classification Flashcards
classification
Classification is the organisation of every living thing into groups
It aims to group organisms to reflect how closely they are related in terms of their evolutionary relationships.
Classification is hierarchical, meaning that large groups are split into groups of decreasing size.
It is also phylogenetic, meaning that organisms in the same group are more closely related
The groups are discrete so an organism cannot belong to more than one group at the same taxonomic level.
Each group is called a taxon.
kingdom
largest taxonomic group
species
smallest taxonomic group
hierarchy of taxa
(king Philip came over for good soup)
kingdom
phylum
class
order
family
genus
species
hierarchical
large groups are divided into smaller ones
phylogenetic
members of the same group are more closely related to each other than to members of other groups
taxon
general term for the groups
discrete
Ań organism can only be in one group at a taxonomic level
classification and its tentative nature?
Classification is based on the information available at the time and is subject to change as new information comes to light. For example, in 2020, work on penguin DNA revealed that there are 4 species of Gentoo penguins and not 1. For this reason, classification is described as having a tentative nature.
domain
larger than a kingdom
three domains;
eubacteria- he ‘true’ bacteria
archaea- these are also prokaryotic but are extremophiles
eukarya- these are all the eukaryotic organisms
extremeophiles meaning
Extremophiles live where environmental conditions are harsh, e.g. in very high or low temperatures (thermophiles or psychrophiles), acidic or very alkaline environments, and areas with high salinity (halophiles) or high pressures.
prokaryotae
Prokaryotae have cells without a membrane-bound nucleus or membrane-bound organelles.
They have 70S ribosomes and a cell wall of peptidoglycan (murein).
They are unicellular.
Some are heterotrophic while others are autotrophic.
what are the five kingdoms?
Prokaryotae,
Animalia,
Plantae,
Fungi and
Protoctista.
animalia
Animalia are multicellular eukaryotic organisms.
Their cells do not have cell walls.
They are all heterotrophic and have holozoic nutrition, digesting food internally.
They have nervous co-ordination.
plantae
Plantae are multicellular eukaryotic organisms.
They have cell walls made of cellulose.
They are autotrophs, using sunlight as a source of energy to make organic molecules by photosynthesis.
