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