Biology IGCSE - COMPLETE Summary Notes

·
Biology IGCSE

, lopic 1




Characteristics & Classification of Living organisms

Characteristics :




Life processes :
-



All living organisms have a cell membrane , cytoplasm ,
ribosomes & DNA


Movement organisms :
move themselves into new areasto change position Features of animals :


Respiration multicellular
-




:
respire for energy


Sensitivity feed
-




: able to detect or sense
changes & make responses on
organic substances

Growth :
permanent increase in Size
,
cell number cell
,
size o r both
-


have nervous
system

Reproduction :
reproduce to make new individuals (sex cells gametes) =




Excretion : produce toxic waste substances Main features of plants :




Nutrition obtaining :
of food to provide energy - growth, development & repair
-




multicellular

-



growth in tips of roots & Stems

Ingestion feed by
-




taking photosynthesis
-



:
process of in
food

Egestion process of passing out of food digested or absorbed
-




: that has not been



-


Often unicellular

Binomal system (two names :
-



a few micrometers in length (seen with light & electronic


Homo sapiens microscopes)

-enus Specs as -




often have loops of DNA called plasmids

Some have extensions called flagella
-




Living organisms are classified into 5
major groups :
Protoctists :




Kingdoms : animals , plants fungi protoctists & prokaryotes (bacterial
, ,
-




most a re unicellular

·


Species :
group of organisms that can reproduce to produce fertile offspring have nucleus ,
some feed on
organic substances ,
Some do
photosynthesis
Genus : a
group of species that a re
closely related but don't interbreed
Fungi :




-


Sequence of Classification :
-



Visible with a
light microscope


Kingdom , phylum ,
class , order , family , genus species
,
-




Usually multicellular

-



feed by Saprophytic Con dead or
decaying material

Organisms by making spores that get by the wind
·




share features because they originally descend from a reproduce carried
common ancestor



Morphology overall form & shape of (wings legs)
·



:
organism ,
n .
of
Anatomy detailed body structure (determined
·
:
by dissection)

, Topic 1




Characteristics & Classification of Living Organisms

Classifying animals :




Vertebrates have :
a backbone & internal Cartilage
skeleton made of or bone Invertebrates : animals without a vertebral column & backbone

-


fish amphibians reptiles birds & mammals -




arthropods crustaceans myriapods insects
, , , , , ,




Fish :
Amphibians :
Arthropods : Crustaceans :




-


live water
permanently
-




Smooth moist skin
-



largest group animal -head throax & abdomen
in in
Kingdom ,



-




fins eyes lateral line
-


live land return to water to breed
-




Segmented body
-


exoskeleton, Compound
, ,
on
, eyes
-




They breathe dissolved
-


external fertilisation -


external Skeleton (exoskeleton)
-


two pairs of antennae
oxygen
-




Their skin is covered in scales
Leggs released into water ↳ they outgrow their skeletons
-




5-20 legs
exituna shark , ,
cod , catfish . . . tadpoles have gills ,
adults have lungs -jointed legs -breathing using gills

In water they can breathe through their s k i n live on
dry land


Reptiles : 2x :
frogs ,
toads Salamanders
,
four types crustaceans , :
Myriapod :




dry scaly Centipedes
-




skin insects, arachnids & millipedes
-




,
myriapods ,



-




Can live in dry regions
Birds :
-



long body
-



Internal fertilisation -feathers front limbs ,
a re
wings
Insects :
-




Centipedes :
car nivores


↳
-



external development teeth beaks 3 parts / pair of
legs
-


no
head thorax abdomen
segment
-



:
, , , per


lay Internal fertilisation 3 pairs Millipedes
-




herbivores
-




the thorax
-
-




eggs on :




-




lungs to breathe
-


external development , lay eggs
-




many have 2 pairs of wings ↳2 pairs of legs per segment
ex : Crocodiles lizards snakes . . .
, ,
-




homeothermic (warm blooded -
one
pair of anntenae

ex : hawks , eagles parrots sparrows, ,
...
-




covered by a waterproof cuticle Arachnids :




Mammals :
-



bodies divided to 2 parts
-



have hair fur
-



4 pairs of legs wings
or no
,




-



Internal fertilisation & development -



Several simple
eyes
-




Females suckle their have
young mammary glands
-




, poison fangs

lungs
-




for breathing
-



Homeothermic (warm blooded

ex : dolphins leopards , ,
humans bears . . .
,

, Characterisation & Classification of Living organisms

Ferns :




-



have leafs called fronds

reproduce by
-




spores


Roots anchor & prevent the plant from being
-


blown
away


they also absorb water & mineral ions



reproduce sexually
-




Monocotyledons petals : in multiples of 3
,
Parallel leaf veins



dicotyledons : petals in multiples of 4&5
, reticulated leaf veins



Dichotomous
keys identify organisms by
·




: visible features