three domains of life

varieties of life which exist on earth

science of classifying organisms

allows us to understand the past evolutionary history and present diversity

carolus linnaeus (swedish botanist) in the 1700s

a hierarchy of groupings called taxa

cell: is basic structural and functional unit of all organisms DNA: universal genetic language for all organisms

the architecture of cilia. eg of wind pipe and paramecium is the same

evidence of common ancestry of all life

this is a group of population where members can interbreed producing fertile offspring, but can’t successfully breed with members of different groups

evolutionary history of a species or group of related species

hypothesis of evolutionary relationships

represents the separation of two lineages from a common ancestor

group that share an immediate common ancestor that’s not shared by any other groups

bacteria, archaea, eukarya

bacteria and archaea

• were the first organism to exist on earth • can thrive in any condition eg, hot , cold, acidic, salty

• mostly unicellular but some can form colonies • they’re 0.5-5 micro meters which is smaller than eukaryotes which are 10-100 micro meters • they have different shapes such as coccoid, rod and spiral

they have a cell wall made of peptidoglycan which is a network of sugar polymers that’s cross-linked by polypeptides

• some can live in extreme environments and are called extremophiles. eg halophiles: high saline environment thermophiles: in very hot environments • archaea’s have protein and polysaccharides but lack peptidoglycan

• includes protists and three kingdoms: • plant: produce food through photosynthesis • animal: ingest their food • fungi: absorb nutrients through roots

epithelial, nervous, connective, muscle

• covers the outside of body and lines the organs and cavities • the cells are closely packed together • there are different shapes such as cuboidal, squamous and columnar • the different types are stratified, pseudostratified and simple

• it binds and supports other tissues • there are 3 types of tissue fibres made of protein: collagenous, reticular, elastic fibres -2 types of cells that are in connective tissue are: fibroblasts and macrophages

• loose connective tissue- holds organs in place • adipose tissue- stores fat • bone- mineralised and forms skeleton • blood- blood cells • cartilage- strength and flexibility • fibrous tissue- in tendons and attach muscles to bone and ligaments