4.1 Species, communities and ecosystems Flashcards
species
groups of organisms that can potentially interbreed to produce fertile offspring
populations
a group of organisms of the same species who live in the same area at the same time.
autotrophs
organisms make their own carbon compounds from carbon dioxide and other simple substances
heterotrophs
some organisms obtain their carbon compounds from other
organisms
trends in plant and algae nutrition
Almost all plants and algae are autotrophic – they make their own complex organic compounds using carbon dioxide and other simple
substances. A supply of energy is needed to do this, which plants and
algae obtain by absorbing light. Their method of autotrophic nutrition
is therefore photosynthesis and they carry it out in chloroplasts.
parasitic
plants or algae that do not contain chloroplasts and they do not carry out photosynthesis.
These species grow on other plants, obtain carbon compounds from
them and cause them harm. They are therefore parasitic.
consumers
heterotrophs that feed on living organisms by ingestion.
detritivores
heterotrophs that obtain
organic nutrients from detritus by internal digestion.
saprotrophs
heterotrophs that obtain
organic nutrients from dead organic matter by external digestion.
communities
formed by populations of different species living together and interacting with each other.
ecosystems
A community forms an ecosystem by its interactions with the abiotic environment.
inorganic nutrients
Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environment.
what chemical elements are needed for living organisms?
carbon, hydrogen and oxygen
nitrogen and phosphorus
and fifteen others
nutrient cycles
chemical elements can be recycled - Organisms absorb the elements that they require as inorganic nutrients from the abiotic environment, use them and then return them to the environment with the atoms unchanged.
requirements for sustainability of ecosystems
nutrient availability
detoxification of waste products
energy availability.