IB BIOLOGY OPTION G UNIT 5 NOTES
G1, G2 & G3 // 5.1, 5.2, 5.3
5.1.1 Define species, habitat, population, community, ecosystem and ecology
Species: A group of organisms that can interbreed and produce fertile, viable offspring
Habitat: The environment in which a species normally lives or the location of a living organism
Population: A group of organisms of the same species who live in the same area at the same time
Community: A group of populations living and interacting with each other in an area
Ecosystem: A community and its abiotic environment
Ecology: The study of relationships between living organisms and between organisms and their environment
5.1.2 Distinguish between autotroph and heterotroph
Autotroph: An organism that synthesises its organic molecules from simple inorgance substances (e.g. CO2 and nitrates) - autotrophs are producers
Heterotroph: An organism that obtains organic molecules from other organisms - heterotrophs are consumers
5.1.3 Distinguish between consumers, detritivores and saprotrophs
Consumer: An organism that ingests other organic matter that is living or recently killed
Detritivore: An organism that ingests non-living organic matter
Saprotroph: An organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion
5.1.4 Decribe what is meant by a food chain, giving three examples, each with at least three linkages (four organisms)
A food chain shows the linear feeding relationships between species in a community
The arrows represent the transfer of energy and matter as one organism is eaten by another (arrows point in the direction of energy flow)
The first organism in the sequence is the producer, followed by consumers (1°, 2°, 3°, etc.)
Examples of Food Chains
5.1.5 Describe what is meant by a food web
A food web is a diagram that shows how food chains are linked together into more complex feeding relationships within a community
5.1.1 Define species, habitat, population, community, ecosystem and ecology
Species: A group of organisms that can interbreed and produce fertile, viable offspring
Habitat: The environment in which a species normally lives or the location of a living organism
Population: A group of organisms of the same species who live in the same area at the same time
Community: A group of populations living and interacting with each other in an area
Ecosystem: A community and its abiotic environment
Ecology: The study of relationships between living organisms and between organisms and their environment
5.1.2 Distinguish between autotroph and heterotroph
Autotroph: An organism that synthesises its organic molecules from simple inorgance substances (e.g. CO2 and nitrates) - autotrophs are producers
Heterotroph: An organism that obtains organic molecules from other organisms - heterotrophs are consumers
5.1.3 Distinguish between consumers, detritivores and saprotrophs
Consumer: An organism that ingests other organic matter that is living or recently killed
Detritivore: An organism that ingests non-living organic matter
Saprotroph: An organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion
5.1.4 Decribe what is meant by a food chain, giving three examples, each with at least three linkages (four organisms)
A food chain shows the linear feeding relationships between species in a community
The arrows represent the transfer of energy and matter as one organism is eaten by another (arrows point in the direction of energy flow)
The first organism in the sequence is the producer, followed by consumers (1°, 2°, 3°, etc.)
Examples of Food Chains
5.1.5 Describe what is meant by a food web
A food web is a diagram that shows how food chains are linked together into more complex feeding relationships within a community