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Explain two examples of evolution in response to environmental change; one must be antibiotic resistance inbacteria
evolution occurred in:gene tt gives resist. to antibiotic transferred to bacterium by
(transformation) some bact resist, some not
doctors/vets use antibiotics to contro bact
natural selection favours bact resis, kills non
antibiotic resis bact prod and spread replace non resis, = most bact resist
docs/vets change to another, eventually resist develops as well,
resist bact evolved
antibiotics used to control disease caused by bact in humans
increasing probl with disease causing bact being resistant to antibiotics
percentage cases gonorrhea caused by antibiotic resistant strains
trend many other diseases = same
genes tt give resist to antibiotic can be found in micro organisms tt naturally make tt antibiotic
evolution melanism ladybugs
two spot ladybug
small beetle usua red wing cases w. two black spots
red color warns preds = tastes bad
melanic forms also exist w. black wing cases, melanic form absorbs heat more effic than red
has selective advantage when sunlight lvls low and diffi for ladybugs warm up
natural selection evol in resp to pollution
melanic form common in indus area, declined in 1960 correlates with decreases in smoke in air
air darkened by smoke = warm up quicker, if smoke gone, adv lost and warming coloration more import
as smoke concentration rises, melanic form rises, over time smoke decre so melanic form decre
Outline the binomial system of nomenclature
int' nomenclature syst to identify species,species has two names.
used together to give a precise reference to this species.
is given first and is always written with an upper case letter. e.g. Homo
epithet follows the genus and is written in lower case e.g. sapiens
List seven levels in the hierarchy of taxa—kingdom, phylum, class, order, family, genus and species—using an example from two different kingdoms for each level
group organisms with similar characteristics, which can interbreed prod fertile offspring
Distinguish between the following phyla of plants, using simple external recognition features: bryophyta, filicinophyta, coniferophyta and angiospermophyta (4)
(mosses, liverworts and hornworts)
stems radial symmetry (mosses)
stems bilateral symmetry (liverworts), no lignin
no true leaves or
reproductive structure are called sporangium which are on long stalks with
spore is released from the sporangium to develop into another plant.
leaves usu curled up in bud, pairs leaflets
roots non woody stems
height up to 20m
: sporangia (sori) contain reproductive spores
(conifers and pines)
trees (100m), shrubs,
woody (lignin) stems,
waxy narrow needle like leaves, cuticle
.vascular system tracheids)
: seeds, develop fr ovules on surface scales o female CONES, male cones produce pollen
(flowering plants and grasses) deciduous trees
stems are into shrubs and trees are woody
vascular bundles (xylem/ phloem )
annual or perennial
reproduction:ovules in an enclosed carpel structure.
pollen grains produced from anthers
variety of pollen transfers vectors
Distinguish between the following phyla of animals, using simple external recognition features: porifera, cnidaria, platyhelminthes, annelida, mollusca and arthropoda.
No body layers
Body plan is built around water canals that circulate nutrient through the sponge for ingestion by specialised cells.
no clear symm
attached to surface
There is no mouth or anus
(Jelly fish, Sea anemones, Corals)
These have 2 layers in the body plan.
is a radial symmetry.
.Single entrance that serves the the cavity
mouth but no anus
(flatworms, tapeworms, planaria)
3 layers in the body plan
.One entrance to 'gut' which can have many folds to increase surface area (mouth no anus)
.largely parasitic includes flukes
(segment worms, earthworms, leeches)
3 layers to the body plan / bilateral symmetry
body divided into ringed segments with some specialisation of segments
Mouth connected via gut to a separate anus.
Skin surface used for gas exchange.
(Snails, slugs and octopus, clams, squids)
Bilateral symmetry with significant modification.
-Foot, a muscular structure used for movement and burrowing.
-Central visceral mass containing all the organ structures (separate mouth and anus)
-Mantle a folded membrane structure that can surround other tissues and create a cavity containing a gill.
-shell usually present
-mouth and anus
-segmentation, but not visible
(Insects, Crustaceans, Spiders, Scorpions, Millipedes, crabs)
3 layer body plant with bilateral symmetry.
Jointed body segments.
Separate mouth and anus.