natural selection choses
what is correct for a
environemnt
Annotations:
eg. when Austrllia drifted north and became hotter the eucalypt became prminant because of its ability to resprout quickly after a fire
chemical
through natural
selection and
population can
develop
resistance
Annotations:
mosquitos and DDT- in 1940's DDT was used as a pesticide in faring and preventing deiseases, eventuallty it was discontinues as studies showed mosquitos had developed a resistance to it and it was also a human carcinogen
competition
'survival of the
fittest'
Annotations:
Dingo > hunting competition vs Tas. Tiger's > Extinction
evidence for evolution
Palaeontology(fossils)
and transitional
forms
Annotations:
Archaeopteryx; transitional form between reptiles to bird found over 150 million years old
biogeography-
geographical
distrubution
Annotations:
emu, ostrish, rhea, kiwi
comparative
anatomy
Annotations:
sharks and dolphins proving different organisms can evolve into similar
comparative
embryology
divergent - same to
different -finches on
galopgas
convergent
-different to same
-sharks and dolphins
before - gorillas human closest relative
after DNA testing- chimps are
DNA Hybridisation
Greogor mendel
(1822-1884)
how characteristics were passed down
in pea plants
procedure -create pure breed tall and short
-breed them to created 100% hybrid -breed
them to create 1:2:1 ratio -REPEATED
Conclusions- characteristics controlled by factors -factors separate
when gametes are formed -gametes unite, ratios are
predictable dominant can mask recessive
gene- section of DNA
that controls
charateristic
alleles- different
forms of a gene
DNA
structure
DNA wound around
histone
nucleotides
sugar phosphate
and base pair
3 bases-codon
Meiosis
result- 4 genetically different hapliod cells
ensuring
diversity
crossing over of
genetic material
-metaphase
random segregation -how
they line up in middle
DNA replication
unwinds -unzips -nucleotides attach
to corresponding base
production of polypeptides
Transcription- base sequence transcribes onto
mRNA, then taken to ribosome
Translation- tRNA then carries specific amino acid to mRNA
attached to ribosome and releases it onto chain
amino
acid<polypeptide<protein
mutation -radiation
20's worker in watch factory licking radium, dies 20's and 30's
1945-Hiroshima and Nagasaki survivors
chernobyl - nuclear reactor exploded
1896 W. Grubbe discovered it shrinks tumours
Beadle and Tatum
created mutated strains of mould on bread,
mutated didnt create an enzyme
concluded one gene for one enzyme -later
one gene one polypeptide
mutagen
causes mutation
Sutton and Boveri
Boveri -sea urchins
Annotations:
importance of chromosome in maitenance of health
Sutton -grasshopers
Annotations:
chromosome carried factors
each chromosome contains many factors
Morgan -fruit flies -genes can be
linked to the x chromosome