5 kingdoms

Starter Recap Give definitions for these key words Taxonomy The study of the principles behind classification Classification The process of organising of living organisms into groups. Natural classification – grouping according to how closely organisms are related and reflects evolutionary relationships Phylogeny The study of evolutionary relationships between organisms

Learning Objectives Success criteria Define characteristics of the organisms in the 5 kingdoms Success criteria Learners should be able to demonstrate and apply their knowledge and understanding of: (i) the features used to classify organisms into the five kingdoms: Prokaryotae, Protoctista, Fungi, Plantae, Animalia To include the use of similarities in observable features in original classification. (ii) the evidence that has led to new classification systems, such as the three domains of life, which clarifies relationships To include the more recent use of similarities in biological molecules and other genetic evidence AND details of the three domains and a comparison of the kingdom and domain classification systems.

5 kingdoms Proposed by Robert Whittaker PROKARYOTES 5 kingdoms Proposed by Robert Whittaker Outline the key features of the 5 kingdoms, give some examples (Use the PDF in the folder as template)

Prokaryotae Bacteria Unicellular (<5mm) No membrane bound organelles e.g. nucleus, mitochondria No visible feeding mechanism

Fungi Eukaryote Unicellular/multicellular Nucleus and membrane bound organelles (no chloroplasts) Chitin (polysaccharide) cell walls Mycelium and hyphae No mechanism for locomotion Saprophytic (they cause decay of organic matter) Store food as glycogen

Plantae Eukaryotic Multicellular Nucleus and membrane bound organelles including chloroplasts Cell walls made of cellulose Most don’t move Autotrophs (makes it’s own food by photosynthesis) Store food as starch

Animalia Eukaryotic Multicellular Nucleus and membrane bound organelles (no cell walls or chloroplasts) Moves with the aid of flagella, cilia or contractile proteins Heterotrophs - get energy originally from plants Food stored as glycogen

Protoctista Eukaryotic Mainly unicellular Nucleus and membrane bound organelles (some have chloroplasts) Some are sessile but others move by cilia, flagella or amoeboid mevement Autotrophic and heterotrophic

Past Paper Question

Answers

Evolution of classification systems Carl Linnaeus started it all off 250 years ago using visible features of organisms - limited C17th microscopes allowed us to look at cells, later electron microscopes allowed us to look inside cells Physiology How living organisms work Biochemistry Comparison of biological molecules eg. Cytochrome c (protein used in respiration: almost all species have it, but it is not identical in all, the more similar the amino acid sequence the more closely related the organisms) DNA Comparison of DNA sequences – probably most accurate

Kingdom vs Domain In 1990 Carl Woese suggested 3 Domain classification system based on fundamental differences in ribosomal RNA (rRNA), cell membrane lipid structure and sensitivity to antibiotics He divided the prokaryotes into Bacteria (Eubacteria) Archaea (Archaebacteria) This is now widely accepted

Taxonomic Hierarchy: Domain

3 domains – 6 kingdoms Eukarya – 80s ribosomes Archaea – 70s ribosomes RNA polymerase contains 12 proteins Archaea – 70s ribosomes RNA polymerase 8-10 proteins Known as ancient bacteria that live in extreme conditions Bacteria – 70s ribosomes RNA polymerase contains 5 proteins Known as true bacteria found in all environments

Task – exam question Describe how and why classification systems have changed? (6 marks) Living organisms classified into 2 kingdoms based on major differences in characteristics Example given animals ate and moved, plants didn’t Microscopes allowed smaller details to be observed Organisms divided into 5 kingdoms Plants, animals, fungi, protoctista, prokaryotes Advances in science allowed DNA and proteins to be studies Provided evidence for evolutionary relationships 3 domain system proposed Relevant scientists mentioned (Linnaeus, Whittaker, Woese)

Flipped learning task for next lesson This is a remarkable educational resource and will help you to appreciate the importance of Darwin’s ‘tree of life’ in helping to make sense of the origin of animal life on Earth. http://www.wellcometreeoflife.org/ Watch the opening video by David Attenborough and become familiar with the interactive video. The next lesson we will be in the computer suite