classification Flashcards
what is the definition of classification?
process of placing living things into groups
each species need to be carefully studied before it can be correctly placed in groups of similar organisms
the reasons we group species is because?
list four
-for our convenience
-to make the study of our living thing more manageable
-to make it easier to identify organisms
-to help see relationships between species.
who devised the classification system that we still use today
Carl linnaeus
name the eight taxonomical groups
-domain
-kingdom
-phylum
-class
-order
family
-genus
-species
describe the eight taxonomical groups of the modern classification system
describe each of the taxonomic groups
-domain- highest taxonomic group, archaea, bacteria (eubacteria) and eukarya
-kingdom-traditionally there are five main kingdoms, animalia, plantae, fungi and protoctista. fungi protoctista fungi animalia and plantae are all eukaryotic as they possess a nucleus and all single-celled organisms without a nucleus are classified as prokaryotae.
-phylum- major subdivision of kingdom, contains all the groups of organisms that have the same body plan e.g possession of a backbone.
class- a group of organisms that all possess similar traits such as number of legs
order- a subdivision of class that uses additional information such as whether the mammal is a carnivore (order carnivora) or a herbivore (order herbivora)
family- group of closely related genera
-genus- group of closely related species
-species- may show variations but are essentially the same.
this classification system originally had five levels what caused it to change
-kingdom as more organisms have been discovered and described the original classification system had to be modified and expanded. we have more kingdoms which are grouped into larger categories called domains. kingdoms are divided into phyla which are divided into classes which are divided into orders which are divided into families.
-class
-order
-genus
-species
whats the issue as you descend down lower taxonomic groups
it becomes increasingly difficult to separate closely related species and to place species accurately. a more and more detailed description of the species is needed.
as more and more organisms were discovered and described more kingdoms meant that they were classified into domains.
there are three domains
eukarya
bacteria
archaea.
the organisms in the different domains contain a unique form of rRNA and different ribosomes.
list each
eukarya- has 80 s ribosomes RNA polymerase contains 12 proteins
bacteria (eubacteria)– has 70s ribosomes RNA polymerase has five proteins
Archaea- 70s ribosomes are very similar to eukaryotic ribosomes. RNA polymerase has between 8 and 10 proteins
Archaebacteria and Eubacteria are both single celled prokaryotes however eubacteria is classified as its own kingdom because it has different chemical makeup how?
eubacteria contain peptidoglycan (polymer of sugar and amino acids) in their cell walls whereas archaebacteria don’t.
6 kingdom system is what
porkaryotae is split into eubacteria and archaebacteria because although they are both single celled prokaryotes, eubacteria is classified as its own kingdom because it has different chemical makeup to archaebacteria. eubacteria has peptidoglycan cell walls whereas archaebacteria do not.
archaebacteria is known as ancient bacteria. they can live in extreme environments
the extreme environments they can live in include hot thermal vents, anaerobic conditions and highly acidic environments. e.g methanogens live in anaerobic conditions in sewage treatment plants and produce methane.
eubacteria also known as true bacteria
archaebacteria are chemically different from eubacteria so most scientists use the three domain six kingdom system. three domains bacteria (eubacteria) eukarya and archaea and six kingdoms (eubacteria, archaebacteria, Animalia, Plantae, fungi and Protoctista.
binomial system definition
system that uses species name and genus name to avoid confusion when naming organisms.
why does a common name not work well
Genus first letter is capital eg H sapiens.
bionomial nomenclature identifies evolutionary links between species and also avoids confusion of a common name so that species can be recognised by one name.
-same organism might have completely different common name in different parts of one country
-different common names are used in different countries
-translation languages and dialect may give different names
same common name might be used for different species in different parts of the world. latin is a universal language whenever a species is given a common name its universal
every scientist in every country will use the same common name. this avoids confusion by using common names.
biological definition of species
a group of organisms that can freely interbreed to produce fertile offspring
phylogentic definition of species
a group of individual organisms that are very similar in appearance of anatomy,biochemistry, genetics and physiology.
definition of sympatric speciation
over time, two populations living in the same location become so different that they can no longer breed to produce fertile offspring and so are classified as two species.
why classify organisms?
-to identify species, to predict characteristics and to find evolutionary links between organisms.
phylogeny definition
study of evolutionary relationships between organisms
