to access sunlight
• Some plants have larger leaf surface areas to help plants in the shrub or floor layer of the forest to catch light
• The "competitive exclusion principle states that two species cannot occupy the same niche if one species is better adapted to the niche than the other