Prokaryotes
Organisms which belong to the kingdom Prokaryota (used to be called Monera). These organisms include the bacteria and the cyanobacteria (used to be called blue-green algae). Prokaryote means 'before nucleus'. The main feature of all the prokaryotes is given in their name - they evolved before the nucleus became the place to keep the DNA. So all prokaryotes have no nucleus. The prokaryotes:

have no nucleus
have a loop of naked DNA (DNA that is not associated with histore proteins) that is not arranged in linear chromosomes.
have no membrane bounded organelles
have smaller ribosomes than in other groups
carry out respiration not in mitochondria, but on special membrane systems (mesosomes)
have cells smaller than those of eukaryotes
may be free-living or parasitic; some cause diseases

Protocists
All members of the kingdom Protocista are eukaryotes. This group contains organisms that are single-celled. It also contains some multicellular organisms, e.g. algae.
The smaller memners of this kingdom used to be known as protocists. The protocists:

are eukaryotes
are mostly single celled
show a wide variety of forms
show various plant-like or animal-like features
are mostly free-living
have autotrophic or heterotropic nutrition - some photosynthesise, some ingest prey, some feed using extracellular enzymes (fungi) amd some are parasites.

They do not qualify to belong in any of the other kingdoms.

Fungi
The members of the kingdom Fungi are a group of organisms in which the body consists of a mycelium - a network of numerous strands called hyphae. The cytoplasm is surrounded by a wall of a polysaccharide called chitin. The cytoplasm is usually not divided into cells. It has many nuceli. A few fungi are cellular. The fungi:

are eukaryotes
have a mycelium, which consists of hyphae
have walls made of chitin
have cytoplasm that is multinucleate
are mostly free-living and saprophytic - this means that they cause decay of organic matter

Plants
The green plants are all multicellular organisms. They gain their nutrition from photosynthesis. This means that they are autotrophs. The plants:

are eukaryotes
are multicellular
have cells surrounded by a cellulose cell wall
produce multicellular embryos from fertilised eggs
have autotrophic nutrition

Animals
The animals are multicellular organisms that gain their nutrition by digesting and absorbing organic matter - they are heterotrophic. The animals:

are eukaryotes
are multicellular
have heterotrophic nutrition
have fertilised eggs that develop into a ball of cells called a blastula
are usually able to move around

	Created by siobhan.quirk over 11 years ago

Undergraduate Biology (Biodiversity and Evolution) Note on The Five Kingdoms, created by siobhan.quirk on 25/05/2013.