4.2.2: classification and evolution Flashcards
what are the taxonomic groups?
kingdom
phylum
class
order
family
genus
species
what are the three domains?
1) archaea
2) bacteria
3) eukarya
why do scientists classify organisms?
- to identify species
- to predict characteristics
- to find evolutionary links
- by using a single classification system, organisms can be identified worldwide
what is a species?
a group of organisms that are able to produce fertile offspring
how does the binomial nomenclature mean?
genus first then species in italics or underlined
what are the 5 kingdoms?
- prokaryotae
- protoctista
- fungi
- plantae
- animalia
what are the general features of prokaryotae?
- unicellular
- no nucleus or other membrane bound organelles
- small ribosomes
- no visible feeding mechanism
what are the general features of protoctista?
- mainly unicellular
- a nucleus and membrane bound organelles
- some have chloroplast
- nutrients acquired by photosynthesis and digestion
what are the general features of fungi?
- uni and multicellular
- nucleus and cell wall containing chitin
- no chloroplasts
- most store food as glycogen
- nutrients are acquired by absorption
what are the general features of plantae?
- multicellular
- nucleus with membrane bound organelles
- all contain chlorophyll
- food stored as starch
- nutrients acquired by photosynthesis
what are the general features of animalia?
- multicellular
- nucleus with membrane bound organelles
- no cell wall
- no chloroplast
-food stored as glycogen - nutrients acquired by ingestion
what are the key features of eukarya?
- have 80s ribosomes
- rna polymerase, responsible for most mrna transcription
what are the key features of archaea?
- have 70s ribosomes
- rna polymerase of 8 to 10 proteins
what are the key features of bacteria?
have 70s ribosomes
RNA polymerase contains 5 proteins
what are archaebacteria?
can live in extreme environments
what is eubacteria?
“true” more common bacteria
what is phylogeny?
name given to evolutionary relationships
what are the advantages phylogenetics?
can be used to compared to classification systems
- scientists are forced not force classifications
- classification systems imply organisms are similar even though they may not be
what is the evidence of evolution?
- palaeontology - study of fossil records
- comparative anatomy - similarities and diffs between organism’s anatomy
- looking at biochemistry of diff organisms
what is the difference between interspecific and intraspecific variation?
- interspecific = between members of different species
- intraspecific = differences between organisms within a species
what are the causes of variation?
- genetic mutations
- change in environment
what are the genetic causes of variation?
- alleles (genes have different alleles
- mutations (change in dna sequence - genes - proteins that are produced)
- meiosis (two parents genetic material mixed)
random fertilisation
what is the difference between continuous and discontinuous variations?
- continuous = a characteristic can take any value from one extreme
- discontinuous = no in between values, variation determined purely by genetic factors into this category
what are normal distribution curves?
when continuous variation data is plotted onto a graph resulting in a bell-shaped curve
what are the 3 types of adaptations?
1) anatomical - physical features
2) behavioural - the way an organism acts
3) physiological - the processes that take place inside on organism
what are 3 examples of anatomical adaptations?
- body covering
- camouflage
- teeth
what are three examples of behavioural adaptations?
- survival behaviours e.g. playing dead
- courtship
- migration
what are 3 examples of physiological adaptations?
- poison production
- antibiotic production
- water holding
what are analogous structures?
when they perform the same role, but the structure is very different
why does natural selection occur?
due to pressures or a change in the environment
what is the process of natural selection?
- means there are different alleles present within the population
- the organisms that are best adapted to the selection pressure (have the advantageous allele) have increased chance of survival
- they are more likely to outcompete, survive and reproduce
- they pass on the advantageous allele to their offspring, making it more widespread in the population
how has drug resistance occurred in microorganisms?
- mrsa has developed resistance to many antibiotics
- bacteria reproduce rapidly so they evolve in a short time
- when bacteria replicate, their dna can be altered = die or mutations
- s.aureus developed mutations to be resistant to methicillin
- when bacteria were exposed to antibiotioc, resistant inndividuals survived and reproduced, passing on resistant alleles
