Diversity of Organisms and Classification

Classification n Taxonomy – sorts all living things into groups. n We use way an organism is ‘built’ to split into groups – organism with similar ‘body plan’ will be in same group n Scheme based on work by Linnaeus ( 18 th century)

Classification of Organisms Kingdom Phylum Class Order Family Genus Species

n The smallest group of organisms classified which can interbreed with each other to produce fertile offspring n Scientific name : unique to species n Bionomial name- 2 parts –Part 1 genus –Part 2 something no other organism in genus can have. n e.g. scientific name of human : Homo sapiens

Keys – how to simplify classification n Keys – easy to follow representations of classification systems n Most common- dichotomous keys –TWO choices at every point – start with one group and slowly divide until no further choice –Set out: branching or tabular

Five Kingdom System n Prokaryotes n Protoctista n Fungi n Plants n Animals n And Viruses?

Viruses n Non cellular – no membranes and organelles missing n Made of organic substances like proteins and fats n Contain DNA or RNA n Can reproduce inside another living organism (parasitic)

Prokaryotes(Bacteria) n Unicellular, microscopic n No membrane bound nucleus n Some have no chlorophyll –Saprophytic or parasitic –Saprophytic: feed on dead substances –Parasitic: obtain nutrients from living organisms

Protoctists n Unicellular or simple multicellular, microscopic, diverse group, wide spread in water n Nucleus surrounded by a membrane is present = Eukaryotic n Autotrophic or heterotrophic

Fungi n Eukaryotic (cells have nuclei) n Made up of hyphae –Mycelium : a mass of hyphae n No root, stem and leaf n No chlorophyll –Saprophytic or parasitic n Reproduce by forming spores

Animals n Eukaryotic (cells have nuclei) n Divided into two groups according to the presence or absence of backbone: –Invertebrates : without backbone –Vertebrates : with backbone

Invertebrates

Invertebrates: Phylum Athropoda Myriapoda Crustacea Arachnida Class: Insecta Insecta

Invertebrates Mollusca Echinodermata

Vertebrates n Divided into 5 groups: –Fish –Amphibians –Reptiles –Birds –Mammals

Fish n Aquatic n Cold-blooded n Body covered with wet and slimy scales n Streamline body for easy movement through water n Fins for balance and to control movement n Gills for breathing n External fertilization

Amphibians n Cold-blooded n Moist, scaleless skin n Limbs present –tetrapods n Larvae (tadpoles) use gills for breathing; adults use lungs n External fertilization

Reptiles n Cold-blooded n Body covered with dry, hard scales n Live on land n Breathe with lungs n Internal fertilization; lay shelled eggs

Birds n Warm-blooded n With feathers n With wings n Beak for feeding n Lungs for breathing n Internal fertilization; lay shelled eggs

n Warm-blooded n Hairs on skin n Females have mammary glands for producing milk n Lungs for breathing n Diaphragm present n Internal fertilization; embryos develop inside mothers’ bodies Mammals

Plants n Eukaryotic n Most plants contains photosynthetic pigments (e.g. chlorophyll) for photosynthesis –Autotrophic n Can be divided into two groups: –Non-flowering plants –Flowering plants

Non-flowering plants n 4 groups: –Algae –Mosses –Ferns –Gymnosperms

Algae n Aquatic n Simple multicellular plants n No root, stem or leaf n Contain photosynthetic pigments (e.g. chlorophyll) for photosynthesis

Mosses n With simple leaves and stems n No root –with rhizoids for anchorage and absorption of water n No vascular tissues n Reproduce by spores n Found in damp area

Ferns n With true roots, stems, leaves and vascular tissues n Reproduce by spores n Live in damp places

Gymnosperms n Reproduction by producing seeds –Seeds develop in cones, not enclosed by fruits  naked seeds n Needle-shaped leaves to reduce water loss

Angiosperms (Flowering plants) n With flowers for reproduction n Seeds are produced inside the fruit (matured ovary)

Two groups of flowering plants MonocotyledonsDicotyledons CotyledonsTwoOne Leaf venationNettedParallel Root systemTap root systemFibrous root system