10.1 Classification Flashcards
taxonomic groups
kingdom (broadest and biggest group)
phylum (phyla)
class
order
family
genus (genera)
species (smallest and most specific)
Linnaean classification
It was developed by Swedish botanist Carolus Linnaeus in the 1700s. He tried to classify all living things that were known at his time. He grouped together organisms that shared obvious physical traits, such as number of legs or shape of leaves.
Newest level of classification
domain
-> top of hierarchy
Why do scientists classify organisms?
- To identify species: using clearly defined system of classification to easily find out which species an organism belongs to
- To predict characteristics: if multiple organisms in a group have a specific characteristic, it is likely another species in that group will also have that characteristic.
- To find evolutionary links: species in the same group probably share characteristic due to being evolved from a common ancestor
Why do scientists use one single classification system?
to easily share research as links between different organism can be seen even if they are continents away
How are organisms classified?
Separated into 3 domains (archaea, bacteria & Eukarya)
As you move down, there are more groups at each level but fewer organisms in each group (more similar and share more characteristics)
System ends with organisms being classified as individual species (each group only contains one type of organism
Define species
a group of organisms that are able to reproduce to produce fertile offspring
Why can different species not reproduce fertile offspring?
e.g. mules (horses and donkeys) are infertile because their cells contain an odd number of chromosomes (63)
–> means meiosis and gamete production cannot take place correctly (all chromosomes must pair up)
binomial nomenclature
the two part scientific name given to an organism
1st Word: indicates organism’s genus (generic name aka family name)
2nd Word: indicates organism’s specifies (specific name)
Naming rules
scientific name should be presented in italics
If not italics then they should be underlined
–> Only Genus should have a capital letter
5 kingdoms
Prokaryotae (bacteria)
Protoctista (unicellular eukaryotes)
Fungi (e.g. yeasts, moulds, mushrooms)
Plantae (plants)
Animalia (animals)
Prokaryotae (general features)
unicellular
no nucleus or other membrane-bound organelles (ring of DNA and small ribosomes)
no visible feeding mechanism (nutrients are absorbed through cell wall or produced internally by photosynthesis)
Protoctista (general features)
mainly unicellular
a nucleus and other membrane-bound organelles and sometimes contain chloroplasts
sessile but others move by cilia, flagella or by amoeboid mechanisms
nutrients are acquired by photosynthesis (autotrophic feeders), ingestion of other organism (heterotrophic feeders) or both.
Some are parasitic
define sessile
sessile: permanently attached or fixed (not free-moving)
Fungi (General features)
unicellular or multicellular
a nucles/ other membrane/bound organelles and a cell wall composed mainly of chitin
NO chloroplasts or chlorophyll
NO mechanisms for locomotion
most have a body or mycelium made of threads or hyphae
nutrients are acquired by absorption from mainly decaying material (saprophytic feeders)
some parasitic
most store their food as glycogen
Define mycelium, hyphae
mycelium: the mass of interwoven filamentous hyphae that forms especially the vegetative portion of the thallus of a fungus and is often submerged in another body (as of soil or organic matter or the tissues of a host
hyphae: comprised of hypha, which are the long filamentous branches found in fungi and actinobacteria (shown below). Hyphae are important structures required for growth in these species, and together, are referred to as mycelium.
Plantae (general structures)
multicellular
a nucles/ other membrane/bound organelles and a cell wall composed mainly of cellulose
all contain chlorophyll
sessile but gametes of some plants move using cilia or flagella
nutrients are acquired through photosynthesis (autotrophic feeders: make own food)
store food as starch
Animalia (general structure)
multicellular
nucleus/ other membrane/bound organelles (No cell walls)
no chloroplasts
moves with aid of cilia, flagella or contractile proteins
nutrients are acquired by ingestion (heterotrophic feeders)
store food as glycogen
Changes to classification systems
Scientists can now study the evolutionary relationships between organisms for classification
–> when organisms evolve, external and internal features change just like DNA
–> in order for characteristics to change, their DNA must also change
–> by comparing similarities in DNA and proteins, scientists can discover these links
No. of ribosomes and rRNA of domains: Eukarya
80s ribosomes
–> RNA polymerase (repsonsible for most mRNA transcription) contains 12 proteins
No. of ribosomes and rRNA of domains: Archaea
70s ribosomes
–> RNA polymerase of different organisms contain between 8-10 proteins (similar to eukaryotic ones)
No. of ribosomes and rRNA of domains: Bacteria
70s ribosomes
–> RNA polyermase contain 5 proteins
No. of ribosomes and rRNA of domains: Bacteria
70s ribosomes
–> RNA polyermase contain 5 proteins
Woese’s system
grouped organisms using differences in sequences of nucleotides in cells’ ribosomal RNA
–> as well as cell membrane lipid structure and their sensitivity to antibiotics
6 kingdoms:
Eubacteria/ Archae-bacteria/ protoctista/ plantae/ fungi/ animalia
Archaebacteria
ancient bacteria that live in extreme environments
e.g. hot thermal ents, anaerobic conditions, highly acidic environments
Eubacteria
true bacteria found in all environments
