three domains of life Flashcards
what is biological diversity
varieties of life which exist on earth
what is taxonomy
science of classifying organisms
why is classification important
allows us to understand the past evolutionary history and present diversity
who made the Linnaean classification
carolus linnaeus (swedish botanist) in the 1700s
what does the linnaean classification consist of
a hierarchy of groupings called taxa
what are examples of unity in diversity of life
cell: is basic structural and functional unit of all organisms
DNA: universal genetic language for all organisms
state an example of unity in the diversity of life
the architecture of cilia. eg of wind pipe and paramecium is the same
what can a genetic code provide
evidence of common ancestry of all life
what is the biological species
this is a group of population where members can interbreed producing fertile offspring, but can’t successfully breed with members of different groups
what is phylogeny
evolutionary history of a species or group of related species
what is phylogenetic tree
hypothesis of evolutionary relationships
what is a branch point
represents the separation of two lineages from a common ancestor
what is sister taxa
group that share an immediate common ancestor that’s not shared by any other groups
what are the three domains of life
bacteria, archaea, eukarya
which of the three domains of life are prokaryotes
bacteria and archaea
what are prokaryotes
- were the first organism to exist on earth
- can thrive in any condition eg, hot , cold, acidic, salty
describe prokaryotes
- 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
describe bacteria
they have a cell wall made of peptidoglycan which is a network of sugar polymers that’s cross-linked by polypeptides
describe archaea
- 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
what is the domain eukarya
- includes protists and three kingdoms:
- plant: produce food through photosynthesis
- animal: ingest their food
- fungi: absorb nutrients through roots
what are the 4 types of tissue
epithelial, nervous, connective, muscle
describe epithelial tissue
- 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
describe connective tissue
- 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
what are the 6 major types of connective tissue
- 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
describe muscle tissue
- responsible for nearly all body movements
- they have filaments of actin and myosin which allows muscles to contract
- there three types of muscle tissue are skeletal, cardiac and smooth muscle
describe nervous tissue
- split into 2 categories: neurons which transmit electrical impulses and glia which form myelin that supports and protects neurons
