B4.2 - ecological niches (4d) Flashcards
what is an ecological niche?
role or functional position of a species in an ecosystem, including biotic (with the community) and abiotic interactions ( with the habitat) that can influence growth, survival and reproduction including how a species obtains food
- no 2 species can occupy the same niche
what does obligate mean?
obligate - restricted to a particular, named, function or mode of life
what does facultative mean?
facultative - capable of but not restricted to a particular, named, function or mode of life
what is an autotroph?
an organism that uses external energy sources to synthesise carbon compounds from simple inorganic substances
what is a heterotroph?
an organism that uses carbon compounds obtained from other organisms to synthesize carbon compounds they require
what are the 3 types of organisms that use carbon compounds obtained from other organisms to synthesize the carbon compounds they require?
obligate anaerobes
facultative anaerobes
obligate aerobes
what are obligate anaerobes?
single-celled organisms that have no tolerance to oxygen and are positioned by it
- live in habitats where air cannot reach such as animal intestines, soil or deep water
- e.g) clostidium is a genus of obligate anaerobic bacteria
what are facultative anaerobes?
organisms that are not hurt or killed by the presence or absence of oxygen
- they can carry out both aerobic and anaerobic respiration, which is used when oxygen isn’t available
- e.g) saccharomyces cerevisiae is a single-celled fungus, whose anaerobic respiration process is used by humans in baking and alcohol production
what are obligate aerobes?
organisms that require oxygen and cannot release energy from food nutrients without it
- can only carry out aerobic respiration
- e.g) mycobacterium tuberculosis are pathogenic bacteria that often infect the lungs of animals
what is photosynthesis, including the range of organisms that use this mode of nutrition?
photosynthesis is the mode of nutrition in plants, algae and several groups of photosynthetic prokaryotes
- autotrophic nutrition where organisms use light energy to make their own food from inorganic molecules
- photosynthetic organisms are a category of producers, as the carbon compounds form the biomass in the first trophic level of a food chain
what is holozoic nutrition, including the range of organisms that use this mode of nutrition?
all animals are holozoic so are heterotrophic and consumers and nutrients are obtained but eating living or recently killed organisms
- food is ingested before being digested internally, absorbed and assimilated
- enzymes are secreted into the gut where digestion occurs
what is mixotrophic nutrition, including the range of organisms that use this mode of nutrition?
organisms are both autotrophic and heterotrophic and can be either obligate or facultative
e.g) euglena is a genus of unicellular protists that live in freshwater
- photosynthetic in the presence of light
- predates on other small organisms in the absence of light
what is saprotrophic nutrition, including the range of organisms that use this mode of nutrition?
bacteria and fungi are sapotrophs and so are heterotrophic
- the nutrients come from organic matter of dead organisms
- food is digested externally and then the digested material is absorbed and assimilated
- enzymes are secreted into the surroundings to carry out external digestion
- can be referred to as decomposes and recycle nutrients
what are archaea?
one of the three domains of life that are metabolically diverse
what is the diversity of modes of nutrition in archaea?
species transfer energy using:
- light for the fixation of carbon dioxide in the process of photosynthesis which is autotrophic nutrition
- oxidation of inorganic chemicals in the process of chemosynthesis, which is autotrophic nutrition
- oxidation of carbon compounds to provide energy for ATP production in respiration, which is heterotrophic nutrition
