a measure of the variety of living organisms and their genetic differences
evolution
process by which natural selection acts on variation to bring about adaptations and eventually speciation
taxonomy
the science of describing, classifying and naming organisms
morphology
the study of the form and structure of the organisms
analogous features
features that look similar or have a similar function, but are not from the same biological origin
homologous structures
structures that genuinely show common ancestry
domains
the three largest classification categories: Eukaryota, Bacteria, Archaea
kingdom
the classification category smaller than domains
There are 6 kingdoms: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia
phylum
a group of classes that all share common characteristics
class
a group of orders that all share the same characteristics
order
a group of families that all share the same characteristics
family
a group of genera that all share the same characteristics
genus
a group of species that all share the same characteristics
species
a group of closely related organisms that are all potentially capable of interbreeding to produce fertile offspring
Archaea
domain made up of bacteria-like prokaryotic organisms found in many places, including extreme conditions and the soil, they are thought to be early relatives of the eukaryotes
Archaebacteria
ancient type of bacteria found in many different environments
Eubacteria
true bacteria (prokaryotic organisms)
Protista
kingdom in the 6 kingdom system that contains all single celled organisms, green and brown algae, and slime moulds
Fungi
eukaryotic kingdom of heterotrophs with chitin in their cell walls
Plantae
a mainly eukaryotic kingdom containing mosses, liverworts, ferns, gymnosperms, and angiosperms
Animalia
a mainly heterotrophiceukaryotic kingdom including all the invertebrates and vertebrates
morphological species model
a species definition based solely on the appearance of the organism observed
sexualdimorphism
describes species where there is a big difference between the appearance of the male and female
molecular phylogeny
analysis of the genetic material of organisms to establish their evolutionary relationships
ecological species model
species definition based on the ecological niche occupied by an organism
mate-recognition species model
species definition based on unique fertilisation systems, including mating behaviour
genetic species model
species model based on DNA evidence
DNA sequencing
process by which the basesequences of all or part of an organism is worked out
DNA profiling
process by which non-coding areas of DNA are analysed to identify patterns
gel electrophoresis
method of separating fragments of proteins or nucleic acids based on their electrical charge and size
phylogenetic tree
model used to show the relationship between different groups of organisms
endosymbionts
organisms that live inside the cells or bodies of another organism
Monera
kingdom in the 5 kingdom system that contains Archaea and Eubacteria
extremophiles
bacteria that can survive extreme conditions of heat, cold, pH, salinity and pressure
Earth's biodiversity is reducing, which may affect the future health of the planet.
Reasons for classification:
internationally recognised for easier communication
identifies different groups of organisms
monitors changes in the populations of different types of organisms
shows how different organisms are related, which makes ancestral relationships clear
aim of taxonomy: group organisms to accurately identify them and represent their ancestral relationships
Taxonomy used to be based solely on morphology, as analogous features were used to classify organisms, but the features may not have the same biological origin. Now, homologous features are used as they show common ancestry.
Carolus Linnaeus - made the first scientifically devised classification system