IGCSE Biology revision notes - Kingdoms, Classification

Section1: Characteristics and classification of living organisms Respiration

Sensitivity Movement

Nutrition

Growth Excretion

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Complex organization, variation (evolution)

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Classification – Taxonomists axonomists (ppl) -> classification key (Questions!) 5 Kingdoms – Distinguished Hierarchy of classification Kingdom -> Phylum (vertebrates) -> Class-> Order-> Family-> Genus-> Species More similarities and fewer differences

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Binomial system of nomenclature  – 2 names (Genus, Species) Vertebrates (vertebrae  – separate separate bone in backbones) 1) Fish  –

Scales (Mucus) -> streamlining

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Lateral line (sense organs) -> vibration

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Operculum -> cover gills (large area -> Gas exchange)

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Fins -> Movement + Stability

2) Amphibians

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Nostrils -> lung

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Wide mouth (Carnivorous)

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Moist skin

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Four limbs – hind limbs webbed

3) Reptiles

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Dry scales skin -> limit water loss

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Tail -> crocodiles

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Limbs

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Mouth – (bony ridges) aid feeding

4) Birds  –

Forelimbs – wing

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Nostril -> lung

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Beak

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Scales (Legs) -> perching

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Feathers -> Flight -> endothermy (insulation heat lost)

5) Mammals

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Pinna (Ear) -> moved -> Mas. Efficiency sound detect

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Whiskers (Sensitive)

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Mouth -> wider variety food

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Penis (Males) -> internal fertilization

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Fur -> endothermy -> Keep Temp.

E.g. Human -> adv. Brains + upright posture

Reproduction

Invertebrates 1) Nematodes (e.g. hookworms)

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Specialized

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Parasites

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Mouth – sucking -> blood

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Muscles(long) -> wriggling

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Long, thing -> do not washed out

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Mucus -> resist attack (digestive juice)

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Anus

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Large sex organs -> Sperms + eggs

2) Annelids (e.g. Earthworms)

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Single segment

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Mouth -> bite

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Clitellum -> bine two worms together

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Chaetae (Bristles) (each segment) -> movement

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Long, cylindrical -> mucus layer -> stop drying out

3) Molluscs (e.g. snails)

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Snails -> single, coiled shell

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Shell -> CaCo3 -> hardened -> protection

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Eye -> tentacle

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Mouthparts -> scrape at vege.

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Foot -> mucle (slimy covering )-> creeping over surface

Body Covering

Annelids

Nematodes

Molluscs

Hard, slightly

Soft -> Not waterproof

Soft -> shells help save

waterproof 

H2O

Segments visible

Yes

No

No

Movements

Chaetae (1 move to 1)

Wriggles (stay 1 place)

Creeps (1 move to 1)

Feeding Method

Herbivores

Mainly parasites

Mainly herbivores (some carnivores)

4) Arthropods

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Metamorphosis [change of body form]

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Exoskeleton

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Jointed limbs

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Insects (mosquito)

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Legs : 3pairs

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Body parts  – 3 -> Head / Thorax / Abdomen

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Adult butterfly -> highly adapted for locomotion

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Spider

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Spider silk (Spinneret produced)-> strong, thin

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Legs: 4 pairs

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Body parts: 2  – Head, thorax / Abdomen (spinneret)

Crustacea (Crabs)

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Unusual

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Segments under body

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Legs: 10/10+

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Body parts: Claw, Jointed limbs, Gills under shell (O2 water)

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Carapace : thick, hardened shell -> protection

Myriapods (millipede)

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Antennae-> sense organs (chemical + moisture)

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Mouthparts-> modified legs (hard edges) -> bite vegetation

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Hard exoskeleton -> protection

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Legs -> Joints + internal muscles-> movements on rough surfaces

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Waterproof -> help living on land

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Body Segmentssssssssss -> flexible + wriggling (nder leaves + stones)

Organisation of living organisms (Multicellular + Specialised) 

Animal Cells 

Red Blood -> haemoglobin(pigment)-> oxygen

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No nucleus

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Biconcave dix shape -> larger surface area -> take up + lose O2 ->flexible -> squeeze through narrow capillaries

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Muslce -> contracts -> closer

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Long + many protein fibres in cytoplasm (enlongated, contractile filament -> change shapes)

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Ciliated – tiny hair-> move mucus in breathing tube + trap dust, microbes

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Motor nerve -> Conduct nerve impulses + long f ibre -> axon -> impulses travel + connects cells

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Plant Cell 

Root hair -> absorbs minerals + water (soil water) + long extension increases the surface area -> absorbing materials

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Xylem vessels -> transport water ->

support plant + No cytoplasm ->

water pass freely + No end wall -> continuous tube + Wall strengthened (waterproof) = lignin 

Cells -> Tissues (a group of cells) -> Organ (several tissues) -> Organ system (group of  organs)

Movement in, out Vital role -> regulating materials pass in + out

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Diffusion (high conc. -> low conc.) - movements within gas / liquid + equilibrium

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Partially permeable membranes (Permeable: glucose / H2O ; Imper. : protein)

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Factors : distance (short), conc.gradient (maintained), temp (higher -> faster), surface area (large)

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Substances

From

To

For

O2

alveoli

blood

respiration

CO2

blood

alveoli

Excretion

Food

gut

blood

nutrition

CO2

air

leaves

photosynthesis

Osmosis

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Biochemical process -> solution

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The movement of H2O through partially permeable membrane down a water potential

gradient

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Diffusion of water molecules

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High conc. -> low conc.

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Across a partially permeable membrane

Plant Cells Higher -> water enters by osmosis Cytoplasm pushes hard -> cell wall + cell + turgid (firm) Normal -> No net movement Cytoplasm presses against cell wall Lower -> water leaves Cytoplasm pulls away <- cell wall + cell -> flaccid (floppy) Osmoregulation Animal Cells Higher -> cell takes in water -> swells + burst (haemolysis) Normal -> equilibrium Lower -> cell shrink -> crenated