principles of classification Flashcards
what does the classification system consist of?
domain
kingdom
phylum
class
order
family
genus
species
what is the reproductive model?
(accepted definition)
what are the limitations of this model?
group of organisms that can breed to produce fertile offspring
organisms may be part of the same species but unable to breed due to factors such as physical barriers
what is Linnaeus’ theory of morphology?
what are the limitations of this theory?
categorising animals based of their external appearance
limitation : some animals show sexual dismorphism (male and female look different)
what is the ecological model of separating organisms into species?
limitations?
based on niche
limitation is that there are niche variations and not all of the same species lives in the same niche
what is the mate recognition model?
limitations?
based on mating habits
limitation is cross breeding / cross pollination can happen
what is the genetics model?
pros/cons
based on genetic evidence
+ accurate
- time consuming, expensive , genome of species will have changed over time
gel electrophoresis method
agarose gel is pores into gel box and wells are made at one end (where DNA will be placed)
box is filled with buffer solution
DNA (negatively charged) put into wells
power turned on
gel electrophoresis:
- why does the DNA travel towards the anode?
- which fragments of DNA travel further?
- what is added to the gel so the fragments can be seen?
- what enzymes are used to cut the DNA into smaller fragments?
- DNA is negatively charged and is attracted to the positive charge on the anode
- smaller fragments of DNA travel further and faster
- blue bromide and then use UV light (fragments fluoresce)
- restriction endonuclease enzymes are used to cut DNA into smaller fragments
what are the uses of gel electrophoresis ?
get DNA fingerprint for forensic research /paternity tests / learn evolutionary relationships
check a PCR
find genes associated with a disease
name three ways the scientific community evaluates data
scientific journals
scientific conferences
peer review (evidence is studied)
how can DNA tell you how long ago there was a common ancestor?
the more differences in DNA / mutations between two individuals, the longer the time since they have had a common ancestor
how do scientists use DNA from fossils?
analyse the DNA using a polymerase chain reaction and DNA profiling
what was originally thought about humans and Neanderthals?
originally thought humans were direct ancestors, concluded there was just interbreeding between them and humans
what is taxonomy?
classifying and naming living organisms
5 kingdoms
archaea bacteria
eubacteria
protoctista
fungi
plantae
