module 3 - bio diversity Flashcards
changes in population due to selection pressures over time
cane toads
introduced species
no predators
poisonous
variation in predator pop
not all predators equally impacted
reluctant to eat cane toads/have resistance to bufotoxin survive longer
red bellied black snakes
structural adaptation
cane toad areas: head = smaller
cannot eat cane toad
cannot die from bufotoxin
northern quolls behavioural adaptation
peppered moth
rests on lichen trees
prior industrial revolution
variation
more white moths
blend in with tree
reduce predation
industrial revolution
smoke and soot on bark of trees
darker moths blend in
reduce predation from birds
live longer
reproduce more
alleles passed onto next generation
prickly pear
adaptations structural, psychological, behavioural
mangroves
structural
anarobic soil
pneumatophores - breathing tubes for 02 uptake required for respiration
seed dispersal in water
buoyant propagules
behavioural
seed germination
cryptovivipary - seed is germinated on mother plant seeldings can grow more rapidly
prevent saline water in xylem
salt accumilation on old leaves via active transport
physiological
to prevent saline water in xylem
salt excretion under leaf surface
salt filtering in cell layer of roots
structural
red bellied black snakes
cane toads
smaller head
longer bodies - smaller head in comparison to body
snakes not impacted by bufotoxin in the cane toad area didn’t see a change in size/head after cane toad arrival
Darwin observations
finches
different ecological niches
different selection pressures
different food sources
different beak sizes
despite being closely related
Australian animals and plants
eucalyptus - evergreen - different to northern hemisphere due to harsh climate
platy[us and water vole
similar
occupy similar niche
behavioural - the way they swim
structural - their coat
evolutionary change and microevolution
horse
- variation in foot bones
- some individuals better adapted
- changing environment - harder ground
- larger foot bones > travel faster away from predators
- alleles passed on to next generation - sexual reproduction
- microevolutionary changes
- directional selection
- allele frequency shifts to a certain phenotype
toes > longer middle toe > hoof
Darwin theory of evolution - convergent and divergent evolution
divergent evolution
Galapagos finches
- common ancestor
- different species
convergent
platypus and watervole
- similar niche
- similar selection pressures
- structural - fur repells water - fur darker on top lighter on bottom
- behavioural - swim similar
punctuated equilibrium vs gradualism
gradualism
- slow change over time as disadvantageous alleles are gradually removed from the gene pool
- linear speciation
punctuated equilibrium
- long period of stability > rapid change
- more than one result can occur
evidence of evolution by natural selection
biochemical
amino acid sequencing
similarities and differences can be seen by comparing sections of the amino acids in proteins
closely related organisms would have fewer differences
DNA-DNA hybridisation
splitting double-stranded DNA from two different species and lining it up to see if complementary base pairs align
disassociation via heat
split double. stranded DNA from different organisms
Reassociation - complementary base pairs align AT CG
strength of bonds determined by how much heat is required to re-disassociate
more heat - stronger bonds - closer DNA sequence - closer related
DNA sequencing
gene is isolated
dye and computer used to distinguish the four bases
DNA sequencer graph and print the sequencing of the gene
scientists compare
more differences - less related
comparative anatomy
homologous structure
- pentadactyl limb > divergent evolution whale, bird bat
analogous structure
- echidna and hedgehog - protective spikes
- birds/butterfly wings
- similar selection pressures - not closely related
vestigial structure
- tail bone
comparative embryology
- drawings weren’t accurate
biogeography
- ratites
- emu
- kiwi
- ostrich
- no flightless bird in norther hemisphere
fossil dating
relative
modern > old
comparing
creating order - not dates
absolute
radioactive isotopes
transitional
- show “in between” species
limitations
- special conditions
- softer body parts not preserved
- not all fossils have been found
modern day examples of evolutionary change
cane toads
evolve from 10km > 60km per year
genes
faster
antibiotic resistance
conjugation > variation in the bacteria population
antibiotics
kill off bacteria that are susceptible to antibiotic leaving only stronger bacteria resistant to antibiotics
survive
reproduce
biofilms - antibiotics cannot penetrate
S. aureus > MRSA
