1. Five kingdom system
The five-kingdomsystemisthe mostcommonwayof groupinglivingthingsbasedonsimple
distinctive characteristics.The five-kingdomsystemwasdevelopedbyRobertH.Whittakerin1969
and wasbuiltonthe workof previousbiologistssuchasCarolusLinnaeus.
Livingthingscanbe classifiedintofivemajorkingdoms:
• KingdomAnimalia
• KingdomPlantae
• KingdomFungi
• KingdomProtista
• KingdomMonera(Bacteria)
Kingdom Monera
The KingdomMoneraconsistsof prokaryotic,unicellularorganisms.Nonuclearmembraneor
membrane-boundorganellessuchaschloroplasts,Golgi complex,mitochondriaorendoplasmic
reticulumare present.Monerahave acell wall of proteinpluspolysaccharidecompound,butnot
cellulose.Theyreproduceasexuallybybinaryfission.Importantexamplesof Monerainclude
Archaeaand Bacteria.
Kingdom Protista
Protistaare eukaryoticandcan be unicellularorsimple multicellular.Theyreproduce sexuallyor
asexually.Importantexamplesof protistsinclude the organismknownasPlasmodium(whichcauses
malaria),AmoebaandEuglena.There are twomajorgroupsof protistswhichinclude the
Protozoans,whose cellsare similartoanimal cellsinthattheydonot have cell wallsandthe plant-
like cellswhichdohave cell wallsandare similartoalgae.
Kingdom Fungi
Fungi are eukaryoticorganismsthatcanbe multicellularorunicellular.Mushroomsandmouldsare
examplesof multicellularfungi andyeastisanexample of aunicellularfungi.Allfungi have acell
wall made of chitin.Theyare non-motile (notcapable of movement) andconsistof threadscalled
hyphae.Fungi are heterotrophicorganismswhichmeanstheyrequire organiccompoundsof carbon
and nitrogenfornourishment.Theyare importantasdecomposers(saprophytes) andcanbe
parasitic.Theystore carbon as glycogen,notinthe formof starch.Fungi reproduce sexuallyand
asexuallybyspore formation.Animportantexampleof auseful fungusisPenicillium(afunguswhich
was usedtomake penicillin,one of the mostpowerfulantibiotics evercreated).
Kingdom Plantae
Organismsbelongingtothe plantkingdomare eukaryoticandmulticellularorganisms.Theyhave a
distinctcell wall made of cellulose.Cellsare organisedintotrue planttissues.Plants
containplastidsandphotosyntheticpigmentssuchaschlorophyll.Theyare non-motile.Plantsmake
theirownfoodby photosynthesisandare thereforesaidtobe autotrophic.Plantsundergoboth
2. sexual andasexual reproduction.Theystore foodasstarch.Importantexamplesof plantsare
mosses,ferns,conifersandfloweringplants.
Kingdom Animalia
Membersof the animal kingdomare eukaryoticandmulticellularbuthave nocell wall or
photosyntheticpigments.Theyare mostly motile, andtheyare heterotrophic,whichmeansthey
mustfeed onotherorganismsand cannotmake theirownfood.Theyreproduce sexuallyor
asexually.Animalsstore carbonasglycogenandfat. Importantexamplesof thiskingdominclude:
Porifera(sponges),Cnidaria(jellyfish),Nematoda(nematode worms),Platyhelminthes(flatworms),
Annelida’s (segmentedworms),Mollusca(SnailsandSquid),Echinodermata(starfish),Arthropoda
(InsectsandCrustaceans),Chordata(includesall the vertebrates:fish,amphibians,reptiles,birds,
mammals).
Warm-Blooded vs. Cold-Blooded
Warm-blooded creatures, like mammals and birds, try to keep the inside of their
bodies at a constant temperature. They do this by generating their own heat when
they are in a cooler environment, and by cooling themselves when they are in a
hotter environment. To generate heat, warm-blooded animals convert the food that
they eat into energy. They have to eat a lot of food, compared with cold-blooded
animals, to maintain a constant body temperature. Only a small amount of the food
that a warm-blooded animal eats is converted into body mass. The rest is used to
fuel a constant body temperature.
Cold-blooded creatures take on the temperature of their surroundings. They are
hot when their environment is hot and coldwhen their environment is cold. In
hot environments, cold-blooded animals canhave blood that is much warmer
than warm-blooded animals. Cold-blooded animals are much more active in warm
environments and are very sluggish in cold environments. This is because their
muscle activity depends on chemical reactions which run quickly when it is hot
and slowly when it is cold. A cold-bloodedanimal can convert much more of its
foodinto body mass compared with a warm-blooded animal.
Autotrophs - also known as producers, they can make their own food - main producers are
photosynthesizes, which utilize the sun's energy and convert it into chemical energy, which
they use to build their bodies. Considered net producers of O2.
Heterotroph - are consumers, they feed on readymade organic material, they cannot
synthesize their own food, and they are considered net producers of CO2.
Saprotrophs or decomposers- organisms that feed on dead organisms and products of living
organisms. They secrete enzymes on these materials that cause decomposition, and then
they absorb the resulting simple compounds into their bodies. So, they do not ingest whole
food, but rather, they absorb decomposed and digested food. Examples are bacteria and
fungi.
