4.2.2 classification and evolution Flashcards
phylogenetic classification
arranges species into groups according to evolutionary origins
(how closely related species are and how recent their shared common ancestors are)
linnaeus classification system
example of a hierarchy used to classify organisms
binomial system
two names
first - genus
second - species
what are the taxons in the linnaeus classification system
kingdom
phylum
class
order
family
genus
species
the five kingdoms
prokaryotae
protoctista
fungi
plantae
animalia
prokaryotae
unicellular
no membrane-bound organelles
ring of DNA
small ribosomes
absorbs nutrients across surface/some photosynthesise
protoctista
unicellular
nucleus and membrane-bound organelles
nutrients absorbed by photosynthesis, ingestion or some are parasites
fungi
uni or multicellular
nucleus and membrane-bound organelles
no chloroplasts
cannot move
nutrients absorbed from decaying matter
food stored as glycogen
plantae
multicellular
nucleus and membrane-bound organelles
chloroplasts for photosynthesis
food stored as starch
animalia
multicellular
nucleus and membrane-bound organelles
no chloroplasts, move using cilia/flagella/muscles
nutrients obtained by ingestion
food stored as glycogen
how is classification determined
DNA base sequences
sequence of amino acids
- sequences more similar = more closely related
domain
extra taxa above kingdom proposed by carl woese
three domains = archaea, bacteria and eukaryota
- organisms split based on type of rRNA and ribosomes they have and their cell membrane structures
what kingdoms are in the eukaryota domain
animalia
plantae
protoctista
fungi
what domains are prokaryotae in
either bacteria (everywhere so most bacteria in this kingdom) or archaea (extreme environments)
what evidence supports the theory of evolution
fossils
DNA base sequences
molecular evidence
anatomical adaptations
internal/external physical features
behavioural adaptations
changes in how an organism behaves (genetic or learnt)
physiological adaptations
processes that take place within an organism
interspecific variation
differences between members of different species
intraspecific variation
differences between members of same species
often introduced through mutations or environmental factors
continuous variation
traits controlled by many genes and impacted by environment
-shown by histogram
discontinuous variation
traits controlled by a single gene, environment has no impact
-shown by bar chart
what causes evolution
natural selection that allows species to become better adapted to their environment
what is evolution
the change in allele frequency over many generations in a population
process of natural selection
- random mutations occur in population
- introduces genetic variation into population
- some mutations are harmful, but some now alleles created by mutations provide organism with survival advantage - conditions called selection pressures that drive natural selection determine if the allele is advantageous
- new allele provides reproductive selective advantage, more likelihood of reproductive success
- increase (change) in allele frequency over generations leads to evolution
example of natural selection
antibiotic resistance
-random mutation creates allele that provides resistance in bacteria, survive when exposed to the selection pressure (antibiotic), pass allele on over generations
-caused by widespread overuse of antibiotics
