classification Flashcards
define classification
is the act of act of arranging organisms into groups based on their similarities and differences
why do we classify organisms
it makes it easier to identify and study them
why do we classify organisms
it makes it easier to identify and study them
what is taxonomy
is the study of classification
name the 5 kingdoms
• prokaryotae
• protocista
• fungi
• plantae
• animalia
what are the features of the prokaryotae kingdom?
unicellular, no nucleas, less than 5um
what are the features of the protoctista kingdom
eukaryotic cells, single celled or simple multicellular, often live in water
what are the features of fungi kingdom?
eukaryotic, chitin cell wall, saprotrophic (absorb substances from decaying or dead organisms ), single or multicellular
what are the features of plantae kingdom?
eukaryotic, multicellular, cellulose cell wall,photosynthesis,chlorophyll, autotrophic (make there own food), photoautotrophic (produce there own food using light)
what are the features of anamalia kingdom?
eukaryotic, no cell wall, multicellular,heterotrophic (consume plants and animals)
the nomenclature used for classification is called the
binomial system
binomial system is on what language?
latin
how is the binomial naming system structured?
first part is the : genus with a capital first letter
second part: species with lower case
names are always written in italics or underlined if hand written
Genus species
phylogeny is the
study of evolution history of groups of organisms (tells us who’s related to who and how closely)
all organisms have evolved from
shared common ancestors shown by a phylogenetic tree
according to phylogenetic a species is
the smallest group that at shared a common ancestor (end of a branch)
on a phylogenetic tree close related species
diverged away from each other most recently
according to the phylogenetic tree : closely related species
diverged away from each other most recently
what are the names and order of the taxonomic hierarchy
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
classification systems are based on a range of evidence including:
- observable features (all they used in early classification systems)
- molecular evidence (the similarities in proteins and DNA)
- Embryological evidence (comparing similarities in the early stages of an organism’s development )
- Anatomical evidence (the similarities in the structure and function of different body parts)
- behavioural evidence (similarities in behaviour and social organisation of organisms)
what are the cons of observable features as evidence for classification systems
scientists don’t always agree on the relative importance of different features and groups based solely on physical features may not show how related organisms are
how do we use molecular evidence to classify
• you can compare how the DNA is stored and the sequence of DNAbases
• you can compare the sequence of amino acids in proteins
what led to the proposal of the three domain system
new evidence: molecular evidence
(prokaryotae were reclassified as two because evidence showed large differences between archea and bacteria )
molecular evidence- the enzyme RNA polymerase is did in bacteria and archaea. moreover Archeae have similar histones to eukarya
cell membrane evidence- the bonds in lipids in cell membrane of bacteria and archeae are different the development and composition of flagellate are also different.
it’s now accepted that the two evolved speratley archeae more closely to eukarya than bacteria
give an example of how scientific knowledge is always changing and improving
the development of the three domain system
how do the 5 kingdoms vs 3 domain systems differ
in the old one all organisms were in one of the 5 kingdoms
the new system has 3 domains large super kingdoms above the kingdoms in the taxonomic hirearchy
the prokaryotae kingdom has been replaced by two domains arches and bacteria leaving only 4 kingdoms
beyond that it’s the same
