Learning objectives
-
- identify organisms using diagnostic features of the five Kingdoms
- use diagnostic features to divide kingdoms into phyla
- state the taxonomic hierarchy
- observe the rules of binomial nomenclature
- describe the socio-economic importance of the five Kingdoms
Introduction
- Diversity is the variety of living organisms
- Organisms have been grouped together for studies of their characteristics
- The grouping of organisms is called classification
- classification is based on agreed name of each organism
Hierarchy of classification
- Systems of classification are hierchial i.e each successive group contains more and more different kinds of organisms
- Taxon is the general name given to each classification grouping
- Taxonomy is the science of classification of organisms into groups called taxons
- The longest taxon is the species and the most increasive or highest taxon is the kingdom
- Phylogeny is the study of evolutionary traits
- Natural classification of organisms is based on evolutionary relationships
Terminology used
- Kingdom is the largest grouping of organisms’ e.g animalia
- Phylum consists of organisms with many similarities e.g bryophyte, cnidarians etc.
- Class consists of organisms which are grouped into several orders with few similarities
- Order is a group of apparently related families
- Family is a group of apparently related genera
- Genus is a group of similar and closely related species
- Species is a group of organisms capable of interbreeding to produce fertile off springs
Binomial nomenclature
- in this system each organism has two latin names, a generic name first capitalised and the specific name with a lowercased later
- the latin name is internationally agreed and avoid the confusion of local variation in local names
- eg humans are named Homo sapiens
genus-homo
species-sapiens - The generic name is shared with other related species considered to be sufficiently similar to be grouped in the same genus e.g Homo erectus, Homo habilis
The taxonomic hierarchy
- Linnaeus extended binomial system of classifying organisms to introduce more groups than just the genus and species
- there are arranged in a hierachy with the largest group the kingdom at the top to the species
- kingdom → phylum → class → order → family → Genius → species
Kingdom Plantae
Diagnostic features of the Kingdom Plantae
- Eukaryotic;
- Multicellular;
- Photosynthetic/autotrophic;
- Have cellulose cell walls;
- Non-motile;
- Have chloroplasts containing chlorophyll a and b;
- store carbohydrate as starch;
- reproduce sexually and asexually;
- Have vascular system or undeveloped vascular tissue;
- mainly terrestrial;
- some have true roots, leaves and roots;
- alteration of generations
Economic importance of kingdom plantae
- food for most organisms
- can be used for medical use
- manufacturing rubber
- tourism attraction e.g botanical gardens
- for timber
- for experimental use
- plants can be used to make fuel e.g fossil fuels
Kingdom Animaliae
Diagnostic features of the kingdom Animaliae
- Eukaryotic;
- Multicellular;
- Non photosynthetic;
- Heterotrophic;
- no cellulose cell walls;
- store carbohydrate as glycogen;
- no chlorophyll;
- motile;
- have nervous system (C.N.S);
- have endocrine system for homeostasis;
- reproduce sexually or asexually;
- body divided into head, abdomen and limbs;
- all have an alimentary canal ;
- bilateral symmetry except cnidarians and echinoderms;
- triploblastic except cnidarians;
- some are segmented e.g annelids and arthropods
Economic importance of kingdom animalia
- source of food
- animal waste can be used for organic fertilizers
- ivory maybe used for jewellery making
- some animals can used for medical use
- tourism
- for experimental research
- animaal hides(skins) can be used to make shoes from leather
Kingdom Prokaryotae
Diagnostic features of the kingdom Prokaryotae
- lack true nucleus;
- circular D.N.A lies free in the cytoplasm;
- unicellular;
- no membrane bound organelles;
- mesosomes for respiration (instead of mitochondria);
- have 70s ribosomes;
- cell walls of murein (peptidoglycan);
- average diameter 0.5-5 micrometres;
- reproduce asexually by binary fission
Economic importance of bacteria-prokaryotae
- for genetic engineering e.g can be used to form recombinant DNA
- sewage treatment ie digestion of slag
- used to clean oil spoilages esp in sea and oceans
- used for nitrogen fixation
- can be use for decomposition of substances
Kingdom Fungi
Diagnostic features of the Kingdom Fungi
- some are unicellular e.g yeast and some are multicellular e.g mushroom;
- non photosynthetic;
- heterotrophic/saprotrophic/parasitic/mutualistic;
- nutrition is absorptive-digestion takes place outside the body and nutrients are absorbed;
- cell walls made of chitin as the main fibrilar material;
- body is a mycelium a network of fine tubular filaments called hyphae growing from horizontal hyphae the stolon;
- end of hyphae bears sporangia which are a reproductive organ for spore formation;
- eukaryotic;
- store carbohydrate as glycogen;
- asexual reproduction by spore formation;
- non-motile
Economic importance of fungi
- yeast are used in bread production
- used for medical purposes eg as an antibiotic(penicillin)
- decomposition of sewage and organic material in the soil
- production of alcohol for drinking and industry
- experimental use esp for genetic investigations
- food spoilage
Kingdom Protoctista
- Made up of eukaryotes no longer classified as animals, plants or Fungi e.g algae and protozoa
| Protozoa | Algae |
| Non-photosynthetic | photosynthetic |
| Parasitic and some free living | Free living/non parasitic |
| No cell walls | Have cellulose cell walls |
| Small and temporary food vacuoles | Large permanent vacuoles |
| Unicellular | Multicellular or unicellular |
| Some have differentiated anterior and posterior | No distinct anterior and posterior |
| Some motile and some non -Non motile | motile |
- filamentous
- no leaf structure
- no roots
- no stems
- contain chlorophyll a and b
- unicellular algae
Economic importance of algae
- for carbon fixation
- responsible for half oxygen released by plants into the atmosphere
- maybe used as direct food source for humans
- can be used as fertilizers on coastal farms
- green aldgae provide oxygen for the aerobic bacteria which break down sewage